Installing RCR flywheel with factory GM Bolts

#1
I covered some of my experience with taking off the stock flywheel on my LT4 crate engine with Ken Roberts who has been a great help. I had a plan to install and torque the new flywheel bolts tomorrow based on what I reviewed with Ken. But now that I cleaned the threads in the crank and wiped off some black/charcoal residue I figure I’d throw this out to the forum since I am still not 100% sure.

Being a new builder I appreciate All the help so far. Here is a list of where I am at.

1)loosened and removed the stock LT4 flywheel
2)Oil started pouring out of the bottom two holes,
3)Apparently the engine is filled with oil and when you remove the bottom two holes on the crank shaft which hold the flywheel oil starts coming out,
4)pretty much got oil all over all the threads on the flywheel bolts and crank shaft.
5)Drained the oil and ordered new GM Flywheel bolts
6)So the plan was to clean all the threads in the crank shaft as best I can with brake cleaner and install new bolts.
7)The factory bolts have some type of thread lock on them and are designated as one time use so I bought all new ones.
8)So tonight I cleaned the threads out with Q tips and brake cleaner and there is a black substance on the threads which to me looks like anti-seize. It is definitely not engine oil which is gold-brown. It is more a chacoal color.
9)So now that the threads are clean I am wondering what the best approach is....

A)Install and torque the bolts as-is without applying either blue loctite or anti-seize?
B)Apply blue loctite and install?
C)Apply anti seize and install?

Any guidance would be appreciated. Thanks, Joel

Picture of new stock bolt...
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#2
The new bolts already have the threadllocker on them in stick form. You could chase the threads in the crank with a thread chaser but don’t use a tap.
You could use a pipe cleaner or rifle brush to be more aggressive with the thread cleanup.
 
#3
The new bolts already have the threadllocker on them in stick form. You could chase the threads in the crank with a thread chaser but don’t use a tap.
You could use a pipe cleaner or rifle brush to be more aggressive with the thread cleanup.
Ken, so just clean them as best I can and use nothing on the bolts? What do you think that black/charcoal residue is?
 
#4
That’s probably just the remains of the threadlocker that was contaminated with oil. Were the bolt holes at the 12 o’clock position also the same black colour. Did oil contaminate them as well? Install the bolts dry. No anti seize. I’ll read my C6 Corvette factory shop manual to see what it mentions.
 
#5
Factory manual said to install GM #12345382 threadlocker . Tighten bolts first pass to 22ft/lbs. second pass at 40 degrees. (Torque to yield) This was for a LS7 engine though. The threadlocker is already installed on your bolts so you are good to go.

Make sure the bearing isn't still in the crank. Perhaps now is a good time to install the new bearing in the flywheel.
 
#6
That’s probably just the remains of the threadlocker that was contaminated with oil. Were the bolt holes at the 12 o’clock position also the same black colour. Did oil contaminate them as well? Install the bolts dry. No anti seize. I’ll read my C6 Corvette factory shop manual to see what it mentions.
Thanks Ken, oil contaminated all the bolts. They all had the black residue. I found a thread on LS1tech where they gave the same advice and to not use any threadlock or anti-seize. The more I think about it, it is probably the oil mixed with the blue threadlock and turns this blackish color. Appreciate you fielding all these questions.
 
#8
Poor advice to put them on without threadlocker (LS1tech). Especially when GM pre installs it on the bolts.
WhatI meant to convey is that they have the bolts with the factory thread-lock pre applied and were told the bolts can be installed as-is with no additional thread-lock.
 
#9
Ken,

I followed your advice and picked up a digital copy of the 2016 Corvette service manual. It’s only 7000 pages! I found what I was looking for.

Even though the bolts have that coating on them and are described as torque to yield fasteners. This link has a good explanation of what they are...
https://dannysengineportal.com/torque-to-yield-bolts-what-are-they/

The instructions say to also use threadlocker. So that charcoal color residue must have been the threadlock.

Here is the page right out of the manual. Great to have a definitive answer.


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