I have a good 350 4-bolt block. It wasn't pushed as a Hi-Po performer and it's never been rebuilt. It was magnafluxed and passed the inspection.

Is an Align-Bore required or is this a waste of money in this case. It will get a new standard cast crank and Clevite 77 bearings.

I've heard that all I have to do is lay in the crank and see if it rotates freely after the caps have been torqued. Is that a good check? The engine will be producing about 360-380 HP. For that matter, if I torque the main bolts and it doesnt rotate freely, will I need new bolts since I torqued the first set?

Thanks!

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Whoops computer error.

[This message has been edited by Gene Chas (edited 07-23-99).]

I can't remember how me used to measure the straightness of the bores. Measuring round is easy, I'd be curious to hear how it's done these days. In any case I'm sure we did on an inspection table with a height gauge among other things. I couldn't do that at home.

Sure saddling the crank in the bores and checking it's rotation is an ok method, but what's your reference point? I mean someone that checks three of these a day, or more, knows what amount of drag is right.

Put it togehter first and plastiguage it to check your clearances. Unbolt, remove the putty, clean and rebolt and give it a whirl ( with oil of course ). You'll also want to check crank end play at this time.

I don't know how it's done today, but we used to bolt/unbolt quite a few times during the assembly of a "blueprinted" motor. My recollection was that we were 20% under final torque until the final assembly when we'd use the full torque spec. You're not going to screw up the bolts by doing this.

Sometimes using fresh bolts, like on rods, will screw up the roundness of the big end. So new bolts are always installed prior to machining.

In all honesty, if I wasn't using a strong billet steel, tuftrided crank, I wouldn't bother with an align bore. Unless the block's mains are way off.



[This message has been edited by Gene Chas (edited 07-23-99).]

ddoler, align bore is usually used to repair a block that has had a main bearing spun. SBC's are not known for this and it's easily visible if it has happened.

For the really nice rebuild the block can be align-honed which removes less material. This gets the main bearing bores in good alignment and back to perfect size.

Your block probably does not actually NEED either one of these procedures. Both jobs move the crank closer to the cam and result in a looser timing chain. Align honing gives a nicer finish on the bores which is supposed to let heat tranfer out of the bearing better. I notice that untold millions of SBC's do just fine without it.

One of the other reasons to have this done is if any of the main caps are loose in the block registers that locate them. The little steps can be peened to tighen up the fit, I'd plan on align-honing afterward if this is the case. The caps are supposed to be sort of a snap-fit in the block, maybe requiring a little hammer tap to get them to seat down in the register.

If you're concerned about this for some reason ask your machinist to check the bores with a straightedge and a micrometer or dial bore gauge to see that they're in alignment and on size.

Usually, the wear patterns on the old bearings tell the story if you have them.

Tom

Tom's last comment says it all. Look at the old bearings and see what kind of wear pattern they have. Also inspect the old crank for wear.
If you don't have the old parts then drop in a new set of upper bearings and then the new crank. Apply a thin layer of Machinist bluing to the exposed portion of the main bearing journals.
Turn the crank one turn. Pull out the crank and inspect the bearings. If the main bearing bores are out of alignment the bluing will tell the story.
Its not too common for a small block to need align boring or honing

The average person does not have the necessary "stuff" to properly check a crank. Having a set of micrometers and knowing how to use them is just part of the deal.

I don't know how you can tell how round the journals are with just a micrometer? It would be a very tedious job. When I ground cranks we used a thing called an Aronald gauge, it measured in tenths as we spun the crank on the grinder. More cranks have been ruined on the polisher, bareled. The jerk on the polisher tapers the crank from the edges, sometimes as much as .001.

Straightness was measured on a set of precision roller V blocks.

To check the bore of the block caps, you need a Sunnen or like dial bore micrometer that cost $400 and the $1100 setting micrometer.

Unless you have all or some of these tools and know how to use them, take the thing to a machine shop, a place like BillK owns, and pay the man to check it.

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Wally
Gold #67
67 malibu

[This message has been edited by Wally (edited 07-23-99).]

Wow, measuring tools have gotten expensive over the last twenty years! Kick my self for selling the Kennedy full of it.

Gentlemen, you've probably saved me $150 bucks. Thank you.

I bought the block from Sundell Automotive. Ron says the block is a very good one thats been magnafluxed and has passed their inspection. He suggested align-hone as a good practice. I've bought a lot of parts from them over the last two years I trust them.

I'm going to take the advice that an align-bore is overkill in my situation. As for the rest of the plan, Will the PAW cast crank sit right down on the Clevite 77 bearings and can I assemble the new rods right from the box with the pistons attached and bolt them up?

I expect about 350 HP from this motor. I'm pondering hypereutectic pistons but am leary because I understand that I have to manually gap the rings. For a mild performing engine such as this, I'd think cast crank and pistons would be fine and that a detailed blueprinting job wouldn't be needed.



[This message has been edited by ddoler (edited 07-24-99).]

ddoler, not all rings sets have to be gapped by hand.most ring sets can be bought either way.speed pro has rings that are pregapped or you can get sets that need to be gapped from the cheap cast ones to their plasma moly rings.the reason you would want to gap the ring yourself is you can set them to the gap you want.Pregapped rings work just fine on hypereutectic pistons.you might want to check out the federal-mogol(speed-pro rings,fel-pro gaskets,carter,etc.) wedsite,lots of info on what your looking for.www.fmperformance.com

If it were mine I would spend the money you plan on saving on a balance job. This is the best investment you can make when building your engine, even if it is bone stock. The engine will run smooth and if your are getting parts differant places I would say it is a must that you have it done. Also if you are getting rods from from someone make sure they all have the same beam thickness. A thinner beamed rod started coming in the 305 and then stated showing up in the 350's. I have seen these mixed and matched and it is not a good idea to do so.

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Gold Member #164
http://sites.netscape.net/1969ss/homepage

ddoler, in general, HT pistons don't need special ring end gaps. The HT pistons sold under the KB (Keith Black) brand are made different and require a large ring end gap on the top ring only, I believe it's 0.026" for a 350. I generally don't use these on long-life street engines for this reason. The bigger the end gap, the more blow-by. Personally, I like to run a Sealed Power or TRW or F-M HT or forged piston.

Tom

This is an interesting posting with good answers but I want to add just a bit.

As has been stated above align boring is usually to fix damage, like a spun bearing.

I am one that feels that an align bore should always be finished up with an align honing.

You can do just the align hone if you are going to build a race engine to force things nice and true.

The finish of the align hone is superior to the bore finish. The align hone fits the back of the bearing shell tighter to the bore which is an aid in transferring heat.

It is interesting to note some famous engine builders like Grumpy Jenkins - in his book he is quite cavalier about not align boring or honing. He states just set the clearances, install the crank with oil on the bearings and crank, tourque to specifications and check to see the crank rotates without any binding. If there is binding something is wrong, check it out and if it is the bore of the block - get another block.

Conversely Smoky Unick insists that you align hone the block as part of a "good" build.

On my last build I replaced the main bolts with ARP studs and the builder insisted on align honing the block. I must admit the crank rotated like on jewels, not a hint of any binding as I rotated it through.

BillK has an engine of mine now for a street machine build, and if he/we think things look good I probably will not bother with the hone job.

John

This information isn't easily visualized by a new engine builder such as myself. A hone will, if I understand it just surface the block to better seat the bearing shells where a bore attempts to truly align the bore. Each will take off metal, but the hone is less intrusive and is just fine for a strong street engine.

Clear now! Thanks!

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