.0032 Main Bearing Clearance?
KCS, the pump TMS sent with this motor is the Moroso 22120. It does say it’s a high volume pump.
What would you guess oil pressure would be with the 20w50 VR 1 that Thompson recommends?
And as it was mentioned that the motor would have to live its life on 50w, is there anything inherently wrong with that? Again, I’m trying to give Thompson the benefit of the doubt here, I can’t find any negative press with them, but nor do I have any idea why the motor was set up this way...
What would you guess oil pressure would be with the 20w50 VR 1 that Thompson recommends?
And as it was mentioned that the motor would have to live its life on 50w, is there anything inherently wrong with that? Again, I’m trying to give Thompson the benefit of the doubt here, I can’t find any negative press with them, but nor do I have any idea why the motor was set up this way...
It’s probably not ideal, but there really isn’t anything wrong with it. Some of the 4” stroker cranks had a tendency to flex a little under abuse. You would see wear on the #2 and 4 mains, and on the thrust bearing faces. Being a nitrous engine, they’re probably running that loose to avoid the bearing wear. I wouldn’t really stress about it.
I’ve never used the Moroso, so I couldn’t make an educated guess, but I would say about 30-40psi hot idle and then whatever the relief spring is set for at WOT.
It’s probably not ideal, but there really isn’t anything wrong with it. Some of the 4” stroker cranks had a tendency to flex a little under abuse. You would see wear on the #2 and 4 mains, and on the thrust bearing faces. Being a nitrous engine, they’re probably running that loose to avoid the bearing wear. I wouldn’t really stress about it.
It’s probably not ideal, but there really isn’t anything wrong with it. Some of the 4” stroker cranks had a tendency to flex a little under abuse. You would see wear on the #2 and 4 mains, and on the thrust bearing faces. Being a nitrous engine, they’re probably running that loose to avoid the bearing wear. I wouldn’t really stress about it.
So, if my understanding is correct on what to take away from this thread, the bearing clearances won't hurt anything as long as pump and oil weight are correct for the build. As far as power and longevity it shouldn't give me any issues at all?
I don't imagine anyone see's any point in rolling in tighter bearings at this point, but rather just run it as it is?
Launching!
Joined: Mar 2019
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Now that you mention that, I do remember Thompson saying something about that flex or oscillation, which to your point, may be why they opened things up a bit.
So, if my understanding is correct on what to take away from this thread, the bearing clearances won't hurt anything as long as pump and oil weight are correct for the build. As far as power and longevity it shouldn't give me any issues at all?
I don't imagine anyone see's any point in rolling in tighter bearings at this point, but rather just run it as it is?
So, if my understanding is correct on what to take away from this thread, the bearing clearances won't hurt anything as long as pump and oil weight are correct for the build. As far as power and longevity it shouldn't give me any issues at all?
I don't imagine anyone see's any point in rolling in tighter bearings at this point, but rather just run it as it is?
Another note is the high temp, high shear (HTHS) rating of the oil is more of an indicator of oil film thickness in the bearings, and while the oil grades require a minimum HTHS for each grade, they don't have a maximum. The new Corvette's recommend M1 ESP 0w-40 has a HTHS of 3.53 cP which is actually lower than the M1 ESP 5w-30 at 3.58 cP. Many high end PAO/POE oils like Driven LS30 5w-30 and Red Line HP 5w-30 have HTHS ratings in the 3.5-3.7 range, well into 40 grade territory, but flow like a 30 grade.
I would check with the lifter manufacturer to see what oil grade is acceptable for them. People sometimes don't consider the lifter clearances are set around an intended oil weight as well.
I chose 5w40 synthetic Amazon basics or shetl rotella t6 5w40 for a good all around.
