Yes i have a qeustion regarding the line boring procedure with aftermarket center caps ive already have within spec of each register, drilled and tapped splayed mains. I punched through to the water jacket drilling these, but this machinist i know has told me he does it all the time, just puts the ARP moly anti sieze lube on it to seal and protect the splayed bolts.. But i have different plans, i have on hand two 7.5 pound morosos block filler jugs, and i plan on sealing the top of the bolt holes off from the water jacket with the filler and the bolts, on the ends of the bolts some flower so the ends of the bolts dont stick to the filler (or possibly some engine oil). But the qeustion concerning me is how much meat will this guy take off?? Will i be able to spin this thing to 6700 rpms safely?? Nothing else concerns me. The rear main seal, i heard they will punch this out too and itll be hard to seal this???
shucks, i am 2bad2brich and ill seal the rear piece myself.. Thanks ill look into some ******** main bearings no biggy...
Relax. Your cyl. head bolts already go into water jacket. A few thousandths off the caps will not keep the seal from sealing. As for nothing else concerning you, you might want to consider a Cloyes timing chain made for line bored engines.
umm i was asking bout the main saddle boring. If they bore my mains saddles out to 2.90 (stocks 2.84) and i have to go with bigger bearings, can they withstand the punishment of 6700 rpms tops? And another thing if they do this main saddle line bore process, will i be able to seal the 2 piece rear main? Someone said its almost impossible but if thats the case i wanna second opinion...
ok whew... Your response has made me feel alot better bout having this machined. Someone had a bad day i geuss answering my post on a different site. Thanks
Line boring or honing[which I prefer if it just needs a little clean up] is fine. They make a real seal just for 400s that have been line bored. If you need that part number, PM me.
Why are they boring the saddles larger? What they should do is offest alignhone so that the crank stayes where it is. If they just run the boring bar down thru there centered on the existing register then the boring bar takes equal amounts off both top and bottom and in effect moves the crank closer to the cam. Bad ju-ju. The timing chain will have slop and the connecting rods can bump into a big cam. You can buy specail timing chains from rollmaster that are a couple thou tighter, fel pro 2909(? i believe) is the rear seal and you can modify the cam lobe center or get small base cams to get connecting rod clearance - but those are bandaids and it is best to get proper machine work done to begin with. The block fill will not make the block water tight, it'll support the cylinders but it'll be porous enough that water can get thru there - it'll freeze too. Next time find a '509' block and you won't hit water for for the spayed holes.
Lets start with the rear main seal. If correctly cut, you will have absolutely no issues with it sealing. Any issues with it sealing, could simply be from the person ***embling the engine. Remember, now the seal inside diameter has been cut as what should be a precision one off process and not a production process by the factory. This meaning in theory, it should or could seal better, once the seal is properly installed. Now as far as the main bearing bores, some people only line bore and let it eat. Not in my shop ever do we just line bore. I'm not saying its wrong, I just do strictly very high end builds. We line hone after the line bore, always. The line bore is just to prepare or set up for the line hone as to not hurt the mega-$$$ line hone mandrell or its stones. When I align hone a block you get it back plus or minus .0001 for taper, out of round, and to size. Yes that's .0001" or 1 tenth of a thousanths of a inch. Now for the mains saddle bores. If the machinist line boring knows what he is doing, the bore PRIOR to the machining operation will be correctly set up meaniing in the verticle and in register, so that the boring process will only cut the meat from new caps and possibly slightly skin the block housing bore halfs. After that p*** or p***es, you now make the decision to recut the parting or mating surface of the caps and prepare for the line hone or finish operation. Based on how much or little you cut and hone, you keep in mind for the needing for a line-hone timing chain set. A whole seperate "final ***embly" or blueprinting issue, I mean you could be running a timing belt I dont know. Your block sealer deal should work, but next time its a tedious process but drilling the splayed bolt holes without hitting water is the goal. This process takes time and measurement, but easily done. I know the angles involved makes it harder, yet easily done. If after your finished and built and have some water seapage internally, the MOROSO ceramic block sealer works wonders. Finally, as far as a RPM limit, any of the processes mentioned should have ZERO impact on your peak RPM levels. Only the componants used and the quality of the final ***embly to a degree should effect that. This includes the balancing of the rotating ***embly. If your building a high RPM and output engine, this is another reason to line hone and not just line bore. In conclusion, this process is done all the time in race shops around the country. Done correctly, you should have ZERO issues with every aspect of ***embly and running of this engine. No bearing, no sealing, no balance, and no final ***embly issues what so ever. Again, I want to stress, my engines NEVER just have a lline bore only. NOT saying this is wrong, if the boring is done correctly, you should be good to go. If for another $100 or so, you can have it line HONED, I would do it, TR
I just wanted to add, that prior to line boring the machinist can put some ****M or machinist blueing on the block side of the housing bores. This way you can quichly see if the cutter is cutting into the block side of the bores and not just removing meat from the new caps as it should be. There will always be some minor deflection of the boring bar just by design. Also as the cutter comes around and hits the edge of the new cap to begin cutting each turn the bar will deflect slightly. Remember we are measuring in 1 ten-thousanths of an inch here. 4 deciamal places. Look at his dial bore gauge, does each increment read .0005" or .0001". This is a great clue as to the precision of his work. A simple production type performance shop, line boring only, and a dial bore gauge measuring .0005" increments, is just that. A true race shop on the other hand will line-hone and his gauge will read to .0001". Nothing wrong with the first scenario, a good machinist is just that, a good machinist, and he should be able to give you very satisfying results. My advice would be, be particularly precise in your final ***embly, check and re-check. After the line boring operation, the dial bore gauge is the tell-all of how it turned out. Best of luck, TR
No one mentioned that if you are overboring the main saddles you may need to recut the bearing tab slots. 6700 is nothing for a well built SBC.
ALSO... No one mentioned that if it's a 2 bolt main, 509 block, you just weaken the block by going with splayed mains. It's a fact that the 2 bolt main - 509 block is stronger than a 4 bolt main - 400.
I've never heard of overboring the mains when line boring. I've always used stock bearings and timing chain after having my blocks line bored. There's no reason a quality machine shop would not be able to keep things in alignment after the operation if they do it as Traditions Racing described.
I am building a high end 400 for a project and I went through three used Chevy blocks and none of them were good enough for building. I ordered a new Dart SHP block from Jegs and the cost savings over machining an old block was amazing. For $1500 you get a new block with all blueprinting done and your choice of 4" or 4.125" bore. Dart builds them with priority main oiling galleries, thick decks and the siamese bores will go out to 4.155 with a guaranteed .230 wall thickness. It just doesn't pay to try and save an old block. For a little over $2000 Dart makes a "Little M" block that has four bolts on all five mains plus their standard features and should be good for 1000HP.
Hey Traditions, I am evidently on your list of people that you cannot receive PMs from. So I am going to ask you publicly. How's the world treating you friend? I have actually seen blocks that needed a bit removed from the saddles to make them straight. Not very often but it does happen. Someone told me that it happens when you toss a crank but I think it is just a sloppy job from the factory. You don't use oversized bearing to overcome the problem it just moves the crank a little closer to the cam shaft. I guess that is why companies like Cloyes make timming chains for blocks that have been align bored.
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