Where did the upper half of my timing belt tensioner go?

[forcefed86]

Well I dropped the pan today because I had some fine metal in the oil filter. . Found a little allen head flush screw in the pan. Apparently this is all that is left of the timing belt tensioner?

Stuck my hand up in the front cover and the little plastic wear tab that presses against the chain is completely gone? Just a bear metal spring about the width of a paper clip pressing against the timing chain for tension now. That is where all the metal was coming from.

Dropped all the caps and all of them looked good. Looks like some material went through the #3 main very edge of the bearing is a little chewed up. But the rest of the bearings on the rods and mains all looked pretty good. I'll install all new bearings of course.

Any idea what could cause the tensioner to wear down to nothing? I don't see a way around pulling the whole front cover off to fix it unfortunately. Are their any tricks to replacing it without pulling the cover?

Thanks!

 

[TurboBob]

what kind of chain are you running?

B

 

[forcefed86]

I had read that the double rollers tear up the tensioners. I thought I was just running the factory type chain. I ordered the summit rebuild kit and it came with it. Looking at the summit site now though, the rebuild kits don't come with timing chains... Strange stuff.

I suppose I could have had a brain fart and ran it with a double roller. Any way to easily see up through the bottom of the pan? Can I measure the width of the chain or something? What shoudl the factory width chain be?

Thanks!

 

[bison]

Replace the chain and don't run a tensioner and consider yourself lucky the chain didn't jump a few teeth.

 

[forcefed86]

Pretty sure I read into this when I built the motor last winter. Could have sworn I went with the factory timing chain set and tensioner because I heard the double rollers all had to much slack.

I'd like to verify what chain I have before tearing into it. I think I may have an older double roller that was on my old motor. I'm assuming the OEM chain would be roughly half the thickness? If I have a double roller why bother tearing into it? Couldn't I just pull the spring and call it good? I'm not seeing any damage to the chain really.I split my filter after every race. And I don't really put many street miles on the car, just to and from the track.

 

[ek02]

You should be able to see the crank gear and chain with the pan off. The double roller will have 2 sets of teeth across the crank gear and the chain will look like 2 bicycle chains. The factory gear will have solid teeth across the whole gear. I have run double rollers with tensioners many times with no problems, but I do not use the tensioners anymore after hearing about the rubber ending up in the pan. The double rollers do have a lot of slop, but the drive side is under tension when the engine is running and does not seem to cause problems. I spin mine to 6500 with billet gears regularly with no problems.

 

[haywire4130]

if you remove the cam sensor you can peek in at an angle with a flashlight and see it. the stock chain is smooth on the backside and the double roller (like said above) is like 2 bicycle chains

 

[forcefed86]

Thanks for the tip. I think I can see everything with the pan removed. It has chain texture on both sides. Pretty sure it's a double roller. Doh! Rotating the motor by hand I don't se any damage to the chain. And I know the plastic wear tab was there last time I had the pan off about 30 miles ago. I think I'll replace all the bearings and pull or clip the spring out.

Thanks all...

 

[forcefed86]

So after comparing some pictures online the back side of the chain is "smooth". Not sure why the tensioner ate itself. I was able to get some needle nose vide grips up in the cover and bend tensioner tab 90* so its no where near the chain now. Chain feels really loose to me. Also I don't see 2 sets of teeth. I see one large tooth.

To make things more confusing... I looked at my old summit order and it states its a Comp Cam PN 3226. Summit calls this out as a double roller in the cam package. But if you look it up individually it says nothign about being a double roller and says "factory replacement"?

This is an exact picture of my timing set. How is this a double roller?

Buick,Olds,Pontiac V6 Timing Chain Set



My chain looks like this one... (excuse the wang shape, not my image)

 

[Scott Atk]

Pull the cover, you said the tensioner is destroyed and the chain feels "really loose" Why are you trying to figure out a way to look at it without pulling the cover?

 

[forcefed86]

From what I’ve read double rollers do feel “loose”. Unfortunately “loose” isn’t a spec so I’m trying to find such a thing before pulling the cover for nothing. The engine has 1500 miles on it if that, and it’s a pain to pull the cover. If the play in the chain is “normal” why pull it? I’m sure some would pull the whole motor apart if a tensioner already went through it. I wish I had that kind of free time and money. This is a cheap motor on a cheap rebuild. There comes a point when throwing more money and time at it is no longer justified IMO.

 

[pacecarta]

btw the little allen screw (plug) fell out of the top of the aftermarket timing cover

 

[forcefed86]

Could you show me what you are talking about? I don't recall one? I was thinking it was some sort of backing on the tensioner? I wasn't aware I had an after market timing cover?

 

[chopped39]

From what I’ve read double rollers do feel “loose”. Unfortunately “loose” isn’t a spec so I’m trying to find such a thing before pulling the cover for nothing. The engine has 1500 miles on it if that, and it’s a pain to pull the cover. If the play in the chain is “normal” why pull it? I’m sure some would pull the whole motor apart if a tensioner already went through it. I wish I had that kind of free time and money. This is a cheap motor on a cheap rebuild. There comes a point when throwing more money and time at it is no longer justified IMO.

Is there steel caps installed on this block? Was block linebored? If so the chain will be looser than normal (crank closer to cam) need a shorter chain. even if you get a double roller it has to be shorter if caps have been done. Pull the cover and install a double roller and be done with it. Its cheap insurance.

 

[forcefed86]

Not it's a factory original block all STD never been to a machine shop

 

[ek02]

That sure looks like a stock type chain. Without the tensioner, any chain including a double roller will have slop in it. You probably should go ahead and put a double roller in it and sleep well at night. I have never tried a tighter chain designed for a line bored block in a standard block, but it may work better. The extra slop without a tensioner has always bothered me, but it's hard to argue with the success everyone seems to have with the double roller and no tensioner. Pulling the front cover is painfull, but less painfull than bent valves if the chain fails.

 

[forcefed86]

Guess I wasn't crazy when installing the tensioner.

So even though Jegs tells me this is a double roller... (if you click overview) I finally got an answer back from comp cams (a week later) and they tell me it isn't a double roller. So not only did I get ripped off... (cam kit claimed it came with a double roller) I now get to tear it apart. yay!

So my question would be why did it get torn up in the first place?

Comp Cams 3226 Comp Cams Timing Chains

On a side note I was looking at my LS1 today (40k miles) . It is not a double roller and had a full 1/2" of deflection on both sides. (no tensioner) This is considered normal per the FRM.

Something like an adjustable tensioner installed from the outside of the timing cover sure would be easier!