Engine failure from a 20 dollar part!!!

[gnpoweredrail]

Why is it Im reading not to use a tensioner on a double roller timing chain??

Mine failed friday night and destroyed alot of stuff.

How do I know what length chain to buy? Who sells Rollmaster?

So this stupid little part which was fine for over 2 years of abuse in this current engine or over 20 years in another engine in my old car let loose and destroyed the following....
front cover,cam sensor,oil pump,all intake valves,possibly pistons,timing set.


The pictures of metal on the red fender cover is whats left of the metal support in the tensioner..

 

[TurboBob]

its more of a 'damper' than a tensioner....

did you use it on a roller chain or a stock style chain? (as far as I know, you are not supposed to use it with a roller style chain)

Bob

 

[gnpoweredrail]

it was a roller on this engine...and engines past.Ive never had a problem untill now.
I used it because the looseness of the chain.Maybe I had wrong setups without knowing it...but this current setup has been running in a street car before I bought it and then in my sandrail for the last 2 years getting really abused.

 

[bison]

Why is it Im reading not to use a tensioner on a double roller timing chain??

You dont run a tensioner with a double roller because its not designed to run with one. If you run one it will wear out and eventually fail like yours did then the chain will be sloppy from the lack of tensioner and it will jump like yours did and do a lot of damage. There are directions around on choosing the correct set. You need a baseline to start with. Once the gears are installed you push on one side and note the amount the chain moves inward. Its better off a little looser than too tight. When assembling engines you need a few timing sets at hand to get the best fit. If the block hasnt been touched the std chain set will work almost every time. The cam gear failure on your engine was likely progressive. Those cast gears arent too tough and will wear out with more than stock valvetrain components. Id go right to the Engine Works (Rollmaster) sets with a billet cam gear. They are available with different under sizes and have a crank gear in 2* = or - increments for setting the cam timing.

 

[gnpoweredrail]

Well Im pretty sure its been line honed since it has billet caps..
playing with the chain on the gears it seems to be worn out..I can move the chain back and forth a tiny bit on the sprocket.

 

[gnpoweredrail]

Ive always just run straight up on the cam timing...Its a hydraulic roller with pretty stiff ISKY springs so more than likey the chain and gears were worn

 

[TurboBob]

I've been wanting to try the heavy duty stock-style chain with TA Perf's billet gear (and the stock damper).

Does anyone have any DATA on the relative strengths of it vs a rollmaster? (no folklore please, just facts)

Bob

 

[gnpoweredrail]

^^^^x2

 

[bison]

I've been wanting to try the heavy duty stock-style chain with TA Perf's billet gear (and the stock damper).

Does anyone have any DATA on the relative strengths of it vs a rollmaster? (no folklore please, just facts)

Bob

I haven't seem failure of any of either in normal street/strip use. Theoretically the stock style chains should be stronger. If you study the way the links are connected its easier to see why.

 

[gnpoweredrail]

but the nylon wont hold up right?

 

[TurboBob]

no nylon on the heavy duty stock style sets.

B

 

[gnpoweredrail]

oh...will it hold up to a big roller though??

How do I measure what length I need..I dont want to order the wrong one.

 

[ek02]

The stock type chain is available from TA Performance along with the tensioner. They also have Rollmaster sets, as does Full Throttle. I bought a Rollmaster a couple of months ago and I was told that the only oversize now was .005. They used to have them in .002 increments up to .010, but I guess thay are no longer available. I went with the .005 and it fit snug, but did not have to be forced on. My block was line honed. My old Rollmaster had about 1/4 to 5/16 play on the slack side. The new .005 set has very little play. I have run the chains loose with no problems, but I like the snug fit better. In your photos it looks like the intake valves hit the cylinder walls? They look like flat top pistons, but have no valve reliefs. I ran a roller chain with a tensioner for many, many years with no problem. After seeing many posts on the subject, I no longer use one on a V6 unless it is a stock type chain.

 

[gnpoweredrail]

thanks for the info..the pistons are dished JE's.the valves did not hit the cylinder walls.
I too have used the tensioner on double rollers for 20 years..this particular build over 2 now.
The rail gets thrashed a hell of alot harder than you guys do on the street.

 

[ek02]

I looked at the photos again and now I see where the valves hit the raised part of the pistons, not the walls. I just realized they are at TDC. Optical illusion, it could not be old eyes.

 

[gnpoweredrail]

I think the pistons being JE's will be ok with some clean up and buffing the high sharp spots down.

 

[87-WE2]

There's some info in this thread that might be useful.

http://turbobuick.com/forums/threads/timing-chain.381378/

 

[gnpoweredrail]

Anyone have a Rollmaster for sale?? CS7020 is what I need I think. the .005 version

 

[gnpoweredrail]

There's some info in this thread that might be useful.

http://turbobuick.com/forums/threads/timing-chain.381378/

Its funny you posted that...I just read it before I just posted.

 

[ek02]

As long as the ring lands have not been pinched, the pistons will probably be OK after clean up. If you don't plan to tear it all the way down, I would pull the pistons that have been kissed and check them out to be sure.