All double rollers are not created equal

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David Dickerson

Stickler
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Purchased a timing chain tensioner from Mancini Racing for a 360 magnum stroker build. Also purchased a mopar performance double roller chain from Jegs. I have read a few horror stories about the plastic getting eaten up on the chain tensioner due to either poor quality of the plastic or the shape of the chain. I looked at the chain on my 340, and the top edge of the chain links are flat and smooth. I believe it's an Edelbrock chain. The mopar chain is more like a bicycle chain with hills and valleys. Should I have any concern about using this combo? Wondering if that shape will wear grooves in the plastic. Due to the mediocre chain oiling abilities of this engine, I want to make sure this unit will last. This car won't see a lot of miles put on it, so maybe I shouldn't be worrying about it. Mancini sells it as a set with the same chain as I purchased. They should know what they are doing.
 
I wouldn't buy anything labeled Mopar Performance now. Not unless it's NOS from at least 25 years ago.
 
That doesn't really answer my question. Should I take the chain off the 340 which has about 1500 miles on it and switch it with the other one? I purchased that one 20 years ago. Maybe that's better quality. Possibly made in the US. HaHa
 
That doesn't really answer my question. Should I take the chain off the 340 which has about 1500 miles on it and switch it with the other one? I purchased that one 20 years ago. Maybe that's better quality. Possibly made in the US. HaHa
How in the WORLD would any of us know? You've posted zero pictures for us to compare anything to. I'm not going to advise you based on text. That's not fair to you.
 
Well here you go.

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I think he is worried about the plastic on the tensioner being eaten up by the bottom chain versus the smoother chain.
 
What will you do for camshaft timing if you use the older chain?
 
someone here mentioned that the plastic on the tensioner will wear until the rollers start to contact the plastic. makes sense. i would just run it if if it is already setup...
 
If it was me I would remove the chain and deburr/smooth all the exterior surfaces. The exterior surfaces have no effect on timing since the chain wear occurs on the inner part (critical part) of the chain.
 
someone here mentioned that the plastic on the tensioner will wear until the rollers start to contact the plastic. makes sense. i would just run it if if it is already setup...
That certainly sounds right. My concern would be about the plastic that wears down until that point. Going right into the oil pump. I've actually torn down several engines .....mostly 3.9s that came with tensioners and never seen one that was worn badly. Then, you get online and read all kinda horror stories......even still I've never SEEN where anybody ever posted one that was torn up. Not one.
 
Toss the tensioner and get a "True roller chain" Not a "roller chain" Big difference. If you can't spin the individual rollers the chain is garbage.
Many guys use the tensioner. The tensioner was designed to use with the V6 engines in the late 80's due to the cam tunnel and the crank bore being out of spec. It was a cheap fix for bad machine work. I won't use them . Why put pressure on a tight chain to give it more tension just to promote stretch. But to each his own.

You can see by your pictures both of you chains are to long. When you can see the slack you will have issues. Get a new chain. You only get what you pay for.


Roller Timing Chains

Roller timing chains have been available since the 1960s. The chains have a semi-floating tube that covers the chain links, allowing the chain to literally roll over the gear teeth. This helps reduce friction and chain stretch.

There are two types of roller timing chains available. The single roller chain is much like the chain on a bicycle—the links or side plates of the chain pass over and around a single set of teeth in each gear. A double roller chain is exactly what the name implies—gears with dual sets of teeth with a chain link for each set. Many late model OE engines, like GM’s LS-series V8s, have a single roller timing chain. A single roller is also ideal for most high performance street engines. When you get way up in the horsepower and rpm strata where big lift cams and very high valve spring pressures come into play, a double roller chain can better control harmonic vibration at the cost of a little additional weight. That means more stable cam timing in the engine where even a little deviation can cost horsepower.

A variant of the roller chain is the “true roller.” This chain has pins or rollers that actually spin as they ride over the gear teeth. This further reduces friction compared to standard roller chains with rollers or pins that are fixed in place. You can get a true roller chain in single or double roller versions.

Some roller timing chain sets are manufactured with larger than stock pins. These are typically found in standard roller chains. This design yields a stronger, more durable chain, but adds more friction than a true roller.

Roller timing sets with iron cam gears have wear issues on iron engine blocks. Most engine builders machine the backside of the cam gear or the block area surrounding the cam nose to accept a bushing or a Torrington bearing. This prevents galling between the cam gear and the block. Many roller chain sets have steel gears to eliminate the problem altogether.

Another issue with a roller chain setup is the “chordal action,” a whipping motion that happens when the chain turns on the gear teeth. That whipping motion can literally turn the chain into an “S” shape. Chordal action can weaken the chain and also negatively affect valve timing, ignition timing, and mechanical oil and fuel pumps. That’s why it’s important to check the timing chain on regularly. If it’s tired, replace it.

That’s the short course on timing chains. If you’re planning to build a new engine, rebuild an old one, or simply replace a worn-out timing set, you now have a better idea of what chain will provide the performance you require.

This true roller chain below was on this race motor for 8 years .Its still tight and I'll reuse it on a street motor.

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That certainly sounds right. My concern would be about the plastic that wears down until that point. Going right into the oil pump. I've actually torn down several engines .....mostly 3.9s that came with tensioners and never seen one that was worn badly. Then, you get online and read all kinda horror stories......even still I've never SEEN where anybody ever posted one that was torn up. Not one.
More then likely they are ashamed to . Or they think the groves wore in the plastic are normal. Some of these tensioners after installed are still on the engines so how would anyone know.
 
The chain tensioner should be used with a silent chain, (link chain) only. This is an all new set-up install maybe three years ago, you make the choice.

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These Tensioners are only to be used with a cordial link chain as described by mopar. Otherwise the tensioners cause vibration and excessive wear. This is the info from a mopar article where I copied these pictures from.

018-hughes-engines-cloyes-timing-chain-tensioner-mopar-silent-link.jpg

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These Tensioners are only to be used with a cordial link chain as described by mopar. Otherwise the tensioners cause vibration and excessive wear. This is the info from a mopar article where I copied these pictures from.

View attachment 1715862091
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That's pretty strange considering every 3.9 V6 I've ever torn down that was original had a tensioner and a factory installed double row chain.
 
The chain tensioner should be used with a silent chain, (link chain) only. This is an all new set-up install maybe three years ago, you make the choice.

View attachment 1715862088
...and see that's the incorrect type chain, too. The links should be straight, like the original double roller in the OP's post. Then I don't think there'd be an issue.
 
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