As some of you may know my idle's been goofy. Well today I regrounded my MAF because it was reading damn near 17 mV, now it's down under 2 mV. So that's all fine and dandy. I decide I'll put my new timing chain tensioner in and change my oil. So I go pick up some oil and the car runs as well as it ever did. So I swap out the tensioner and change the oil. Now my car idles like shit and runs like shit. It idles in quick grunts like I've got a lumpy cam, and the engine misses, lost a lot of pull. I had to totally adjust the idle screw so it would even stay running. I can't even check the timing, the light barely blinks if at all. Not to mention I can't see the timing marks. So I'm thinking maybe the POS timing chain jumped a tooth after I put the new tensioner in. Why that would be, I dont know, I put the new tensioner in without a hitch (other than I lost one of the lock washers). There's a lot of teeth for that chain to slip over though, for it to have skipped a tooth. Maybe the distributor just skipped a tooth? I can't advance the timing to compensate because it's as far clockwise as it'll go, and retarding it seems to make things worse. I also noticed more valvetrain noise coming from the intake (I'm still running the ghetto open airbox) but I figured that could be due to the chain being tighter. So how do I go about figuring this out? Good news is, my oil leak is my timing cover, so once my truck is driveable, I pull the car in and swap in an Avenir. :) But in the meantime I'd like to figure out what the deal is, for my own learning benefit as much as getting the car running better. I would really appreciate any help.

The tensioner may have not popped out. Either pull the valve cover and take a look, or remove the tensioner to see. You *did* soak the tensioner in a cup of oil, and compress and latch it before you installed it right?

C

I'll pull the VC tomorrow. I did latch it but no I didn't soak it in oil. And I put it in right side up. My FSM is no help in even understanding where the distributor shaft engages anything else. I'd like to be able to crank the 1st piston to TDC and check my rotor position but I'm not sure of the correct process to do so.

You should use a wrench to turn the crank until you here the new tensioner release... otherwise it won't be when you first start and could skip.

Chris

I pulled the VC off this morning and the tensioner is extended. I tried to check my timing again and it's retarded quite a bit and like I said, I can't just advance the distributor to compensate. So I'm guessing that the chain must have slipped down on the crank end. So what the hell do I do to fix this? I know I have to get the crank and valves back into sync but I'm not clear on how to do that. And there's no convenient "So your timing chain slipped, here's how to fix it" section in the FSM.

The chain CANNOT fall off the crank, there isn't enough room. See here (http://www.sr20development.com/Instructions/JWT-CAM-INSTALL-SR20DE.PDF) for a reference. It says "It is impossible for the chain to jump on the crankshaft sprocket because there isn't ennough room between the sprocket and the cover".

I know Eric96SER posted an excellent message about how to time the cams when you're not sure what's what.

Here's a few hits
http://www.sr20deforum.com/search.php?s=&action=showresults&searchid=178803&sortby=lastpost&sortorder=descending

Good luck

Chris

Right chris - but I'm thinking it skipped on the upper end, if you start the motor with no tension on the chain at all, I'd think it'd be viloent enough to cause it to skip a tooth up top.

Chris

Thanks for you guys' help. That cam install PDF helps a ton, now I can at least put the crank at TDC and see if my cams are where they're supposed to be, not to mention I should be able to set the crank where the timing was set and and pull the cap off and see if the distributor is where it should be. If it did skip a tooth up top whats the solution?

Originally posted by Toolapcfan
If it did skip a tooth up top whats the solution?

Remove and reinstall the cams.

Chris

Ok that's what I figured, I might attempt this this evening. Let me know if I've got the procedure correct. I pull the VC and rotate the crank until #1 is at TDC. Then I look to see if the dowel clock positions are off on my cams, if not, then I know my chain didn't slip and I start looking elsewhere for my problem. If they are off, then I need to remove the cam gears to get slack in the chain and to rotate the cams at the right clock positions. Bolt the cam gears back onto the cams and put the VC and other shit back on.

Ok, I've got #1 at TDC and my intake cam is at what looks like 10:30 and my exhaust is at 12 and I've got 9 whole links between the two timing marks, the intake mark lands right in the middle of the 10th link. Apparently there should be 20 pins between the marks, I've got 19. So apparently it skipped one tooth, advancing the intake cam by 10*. (There appears to be 36 teeth on the gear, someone correct me if I'm wrong).
http://www.imagestation.com/picture/sraid60/pdd3c278adcdd20da042eb5a7a2bc2ff9/fc40f419.jpg

http://www.imagestation.com/picture/sraid60/p24c642de56b19073e4b74a2c365ce49c/fc40f40c.jpg

Well, I have 20 links between timing marks now and guess what? When the engine is warm I have NO throttle response whatsoever. If I floor it and wait a few seconds it'll rev up and then when I let off I get a little backfire. Someone please tell me what the fuck is going on here. :( I suppose the timing could be off but considering I haven't touched it since it was running right I can't see it being off, and I'm too tired to check it now. I'm pretty sure I was at TDC, I had the plug out and the piston was at the top while the crank pully mark was on the TDC pin when I took those pictures. And the valves are closed, which makes sense for the compression cycle. I even pulled the cap to see if the rotor was on the #1 contact, and it was.

Originally posted by Toolapcfan
Well, I have 20 links between timing marks now and guess what? When the engine is warm I have NO throttle response whatsoever. ... :(
I suppose the timing could be off but considering I haven't touched it since it was running right I can't see it being off, and I'm too tired to check it now.


Did you change the chain on the intake cam sprocket? When you described your timing problems, it made me think that you should be moving the exhaust cam by one link, not the intake cam.
Check your compression and post the results.

Which cam did you move? The exhaust cam pin should be straight up and down. From your picture, it looks like the cam is around 11:30. I had the same problem with a guys car this weekend. I lined the cams up like they need to be, and the car wouldn't start. I took stuff apart so many times, I can't even count. We never figured out what was wrong. He had 21 pins between the marks. When you put the motor to TDC, are you using the 2nd mark from the left(should be yellow)?

I'm only counting 19 in the pic. Looks like the exhaust cam is off a tooth. It should be approching the 1 oclock position according to the FSM.

If I'm feeling up to it this evening I'll pull it all back apart and I'l advance the intake cam back to where it was, as well as advance the exhaust cam 1 tooth. That would put where you guys are talking about. We'll see what that does. I thought the intake was suppose to be at 10 and the exhaust at 12, but from what you're telling me James, the should me more like 12:20 which would be a single tooth advancement. (36 teeth would equal 10 degrees of rotation or 20 minutes of rotation if using clock incriments). Let me think out loud here. Let's say the cam timing was all fucked up, like the chain slipped a ton. The way you would need to fix that would to be to put #1 at TDC on the compression stroke, which again, would mean the valves should be closed when the piston is at the top of the stroke. Now, the only other info you'd need to get the cams positioned properly would be to know at what clock positions the timing marks on the cams should be at when #1 is at TDC of the compression stroke. Once set, a person should be able to advance the crank by hand and see the exhaust lobe opening the valves just after the pistion has reached the bottom of the compression stroke. Then continuing to crank the engine over, the piston reaches TDC again on the intake stroke, so the intake cam should be open and the exhaust closed. The piston reaches the bottom of that stroke and the intake valve closes and up it goes then into the compression stroke again with both valves closed. Hopefully I'll feel better this afternoon and be able to take a look at things. I really appreciate you guys helping me out, otherwise I'd be fucked.

You are on the right track, but not really. The parts of the cams that need to be at 10 and 12 are the pins that hold the gears to the cams, not the timing marks, which you have as red in your pics. I see where you are getting confused by them. The easiest thing to do it put the exhaust cam pin at 12:00. Now from the red mark, count 20 pins on the chain, the the red mark on the intake cam gear should be between 20 and 21. The pin on the cam should also be at 10:00. Follow me? Its not hard, but I think we were talking about the same marks, so you were getting confused. If you have a Haynes manual, it shows were the cams need to be, and it uses a picture from the FSM.

Well all is good. Thanks to all you guys. :) I owe you one. I'll give you all a nice discount when I get my site up and running. :) A couple things I've learned in the past few days that might be beneficial to others who've not done this yet:

Having had the tensioner in and out many times during this, I found that the hook will not release if #1 is at TDC on the compression stroke.

The chain can only slip on the exhaust cam gear, it's physically impossible elsewhere. It was mentioned that it can't slip on the crank gear, but I also found it can't slip on the intake gear either.

Like Chris said, crank the engine manualy to allow the tensioner to fully extend before putting things all back together and starting the car. It also doesn't hurt to pull the VC to make sure all goes well, I found that the chain slips awefull easily even when you're being careful.

Despite that JWT cam install write up, the wood block thing doesn't work, at least not with a new tensioner. Everytime I pulled the intake gear off, the tensioner would extend a little more, just enough that I had to take it out so I could get the gear back on. And yes, I did build the wedge according to the specs, I'm a 4th generation carpenter as well, so it wasn't me that failed, t'was the wedge, that failed me! :) Not to mention the time it takes to make the damn wedge is about how long it takes to just take the damn tensioner out. :)

Not all wrenches will fit into the narrow spot where the hex is on the cams. And unless you've got a brand new adjustable wrench, it likely won't stay tight and will slip out. Mine was brand new and only lasted enough to bust the intake cam bolt loose the first time when I adjusted the wrong cam and a second time when I took the exhaust cam bolt loose. It wouldn't stay adjusted to get the intake cam loose again. Anyway, I had my dad pick me up a 1" wrench and I had to grind a good 1/8" off of the head width so that it'd fit. I think craftsman would fit though, all mine are narrower than the AM Pro my dad picked up at Advance Auto.

Glad to hear it's all good! One thing I've started doing is disconnecting the coil wire and cranking the engine over *before* putting the valve cover on. I run it until oil starts flowing out of the oiler tubes.

Chris

Not a bad idea. I think it'd be smart to install an electric oil pump that acts just as a primer to put the car up to pressure before starting. Then it stops running after that and the mechanical pump dos all the work.