Timing Chain Tensioner 318/360

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Musclecar

Musclecar

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How many have heard of using a timing chain tensioner on a 318-360? A buddy of mine turned me on to this trick. Seems when you rebuild an engine, within 50 miles, you have timing chain slop. A timing chain tensioner from a mid 90's Dakota V6 is a direct bolt in improvement for the 318/360 engine. The tensioner plate replaces the camshaft retainer plate, and is very easy to install. See the pics.
 

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Hi, yes, it´s a direct fit without modification, not a bad idea! I put one on mine, was around 40 bucks.

Michael
 
Yeah, it's such a direct bolt on that Mopar Performance offers an HP piece especially for the V6 and small block.
 
I have a rather unpopular opinion on that item, so flame away.

It is nice and all, and was made for 3.9 v6 because of the inherent problems with that motor. It was not designed as a v6, it was a quick solution to the lack of a v6 in the line, by dropping two cylinders from the LA motor. The 3.9 had more harmonics and vibrations than the Supremes.

But if you look how a timing chain works, one side is a tension side (cam drag/pull loads the crank) and the slack side (chain returning from crank to cam).
In my opinion there should be no cam timing variation that is worth the added friction from the chain tensioner on properly built LA motor.

I may be wrong, but that is how I feel on the subject.
 
I have been using them for well over 10 years now. Every single SB that leaves my shop gets one. I have seen a difference in the timing using these, and I see no reason not to use one.

Added friction? None at all.
 
So are you saying the chain doesn't rub on the tensioner? If it does, it adds friction.

Why did Mother Mopar put these on v6s, did they ever put them on v8s?
 
I agree that there is only one direction of "pull" on the chain. But timing will vary because if you've turned a few engines by hand you can feel the drag when a spring or springs opposes the valvetrain. Combine that with the crank flexing torsionally (which they all do to an extent) and the steady "pull" isnt steady. At higher roms this can cause the timing to fluxuate and as a chain streches (again, they all do that too) it get's worse. So for me, it's just a way to extend the service life of a timing set and help stabilize the timing for $30.

I'll add as far as drag goes, a rope rear main (also a favorite of mine) adds a ton of drag. the tensioner has none discernable by turning it.
 
moper said:
I agree that there is only one direction of "pull" on the chain. But timing will vary because if you've turned a few engines by hand you can feel the drag when a spring or springs opposes the valvetrain. Combine that with the crank flexing torsionally (which they all do to an extent) and the steady "pull" isnt steady. At higher roms this can cause the timing to fluxuate and as a chain streches (again, they all do that too) it get's worse. So for me, it's just a way to extend the service life of a timing set and help stabilize the timing for $30.

I'll add as far as drag goes, a rope rear main (also a favorite of mine) adds a ton of drag. the tensioner has none discernable by turning it.
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sold me,thanks
 
bad440 said:
sold me,thanks
Click to expand...

Same here, I had never used one for the reasons I mentioned, but I just ordered one for the 360 I have on the stand. I am here to learn, maybe I will see some improvement that justifies it.
 
The drag/friction is so minimal, you wont loose any power. But you will gian power by keeping the timing of the cam and dist more stable. For the money, its a great item.

If you use a slash sheild for the front seal, you may have to trim a corner of the tensioner to clear it, no big deal.
 
So far so good!
 

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All the old Datsun "L" series inline sixes used timing chain tensioners that were preloaded with a piston and plunger assembly that was fed STRAIGHT from the main bearings and pressed against the timing chain to keep it tight. Only drawback was, as the engine aged and oil pressure dropped, they were prone to jump time. But even with a tensioner aided with oil pressure, there was little to no friction on the chain.
 
MRL Performance said:
The drag/friction is so minimal, you wont loose any power. But you will gian power by keeping the timing of the cam and dist more stable. For the money, its a great item.

If you use a slash sheild for the front seal, you may have to trim a corner of the tensioner to clear it, no big deal.
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I had always viewed them as a bandaid on the 3.9, as the only time I ever saw one on a Mopar I have taken apart, was on the 3.9 that was in my Dakota.

I picked up a real low mile 91 360 last Saturday, so I am going to put one on it.
 
What is pushing the tensioner into the chain, I can't tell by the picture.
Is it using oil pressure or a spring?

onig
 
The owner of Milodon pointed out to me that the Mopar small block motors have one of the longest cam to crank centerlines of all V-8's! The longer that distance, the more chance of stretch. Mopar small blocks are notorious for loose chains.

One reason I heard for the factory tensioner was to reduce timing chain noise that custormers complained about.

I installed a real nice Rollmaster timing set on my new motor. It felt real tight. Then we degreed the cam. THEN we added the tensioner and degreed the cam again... ONE degree difference with the tensioner!

One degree might not sound like much, but that was a brand new high quality chain.
 
onig said:
What is pushing the tensioner into the chain, I can't tell by the picture.
Is it using oil pressure or a spring?

onig
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It´s using a spring, leaf spring type under the plastic part in the left (see pictures).

Michael
 
what engines can this be pulled off of? Do newer magnum V8's and 6's have them? Id rather get one from the wrecking yard then spend 40 bucks on one from the dealer
 
I originally had one on my stroker, but when I had Brian at IMM (ou812), he recommended against using one. If I remember right, I think he said on high performance engines, it will just eat up the block on the tensioner, than all that plastic ends up in the oil pan/pick-up/filter/etc.
 
mshred said:
what engines can this be pulled off of? Do newer magnum V8's and 6's have them? Id rather get one from the wrecking yard then spend 40 bucks on one from the dealer
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It's not the type of item I'd reuse, but I suppose you could try. They come with a pin installed that holds the tensioner away from the chain. You pull the pin before you button things up & it allows the tensioner shoe to press against the chain. Not sure how hard it would be to try to back one up & put some kind of pin in it so you could reinstall it.
 
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