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bkrygier 12-03-2003 05:17 AM

chain tensioner wear
While getting ready to install new tensioners I noticed there is a lot of wear on the chain housing. the chains seem to be centered on the rails and on all of the sprockets. Could it be rails were not installed correctly or maybe the engine has been repaired already ?
1983 sc 3.0 engine # 64D5446

Bruno Krygier

Tim Walsh 12-03-2003 05:46 AM

a most interesting situation. I would measure the sprocket depth and see how off if it is (should be less than 0.25mm). With wear like that on your chain tensioner and your housing I would really wonder. The chain ramps guide the chain but they don't set how deep the chain is in the housing.

Doug Zielke 12-03-2003 08:15 AM

There seems to be a lot of sludge on that idler sprocket....wonder what the inside of the motor looks like??

Wayne 962 12-03-2003 02:03 PM

Where is it hitting the housing?


bkrygier 12-03-2003 02:24 PM

It dosn't hit the hhousing , When I turn the motor by hand the chains run straight they are lined up and run right on the center of the chain rails. I am wondering if the tensioner was replaced years ago and that is what did the damage? I would hate to put everything back together not knowing for sure

William Miller 12-05-2003 11:25 AM

I would say it's old dammage, but the wear marks look pretty clean.
This could happen if the sprkets were way out of alignment or a very worn chain and tensioner slopping arround in the case.

aigel 12-05-2003 11:33 PM

My vote goes towards old damage. However, you want to make sure all those shavings that were created aren't in your engine any more!


Wayne 962 12-07-2003 01:51 PM

You said:

"I noticed there is a lot of wear on the chain housing"


"It dosn't hit the housing..."

Two statements that contradict each other?

I guess I don't understand the question or the situation.

My original question could be reworded as "where is the damage to the housing?"


bkrygier 12-07-2003 02:43 PM

Sorry for not being more clear. the wear on the housing is behind the numbers #1 #2 and #3 in the photo. The chain at one time must have been loose and wore into the housing. As much as i can tell now the chain is rides straigt on the chain rails. so I was thinking this was prior damage and maybe had the tensiners put in at one time. I hope this is more clear

smestas 12-09-2003 02:00 AM

I think this might help. Look at wear inside the green circles.

KTL 12-09-2003 10:28 AM

The rails snap into place and are thererfore hard to install wrong.

This could be a cam sprocket not parallel to the intermediate shaft, but that would be a noticeable noise as soon as the motor was started (after a rebuild or cam work) and then shut down to investigate. A situation like this should never arise because some binding/resistance and noise would occur when turning over the motor by hand as you were doing the repair work.

Those spots in the green circles are where the chain bounces off the chain housing and ramp when a tensioner goes down. Otherwise known as the "chain dragged out of a metal garbage can" sound.

If your car isn't making that sound now, i'd have to think that picture is previous damage. Not something happening now.

bkrygier 12-09-2003 04:32 PM

Thank you Keven and everyone else with input. This is what I am thinking also prior damage

jgparker 12-09-2003 06:59 PM

Since the inside of the chain housing is brown from oil stains, and the damage is clean, I would have to conclude the contact might be fresh. Also, the wear on the idler scares me too. Is the inside of the chain worn too? I would check the sprocket alignment very, very carefully before I would blow this symptom off. Every odd behavior is a clue... Don't miss an important one.

bkrygier 12-15-2003 03:39 PM

here is an update on the chain housing wear. It is the left side camshaft sprocket that was installed the same as the right side instead of being reversed with the cup side out

jgparker 12-15-2003 04:12 PM

Good catch BK. In hindsight, I can see that the pulley is backwards in the picture. Looks like your tensioner update is going to turn into a bigger job. (Re-aligning the sprocket, and retiming the cam). You might consider replacing the chain while your at it too... real big job.

Good luck,


KTL 12-15-2003 07:50 PM

My apologies for a bad diagnosis. That wear on the housing is obviously due to what you pointed out as being the left cam gear installed backwards.

Like I said previously, that sound would be very noisy as soon as the motor was started after the work was done. Someone should have shut it down right away and investigated. The sound should have been present turning over the motor while timing cams and setting valve clearances!!!!!!

When the chain doesn't ride parallel, it wears the gear sides fast. Just like jgparker pointed out on the idler gear. This same wear is going to be on the intermediate shaft gears for that side. To fix it right, those int. gears, along with the idler gears should be addressed as well. Worn gears will wear a new chain in short time.

William Miller 12-16-2003 08:58 AM

Can you see in the hole to see if the idler sprokets were installed right?
I can't remember exactly but I think they could be put on backwards too.
Great catch! Now you got me wondering. Do you know where your sprokets are?

Kevin, when I installed my chain ramps I noticed that they can in fact be pushed in too far. Mine didn't exactly "snap" but I could feel it like a detent. I put the first one inn too far and had to pull it back out to the right spot.

BK, where are you goint to go from here? It looked like you saved yorself from a future catastrophe, but I doub't you thought this projects would take you this deep.

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