Every body says that you must have your engine align bored with the fasteners you will use, Main stud or bolt. But why? If you do not plan on going over 6,000 RPM and can put it together and the endplay is good and the crank will rotate just as free, the main caps are the same and the bearings still match great, why? I can understand the idea for a engine that does not meet that criteria, but the factory doesn't align bore them.

 

The factory does line bore the block. Otherwise the 5 main saddles wouldn't be in a straight line.
Some manufacturers engines are suggested to be line bored during a rebuild since the casting may shift a bit after many miles and heat cool cycles takes it's toll. For a regular rebuild with stock fasteners, it usually isn't necessary unless you see signs indicating otherwise.
Look at the main bearings. if some are worn differently ( one worn bottom and one worn top), this is one sign that it's necessary.
If you're switching to studs, then it should be done since the saddles will distort so to speak a little differently than if conventional bolts were used.

 

Here's my opinion on this, I'm sure some will disagree, but it works for me.
If I have an engine that I know the history of, it came out of a running car, with no knocks and good oil pressure, I have carefully taken those engines apart, inspected them, polished the crank, honed the cylinders and installed new rings, bearings, oil pump and cam/timing chain. That would not really be a "rebuilt" engine, it would be an engine that was "freshened up", and I would not pass it off as rebuilt. I have had great success doing this, and have run these engines over 6,000 rpm w/out issues.
Now, once you decide to start changing things, like pistons and cranks, at that point you're changing parts that will have to work together. These parts have never been together before, so to insure that they will WORK TO THEIR BEST EFFICIENCY you have to make sure that all parts are machined to a specific tolerance. One of the ways to do this is to make sure the bores are square with the crank. In this manner, you guarentee that the parts are matched. In the case of line boring this is done with the bolts or studs that you will use. The reason is that every bolt or stud has a different stretch potential, and different manufacturing tolerances. For this reason, you have to install the fasteners that you intend to use. If you change rod bolts you have to do the same thing, bolt the caps to torque (or measured stretch) and rebore the hole. After the align boring is done, then the cylinders are machined to the crank, so that they are straight, and the rings fitted. Anyway, all of this, (and balancing) is part of blueprinting an engine, an often overused term that basically means matching all of the parts together so they work most efficiently. The stock car crowd usually uses closer tolerances and the dragster guys run pretty loose. How well do matching parts work together? Well the P/stock national record is held by a 66 chevy biscayne at 12.78@102.88 mph. the A/stock record is 9.89@135.72mph in a Ford Fairlane. That's haulin' butt for just a set of headers and a gear change.

 

BS this is the second time i've seen blueprinting defined as a set of optomized parts on this site. the 1st time the guy quoted a book and most everyone beat him up saying that wasn't the defination of blueprinting. the majority seem to feel blueprinting was assembling an engine to a set of specs.

you've been grossely misinformed if you think all it takes to compete in stock class racing is a set of gears and headers.

 

Well, if you assemble an engine to a set of specifications, either the builders or the factorys', according to their or your specifications, then that would be "blueprinting", but , it goes farther than that. After going through all of the work, it wouldn't make sense not to balance the assembly as well. As far as those stock class records go, about all they can run is a set of gears and headers, everything else has been optimized for the application. I used this to illustrate my point on optimizing stock parts. Any stock class racer knows that "stock" isn't "factory stock".
And I'm throwing the BS flag back to you

 

Is this thread about align boring or what it takes to compete in NHRA Stock classes?

There are two processes out there - align boring, and align honing. All blocks are align bored from the factory. That is why you have to put the main caps back in the same position they came from. Align boring maintains the distance between the crank and cam centerlines.

Align honing is similar to rod big end resizing. A small amount of material is removed from the mount face of the bearing caps, the caps are reinstalled, and a hone bar is slid in and the assembly honed to the proper bearing OD.

The two reasons other than odd bearing wear pattern to do one of these operations are spun bearing (pretty rare), or the cap location wasn't maintained when the engine was disassembled.

Oh, guess there's one other reason: Converting to splayed or billet caps.

 

how said anything about nhra stock classes? ihra runs it too. BS why are you "throwing the flag back at me? i never posted it in my reply to you.

 

Oh. my bad. I do sincerely apologize, I totally made a mistake there. When you started out the line with BS, I misstook it for something else.
If you have an old block, which most people generally prefer, because it has done it's core-shift thing. Then the original line bore has probably moved around a bit. The only way to fix that is to bring all of mains into alignment, and match the bores to those mains. Match the deck and the cam bore to that as well. Now you have a block you can work with.
The stock class thing was an illustration on what can be doen with stock parts, nothing more...done.
And EDE, again, I apologize.

 

I have heard that many people do not align bore and may use different fasteners. Their's always seems to work out. However I have talked to machine shops that have had people come in with crank problems because it was not align bored. Yes I know this is a bad idea but, I am going to skip the insurance. The pre-mentioned applies to me. It has been spin balanced and the block was in immaculate condition. I could have just re-ringed it and been good to go. The crank had maybe a hand full of scratches, no bore ridge and all tolerances including endplay was well below rebuild level. I gave it a good rebuild anyhow. I do not plan on taking it above 6,000 RPM at all. It will only see that high maybe a few times a week. So I am going to try it. Worst case I send my crank in as a core and align hone it if I am wrong.

 

Well if you're going the inexpensive route, just keep the stock fasteners. I personally would not change fasteners on the crank or rods w/out remachining the holes. I'll probably get heat for this by someone, but if you don't get carried away you can use the old stuff over. I've seen NASCAR guys use a bolt stretch method to tighten things down (no torque wrenches) and if you remove the fastener, and it "shrinks" back to it's original size, they'll (sometimes) re-use them. Actually the hi $$$ guys won't but somebody will. You can of course change out the head bolts, some guys like studs, but if you use them, you may not be able to get the heads off in the car. For an almost stocker, either re-use the original, or change out the bolts. One other thing, if you plan to use 1.6 rockers, and the heads have been cut, or the block decked, make darn sure the pushrods don't intefere with the guide slots.

 

I just went with ARP head bolts. The block deck was squared off at .01 removed. I have already mocked up the valvetrain and found that everything worked and cleared great even without gaskets. Guid plates are not an issue for clearence.

 

Most builds do not require the block to be align bored. Like 57 mentioned if a bearing spun that would be a good reason to have this process done or if you had to drop in a sleeve. Ive only had one 350 align bored because I went with aftermarket main caps.

Funny I read in the local paper of a 400 short block for sale that was "align BOARD" wonder if they use oak or pine for that process?

 

Tibo, If you run 1.6 rockers, and you've had the heads cut or the block decked, please check the clearance of the pushrod clearance to the giude slots. You'll thank me later.

 

Done. That was also checked. Thanks for the word of caution though. I guess you had some bad experience. What material were the guide plates made from? And what heads were they?

 

Just so you know that you can't do this with stock fasteners. ARP gives the tightening spec in both ft/lbs and stretch.

 

What happened is that the 1.6 rockers caused the pushrods to just tap the oval guide slots that were in the head itself. It would have probably started and ran OK, but if you stood on it, it would've been bad. Because these slots are cast, sometimes they're OK, sometimes they're not. If you have the deck or heads cut, it aggravates the problem.
Yes AM, It depends on the bolt. Usually the bolts designed to be stretched have a hole in the end for the gauge to set in. Just do what the mfg. recomends.