Timing Chain Guides Too Tight? SR20DET

[CamryOnBronze]

So, I think I made a mistake when my friend and I put my engine back together. Basically, I tore it down to the block to install the head gasket, head studs, new timing chain components, etc. With everything for the most part back together this evening, I went to install the timing chain tensioner and the chain still has a lot of slack to it. I tried turning the crank pulley counter clockwise to get it to engage like the FSM suggests, but it still did not gain any tension. When I removed the tensioner, it had extended- meaning that it was exerting force on the timing chain guide as it should.

My question is this- should the timing chain guides be able to pivot freely? For example, should I be able to poke my finger down in the head and move the timing chain guides back and forth? Right now, I cannot move the guide at all, even with a decent amount of force from my hand. I am thinking that when we installed the guides, we tightened them too much and now the tensioner cannot move the guide to allow it to pivot and remove the slack from the chain.

I am bummed, but glad I caught it now before the engine is back in. Curious to know your thoughts. The torque spec for the guides is only 12-15 ft lbs I believe, so I am guessing that I over tightened them somewhere along the line. I don't remember if I torqued those specifically or not since this was back in February- I should have torqued everything though. Just want to know if this is a plausible hypothesis. Thanks in advance guys.

Damon

[jspaeth]

So, I think I made a mistake when my friend and I put my engine back together. Basically, I tore it down to the block to install the head gasket, head studs, new timing chain components, etc. With everything for the most part back together this evening, I went to install the timing chain tensioner and the chain still has a lot of slack to it. I tried turning the crank pulley counter clockwise to get it to engage like the FSM suggests, but it still did not gain any tension. When I removed the tensioner, it had extended- meaning that it was exerting force on the timing chain guide as it should.

My question is this- should the timing chain guides be able to pivot freely? For example, should I be able to poke my finger down in the head and move the timing chain guides back and forth? Right now, I cannot move the guide at all, even with a decent amount of force from my hand. I am thinking that when we installed the guides, we tightened them too much and now the tensioner cannot move the guide to allow it to pivot and remove the slack from the chain.

I am bummed, but glad I caught it now before the engine is back in. Curious to know your thoughts. The torque spec for the guides is only 12-15 ft lbs I believe, so I am guessing that I over tightened them somewhere along the line. I don't remember if I torqued those specifically or not since this was back in February- I should have torqued everything though. Just want to know if this is a plausible hypothesis. Thanks in advance guys.

Damon

1) Did the tensioner release yet? (You have to crank it a bit to get the tensioner to release.

2) Do you know that the tensioner operates on oil pressure?

EDIT:

Not sure I read your post correctly.....I think the one timing chain guide can pivot a bit so that the chain is not hitting up against something rigid.

[CamryOnBronze]

I did not know that the tensioner operates on oil pressure, so that is good to know. The guide I am referring to is the one on the intake side of the engine- the one that the tensioner buts up against.

I am thinking that the tensioner released but did not tighten up the chain at all. I preloaded the tensioner before putting it in, and when I pulled it out it was extended. I guess the question is, should I see the slack come out of the chain right away when I put the tensioner in and crank the motor a bit? I am just feeling like something isn't right... :/ and wondered if there should be any play/free movement in the guide on the intake side or not. Thanks for the fast response...

[jspaeth]

When you first put the tensioner in, it is "hooked" and not extended right?

Then you need to crank the engine a bit to get it to release.

I am not sure if I remember just how tight it should be, but the guide shouldn't exactly be flopping around.....

[CamryOnBronze]

Yes, when the tensioner goes in it is "hooked." When it came out, it was extended.

I agree that it shouldn't be flopping around, but I can't get it to budge at all either. I remember when we put the head back on and slid the guides through the head, we had to use a lot of force to get it to budge out of the way enough to clear, which is also contributing to me thinking that the bolt is way too tight and preventing the guide from moving under the tensioner's force.

I'll wait for a few others to chime in, but I am thinking I might pull the head/oil pump back off and retorque everything just to be safe before dropping it back in the car. No sense risking something like this- it's my own fault for not ensuring that every piece was torqued exactly to spec the first time.

[jspaeth]

Yes, when the tensioner goes in it is "hooked." When it came out, it was extended.

I agree that it shouldn't be flopping around, but I can't get it to budge at all either. I remember when we put the head back on and slid the guides through the head, we had to use a lot of force to get it to budge out of the way enough to clear, which is also contributing to me thinking that the bolt is way too tight and preventing the guide from moving under the tensioner's force.

I'll wait for a few others to chime in, but I am thinking I might pull the head/oil pump back off and retorque everything just to be safe before dropping it back in the car. No sense risking something like this- it's my own fault for not ensuring that every piece was torqued exactly to spec the first time.


Sounds like a good plan, better safe than sorry.

[CamryOnBronze]

So I found this thread...

DIY: Rebuilding an SR20DET : SR20DET Forum (rear-drive) (http://forums.nicoclub.com/diy-rebuilding-an-sr20det-t309576.html)

and noticed a couple of interesting things:

1. Priming the oil pump- I did not do this when I installed mine, so I need to do this while I take it apart.

2. This thread details installing the oil pump after the head has already been placed on the engine. I have heard conflicting reports about this- most said that the head should be removed when replacing the oil pump so that the head gasket is not damaged and seals correctly. Here is the explanation from that thread:

Apply the silicon to the block side and head side of the front cover. While you're at it, apply some gasket maker to the front of your headgasket where it seals to the head.

You removed the oil pump drive to allow you to maneuver the front cover on without damaging the headgasket. If you try to install the cover with the pump drive still in place, you run the risk of crumpling the headgasket.

Any experiences with installing the oil pump after the head has already been reinstalled? If this is possible, it would save me a TON of work, since I would only need to removed the upper/lower pans and oil pump in order to prime the pump and check the torque on the timing chain guides.

[CamryOnBronze]

So I'm not sure if this makes sense or not, but here is how far the timing chain tensioner can go into the housing with it preloaded before it hits the guide and stops:

http://img821.imageshack.us/img821/1474/0612001445.jpg

If I tighten it down, the tensioner releases but doesn't seem to take much slack off of the timing chain. Even if I turn the crank pulley, the slack is still present when I stop turning it. I think I am probably going to end up pulling the oil pans and oil pump now to make sure the guides are not over torqued, but I am open to feedback in the mean time.

[CamryOnBronze]

So for future generations of idiots like myself, the problem was that I swapped the bolts for the left and right timing chain guides. The guide on the exhaust side of the motor is static and the guide on the intake side of the motor pivots from the force of the tensioner. I had the wrong bolts on each side, preventing the guide from pivoting like it needed to.

Stupid mistake, but glad I caught it. Hope this thread helps someone out someday. :D Thanks guys.

[conrad_s13.5]

...just saved me!

thank you!

[CamryOnBronze]

Not a problem, I am glad this could help someone else out- it was a stupid mistake for sure!