3100 Timing chain replacment...

[IsaacHayes]

Any tips on replacing the timing chain? Timing and the cam bolt is the only thing I have concern about... Like is there any possible way to damage the cam bolt? What do I use to hold the cam from spinning when tightening back down? Just block the fly wheel again?

Oh and how bad is this slack? (~200,000 miles)

[PCGUY112887]

My first question is why in the world is your timing chain so big? The one on my 3500 was half that thick... like a bike chain. I figured they used the same chain on all of em?

Regardless that's a fair ammount of slack, GM has a spec to it but I would just replace it while your there.

All I did was stuck something through one of the holes in the cam sprocket and turned the bolt till it stuck on something (a casting boss) then torqued the bolt loose. That bolt was on TIGHT on my 3500, had to use a breaker bar. You could block the flywheel as well if you can get to it already.

After that the whole sprocket just comes off, it's keyed to the cam. Pull it off, pull the chain off. When you put it back line the mark on the crank (it's a little dot on one of the sprockets) up with the line on the sprocket (so they point to eachother) and put the new chain back on. Lube the chain up good before you put it on, it will be a bit tricky just gotta kinda put the chain around the top sprocket and guide it onto the lower sprocket while you push the cam sprocket onto the cam, ensuring you keep it lined up.

Tighten bolt back up to spec using the same method as before, no loctite or anything required (GM book says nothing about using anything).

[IsaacHayes]

Cause the 1994 3100 is a beast!!! LOL I think that they changed to a smaller chain sometime but I don't remember the year. Supposedly a different tooth setup that's quieter I think.

When turning the motor over by hand I could hear this noise and it didn't sound good. Now I know it's the chain. Also some links were bulging like the might pop out, but may just be because they were on the edge of the sprocket. It snaps and slaps quite loud.

Yes I can block the flexplate, I had to to get the crank pulley off to take the timing cover off in the first place. The motor is still in the car as you can see.

Ok, so the cam is keyed too. Cool, so just put em back on lined up. Sounds simple. I'll loosen all the rockers just to close the valves just in case I have to rotate it all to line it up.

Thanks

[CNCguy]

My first question is why in the world is your timing chain so big? The one on my 3500 was half that thick... like a bike chain. I figured they used the same chain on all of em?

The old style is considerably larger and I would think also stronger. I snapped a pic of them side by side along with a double roller setup...... huge difference.

[3400-95-Modified]

Not stronger... I used a 94 setup on my old 3400 and it stretched badly quickly...

I thought the same thing but maybe it's the way its designed or something.

I now have the thinner chain on my hybrid and I haven't had a problem yet with the LS6 springs... Only knock I have is from my AC compressor not being fully bolted down.

But yes I would say you need to replace that.

Just hold the flywheel with a screw driver to loosen and tighten the cam bolt, you shouldn't have a problem with that since the direction the motor turns is tightening the bolt... its not like its opposing it.

You should do a whole gear set too since the sprockets are probably worn, and also the center guide should be swapped out. You can get a whole gear chain set, but the center guide I think is separate.

[bszopi]

And as a replacement, I would get one from a dealership. When I did my cam swap several years ago, I installed a set from Cloyes. When I swapped in the 3400, I had a look at the chain in the 3100 and it had more slack in it than the stock one with only a quarter of the miles on it.

[IsaacHayes]

Yeah I already ordered a cloyes.... comes in on tuesday. I have to get this running because the spare car I'm driving has a huge hole in the metal brake line under the center of the car. Just parked it empties the break reservoir. I have no tubing or benders or flaring tools to fix it right now. POS taurus, nothing works on it.

I ordered the timing chain kit, which online shows as the same price as just the cloyes chain.. I don't know what the parts store ordered for sure. It may be right but a lot more than $40.... We'll see I guess.


The crank gear doesn't seem worn, I haven't looked at the cam gear yet. Why would the guide need to be replaced? Doesn't look worn either than I can tell.

[3400-95-Modified]

with that much slack i'm sure there are some groves in the guide. Its just a good idea to replace the whole setup at once.

And Brad, I used a Cloyes chain too in my old 3400 that I just took out, at 60k I think it has quite a bit of slop too...

[IsaacHayes]

Well parts come in today. They ordered the wrong thing. They just got the chain but not gears. So I had them re-order and also got a guide. The chain is the same cost as the chain and gear set!

Will I get an increase in power from having a tight chain? I mean if it's got that much slop is it retarding my timing?

[IsaacHayes]

What do I seal the bolts back up with that go into the coolant passages??

I have some gasket seal stuff #2 but I was told to use silicone... The stock stuff looked white..

[PCGUY112887]

I used a bit of RTV on each side of the timing cover gasket, since the gasket is a crappy paper gasket and someone else suggested using a bit of RTV as they did. Worked fine for me.

For all of the bolts, I used blue threadlocker.

[IsaacHayes]

I used RTV on both sides of the gasket, in the corners, and on the bolts, especially the ones that go into coolant passages.

No leaks so far!

For the chain, I ended up re-using the stock gears, as when I put on the new ones the chain had more slack than when I re-used the old ones. So just a new chain, and dampener. The dampener had a crack and was worn.

The stock dampener was like hard plastic over the metal, I'm guessing it was rubber at one time and got hard over the years? The new one was coated in rubber.

Lots less slack, and no noise when turning the engine over by hand!

Oh and best of all, what I thought was piston slap, or lifter noise on this 200,000 mile 3100, was just the timing chain. This motor is WHISPER QUIET now. The injectors are the loudest thing on the motor!!! It's sweeeet!

[3400-95-Modified]

Whisper quite is over rated...

nothing like hearing the wonderful ping of headers

[IsaacHayes]

Shush!

[3400-95-Modified]

HAHAHA... at least you finally have a real picture of your upper on your motor though Looks nice.