I just put the crank in my 416 and checked endplay - I have .002". I know factory spec is .002" -.007" but clearly I need some more. I have the dial indicator set up perpendicular to the crank snout on a magnetic base and I pried on the crank throws with a long screwdriver. I pried at a few different points front to back.

Next, I smacked the crank back and forth with a dead blow several times to try and seat it but it's still the same .002".

So looks like the crank needs to come out. Then what? What is the best procedure here? I read in the small block stroker engines book that you take the crank out and run the thrust bearing ends across some emery paper to get some more clearance. OK to do it this way?

It actually looks like this may have already been done by the machine shop before I got it back; they align bored it. He didn't say what the thrust clearance was and I forgot to ask but it must have been close to what I am getting.

So can I go with the procedure that's in the book? Not drilling the caps or anything like that.

Thanks,

Greg

Check the endplay with out #3 cap in place. There is a good possibility that when they did the align bore, they didn't get the cap cut square. If it gets better with the cap off, that's the problem.

Hmmm - everything was pretty much dead nuts when I was checking clearances with a dial gauge. Seems odd that it would be the cap itself, he didn't have to cut a whole lot, maybe a few thousandths.

Guess I can check it though, I likely have to take the crank out anyway.

I've put several smallblocks together at .003" , I would run it.

The clearances will be ok, because it was honed to size. If the cap was cut out of square when prepping for the honing process, then the flange area of the cap may not be perpendicular to the bearing bore. It doesn't take much to close up a few thousandths of endplay.

I guess that makes sense, didn't really think about it like that. But, I still think an out of square cap is the less likely cause for now.

It might not be, but I thought I'd mention it since I had it happen to me once. Checking without the cap will tell for sure.

It can still change from crush, and the housing bore size affects that. If it's all square and you've knocked the crank home from the rear as a normal assembly with the cap snug and you still don't have enough, you can do this.

Get something that's ground flat, granite, ect. Take some wet 400, or 600. Put the paper on the ground surface. Take both sides of the thrust bearing and place them together as they go in the motor with the front side of the bearing halves against the paper. Evenly, lightly, circularly sand a couple thou off the front of the thrust. The rear (where the load is will be unaffected), and you'll get what you need. I can find no reason to have .004 in a race motor. .006 would be bare min for me, and I'd rather have .008.

The lesser quality the crank, the more i'd want given how much flex goes on, as the power goes up. JMO

Don't we all....LOL sorry had to

Rickster

yuk yuk yuk,,, too true..

I check the endplay with no caps, and then recheck after each cap is installed. I do #3, or thrust cap, last. It is not uncommon to lose .001 to .0015 after installing the #3 cap. If you lose more than .002 after setting the #3 cap for maximum endplay, the parting line is not square to the thrust face. A good machinist will put a bearing in the thrust cap when facing the parting line surface during the align hone process.

I have had a #1,#2 or #4 cap hit the crank and limit endplay, as well as the parting line on #3 cap take all the endplay away. as stated in another reply start by removing the #3 cap and re-measure endplay.

Thanks for the replies, will check it out again tomorrow.

Maybe..........but he only has .002 NOT .003. That's the same as saying you want .0025 on the rods and it has .0015, run it. Would you do THAT?........ And I'm like DT, for a RACE motor, both of those are TIGHT. Now while this might not be an all out race build, it ain't stock either, being a 416. Depending on what crank it has, I would be looking for .005 minimum and would probably go .006

Monte

Try loosening all the main caps and just snug them, then with a lead hammer or dead blow hammer smack the crank forward and backward.Make sure if you are using a stud kit that the studs are not solid tight.Turn them in till they stop and back them off 1/4 turn.Some times the stud get tight in the cap and throw off the alignment.Buy doing it like this you have a better chance of getting the correctly indicating the cap location.One tight stud can throw the cap alignment off.

OK, looks like I have enough clearance now, it's at .008".

I went through the checks mentioned previously; I took the #3 cap off, re-tested and still had .002". The all the caps came off, tested again and still the same so clearly it was the bearing.

So I went and did the sanding procedure - I rubbed the thrust bearing surface on some wet, 320 grit sandpaper. The flattest surface I could find was my drill press base so I set it down on there and went to town.

Once I started, I checked the outer width of the bearing with a dial caliper to gauge how much material I took off but I couldn't get consistent readings. (prolly my cheap-o digital dial caliper)

Anyway, after several rounds of sanding/cleaning/sanding I put the crank back in without the caps to see where it was at and I got .008". Obviously I have to check it again when everything is torqued down but clearly it's within the correct range now. Even if I lose 1-.002" I should still be within acceptable margins.

Bob, the studs are just finger tight before I put the caps on. They have an allen key slot at the top to ease with installation. Once they are down I just give them a little snug to make sure they are all evenly seated. That's it, no real force.

Thanks for all the help. Will report back later when the caps are torqued down.

Well, I put everything together again and am only at .004-.005". Better but I'm guessing not optimal, even though it's in the middle of the factory spec range.

As stated before, the .008" clearance was measured without the caps. I re-installed the caps except for #3 and measured - definitely .004" to .005". The .005" was if I really lean on it with the screwdriver.

Put the #3 cap on, no change from without it so looks like the #3 cap is probably OK. Maybe it's another one?

So is it OK to leave it or am I really rolling the dice here? My gut tells me to leave it. What kind of things happen with insufficient endplay? Frankly, I'd rather not keep messing around with this any more.

If it matters, this combo is probably not going to see a ton of RPM, maybe 6,500 give or take. This is mostly a street machine that I hope to get down the track regularly though if I can ever finish the engine.

Go back and back out the studs 1/4 turn especially on the thrust bearing,smack the crank each way a few times,check end play,torque the caps and recheck.If your leaning on the screwdriver your getting false readings.You should feel the movement with out putting a ton of force against it.It only takes one tight stud to push the cap.Some of the after market stud show uneven thread spirals off the bolt centerline and when tightened the are not exactly straight or 90 degrees of the hole in the block and cap.