2G Auto-tensioner specs vs move pin freely

[Buga]

Hello!

Another thread about timing belt, but I believe this hasn't been discussed yet.

I'm replacing timing belt in a 4g63t Eclipse GST 1995' 2G where after following manual instructions and turning crank 6 times + waiting for 15 minutes I'm able to end up within spec, about 4mm for auto tensioner protrusion (using the drill bit method to check the gap) but the grenade pin hole does not align to put the pin back.

So the thing summarize as these 2 cases:

1) If I tension the pulley to end up within tensioner measure spec, (between 3.8mm - 4.5mm) the granade pin won't fit back, holes are misaligned.
2) If I tension the pulley to end up with the grenade pin to move freely, the tensioner is out of spec, it measures less than 3mm.

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In the following pic shows a drillbit of 4mm confirming that measure between tensioner body and tensioner arm is about 4mm, another drill bit of 1,5mm is hanging on the tiny hole only, not going through 3 holes, see next pic.

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In this pic I removed the 4mm drill bit and it shows that holes are misaligned.

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All parts I'm using are OEM, my last guess is that auto tensioner holes are not machined exactly as it were when this manual was wrote.

Oh and I also checked to fully release the tensioner and measured that it extends to 12mm, that confirms it's in spec.

I believe I should just ignore the pin and focus in gap between tensioner body and tensioner arm.

What do you think?

 

[1990TSIAWDTALON]

Here's my take on it and the way I do it everytime, and I build quite a few of these.
Set it with the grenade pin (more compressed than the FSM says).
Here is why. Components wear, belts stretch and that tensioner isn't ever gonna get tighter only looser. I haven't ever had an issue doing it that way. Take it or leave it as its just an opinion, but I feel strongly about it. Either way will work, I will add that. Best of the build to you!
Marty

 

[pauleyman]

Hello!

Another thread about timing belt, but I believe this hasn't been discussed yet.

I'm replacing timing belt in a 4g63t Eclipse GST 1995' 2G where after following manual instructions and turning crank 6 times + waiting for 15 minutes I'm able to end up within spec, about 4mm for auto tensioner protrusion (using the drill bit method to check the gap) but the grenade pin hole does not align to put the pin back.

So the thing summarize as these 2 cases:

1) If I tension the pulley to end up within tensioner measure spec, (between 3.8mm - 4.5mm) the granade pin won't fit back, holes are misaligned.
2) If I tension the pulley to end up with the grenade pin to move freely, the tensioner is out of spec, it measures less than 3mm.

You must be logged in to view this image or video.

In the following pic shows a drillbit of 4mm confirming that measure between tensioner body and tensioner arm is about 4mm, another drill bit of 1,5mm is hanging on the tiny hole only, not going through 3 holes, see next pic.

You must be logged in to view this image or video.

In this pic I removed the 4mm drill bit and it shows that holes are misaligned.

You must be logged in to view this image or video.

All parts I'm using are OEM, my last guess is that auto tensioner holes are not machined exactly as it were when this manual was wrote.

Oh and I also checked to fully release the tensioner and measured that it extends to 12mm, that confirms it's in spec.

I believe I should just ignore the pin and focus in gap between tensioner body and tensioner arm.

What do you think?

This has been a debate for quite some time. The grenade pin method is slightly tighter than oem specs, as Marty stated. Many of us have chosen to use it for the reason stated and because its easy. In my opinion both methods are correct. I use the pin method and have for 20 years or more and countless motors. Use whichever one makes you comfortable.

 

[MindBlowin03]

Another vote for either working fine. The first 10 years of building DSMs I did exactly as the FSM said but the last 15 years I've done the pin method. I've never had an issue with either.

 

[19Eclipse90]

@Buga - what are the (3) numbers cast into tensioner body?

 

[danl]

Make sure the timing tensioner arm does not have a divot worn into it from the tensioner.

 

[chrysler kid]

This has been heavily debated, you can use either method. I set the gap in the arm to the body of the tensioner, others use the pin. Some twisted f*cks on this forum remove the engine from the car and measure the gap with a caliper gauge.

I have been able to hear other dsm with belt tension set too tight, the arm will rattle against the tensioner.

If you really want to get me specific, Kevlar belts have much less flex to them and I use the arm gap, on a non Kevlar belt I will set with the grenade pin as the belt will have a slight stretch over the course of its life as it gets worn in

 

[Buga]

Thank you all for your comments, +10 peace of mind

@Buga - what are the (3) numbers cast into tensioner body?

Hello! It's 587, when I bought it, ~10 years ago I remember I triple checked before ordering it, IIRC there was a change on it during 95' I'm reusing since I barely drive the car, I made about 3k miles in 10 years, crazy now that I think about it. I should drive it more.

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Make sure the timing tensioner arm does not have a divot worn into it from the tensioner.

Good one! that could explain the mismatch between pin and protrusion but the contact surface seems to be just fine, no visible wear.

 

[danl]

The factory grenade pin is a bit smaller in diameter than a drill bit, making it easier to set the pin distance to 0.150" and get a pin through. On the tight side, the main concern is setting it too tight as this can, in some instances, put too much pressure on the oil pump, leading to failure. At 0.150 extension I have never had that issue.

I can tell by how clean your timing side is that you are well organized and pay attention to detail. People like you don't typically have problems. I know it's a stressful setting, but it will be fine. Button it up and enjoy the car!

 

[FIBA M - EC17PSE]

If it is too tight you will hear a whine like a bearing whine.

We all have our ways of doing it but most use the if the pin goes in after 6 rotations it is good. If not adjust from there. Has worked many times and always does

 

[19Eclipse90]

Hello! It's 587, when I bought it, ~10 years ago I remember I triple checked before ordering it, IIRC there was a change on it during 95' I'm reusing since I barely drive the car, I made about 3k miles in 10 years, crazy now that I think about it. I should drive it more.

You’re not alone, then, though we never really did determine “why”. See: What did your do to your DSM today.

Something funny with at least some of the ‘587’ tensioners.

 

[Buga]

You’re not alone, then, though we never really did determine “why”. See: What did your do to your DSM today.

Something funny with at least some of the ‘587’ tensioners.

Thanks awesome!! I'm not alone, that's exactly what I observed, and I totally agree with the comments about the manual, the steps I'm following does not specify any date and even the sketchs of the tensioner does not look like 587 model.

I'm thinking to stick with the 4mm gap, because after reading that I can confirm the hole is closer to the crown in this very specific model. I guess the other tensioner models by using the pin method they end up pretty close to spec (probably lower side ~3.8mm) but not in my case.

I should keep searching for the original one that came with the car from factory just to compare

 

[19Eclipse90]

I'm thinking to stick with the 4mm gap, because after reading that I can confirm the hole is closer to the crown in this very specific model. I guess the other tensioner models by using the pin method they end up pretty close to spec (probably lower side ~3.8mm) but not in my case.

That’s what I would do.

Extra thoughts on this, all speculative - obviously, the grenade pin trick worked for 1G vehicles. In the 1995 model, the tensioner design changed and, with the 587 tensioner, so did the grenade pin trick.

But since it was well known from the 1Gs, complaints from the service techs made their way upstream, forcing a tensioner redesign to maintain that easier method of setting proper tension?

I know there’s the timing cover difference as well but it would have been easy to update the timing cover on all the cars with the 587 tensioner at the same time. Idk. Thinking out loud.

 

[HyeToki]

I followed the recommended specifications for the tensioner during my engine rebuild, and the results have been excellent. While initially referencing the manual, I observed that the 1G tensioner rotates clockwise (with the two holes positioned on top), which increases belt tension when the bolt is tightened.

In contrast, the 2G tensioner rotates counterclockwise (with the two holes positioned on the bottom), which results in a loosening effect when tightened. Due to this inconsistency, I chose to rely on the specified guidelines rather than the manual’s approach, and the outcome was successful.

Good Luck!

 

[1990TSIAWDTALON]

Yes, the 2g tensioner is always snake eyes down and 1g snake eyes up. They will touch the water pump if done the wrong way.