2.8 Timing Set: Y-Guide

[85_Olds_Ciera]

Anyone know function of Y-Guide between timing chain?

[ForcedFirebird]

Anyone know function of Y-Guide between timing chain?

You mean the tensioner?

[geoffinbc]

It is just a damper in case of any slap that may happen. You need it so don't remove it. If it is broken, which is common with age, then you need to replace it.

[ForcedFirebird]

^^^yeah it's actually a dampener on the 660's.

[85_Olds_Ciera]

It is just a damper in case of any slap that may happen....

I replaced it...sides of it were wore down, and upper right corner was "chipped" off...maybe when OEM Cam Gear was shedding nylon teeth. GM-Denver only had five left in stock...$26.00.

On small-block chevy, you don't see a damper.

I would think centrifugal force would cause chain to go outward...but based upon the wear pattern, the chain does rub on it.

[barrok69]

I wonder how hard it would be to actually make a tensioner. It would probly improve chain durability.

[85_Olds_Ciera]

I wonder how hard it would be to actually make a tensioner. It would probly improve chain durability.

For $26.00 US, I'll pay the price...there may be aftermarket Y-Guides...I never looked....it might be done, but one would have to be familiar with type of rubber compound used, and what shapes are available.

If I didn't toss it, I'll take a photo of it today...

[barrok69]

For $26.00 US, I'll pay the price...there may be aftermarket Y-Guides...I never looked....it might be done, but one would have to be familiar with type of rubber compound used, and what shapes are available.

If I didn't toss it, I'll take a photo of it today...

no i'm talking about an actual tensioner, not a guideplate. something that would maintain chain tension... like the tensioner on the serpentine belt.

[85_Olds_Ciera]

no i'm talking about an actual tensioner, not a guideplate.

1987 3.8 GM had a spring loaded chain tensioner on it...something like this might be converted...but, one might want to know why they (engineers) didn't use a spring loaded tensioner on 2.8 motor....is its "slap" more "violent" during start/stop cycle?

All the guideplate would do is kept it from slapping inward....but on SBC, they don't use them on stock motors...don't know about hot-rod motors (high rev motors).

[ForcedFirebird]

I think it might be an easy mod to make the dampener into a spring loaded version. I'll check them out, have a spare Gen1 and Gen 3 there to look at.

[85_Olds_Ciera]

I think it might be an easy mod to make the dampener into a spring loaded version.

I only know GM-Denver had five in stock...I don't know what that means for GM, or for aftermarket builders.

On mine, the rubberized sides were worn down...I didn't see what held them on...

It's been too cold around here to work on cars, but maybe next week, I'll look for the one I took off.

[geoffinbc]

I replaced it...sides of it were wore down, and upper right corner was "chipped" off...maybe when OEM Cam Gear was shedding nylon teeth. GM-Denver only had five left in stock...$26.00.

On small-block chevy, you don't see a damper.

I would think centrifugal force would cause chain to go outward...but based upon the wear pattern, the chain does rub on it.

You don't see it on a small block because the cam and crank are much closer together. Meaning a much shorter chain.

[85_Olds_Ciera]

Meaning a much shorter chain length between the two gears...agreed.

Chain "slap" increases with longer "free space" (distance) between gears.

On a motorcycle, you can see/hear this chain slapping clearly with a "loose chain."
Never have seen what the chain's "drive side" looks like when in motion...but I suspect it "drifts" in the vertical plane.

But on a motorcycle, most chain motion tends to be an "uniform" motion...whereas with vehicle engines, its more like a continuous "jabbing" motion.

Since both sides were wore, then chain slapping is happening to some degree on both sides.

[85_Olds_Ciera]

I think it might be an easy mod to make the dampener into a spring loaded version.

Here's what a 3.8 (87 era) had below on left side; but, I doubt this could be put on outside loop of chain....timing cover would be in the way.