Stroking it!

[Dukes69]

I hate to mention this now, but better late then never . . . I've built a couple engines, and when I do I always wash the block with soapy water and clean it real good, after is has been machined. I also run a tap in all the different holes, especially the mains and head bolt holes. This ensures proper torque. Easy and cheap insurance. The last thing you want is metal shavings in a new engine or a crank that breaks in half due to impropper torque

have fun!

[cbremer]

good news... the bearings worked out. all mains are within spec, so I started assembly today best I can guess is, I bought a 'remanufactured' crankshaft, which means they turned all the journals down .010", and tossed in a set of undersize bearings to match. problem was, i had the block machined, which included boring the mains, making them a bit big/loose. they must have removed .010", since it all worked out.

pics to follow....

brian, that is indeed the mopar performance/Mike Leach tri-Y header. more power! (insert Tim Allen grunt here) I got it from Summit racing for less than I found it anywhere else... but I have to wait a while no hurry, since I have a ways to go on the engine itself.

:hat:

[blkTJ]

is that the MoPar header??? if so I hope you got a helluva deal on it. nice.

[NAILER341]

Originally posted by cbremer
.020 undersize main bearings were delivered this week, and i'll be (re) installing the crank over the weekend.

got the head back from the machine shop too i suppose i'll give the ports a once-over with a Dremel too.

the FSM recommends .002" clearance, but .001-.0025" is acceptable. i was getting >.003" on all the mains (some as high as .004"). this is really all that I was waiting on... now I can really get crackin' on assembly



:hat:

p.s.: I just ordered this beauty:



it's on backorder, but I'm pretty patient :yawn:

BLING-BLING!
i hope all that bearing stuff works out for you... i'm no engine expert, but it seems a lot of measurements are off here.. and you KNOW about them, and are proceding. i hope it all goes well for you.

[cbremer]

.020 undersize main bearings were delivered this week, and i'll be (re) installing the crank over the weekend.

got the head back from the machine shop too i suppose i'll give the ports a once-over with a Dremel too.

the FSM recommends .002" clearance, but .001-.0025" is acceptable. i was getting >.003" on all the mains (some as high as .004"). this is really all that I was waiting on... now I can really get crackin' on assembly



:hat:

p.s.: I just ordered this beauty:



it's on backorder, but I'm pretty patient :yawn:

[codfish]

that is a nice looking block you have there.. how is progress? did you resolve the bearing issues?:oink:

[blkTJ]

just one question... what the heck are you guys talking about???:confused: j/k man, I know so little about building engines.:yay:

[rick]

What bearing clearance are you shooting for in the swapping/mixing of oversizes? If they are all 0.002 - 0.0025, you are sittin in tall cotton... I wouldn't make them tighter. I think factory specs are a ridiculously tight 0.001-0.0015 or something. This is too tight in my opinion. The only difference you will see is in the oil pressure at idle. My mains are 0.0025" on the nose and I run 15-20 psi at idle, then it jumps up immediately off idle to 30-50 depending on rpm and temperature. If the lower oil pressure bothers you, just run 10W-50 oil. I get 20-25 psi at idle with the thick stuff. The larger bearing clearances help protect the bearings under high loads, particularly at low-medium rpm where harmonics and high torque can deform the crank slightly. This is particularly true of a high torque, low rpm six cylinder with inherent vibration issues like a stroker. These engines have a high rotating inertia, so once they are spun up to higher rpms the damper and flywheel actually do very little to smooth things out enough to where the bearing loads are more even, as is the case in most 4 and 8 cylinder engines where the rotating masses are in opposition during most of the crank cycle. This is where tight bearings can eat your lunch. One mishap at higher rpms and that 0.0015" will disappear very quickly and send metal flying. The more oil that flows between the bearing and the journal, the more heat transfer occurs between the metal surfaces. Of course, this is only true up to a point (I'm sure 0.05" clearances are not good), but if 0.0025 is good enough for a big block chevy on nitrous putting down 800 hp, it's good enough for me. Just my $0.02.

[rick]

Sounds bad to me also... I always thought bearings were matched to one another.

There was much debate and many posts in several forums a couple years ago when I built my 258 about hi-vol oil pumps and problems with everything from priming to life of the pump. I had a hi-vol pump the first time I rebuilt the 258 and I had priming problems for the first two oil changes. I put a stock pump in it after the second rebuild and then I had priming problems because I had the wrong oil pickup tube, but the pump was fine after correcting that problem.

Nice looking engine Chuck.

[Dukes69]

Yeah, I'd try all the same bearings, just to see if they are in spec. I've never heard of using different size bearings top and bottom. Sounds eff'd up to me :confused:

[cbremer]

Originally posted by Dukes69
So the hole is out of round? That doesnt sound good. are you using plasti-gauge to check the clearence?

yup... used plastigage. i know what you mean about that method leaving the mains out of round... but the manual says it's OK :confused:

i'll try using all .020" bearings- maybe it'll be a little tight, but within spec. at least that way they'll all be round

[Dukes69]

Originally posted by cbremer
the service manual says I can mix bearing sizes, so i'm going to use the .010" undersize on top, and .020" in the caps, tightening up clearance by .005", putting them all into spec.... hopefully

So the hole is out of round? That doesnt sound good. are you using plasti-gauge to check the clearence?

[cbremer]

and we're under way...




the color is AMC blue since I took the pics, i got the crank and cam installed, and discovered that all but one of the mains are slightly bigger than spec, so now i'm waiting on the next undersize bearings the crank was 'reconditioned' and all journals were turned .010" smaller than factory. that, combined with the hone job at the machine shop, made the journals too big. the service manual says I can mix bearing sizes, so i'm going to use the .010" undersize on top, and .020" in the caps, tightening up clearance by .005", putting them all into spec.... hopefully

pistons are due to arrive on Tuesday, and the head's being rebuilt as we speak! yay

:hat:

[Dukes69]

Originally posted by sarah
rick says don't get a high volume oil pump.
use a stock one!

Why?:confused:

[sarah]

rick says don't get a high volume oil pump.
use a stock one!