Is there any tips I can give my machinist to properly align hone main bores other than shoot for 3.4385" and use 110lbs/30w oil (factory bolts)? He hasn't done a Buick before. Ray
This would be a good time to upgrade to main studs if you ar consideing 500+ HP in the future. Cheryl
I read a post by JW concerning main studs. he said something about not being able to repeat the round bores with studs when torquing. IE he was getting different measurements each time he torqued them down. i seem to recall him recommending against them unless you had a girdle and a partially filled block.
I don't know if your machinist asked you for tips or not, but if he did run the other way!!!! He should know this, Buick or not. When you have big mains then you need more oil flow to keep the bearings cool. You get that by increasing the clearances. Again he should know that. I do Oldsmobiles, very similar to the big mains on your 455 BBB. If you have a problem with repeating mesurements you have another issue. It's not the studs causing the variance. We strap the caps, use ARP studs, put the tunnel size in the middle, make sure the registers are good and tight and grind the crank to the clearance desired. Works well for us on applications well over 500hp.
I recall the thread about the main bores/stud issue. I'm using bolts. The engine in question will be 440/480hp w/killer torque. I can't find the post but it was mentioned to do something with the #5 and thrust bore main when doing the hone. I just wanted to offer the guy some advice if it would help. Ray
No, all of the major Buick engine builders and thousands of GSCA members successfully using main studs with an align hone over 500 hp for the past 30 years are just wrong. Cheryl
Ray, Only real issue here is that he Buicks have a really wide rear main, compared to the rest of the mains. So the rear cap is typically cut about half as much as the other 4. This is typical with Pontiacs and Oldsmobiles, and the same proceedures are followed by most machinists with those engines. One thing that is critical for the job to come out well, is that the caps are cut straight, both vertically and horizontally. JW
Thanks for the advice Jim. I have a good std. main crank. With new Vandervell bearings (old stock w/lead) on the center three there was interference near the parting line in the same area block side, and the opposte side on #1, none at the rear. The crank would turn pretty freely but it was obvious their was interference. Tried some Clevitte 77's and the crank wouldn't even rotate w/o the caps. Thanks to all. Ray
Perhaps they haven't quite caught on yet. Some are still stuck on the rear left-to-right galley bypass for goodness sake. That and the the high volume oil pump being preached as the answer to all oiling problems. Devon
Yes, but these engines are not failing! One engine builders inability to repeat his numbers does not disprove the effectiveness of the modification. The overwhelming empirical evidence proves otherwise, and that is only considering BBB engines. Cheryl
I might suggest that before you get too high on the soapbox, you might want to built about 4 dozen 455's, and study the effects of studs, bolts, block gridles, block filler, cryogentic tempering and billet main caps on the block itself, in relation to how consistant the block pulls when torquing the mains. You will come away with a larger knowledge base to give advice from. I have.. JW
Issue has nothing to do with machining. I would suspect that your first shop didn't torque the block correctly or something when they line honed. Some blocks don't like to be pulled with studs. I have seen it 4 times in the last half dozen years. First came across it in 1989. Since then, I go thru a laborious proceedure to torque, loosen, torque loosen ect the block and check the size each time to make sure it will repeat. If your not doing that, you won't see it. And most guys don't, as it's an unusual proceedure. Care has to be taken to insure proper lube of the threads each time, and quite frankly, it's a pain in the butt that I have come to accept as part of building a BBB. Some Blocks won't consistantly repeat size when pulled with studs. No register problems, no cap issues, no problem with the hardware or procedures. a quick synopsis of what I have found over the years: Filled/gridled blocks are awesome.. they will pull back right to the tenth, all 5 times. But I have not done enough of them to get a good sample size.. only have 5 or 6 instances to look at. naked blocks with bolts will repeat to within a tenth or two- done 3 dozen of them. Some certainly better than others. naked blocks with studs, some are ok, same as bolts, but some won't repeat to within .0003 to save their lives.. about 20 of these over the years. Unfilled block girdle motors- pretty decent for studs- within 1 to 3 tenths typically. Seem to be more consistant with the load spread out over the block by the girdle. Speaking of girdles... a filled and gridled motor won't change the main size without the outer bolts tightened.. but an unfilled one will go about 3 to 5 tenths out of round, if those little studs are not torqued to 25 ft lbs.. Variations are almost always mostly seen on the center 3 mains. Two and Four are the worst. Front and rear main are pretty stable, due to the mass of the block around them. It should come as no revelation to anyone that we have a weak block. Some worst than others. Techinically, just about all of them are "within spec", but that .001 window is pretty wide.. and when dealing with a 455, your best to keep the mains as tight to that middle spec as possible. Ask Dennis Manner sometime what happens to the main housings on a 455, when you bolt an iron intake, on iron heads.. :shock: Running the clearances you do Chris, you don't really have to worry about it, you have plenty of wiggle room. I won't run big clearances, so I have to be more worried that everything is straight and true. JW
I am not convinced you have controlled for all compounding variables in your "studies" or that your method is valid, reliable and repeatable. Continously making these assertions when the evidence of failure is nonexistent is irresponsible and more akin to "Soap Box Standing" or grandstanding then my position. I just want to protect the public from those that wish to be seen as experts at the expense of facts. Maybe you should take a graduate course in research. You may come away with a larger knowledge base to help you make valid assertions. I have............ Cheryl
JW, never argue with a woman! :spank: LOL. But I'm on your side. I've got bolts in my motor, as it was also recommended by my machinist/builder.
Ya, Brent, your right.. you just can't win. Mr Jones, did you ever run across this issue? Over the years I have come to the belief that if the main caps are going to walk with bolts, they are going to walk with studs. I have certainly seen that. My point here was just that if your not going to check this out, your probably best just to use the stock main bolts. They are adaquate to 600 HP and 6000 rpm, and there is no need for studs in a street motor under that power level.
