Ideal Bearing Clearance
 

I am building a pair of 496 strokers and I want to make sure the machine shop and I are on the same page. My last build was two years ago and I did not right down the clearances or lost the papers.

Anyway,, from my memory mains 1-4 .0025 to .003 thrust bearing .003 .00035

Rods .0025 to .003

Is this correct??

I don’t want to get everything home and find out they are way to tight.

Those figures will work just fine.
Eddie

Hey Jim,
Sounds like you got i. I always seem to end up with a little more clearence however I always figure with my boat engines running a little cooler having a little extra clearence won't hurt anything. That way the metal shaving flush right on through nicely. LOL........

That's great your building 496's. I just completed mine this past fall. I'm really excited to see how they perform when the weather warms up this spring. I remember back in the late 80's, early 90's if you had 496's you were the ****. Now I look at these huge 600 plus CI and 34 plus pitch props make me feel left out. I'm still happy with what I have though. I still have way less into my boat than my house. Gellner worked with me on my combo along with custom grind cams that sound pretty wicked. I plan to run one of the engines down to his place to strap on the dyno within the next few weeks. Just need to get year end caught up for the acct. first.

How did you make out on your heads?

take care for now.
John

1-4 Mains .0028- .0031, thrust .0035-.0038 Note: make shure you have the oil pump bolted down and torqued or your reading will be incorrect on the thrust.
Rods .0025- .0027 I always try to keep the rods at .0025-.0026.These clearences can change a little if running thinner oil.
I would also insure that the main and rod journals are not out of round and that the mains are true along with the rod ends.
Hope you have a bore gauge and 2-3" mic. Plastic gauge isn't an option.
Mark

A good general guideline is .001" clearance/inch of bore or shaft diameter as a min. Therefore, .0023 - .0025 on the rods, .0028 - .0032 on the mains. Up to .0035 on the rear main bearing. .006-.010 on the thrust bearing with the crank forced forward.