Cam Timing


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Date: Thu, 8 May 1997 15:14:53 -0400
From: "T. Ryan" 
Subject: variable timing gears fo 20/22R
To: "Toy ota" 

JIm Brink Wrote: Get an adjustable camshaft sprocket;

I put one of these on my 20R Celica with no other mods other thatn a
blocked off egr valve. It made the car rev quicker, feel about 500 lbs
lighter and overall a lot more fun to drive. I got my gear from TRD and it
was the best $65 i could have spent on the car but i don't think they carry
them anymore. Only problem was the gear wasn't marked in degrees so you
either had to degree the cam or trial and error it.

I would like to get another gear for my 84 4Runner. Does anyone have the
phone # for  Toysport or AEM?

  

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Date: Thu, 08 May 1997 19:05:41 -0700
From: James Brink 
Subject: cam's and timing Q's ??
To: Toy4x4@tlca.org

Jack Alford wrote:
> 
> I've got a Schneider low-end cam here that I bought quite some time
> ago and all this talk of adjustable cam timing gears has me wondering
> if the timing of this cam timing has gotten me to wondering how I can
> tell if this cam I'm about to put in has it's timing already advanced.
> Does anyone know to tell ??
> 
>  - jack


Jack,

It is not the timing of the cam itself but the relationship of timing
between the crankshaft sprocket and camshaft sprocket and how the cam is
positioned in it's drive sprocket. 


- -- 
Jim Brink				1986 Standard Bed 4X4/22R
Toyota/ASE Certified Technician		135,000 Miles
brinkjm@earthlink.net			32" BFG All-Terrain T/As
					Stock 4.10 gears
					Rear Lock-Right (TRD)

------------------------------
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Date: Fri, 9 May 1997 09:19:38 -0700
From: Locke Christman 
Subject: adjustable cam/ignition timing
To: "'Toy4x4@tlca.org'" 

All the talk about adjustable cam sprockets got me to thinking about
something strange I recently observed regarding the ignition timing on
my '80 20R.

The valves were pinging under even the slightest load and so I went to
check the ignition timing intending to retard it a little.  When I put
the timing light on and turned the distributor, I could not retard it
below 8 degrees BTDC.  At the time I got to thinking that maybe the
distributor was in wrong (off by one tooth on the gear) so I pulled it
out and carefully slipped it by one tooth.  This did not work since now
the furthest that I could advance the timing was TDC.

I put the distributor back the way it was, retarded it as far as
possible, replaced the cap and rotor (which seemed to help the pinging a
little) and left it, still wondering what's going on with it.

So now I come to my question.  If the cam were advanced with an
adjustable sprocket, would this also advance the ignition timing since
the distributor runs off of the cam shaft?  I have not had the valve
cover off, but I suspect that there might be an adjustable cam sprocket
in there.  Any comments?  I'm going to pull the valve cover as soon as I
get a chance to (hopefully) see what's going on.

By the way, this 20R has 296 kmiles on it and still runs good and burns
clean.  The valves were ground 100 kmiles ago.

Locke



Locke Christman
FEI Company
Hillsboro, OR
lac@feico.com

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Date: Fri, 09 May 1997 13:33:11
From: Ed Ruf 
Subject: adjustable cam/ignition timing
To: Toy4x4@tlca.org

AT 09:19 5/9/97 -0700, Locke Christman wrote:

Since you didn't mention it, I'll ask. You did remove the vacuum advance
for a carb'ed engine or short the check connector of an EFI engine so
you're actually checking the base timing?

Ed

------------------------------

Date: Fri, 9 May 1997 13:06:45 -0700
From: Locke Christman 
Subject: adjustable cam/ignition timing
To: "'Toy4x4@tlca.org'" 

Ed Ruf wrote:

>Since you didn't mention it, I'll ask. You did remove the vacuum advance
>for a carb'ed engine or short the check connector of an EFI engine so
>you're actually checking the base timing?
>
>Ed

Good question.  Yes I did. (removed and plugged the vacuum advance.)

Locke

------------------------------

Date: Fri, 09 May 1997 17:23:07 -0400
From: Ed Ruf 
Subject: adjustable cam/ignition timing
To: Toy4x4@tlca.org

On 01:06 PM 5/9/97 -0700, Locke Christman wrote:
>Ed Ruf wrote:
>>Since you didn't mention it, I'll ask. You did remove the vacuum advance
>>for a carb'ed engine or short the check connector of an EFI engine so
>>you're actually checking the base timing?
>
>Good question.  Yes I did. (removed and plugged the vacuum advance.)

Ok, next question. You mentioned you had the valves ground at ~100K, so we
know the head came off for that. Has the ignition timing ever been checked
after that and found to be correct? If not , possibly the cam was indexed
incorrectly when it was re-assembled after the valve job. I don't remember
offhand want 1 tooth off on the cam/crank alignment corresponds to in
degrees. Anyone have a camshaft drive gear handy to count the # of teeth to
find out?

Ed Ruf   (egruf@visi.net) or for Scramjet related ??? (e.g.ruf@larc.nasa.gov)
1986 Toyota 4x4 SR5 PU @ 122K, 3.5" Rancho susp. lift, RS-7ks, 31x10.5
BFG-A/T, K&N
1987 Toyota SR5 4Runner @ 118K, KYB GasSprings, 30.5x9.50 Cooper Disc.
1982 Honda XL600R Thunderin' Thumper
1986 Yamaha FJ-1200SC @ 15K 
2 yr old, 110#, pure bred white GSD, Kaiser Klaus III, AKC# DL569628/04

------------------------------

------------------------------

Date: Fri, 9 May 1997 15:47:41 -0700
From: Locke Christman 
Subject: adjustable cam/ignition timing
To: "'Toy4x4@tlca.org'" 

Ed Ruf Wrote:
>
>Ok, next question. You mentioned you had the valves ground at ~100K, so we
>know the head came off for that. Has the ignition timing ever been checked
>after that and found to be correct? If not , possibly the cam was indexed
>incorrectly when it was re-assembled after the valve job. I don't remember
>offhand want 1 tooth off on the cam/crank alignment corresponds to in
>degrees. Anyone have a camshaft drive gear handy to count the # of teeth to
>find out?

Ed,

Actually it was the previous owner that had the valves ground so I do
not know the answer to your first question.  You have an interesting
point regarding the cam/crank alignment.

Locke

------------------------------

Date: Fri, 9 May 1997 20:12:38 -0400 (EDT)
From: Spinnetti@aol.com
Subject: adjustable cam/ignition timing
To: Toy4x4@tlca.org

In a message dated 5/9/97 5:35:20 PM, you wrote:

>So now I come to my question.  If the cam were advanced with an
>adjustable sprocket, would this also advance the ignition timing since
>the distributor runs off of the cam shaft?  I have not had the valve
>cover off, but I suspect that there might be an adjustable cam sprocket
>in there.  Any comments?  I'm going to pull the valve cover as soon as I
>get a chance to (hopefully) see what's going on.

no, it only changes the relationship between the valve events and piston TDC.
My friend had similar problems with his truck when he put sidedrafts on, but
he never figured it out

------------------------------

Date: Fri, 09 May 1997 22:48:23 -0400
From: Ed Ruf 
Subject: adjustable cam/ignition timing
To: Toy4x4@tlca.org

On 08:12 PM 5/9/97 -0400, Spinnetti@aol.com wrote:
>In a message dated 5/9/97 5:35:20 PM, Ed Ruf  wrote:
>>So now I come to my question.  If the cam were advanced with an
>>adjustable sprocket, would this also advance the ignition timing since
>>the distributor runs off of the cam shaft?  I have not had the valve
>>cover off, but I suspect that there might be an adjustable cam sprocket
>>in there.  Any comments?  I'm going to pull the valve cover as soon as I
>>get a chance to (hopefully) see what's going on.
>
>no, it only changes the relationship between the valve events and piston TDC.
>My friend had similar problems with his truck when he put sidedrafts on, but
>he never figured it out

Wait a minute, it's late and now you've got me thinking... Oh oh, that's
dangerous.  The distributor is gear driven off the camshaft. If I remember
correctly, isn't this a spiral cut bevel gear? Actually the type of gear
shouldn't matter. If it's driven off the cam and the cam is indexed wrong,
then so is the ignition. Now, if the distributor was driven off the crank,
say like an old 8RC then only the valve timing would be off. Correct? 

Ed Ruf   (egruf@visi.net) or for Scramjet related ??? (e.g.ruf@larc.nasa.gov)
1986 Toy 4x4 SR5 PU@122K, 3.5" Rcho susp.+RS-7ks,31x10.5 BFG-A/T,K&N
1987 Toyota SR5 4Runner @ 118K, KYB GasSprings, 30.5x9.50 Cooper Disc.
1982 Honda XL600R Thunderin' Thumper
1986 Yamaha FJ-1200SC @ 15K 
2 yr old, 110#, pure bred white GSD, Kaiser Klaus III, AKC# DL569628/04

------------------------------
------------------------------

Date: Sat, 10 May 1997 09:48:32 -0400 (EDT)
From: Spinnetti@aol.com
Subject: adjustable cam/ignition timing
To: Toy4x4@tlca.org

In a message dated 5/10/97 6:15:16 AM, you wrote:

>Wait a minute, it's late and now you've got me thinking... Oh oh, that's
>dangerous.  The distributor is gear driven off the camshaft. If I remember
>correctly, isn't this a spiral cut bevel gear? Actually the type of gear
>shouldn't matter. If it's driven off the cam and the cam is indexed wrong,
>then so is the ignition. Now, if the distributor was driven off the crank,
>say like an old 8RC then only the valve timing would be off. Correct? 

Hmmm. now you got me thinking! The gear does'nt "know" where the distributor
is, its just a gear. You set the distributor timing based on crank position,
not by where the cam is (like you would on the 4AGE motor), so even if the
cam is way off, the ignition timing can still be correct. With the cam timing
way off, you can still get pinging etc. because of that.

------------------------------

Date: Sat, 10 May 1997 12:20:34 -0400
From: Ed Ruf 
Subject: adjustable cam/ignition timing
To: Toy4x4@tlca.org

On 09:48 AM 5/10/97 -0400, Spinnetti@aol.com wrote:
>In a message dated 5/10/97 6:15:16 AM, you wrote:
>>Wait a minute, it's late and now you've got me thinking... Oh oh, that's
>>dangerous.  The distributor is gear driven off the camshaft. If I remember
>>correctly, isn't this a spiral cut bevel gear? Actually the type of gear
>>shouldn't matter. If it's driven off the cam and the cam is indexed wrong,
>>then so is the ignition. Now, if the distributor was driven off the crank,
>>say like an old 8RC then only the valve timing would be off. Correct? 
>
>Hmmm. now you got me thinking! The gear does'nt "know" where the distributor
>is, its just a gear. You set the distributor timing based on crank position,
>not by where the cam is (like you would on the 4AGE motor), so even if the
>cam is way off, the ignition timing can still be correct. With the cam timing
>way off, you can still get pinging etc. because of that.

Yes, it can be correct, but it doesn't have to be. The gears on the
distributor and camshaft can only mesh at certain positions:  properly
indexed, +/- 1 tooth, +/- 2 teeth, etc. Same for the relationship between
the camshaft and  the crankshaft. Depending on the # of teeth per gear the
rotational offset is set. The question then becomes are the gears sized
such that one tooth offset in the crank/cam indexing corresponds to 1 tooth
on the cam/distributor indexing? I don't know myself. If it's not, then it
would be possible to differentially index the cam and igition timing. If
so, one might think the adjustment on the distributor would be able to take
this up, maybe, maybe not. 

Guess the real answer is going to be first make sure the distributor isn't
a tooth off, and pull the valve cover to check the valve timing and while
you're their you may as well run the valves.

Ed Ruf   (egruf@visi.net) or for Scramjet related ??? (e.g.ruf@larc.nasa.gov)
1986 Toy 4x4 SR5 PU@122K, 3.5" Rcho susp.+RS-7ks,31x10.5 BFG-A/T,K&N
1987 Toyota SR5 4Runner @ 118K, KYB GasSprings, 30.5x9.50 Cooper Disc.
1982 Honda XL600R Thunderin' Thumper
1986 Yamaha FJ-1200SC @ 15K 
2 yr old, 110#, pure bred white GSD, Kaiser Klaus III, AKC# DL569628/04

------------------------------
------------------------------

Date: Thu, 15 Jan 98 16:29:00 -0500
From: Rosenberger Bud 
Subject: Cam timing-was: 20r and weber tweaking (
To: "mail@UUCP {Toy4x4@tlca.org}" 

I have pasted in 2 former posts about cam timing from this and another   
list that may help.

Jonathan Albrecht wrote:

>I don't know anything about webers (we just bolted it on, and got a shop
>teacher to adjust it), but is there a fast idle/cold idle adjustment?

I have a book on Webers at home and I'll look at it and see if I can   
help.  The exact number would be helpful.  I'm assuming it has an   
electric choke.
   

>Another thing I was wondering about was valve float.  How do you know if
>you have it?

You'll know!  You don't!  Basically there you are minding your own   
business at between 5-9000 rpm (depending on the engine) and it all goes   
mushy.  Power loss and it sounds terrible.  Especially if you have an   
interference engine!  Ouch!
  His truck has an aftermarket cam (downey says it's good
fro 1500-5000 or 5500 or something) and I'd think that between that and
the 20r head it'd actually want to rev up to 5000+..  But when you drive
it, it seams to peak around 3500-4000, and power drops off big time
after 4000.  By 4500 the poor motor is screaming bloody murder and
starting to really slow down.  That's as high as we've taken it (in
gear).  Amazingly, it still has excellent bottom end grunt, and always
has.  Any ideas why this is?  Any ideas about getting it to rev higher?

Did you install an adjustable cam sprocket?  I think you are retarded (   
your timing not you! :)))  Actually, it is advanced but that wasn't as   
funny!

Hope this helps!

Bud

----------------------------------------------------------



Jim Brink Wrote:
A little-known secret amongst 22R builers is adjustment of the CAM (not
ignition) timing. For better overall performance, advancing the cam
timing approx. 3 degrees seems to be the magic number. I've found some
22Rs off as much as 3 degrees retarded from the factory--thus explaining
why some run better than others. I understand LC Engineering has a
really nice adjustable cam sprocket with a variable-adjustable keyway.
It costs about $95.00. Supposedly Toysport has them too. Last time I
checked, TRD was out of stock and did not have an ETA on when more would
be in. The others I have played with just have slots for 0 degrees
(stock) or 3 degrees adv. or ret. A friend of mine from Australia who
owns an auto repair and dyno. shop made up mine on a jig he built just
for this purpose. Seems Australians want more power out of the're 22Rs
as well. I do not know the actual horsepower/torque increases but
seat-of-the-pants driveability is noticeably improved. Remember, for
every gain, you loose something else. Advancing the cam will give you
better low-end response, hurting the top-end and vice-versa. I have not
really played with this modification with aftermarket
headers/exhaust/carburation, etc. so I can't really speak for which
combination works best. Thats your job!


Christopher P. Myer wrote:
>Jeff asked about my procedure for degreeing the cam on the 2xR, so I
>figured that this might be useful for others on this list.  He wanted
>to know if the wheel could stay mounted on the engine. Unfortunately, it
>doesn't stay mounted, and it is a little bit of a pain in the butt to
>install.  It is, however, very important to know when the valves are
>opening and closing, so it's worth the pain.
>
>Based on your exact setup (what accessories you have and whatnot) your
>installation may be a bit different, but here's the basic rundown:
>
>Put the timing mark on TDC (or close to it) and make sure that the dowel
>in the cam timing gear is 12:00.  If it's not at 12:00, it will be at
>6:00 and you'll need to turn the crank another full revolution.  Always
>keep in mind that the cam turns once for each two turns of the crank.
>
>Remove:
> Fan shroud
> Fan
> Crank Pulley (this may turn the engine off of TDC a bit, but
>  that's not a big deal at this point.  Just try to get it
>  close.)
>
>Install the timing wheel on the end of the crank.  Note that these are
>made for wimpy little crank pulley bolts (or for the 3-bolt setup of
>most domestic applications) so you'll usually have to bore out the
>center of the timing wheel the first time you use it.  At this point
>you'll have to check clearances.  You want to ensure that the timing
>wheel isn't hitting anything.  You may have to remove accessories, add
>washers, etc. to ensure that this works.  Confession:  I didn't want
>to pulley the crank pulley off, so I had to build a big round spacer
>out of 3/4" plywood.  This was a lame way to do things, but it worked.
>Go ahead and tighten the degree wheel down well.
>
>Get a piece of really stiff wire (like coat hanger wire) and cut a
>piece off that is about 3" long.  Put a loop in one end.  You're going
>to find an appropriate bolt (one of the bolts in the water pump is
>usually good) and bolt this wire to the block.  Put two 90 degree bends
>in the wire so that the end points at 0 degrees on the timing wheel.
>
>Here is where it gets a bit tricky.  The pointer we just made has to
>point EXACTLY at 0 degrees.  There are two ways to find that:
>
>1.)  Remove the head (yes!) and use the dial indicator.  This is more
>labor intensive, but it is actually easier and there is less room for
>error.  Don't try to find TDC with the dial indicator.  Find a point
>that is before and after TDC and use these to extrapolate TDC.  Put the
>piston as close to TDC as you can and zero the dial indicator there.
>Turn the crank one way until the piston is down a set amount, say .400",
>and note the reading on the degree wheel.  Now turn it the other way
>until it goes past TDC and drops again to .400".  Note this reading.
>Say that you get 44 degrees ATDC for one and 36 degrees BTDC for the
>other.  TDC is when the marker is pointing to 4 degrees, ie, the
>pointer is off 4 degrees.  Turn the crank until the pointer is at 4
>degrees ATDC and then move the marker until it points to 0 degrees.
>Install the head and you're ready to time the cam!
>
>2.)  Use a positive stop to identify TDC.  Less labor intensive, but
>since you're working "in the dark", you worry that you're doing it
>right (at least I do.)  The trick here is to make a positive stop that
>the piston will hit and stop the movement of the engine.  You can buy
>these or, if you're a tightwad like me, you can make your own.  Simply
>take an old spark plug, bust the guts out of it (this is a pain!) and
>then tap the body of the plug for a bolt.  You then screw this down
>into the #1 spark plug hole.  The trick here is to run the bolt in to
>a point that will stop the movement of the engine when you turn it over
>by hand.  You note that point and reverse the rotation of the engine
>and turn it until it stops again.  Note this reading.  Say that you get
>44 degrees ATDC for one and 36 degrees BTDC for the other.  (Wow, this
>is sounding familiar!  See #1 to figure out what to do from here.)  A
>free hint here:  Remove the cam gear from the cam so that you don't have   
to
>turn the cam and valve train while finding TDC.
>
>You can also stick the dial indicator down into a spark plug hole, but
>that makes me very nervous, given the extremely shallow angle that the
>spark plug on the 2xR engine intersects the top of the piston.  Probably
>an ideal method for a hemi-head engine like a 4AG or 3T.
>
>Some tips for checking the cam timing:
>
>a.)  Check the timing on the valve keeper.  Try to put the probe of the
>dial indicator such that it is exactly parallel with the stem of the
>valve.  Check to ensure that no part of the valve train comes in contact
>with the dial indicator as the valve opens and closes.
>
>b.)  Make sure that all of the other valves are completely loosened.
>This way you won't have to push all of the valves as you turn the engine
>over to check the timing.
>
>c.)  Most cam timing cards call for the valve lash to be set to exactly
>0 when checking valve timing.  Note that this means that your actual
>lift will be a little less than what you measure.
>
>d.)  The only thing that can ruin your whole day is if you accidentally
>bump the wire marker you made and move it.  Keep that in mind as you
>make the marker and then again as you're turning the cam through its
>rotations.
>
>e.)  When installing and removing the cam gear, make sure that the dowel
>on the piston is exactly at 12:00.  Putting this gear back on scares
>even experienced mechanics if they haven't installed one on a 2xR
>before.  You have to use leverage to pull up on the gear until the
>chain tensioner collapses, giving you enough slack to slip the gear
>onto the end of the cam.  I use a crow bar with one of the teeth on
>the hooked end broken off.  It takes a lot of force, and it collapses
>with a sudden "pop".  To put the gear on the cam, you have to have
>the two timed PRECISELY!  If it doesn't slip right on, you need to
>turn the cam and/or crank until they are lined up correctly.  (Ok, so
>that's one hand on the pry bar, one on the gear, one turning the cam,
>one finger checking alignment inside the cam gear.  A very understanding
>spouse or significant other is invaluable at this point.)
>
>Dilemma of the procedure:  To what do I fasten my nifty magnetic base of   
>my dial indicator?  Heh, if you find something good, let me know so I
>can use it!  Since the head is aluminum, that doesn't work.  If you
>have a header, you can usually use the base of the header to check the
>exhaust side.  On the intake side, I loosened my intake manifold bolts,
>slipped a big heavy carpenter's square in the opening between the
>manifold and the head, and then tightened the bolts back down well
>enough to hold the square firmly.  This was kind of lame but I made it
>work well enough.
>
>I hope this is helpful.  I also hope that somebody saves this,
>corrects any oversights, and posts it on a web site somewhere (hint
>hint!)
>
>Christopher P. Myer

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Date: Tue, 03 Mar 1998 17:40:37 -0800
From: Jim Brink 
Subject: 22R Timing
To: Toy4x4@tlca.org

Eli Madden wrote:

> 
> I'm reasembling my '87 22R after doing a mild rebuild. I'm
> a little mystified by the whole timing setup. I installed my
> timing chain with the crankshaft ridge sticking straight up,
> the timing mark on the crankshaft gear pointing straight down,
> and the camshaft gear timing mark pointing straight up. The
> marked links of the chain are in their proper places. I have since
> manually turned the engine ove a little, but can bring it back to
> this position fairly easily.
> 
> Is this the position that I want the camshaft and crankshaft to be
> in when I install the distributor? All the descriptions I've read assume
> that things aren't fully disassembled.
> 
> Is Top Dead Center (TDC) when the camshaft timing mark is pointed
> straight up?

Yes, when the cam marks are in the up position and the crank marks are
down, this is TDC. To be sure, wiggle the rocker arms for the #1
cylinder. They should be loose.

> 
> Would installing the crankshaft pulley make things easier? It sounds
> like there is a timing mark on it.

If it makes it easier for you, sure. The mark on the pulley should be on
the 0 deg. mark on the timing cover.

To install the distributor, point the rotor to the 12 o'clock position.
When the dist. is installed all of the way, it should rotate ccw to the
#1 firing postion. This should get you close enough to get the motor
started so you can make the fine, running adjustments.
- -- 

Jim Brink, Toyota/ASE Certified Technician	1986 Toyota Std. Bed 4WD
Manhattan Beach, CA				32x11.50/15 BFG M/Ts
ToyTech@Off-Road.com
************************************************************************
TLCA - Friends of the Mojave Road (FOMR) - CA4WDC

Visit http://www.off-road.com Putting Off-Road, Online!

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Date: Tue, 03 Mar 1998 22:38:56 -0500
From: Clif Moyers 
Subject: 22R Timing
To: toy4x4@tlca.org

Eli,

You want to insert the distributor, as shown in the manual, after rotating
the crank to position No. 1 cylinder top dead center on its compression
stroke.  This is described in the manual on page IG-10.  The manual talks
about the No. 1 rocker arms being loose, indicating both valves are closed,
and thus the compression stroke.  Since I already had the valve cover on at
this point, I removed the No. 1 and No. 4 spark plugs and held a finger
over each spark plug opening while my partner turned the crank through top
dead center (say, 45 degrees before to 15 degrees past TDC).  Remember, 1
and 4 are up at the same time, but one will be doing its exhaust stroke
while the other is doing its compression stroke.  So, if you feel pressure
from the No. 1 spark plug hole, you are on its compression stroke.  If not,
rotate the crank one turn and see if No. 1 then "blows".  Once No. 1
compression stroke has been identified, realign the crank to 0 degrees and
insert the distributor with the rotor pointing at about 10 o'clock as shown
in the manual.

Hope this helps!

Clif  

------------------------------
------------------------------

Date: Mon, 19 Oct 1998 11:28:50 -0700
From: Barney McNamara 
Subject: re: Adjustable cam gear

Michael wrote:
>I was reading Barney's Threads (sounds like a line of cloths).  The stuff on
>adjustable cam gears is interesting.  Can someone, in 2.5 bananna language,
>explain the idea behind these and the relation to ignition timing???

The idea of adjustable cam gears is to set the opening/closing of the
valves in relation to the position of the pistons in the cylinders. 
Zero degrees, TDC (Top Dead Center) is the rotational position of
the crankshaft when piston one is at the very top of its stroke, on
the compression cycle. The goal of the adjustable cam gears is to 
optimize the valve action in relation to the pistons, and compensate
for tolerance variations in the timing chain and the distance between
the crankshaft chain gear and the cam shaft chain gear. The height
of the block, thickness of the head gasket, and depth of the head all
add to the variations in the length of the timing chain in defining the
relationship between the piston position and the valve actions. By having
an adjustable cam gear, all the dimensional tolerances in the system can 
be compensated for, and the optimum valve-piston relationship can be
set. The assumption built into the stock engine is that all these
mechanical variations are minimal, and that adjusting the cam timing
is not required. This is probably true, especially on new engines. But
when trying to get the most out of a rebuilt engine, and allow for
changes due to the reuse of old parts that may be resurfaced, the
adjustable cam gear makes a lot of sense to me.

The ignition timing is also set to be in the proper relationship with
the piston position. It is more critical, and has even more slop in
its tolerance due to the variation in the lobes on the distributor
shaft that actually cause the timing pulse to be generated by the
magnetic pickup in the distributor. Thus, a simple device has been
included in the engine design to set the ignition timing. The use of 
a timing light, and the rotation of the distributor compensates for 
all the tolerances and wear in this setup.
_____________________________________________________________
Barney McNamara              JENNY - 83 Toyota Short Bed  
( barney@flowpoint.com )     stock 22R motor ; 3" body lift
Santa Cruz, Ca.              8" alloy rims; 31" BFG A/Ts
homepage: http://www.scruz.net/~barneym/barnhome.htm
______________________________________________________________

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Date: Wed, 28 Oct 1998 13:50:21 -0600
From: "Brian.Gallus (Exchange)" 
Subject: Cam timing

Ok... I don't understand this whole cam timing thing.  From what I read
in the Toyota manual, the cam timing is not adjustable w/o an adjustable
cam gear.  After I put the engine together (LC Engineering Cam), it just
didn't run right, so I dropped it off at Toyota last Friday to have them
do a quick Diag.  Their diagnosis?  Cam timing is off.  Hmm...  How's
that possible???  Jim?  Can some explain that to me?  I followed the LC
Engineering/Toyota Factory manual to a "T" when assembling the engine,
so I'm WAY confused by how the Cam Timing can be off when not using an
adjustable cam gear...  

So I dropped the truck off again today to have them "just fix it"....
Since it makes no sense to me, and since the quote to fix it wasn't
overly expensive.  Well, Toyota has been working on the 4Runner all day
now, and they still don't have the way that they want it.  I have to
bring my old cam in for them to look at so that they can look at the
indexing mark on the old cam.... Then they will be able to set the cam
timing properly on the new cam...  I guess....  

Does this make sense to anyone?  What the heck could I have done wrong??
- - aside from not lining up the timing chain correctly (which I KNOW is
NOT THE CASE!!!  Went through that process twice now!!)  How do you
adjust the cam timing w/o an adjustable cam gear?????

bkg

Brian K. Gallus
Technical Analyst - Dayton Hudson Corp.
(612) 761-2620
Brian.Gallus@dhcmail.com


============================================================================
Toyota 4x4 page: http://www.off-road.com/4x4web/toyota

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Date: Thu, 29 Oct 1998 09:38:41 -0600 (CST)
From: Brian Wiencek 
Subject: Re: Cam timing

> Ok... I don't understand this whole cam timing thing.  From what I read
> in the Toyota manual, the cam timing is not adjustable w/o an adjustable
> cam gear.  After I put the engine together (LC Engineering Cam), it just
> didn't run right, so I dropped it off at Toyota last Friday to have them
> do a quick Diag.  Their diagnosis?  Cam timing is off.  Hmm...  How's
> that possible???  Jim?  Can some explain that to me?  I followed the LC
> Engineering/Toyota Factory manual to a "T" when assembling the engine,
> so I'm WAY confused by how the Cam Timing can be off when not using an
> adjustable cam gear...  

There are acouple of things - first - did you have your head milled or the
block decked?  Are you mixing pre-84.8 parts with post 84.8 parts? (i.e
timing chain, block or head?)  Remember the pre-84.8 stuff has a taller
center-to-center measurement - that means that the chain is longer and the
deck height of the head is taller.

 Are they saying the cam is advanced or
retarded?  There could be a manufacturing problem with the cam where the
pin hole in the front was drilled several degrees off (not likely)  I'm
sure you're not off 1 tooth on either sprocket - that would be an awful
lot (top gear would be like 7-8 degrees???)

Also are they using LC's specs to index the cam based on crank rotation
(i.e. degreeing in the cam)  Without knowing what the profile of the
cam is supposed to be and when the engineers expected it to open/close 
you're taking a guess at all this Have the toyota mechanics check this 
and if it's way off call LC and ask for a replacement cam - it shouldn't
be that far off unless you've got mixed components as above...

Many 'performance' cams are ground a couple of degrees advanced to get
better 'top end' performance from what the factory cam was ground at.

- - Brian

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Date: Thu, 29 Oct 1998 12:35:17 -0500
From: Eli 
Subject: re: Cam Timing

Brian wrote-
******************
Does this make sense to anyone?  What the heck could I have done wrong??
- - - aside from not lining up the timing chain correctly (which I KNOW is
NOT THE CASE!!!  Went through that process twice now!!)  How do you
adjust the cam timing w/o an adjustable cam gear?????

bkg
******************

When I changed my timing chain, it was a little confusing getting the chain
lined up with the cam properly. The original chain had one marked link,
whereas the new chain had two. I ended up putting the crankshaft in the
proper position, then the cam in the proper position, then figured out how
the chain lined up. 

Not very specific info, sorry. I hope it helps somehow.

Eli Madden

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Date: Thu, 29 Oct 1998 14:45:36 -0600
From: "Brian.Gallus (Exchange)" 
Subject: Cam timing

Just heard from Toyota.  As expected, they cannot set the cam timing w/o
the adjustable cam gear.  Due to the (potential) amount that was shaved
from the head, they were able to get close by messing with the timing
chain, but not close enough.  Ordered the Adjustable Cam Gear from
L/C....

Live and learn.  Jack suggested that I buy the gear when I first ordered
all of the parts...  Serves me right for trying to save a buck...

Thanks to all for helping, especially Brian.
bkg

Brian K. Gallus

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Date: Fri, 30 Oct 1998 08:07:13 -0600
From: "Brian.Gallus (Exchange)" 
Subject: RE: Cam timing

Ok, milling the head should *retard* the cam timing - the cam center
gets CLOSER to the crank center and then the tensioner takes up the
slack on the 'loose' side of the chain - for amount my guess is that
if it was just a clean up around 5-10 thou was taken off, and if it was
warped 20-30 thou (or more) - Fel-pro and others make a gasket that is
thicker to compensate for this, but heck I'd do the adjustable gear
first, and keep the bit of compression increase.

- ------------
I agree with this, but I was foolish enough to rely on someone else to
check the cam timing out of sheer laziness.  I ordered the Adjustable
cam gear ($$$  ouch!!) and it includes specific instructions on indexing
the cam.

Hmmm.. well that's out - unless you've somehow got an '84 timing chain 
set...

Geez... hope not.  I can double check the part numbers.

Well, if you've got all bottom end and NO top end that sounds like your
cam timing is way RETARDED - might be off 1 tooth, and the milling of
the head exaggerated this - I'd have them advance it 1 tooth and then the
milling of the head should retard it a bit and you should be in the
ball-park.

- -------------

Toyota say's it's way advanced.  I'll pull it apart and check once the
parts arrive.

Well, a bad TPS will cause the timing to be a problem when setting - and
the retarded cam timing would make it horrible to use so little advance.
The cam being retarded 8-10 degrees would need a lot of advance to run
OK.

- ------------
AH!  I'm going to re-check the TPS.  Might just order a new one to be
safe.  

Thanks!!!

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Date: Thu, 5 Nov 1998 12:28:58 -0600 
From: "Brian.Gallus (Exchange)" 
Subject: Cam timing... ;-)

My adjustable cam gear arrived yesterday.  It's a Very nice looking part
and came with VERY detailed instructions on how to degree/index the cam
w/o having to disassemble the entire engine.  I'll be doing the work
this weekend and will let you all know how it goes. (Brian, I'll take
pictures first...)

BTW, LC took the time to put 20 degree marks on the thing - very nice.
Some people had mentioned to me just having a machine shop drill some
new indexing holes on my stock gear.  From what I saw in the 3 minutes I
actually looked at it last night, there is no way to effectively make an
stock gear adjustable by less than 5-6 degrees... ;-(

Also, according to the "flyer", advancing the cam lowers the torque
curve, retarding the cam raises the torque curve on the rpm scale...
This would make it consistent with what Toyota was telling me...

later,
bkg

Brian K. Gallus

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Date: Thu, 5 Nov 1998 19:17:27 -0800
From: "Dave Luzzi " 
Subject: Re: Cam Timing

I had an adjustable cam timing sprocket on my 89 VW Golf GTI (8 valve).
Like you said you could move the torque curve by adjusting the 
advance/retard. Of course this was easy to fine adjust because with a 
timing belt, you only had to remove a plastic cover and "detach" the 
outer sprocket portion from the inner camshaft portion by removing 6 
allen screws. I took a long, highway drive trip in it, and before I 
left I advanced the timing to lower the torque peak.8-12 degrees, I 
think.  It made a definitely noticeable difference and hardly affected 
the idle at all. 

I'm sure you know this already, but if you're changing the timing to 
move the torque, ROTATE ENGINE BY HAND to check for valve interference.
(direct quote from my product info flyer)

Enjoy!
Dave Luzzi

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Date: Thu, 3 Dec 98 15:43:00 -0500
From: Rosenberger Bud 
Subject: RE: Timing Sprocket---- Romoval

   

> Here is how I was going to attack the problem, and I was
> wondering if I will F__K up my sprocket, which I would like
> to avoid.  I
> plan on using 2 U bolts to place around the the spokes of the
> sprocket.
> I will then bolt a pipe between the two arms of the U bolts, and use
> that to hold the gear.

I think that will work.  Wrap rags around the bolts/pipe to prevent   
nicking.

I don't know what the SST looks like for this engine but I have seen a   
device that looks like a P or d.  The hole had a bolt in it to bolt to   
the head.  The bolt would be running parallel whit the cam.  The bottom   
of the P was long enough to swing and fit into the teeth on the sprocket   
(at right angle to the center hole).  It works like a ratchet pawl.  You   
bolt the thing in place, engage the tooth, apply torque to the bolt and   
off it comes.

This is very clear in my mind but I'm afraid I haven't described it well   
here.  Email me back and I can clarify, if needed.

Bud  

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Date: Tue, 8 Dec 1998 10:15:14 -0600 (CST)
From: Brian Wiencek 
Subject: Re: Engine rebuild rebuild... ;-)

> I have NO problem running 92 octane in this.  OH!  when the #1 piston at
> TDC, I can feel with my finger that it is slightly higer than the block
> deck....

Well, you've got the adjustable timing gear, so that should account for
any differences in the deck heights as far as adjusting cam timing goes.
As for the piston being above the deck of the block - well you'll
DEFINATELY need to check that one out further.  Measure the deck height
with a dial guage or for a 'cheap trick' use a straight edge laying on the
block or piston, then use feeler guages to check the height - I can't
remember what the compressed thickness of the toyota head gasket is.  You
should probably have at least .010 clearance betwen the head & the piston
top at max travel.  Check the clearances then check the compressed
thickness of the gaskets.  Compression is your friend when trying to make
power.

- - Brian

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