After the line hone and crank checking out okay (with a polish) I am getting just under .003 for the main clearances (checked with plastigauge, unfortunately I have no access to a bore gauge and my snap gauges are absolute junk).

I'm running Clevite H-Series bearings and plan on 10w-30 Mobil 1 after the break in.

While I'm not looking for or expecting 100k miles out of this build and I know most people recommend .0015-.0025 for street use, is this a guaranteed disaster or will I generally be okay with the slightly excessive .003 clearances?

While people disagree with this as well, I am running a HV Melling Select oil pump FYI good to 70 PSI (with all the right variables).

It's bigger than I'd like, but it'll work. You can change your bearings to take another .001" off.

I have to call the machine shop tomorrow and see what he says. I have a feeling, like most machine shops do, they will say it is just fine. Joe is an excellent guy, however, I will still get it in writing everything is okay with some guarantee. So hopefully he will back it up if anything goes awry.

I am also going to see if he will swap out these std bearings for some .001 undersized ones to help those clearances.

Just judging from experiences with engines that me and some friends have built - street, race, and street/strip - its better to err on the tight side (closer to .0015) than on the loose side, if its going to be driven somewhat regularly and see street duty.

Running with looser tolerances like yours isn't necessarily asking for trouble right off the bat, but longevity will definitely suffer. Many race engines are built with looser tolerances like that because it "loosens up" the rotating assembly, and makes for less drag from the oil pump (due to lower oil pressure) and frees up a very small amount of HP. Not at all worth it on a street or street/strip engine though.

Thanks Adam...that's kind of what I figured. When we are talking about longevity are we talking about 10k miles, 50k, or ???

This is a weekend playtoy without heat or A/C and will see around 5 track days a year along with some daily driver status during good weather.

Hard to say, too many other factors. One of the motors I was talking about that was setup around that spec has about 400 passes on it now and almost no street use, and the bottom end is about due for going through...

Well I either...

1. Run it and hope it lasts somewhat

2. Get .001 undersized bearings

3. Turn the crank .010 and get matching bearings


The only thing is I'm using $65 H series bearings and don't want to shell out more than is required. Hopefully the machine shop will exhange the bearings for me and set this right.


Which option does everyone vote for from the three listed above?

3, then 2, then 1.

Is saving $65 really worth taking that chance to you?

No, and in the full scope of things over the last 4 years $65 ain't shhheeeet but it has always been like this with this particular build...this would be the third rebuild (and the damn thing still isn't together). I strongly feel line honing the mains should solve everything.


Even after the line hone is there a possibility there is still a problem with the block or is this a crank issue?

Measure the crank and you'll know for sure.

Yea the machine shop did mic it, check it for straightness, and polish it when they had the block. Apparently it is just on the low end of spec. I guess I could whip out my mic's and do it again...

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Here is a local post I just made...

Heres the scoop...I took my Gen I SBC block to Bell after some recommendations to have it line honed and the crank checked.

Crank checked out fine with a polish and the line hone seemed to go pretty well. So, I buy $130 rod and main bearings from them as well (the $10 a set they said I could have saved over Summit turned into $2 per set so after tax I ended up paying more...).

When double checking everything yesterday the clearances are coming up at .003" for my mains which I hear over and over is too much. Not saying it won't work but probably not for long.


Also, the thrust bearing (#5) on the lower (cap) side is protruding from the side of the cap well more than enough to hang up your nail on. Even after torquing everything down.


So I call Bell today and explain the situation. I was informed the .003" is within spec and will be just fine. Hmmm...figured that one. Also, was told the thrust bearing should be no problem as well because some time they do that.

Not feeling the loose clearances on my street motor, I asked what he suggested. He said just about the only thing would be to turn the crank .010. Fine, exactly what I expected. But, when I asked him if he could swap out my bearings for a set of .010 undersized ones that was a no-go because he didn't make much on those bearings.

We got back to the thrust bearing since I pretty much excepted either run the loose clearances or pay outright for a crank turning and a new set of bearings (I could also try a set of .001 undersized bearings but figured if I'm buying new bearings I'll turn the crank). I asked if he would back that thrust bearing being alright up in writing which we finally got to "if you torque the crank down, set your endplay, and bring it in to me I can ease your mind. Can't back it per say since we're not building it but can ease your mind."


So now I am with a questionable problem with the thrust bearing and workable but loose clearances.


Now, I'm NOT by any means bashing Joe or Bell but wish this could have come out a little better. I guess I am at fault by not explicitly stating what clearances I wanted but even that would have cost MUCH more than the already expensive $210 line hone Joe said.

Well, decided to go with just running it.

My HV pump is rated at only 10% over stock (as opposed to a possible 25%) so I don't fear the normal HV issues but do feel it will 'help' the larger clearances somewhat.