1996 Collector Edition Corvette

[MostMint]

If you choose to punt, maybe a bit more research on how long these typically go, what is the deflection on a new chain? Will it take another 100k miles to get to the 3/8" limit? Maybe it is only 20% of the way from factory spec to out of spec.

Seeing as how you decided it needed a new harmonic balancer, punting does not make sense to me assuming it doesn't have 50k left in it.

There have to be some YouTube videos or other internet content on how to change that drive gear for the water pump. You already have it apart. If that is too much could you not have someone do that work? - assuming the part that has the gear is part of the water pump or timing cover housing.

[wxo]

Regarding the timing chain spec for an C4 LT1/LT4, not even my shop manual had any statement of tolerance in it. The internet was full of advice, but nothing specific that I trust enough to act upon. That's why I called Cloyes tech line. His verbal spec of 3/8" was the best I could find. He stated that at 5/16" deflection, he would reuse the original. So I have that to fall back on. Pursuing the Cloyes race timing set looked attractive to me because of its closer tolerances and better metallurgy than stock. I'm also unsettled about the fact that this timing set is listed nowhere for the LT4 engine, only the LT1. Again, I have the tech's word that "it will fit". If I get it installed and fire it up and find that something is amiss in this area, I'm faced with starting from the beginning in this adventure. All these things considered, I've made no decision yet. At this point, I plan to take a step by step approach to installing the new timing set until and unless I get to a point where I can't go back to the original setup and must make a decision.

[Maverick]

I suggest a test fit of the new chain. I predict it will have a lot less slack than the old one.

[MostMint]

If the tech at Cloyes said he would reuse it, I would jut put it back in there.

Considering you will want to come to your own decision about this, here is some info on the differences between LT1 and LT4:

https://www.lt1howto.com/articles/lt4faq.htm

https://www.grandsportregistry.com/lt1vslt4.htm#CHAIN

Quick glance tells me there were quite a few differences but not major structural block components.

[wxo]

I suggest a test fit of the new chain. I predict it will have a lot less slack than the old one.

Here are reviews of the other timing set recommended by the Cloyes rep: https://www.summitracing.com/parts/clo-c-3039/reviews. Note the comments about timing chain slack. In addition to this, Jeff Creech, who dyno'ed the Vette, made a similar statement..."That's within range, and the new one you install might have similar slack."

[GMJohnny]

WXO… My two cents…. I live in the equipment world. Many times we replace what needs
to be replaced and move on. We do it with our tractor trailers, manlifts, excavators, skid steers,
etc.. I appreciate the “I’m looking right at it, so I should change it” mentality, but that could
lead you to a frame off restoration if you can’t find a stopping place. I’d say use what’s there
if it’s in spec. This is a pleasure car, not a daily driver or race car you’re going to beat on
weekly. The odds of you putting enough miles on it to wear it out are slim. Slap ‘er together
and get ‘er on the road!

GM

[wxo]

Thanks for all your comments, guys. They were, as I expected from this bunch, thought-provoking and useful. I'm shipping the new timing set back to Amazon this morning. One deciding factor was the water pump gear. It's installation requires pressing off a bearing and then pressing off the original gear and then pressing on the new gear and the bearing. That's my point of no return in the decision. I'm comfortable with reusing the original timing set as it is. The K.I.S.S principle also influenced my decision. I do, however, plan to keep an eye out on eBay for an OEM timing set or chain, if it should pop up. I'd like to have one to set aside just in case.

[wxo]

I spend an hour or two today cleaning up the buggered keyway on the crank snout. It appears that the new woodruff key fits satisfactorily. Next is the crank sprocket followed by the rest of the timing set.

I'm editing in some info about the special woodruf key required here. I found this one on eBay from a guy in Florida (Nook & Tranny).

CRANK KEYS
There is no keyway in the hub for the harmonic balancer, so GM used a special cutback key that was flush with the front of the timing gear on the 1992-’95 engines. It’s p/n 10128303.

*When the crank position sensor was added in 1996 for OBD II, the cutback area on
the key was shortened so it stuck out far enough (about 0.100") beyond the face of
the timing gear to index the notched disc that was used for the crank position
sensor. GM p/n 12550096

[wxo]

My decision to go with the original timing set lasted until I noticed that a previous jackleg had incorrectly pressed on the crank sprocket. It was not all the way seated on the crankshaft leaving the two sprockets out of alignment to a small degree. This also caused the damage to the woodruff key I had to deal with. Now I no longer trusted the old timing chain. The only other timing set that was specified for the LT4 is this one that I ordered from Summit https://www.summitracing.com/parts/CLO-9-3651X3. This kit requires changing to a water pump drive shaft gear that matches the metallurgy of the new sprocket set. Once I got the w/p drive shaft back from the machine shop, I was ready to move forward again.

The old chain looks like a bicycle chain in comparison

Look, Ma, no slack.

[Basement Paul]

That thing is a monster, ready for many redline runs!

-BP

[wxo]

Maverick came over yesterday for a technical conference. The topic of discussion was the seeming lack of enough clearance between the "monster chain" and the w/p drive gear and also between the chain and the reluctor. We used feeler gauges to determine that there was a bit over .020" which seemed to us to be enough. To further solidify our thinking, I called Cloyes tech support and learned that .020" is enough. Whew! I really didn't want to take all that mess apart again. Furthermore, after getting everything bolted up and seeing virtually no slack in the chain, I felt vindicated in my decision to go with the new timing set. The old chain had 5/16" of slack. I just hope this variance from stock doesn't precipitate any new problems.

[wxo]

On May 7th, I posted this and IT'S WRONG:
"Just posting this for future reference. I learned from installing the timing cover that the seals in the cover are made from two different materials. The top two seals are Teflon/PTFE and are supposed to be installed DRY...no lube whatsoever on the seal or shaft. The crank seal is rubber and lube must be used on both the crankshaft snout and the seal before installation."

Since I'm replacing the seals and gasket again on this timing cover, I was unsure, again, on which seals should not be lubed so I called FelPro tech support. I learned that the top seal on the timing cover is Viton (not Teflon as I previously stated). It should be lubed.
The middle seal (for the Opti-Spark) is Teflon/PTFE and IT SHOULD NOT BE LUBRICATED.
The lower seal (crankshaft) should be lubed.

[wxo]

I have finally overcome the latest significant hurdle. This one, of all the trials of my patience, may have been the worst. The oil pan installation is complete! I was able to remove the pan by rotating the crank so that the front counterweight is at the 12 o'clock position. It came out because I didn't care about damaging the oil pan gasket. It's another story when you need to work the pan back in with a brand new Fel-Pro one piece gasket in place on the pan. I finally resigned myself to raising the engine to get enough room. Another issue was holding the gasket in place while maneuvering the pan into place. I finally used binder clips to secure it and they did the trick.

[TireSmoker]

I love the binder clip solution!

-Dave

[Basement Paul]

Where there's a will, there's a way. Good work!

-BP