[export13]

I have a technical question for you guys that can offer a detailed explanation. I recently installed a set of s4 cams into my 95 se-r. Before the install my distibutor was in the middle to get 15 degrees, after the install it has to be pushed all the way forward to get it to go to 15 degrees. How can I fix this?

1. Verified top dead center with a long screwdriver.(second mark from left)
2. Intake cam at 10 and exhaust cam at 12
3. 20 rollers between marks on cam gears
4. Car runs good pulls hard above 5000 rpms
5. verified that timing is reading correctly with scanner ( done at autoshop after I paid them 260 to fix , but they did not)

Now I have read almost every post related to this subject but none seem to give enough information. From previous posts it sounds like I am retarded one tooth on the crank or about 13 degrees. This would seem simple to fix but if everything is lined up perfectly the way it is, how in the world would there be a way to remedy this. Now if I did assume I was retarded one tooth on the crank there would be more than one way to fix this. Advance both sprockets forward one tooth or to leave the sprockets stationary and move the chain one tooth toward the rear of the car which would require moving crank counter clockwise to provide enough slack in the chain. I have tried both ways and what happens is that I end of overadvanced ( distributor needs to be almost fully retarded to read 15 degrees. Either way that I go it is too advanced or too retarded. The cams will only line up correctly one way and when this is accomplished I always end up with the distributor almost fully advanced. I have been fooling around with this for over a month now and my brain hurts. I was wondering if there is anybody that can shed light on the subject that can give tech details on what is actually going on.

Note. All the info that I have seen has stated that the distributor has to be in the middle for cam timing to be correct.

Sorry for long post but I wanted to be specific.

 

[lshadoff]

I wrote a while back about this:

http://www.se-r-list.org/pipermail/se-r-club-texas/1999-February/000565.html

I hope it helps.

Lew

 

[export13]

i guess what you are saying is that i will need to pull the front cover and check the number of rollers between the crank and the gears to make absolutely sure everything is lined up.

 

[lshadoff]

i guess what you are saying is that i will need to pull the front cover and check the number of rollers between the crank and the gears to make absolutely sure everything is lined up.

You should be able to have someone rotate the crank and count links to see if it has slipped on the crank pulley.

Lew

 

[JDM_2ner]

im not in undersatnding. If the two silver marks are lined up on the cams, there are always going to be the same number of links between the colored links for the sprockets and crank.?

 

[lshadoff]

im not in undersatnding. If the two silver marks are lined up on the cams, there are always going to be the same number of links between the colored links for the sprockets and crank.?

If you set #1 cylinder at TDC on the compression stroke, then the silver marks on the chain should line up on the cams at 10 o'clock on the exhaust and 12:30 on the intake. I have heard it may take several revolutions for this to occur, but it worked first time for my cam installation.

There are three possible scenarios for a chain skipping one tooth:
on the crank, the intake cam, or the exhaust cam. If one of the cam gears skipped then the silver marks will not line up with the marks on the gears. If it was the intake cam, then the timing will be off because the distributer runs off this cam.

If the crank skips a tooth, the silver marks will line up correctly, but one tooth off TDC. You can compensate for the crank skipping by moving the chain on both cam gears one tooth to compensate.

According to the FSM, you must remove the cylinder head to get the timing cover off. So anything you can do to correct for a skipped timing chain easily is worth it.

I don't remember what I was thinking when I said you can tell by counting links. It doesn't make sense to me now, either.

Lew

 

[honkeybizkit]

you can only count ALL the rollers if you have the timing cover off. 48 from the crank mark to the exhaust mark, 20 from exhaust to intake.

 

[Nismo_SR20]

This sounds very similar to what happened to me. I just advanced the i/e sprockets by 1 tooth, and the distributer is off. The car runs good like this, and better than it did when it was retarded one tooth.

How does your car run? Could JWT made a mistake on the exhaust cam dowel pin or maybe the slot where it connects to the distributer?

 

[export13]

The car runs good to me. I have tried retarding and advancing the chain, but there seems to be no way things will line up after doing either. If everything is lined up correctly when the engine is at top dead center then moving the cam gears or the chain will cause this alignment to change. correct? I have racked my brain for some time now and it just seems like cam timing is correct , but the distributor is just not in the right position.

The only reason I checked the cam install in the first place was because of my 1/4 mile times. I ran a 15.9 at LACR , which is a notoriously slow track because it is a little over 3000 ft. I have greddy cat back, s4 cams , pr intake, motor mounts, kyb struts, pro kit springs, jwt clutch , g5 hotshot header. The runs were all close to 16 seconds flat, with 17 inch wheels in the rear and stock wheels and cheap tires on the front. From reading previous posts about LACR these times are not that bad, but if my timing is somehow retarded about 13 degrees then they could be better

 

[export13]

oh I also have a g20 ecu
my second best time, only one i could find

reaction .617
i1 2.436
i2 6.834
i3 10.371
et 15.991
mph 87.570

 

[Nismo_SR20]

The sprockets dont have to be exactly at 10 and 12 o'clock.

Can you reach 15 degrees with it in the retarded position? When mine was retarded i could only reach 13degrees. After i advanced it by one tooth the distributer position was back aways from the middle.

Here are some pictures of where my sprockets, distributer, and cam positions are. The timing is set at 15degrees.

http://www.cardomain.com/memberpage/336386/2

 

[export13]

mine is at 15 degrees right now. THe distributor position is close to yours but the exact opposite. It is not all the way advanced I could probably get it to go to like 20 to 23 degrees. Before the cam swap it was almost exactly in the middle.

 

[Nismo_SR20]

I just called JWT. He said that if the distributer is not in the same position as before the cam swap, something is off. He told me what all to check, but you have probably checked all that, i know i have.

What gets me is how the chain can be advanced one tooth and retarded one tooth but neither one will put the distributer in the middle. Is there anything else that could cause this?

 

[export13]

I too was talking to jim wolf about a month ago and he did not seem to have a definite answer. He also said to make sure the valves were in the correct positions for top dead center but we got cut off after that and he never called me back. THe only thing that makes sense is if the postion of the dist slot is slightly off, but Jim Wolf uses factory billets when making their cams. Also when I took it the mechanic he claimed that the crank was one tooth retarded but when he gave it back to me it was too advanced( like when I advanced both sprockets one tooth. I really want to pull the front cover to see what is going on but it is a pain and takes forever.

 

[Nismo_SR20]

Try putting the stock cams back in and see if they timing and distributer go to the correct position. That should tell you if it is the JWT cams or not.

 

[export13]

I may just pull the cover when I get enough money for pulleys. I also need to pull the oil pans and replace the front seal to fix some leaks. I could do it all at once.

 

[Cheezit]

My timing chain was rattling. Suspected the tensioner failed. Removed it while NOT at TDC, put it back in, but it did n't lock out, so there really was not any significant tension on the chain.
I rotated the crank to get to TDC and in the process caused the timing chain to skip at least one cam-sprocket tooth. I rotated both Clockwise and Counter-clockwise. Eventually the motor came to a point where it was binding and I was no longer able to rotate the crank manually.
When I continued to rotate the crank manually to bring it to TDC, I could hear the pistons make contact with valves.

I looked at the cam sprocket keys (dowels), and they were slightly off to the left, but evenly so. The FSM says they should be pointing to "ABOUT 10 and 12 o'clock", so despite being a touch off to the left,it did not seem wrong.
The cam lobes for cylinder 1 were pointing away from each other, Intake to 10, Exhaust to 2. I found this a little odd, given almost every comment I have seen says the lobes will point away 180 degrees away from each other symetrically. Mine were facing away from each other symetrically, but not 180 degrees opposite each other. What is the correct orientation in terms of the narrow part of the lobes, Which direction should they be pointing when at TDC?

There were only 18 chain link PINS between the two marks on the cam sprockets, which with the binding convinced me the chain had skipped at least one sprocket tooth. But which sprocket? I had rotated the crank both clockwise and counter-clockwise. The chain just as likely skipped while rotating the crank in both directions.
To correct this binding, I set my crank pulley to TDC and pulled of the intake cam sprocket and positioned the chain so that there would be 20 pins instead of 18 between the two sprocket marks. I did not remove or turn the cam from it's "bed" of cam caps.
I then re-fastened the cam sprocket bolt and torqued it to spec.
Now there are 20 pins between the two sprocket marks, the sprocket keys are slightly oriented towards the left of exactly 10 and 12 o'clock, BUT the Intake cam lobe's narrowest part points to 9.5 and the Exhaust cam lobe's points to 2 (imagine the numbers on a clock).

• WHAT IS THE CORRECT ORIENTATION OF THE CAM LOBES FOR CYL. 1 WHEN CRANK PULLEY IS AT THE TOP DEAD CENTER MARK? Is this difference in cam lobe position normal? If not, how should the cam lobes on cylinder 1 be facing? Please use the numbers on the face of a clock to describe their orientation.
• If it requires adjusting cam position, WHICH CAM? (I did not adjust the sprocket on the exhaust cam)
• If necessary, how should I go about adjusting the cam(s)? I have read several methods among the threads on cam replacement topic, but people argue with each other, and the instructions get lost in the exchange. Please clarify in concise instructions.
• If I am able to push the left-hand chain guide and cause it to move while the tensioner is extended and exerting tension on that guide, this would suggest the guide bolt has become loose, Correct?

 

[Cheezit]

This diagram showing top dead center was passed along to me by sss4me on sr20forum.com