Female 455, As you can see here there are many different ways to get the job done and get it done correctly. For your application a crossdrilled crank with the 3/4 grooved race bearing will be just fine. Even if you dont crossdrill the crank you will be fine. What is more important at the 550-600 hp level is the rod and main clearances. Again... you will find differing opinions when you ask about this subject. But I will say this.... If the clearances are too tight.... your engine will die quickly. So dont make them too tight. Good luck with your build and keep us up to date. Guys and Gals, Sorry that this thread has gone a bit off topic but its great information. Bruce, Thanks for your input!!! The situation you describe, is that on a moldex crank or a stock 455 Buick crank??? Did you ever compare a stock crank to a Moldex? This is why I like this group!!!! We are never afraid to share information!!! Chris, When going low 10s you typically need to spin your engine 6800-6900 rpms. This is a fairly safe rpm zone for a properly prepared 455 Buick engine. But when the car starts hitting the 9.60s or the 140 mph range you really need to start spinning these things to 7100-7300 rpm range especialy if its a heavy car. This is where the oiling (or lack of oiling) issues become apparent. Some of the oiling mods that are discussed in this thread I incorporate into any street engine that I build or help build. I guess I am of the opinion that an oiling system with overkill is never a bad thing. What is the altitude of the tracks up in the north west???? How did this thread get almost 3600 hits already??? o No: Great info!!! Later
John: Most of the tracks in the N.W. are at or very near sea level. The track in Mission, B.C. is probably the best track around. Run by a good group of people.
So what would you say is safe oil clearence on a 600 HP engine? I set mine at .0025 on the mains and .002 on the rods. Also is it worth coating the bearings with this kind of HP and would that change the bearing clearence ?
well since we are talking race engines now ,i was recently at trishield performance and got to see a dyno run on an alum head motor that pulled close to 800 hp at 6300 rpm. thought that was cool :TU: andy
One thing to remember is that it is critical with a stock crank, and race bearings, to make sure that you have the crank nitrided.
altitude John,the altitude of mission is almost sea level,when I ran 10:17 @ 129 and the car is 3300 lbs with my fat but in it.The air was at 1800 ft. I shift it @ 6200 to 6400rpm and go though the traps @ 6600 or so.This is all great info and I think I'm up to speed on all the oil mods on all hp levels thats why I was thinking we all got away from female 455's question instead of a pissing match on her thread .The point I was tring to make was,all the oil mods in the world aren't going to help if it ain't screwed together correctly.Maybe standup69 will chime in and talk about his lack of oil mods on his 69 GS 400 street car,its a 12:8.1 494 stage 3 3675lbs 2years its been together and yes he drives it on the street and at the track 9.90 on a 10" slick I'm sure some day my luck will run out. Chris
Jim, would you please explain why nitriding a stock crank is important? We still lose bearings on our stock crank engine (mostly rods,last time main #4) and have done most of these mods except for the grooved main saddles and added holes in the bearings. We will do that this year. We have another engine with none (except big gears in the pump) of these mods that has run forever. 5 seasons, methanol, 6500rpm, stock rods, big heavy hyper pistons, no balance job, nothing. The other one we try to do everything right and it doesn't last. Biggest difference between the 2 is compression. 10.5-1 lasts forever. 14-1 doesn't. 14-1 is much more fun while it runs though.
Nope, we actually found that the number 7 exhaust valvespring had reached it's cycle life.. it was broken. Upon dissasembly of the motor we found that it more than likely had been that way for a while, as the flame travel and color of the cylinder would suggest poor combustion. So what you saw was more or less on 7 cylinders. Buick Roller cam valvesprings are not known to live long lives, and this set had gone 150+ passes/dyno pulls. Good news is that on on dissasembly, that is all that motor needs. As it relates to this thread, this motor has a crossdrilled billet crank, external oil pump, priority main oiling and runs over 100 psi of oil pressure, with 5-20 synthetic. Motor makes 800 HP naturally aspirated, pushes a 3200 lbs GS into the 9.30 range at 140-143, never seen the high side of 6700 rpm in the traps. With just about 100 runs on this engine, grey is not worn off the mains/rods. To get the car to go faster, we are lightening it up, and building more power, and will push the motor to a higher rpm in the traps. Our hope is that at the next 100 pass interval, going faster and spinning harder, we will see the same lack of bearing wear.
Greg, Racing or "hard bearings" as they are known, have little ability to imbed foreign material, and can actually trap grit between the bearing and the journal grinding up the soft cast iron crank surface. Nitriding the crank surface hardens the crank to a depth of about .003, and will prevent this grit from scaring up the journals. Often when hard bearings are used with an untreated crank, the process I discribe above will not be caught until both the bearing and the journal are damaged. Upon dissasembly you will see badly worn journals and bearings, and it's pretty easy to blame the bearing, when in reality the chicken may have come before the egg.. so to speak. In reality the bearings inability to imbed kept abrasive material on the surface of the crank, trapped between the hard bearing and the soft crank, and ate the crank up first. Federal mogul race bearings are known to be some of the most unforgiving bearings on the market. Even more so than the H series clevites, but even with those bearings, the crank needs to be surface hardened. Even the billet cranks.
In regard to the rest of this thread, I will share the following: I have been grooving the main saddles and drilling the bearings for a while now, on a variety of different race motors, typically over 700 HP. Mike T turned me on to that mod about 4 years ago. He had worked with Buick Power train engineer, and the "father" of the 455, Dennis Manner to develop that mod. I think Dave Mongeon was the first to implement it. I have seen evidence that particular motors can in fact suffer from that modification, if the delicate balance of oil flow vs oil pressure is not maintained. I had one 710 HP STG 1 Super Comp motor that wore the rod bearings nearly to the copper at about 90 passes. The next season, we freshened it up, and did not drill the extra oil holes in the mains. We noticed an increase in oil pressure, and the bearing wear issue disappeared. That particular car's chassis did not allow the use of an external oil pump, and the limitations of even the best timing cover pump became evident on that particular engine. For a motor like is being describe.. keep it simple. By far the most important thing is good machining, this has been mentioned before, but I will put a finer point on that. Few machine shops out there actually have a honing bar for the mains that will work well with our housing bores size. This can result in main housing bores that are badly out of round, with the bore getting bigger at the parting line. I have had engines come into my shop for repair that are as far as .003 out of round, after a failed line hone attempt. These motors always have the rod bearings wiped out, and to a man, their owners claim that the engine had "great" oil pressure. And they do, unfortunately they don't pressurize the rods, as the large clearances at the parting line of the mains prevent the rods from being pressurized properly, and they fail, but that is a localized situation, one which you will never see on an oil pressure gauge. Rod bearing failure and excessive cam lobe/lifter wear are consistent factors in these engines. I have seen several, and fixed them all by correcting the out of round condition of the main housings. I believe that for motors below 650 HP, which run under 6500 rpm, rod bearing failures rates can be as high as 75%, with the housing bore malady that I described being the root cause. Typically a shop that does a lot of Pontiacs and Oldsmobiles will have a dedicated "big housing bore" line hone bar. That is the question you need to ask when looking for a suitable machine shop to machine your Buick.
Kerry, Sorry I never took any pictures of the priority oiling system. Sounds like there are a number of others out there that do this as a profession and are probably better equipped to help you. Tinkering with these is just a hobby for me and I wouldn't want to advise someone on how to do something. It's a lot of work and I don't know if it's the real answer although it probably does supply a better volume of oil to the mains. It's more difficult if you are using a Cool-Runner manifold because you don't have as much room in the valley. John, I've seen 3 moldex cranks. Two were cross-drilled on mains 2 and 4., 1 wasn't. The one that wasn't was in Oliver's engine but it now is. Now, it wasn't so much that I wanted to cross drill those 2 mains but it was, what I felt, "my" only option to help resolve the 3 and 6 rod problem. Now maybe the priority oiling did it but if it did it only masked the root cause. In my case and the parameters that this engine is run in something sensitizes 3 and 6 to starve for oil at high rpms. It's my thinking that if it had to do with grooves in main bearings, bores, lifter bores, oil passages whatever then shouldn't it affect a pair sharing the same main bearing or in the same region? Bruce Kent
Sorry guys Guys please,Bruce,John,Jim,Rick,Kerry I want to clarify where I'm coming from.I meant no disrespect to any of you,I was worried that when all the tech started flying that it would confuse the question at hand.I enjoy and learn from reading things you guy's post and the last thing I want is to see that stop.We have a very intelligent group of guy's here and we need to keep it that way.Jim W can you take Johns post on HOW TO INCREASE BBB LONGEVITY and make it permanent at the top of 400/430/455 race and if female 455 is ok with it put this thread with Johns if possible.Bruce,I would love to see pic's of your priority main oiling system you've probably forgot more then I know.Please keep the info flowing.
No disrespect taken here. I thought it was a pretty good exchange of ideas/solutions. I realized after I wrote the first one that it was beyond what the original request was. Sorry. Thanks for the compliment but I'm sure it's not accurate. I'm just a tinkerer. BK
Nitriding how to Prep Cranks We are talking about Nitriding Stock Cranks as well as Moldex Crank's. Not alot of people can do these Nitriding. Are we talking about doing the Mains and the Rods on these Cranks. I have heard that it bends the Crank and that you have to have the Crank Straightened. Are you taking a Std Crank on the Mains and the Rods and turn it 10-10 Mains and Rods. Can you go into detail what has to be done after you get the Crank back from being Nitrided. I have a Moldex 4.250 Crank and it is Std Mains and Rods. I have had it for sometime and am putting a 507 together. I would like to keep the Crank Std as it has not been use in a motor it is New. I am going to Run H bearings. I am going to but Nitrous to these Motor. I ran H bearings in my 464 with good luck and no Nitrided Crank. Also how many run H bearings. What are the feelings that people have on them. I have Mixed feeling about them on a Nitrous Motor i look at it as a must run H bearings. On all HP engine i think it is up to the Builder. We have built lots of street Motors with out H bearings.
Jeff, Nitriding cranks will not bend them. Only if the crank has been welded or if it is a raw forging that is unheat treated. MPI is real close to me and I had a long talk with the guy there and he has only seen 2 kinds of cranks distort. They would be the ones listed above. Your billet crank is not nitrided? I would get it done. MPI's #860 224-2648 His name is Hugh, give him a call.
Hi Guys, Question.....is or would Cryo'ing the crank in any way be a substitute or compairable to nitriding?o No:
There is no concern with nitriding stock cranks.. but a good crank grinder knows that they grow about .0002 in the process, and accounts for it. They have should be straighen/polished after the process.. once again, a simple inexpensive process in a good crank shop. Kerry.. While I can see the benefit of cyroing a crank (especially a 494 deal) I would be hesitant to say I would do that in place of the nitride process. JW
I would like to get answer. About Nitriding on a Moldex does it have to be turned after done?. I would like someone to go it to more Detail about the nitriding. I would like someone to go step by Step through these. Not everyone that does the Nitriding grind Cranks. So A it get Nitrided. B it comes back Crank Grinder what does he do straighten it ? Grind it ?. What does he do to it. I am going to have these done to my Moldex.
