Here's a question for an expert Nailhead rebuilder: Last winter I rebuilt a 425 for my car. The original crank in it was virgin. It was one that came from the factory with .001" undersize mains. When I took it to NAPA's machine shop, I told them that the crank was already .001" undersized and to bear that in mind. They ground it .010 undersize on both rods and mains anyway. When I re-assembled the motor, I checked each bearing with plastigage. Rods were .002", mains were .003". (I preferred .0015" on each.) I wanted to get my car done in time for Flint, so I let it slide. I noticed that now when I changed the oil with a new filter, she makes a loud knock until the filter fills with oil. Also, when it's hot and after sitting for about 15 minutes, I can hear a faint knocking when I first start it. My old motor never did that. :blast: Aside from the cam bearings being too tight and the valve guides sticking up 1/4" too far (I caught that before the parts left their shop:rant: ) I wish I would have made them grind the crank to the next undersize. I was just afraid it would set it out of balance. If I could get .012" undersized main bearings I would but they don't make them. My oil pressure is good and I am running 10w-50 synthetic oil. Am I being too fussy over a thousandth or two or is this a real problem? o No:
I have used .002 and .003 for race engines, but that is because they have no break in time. Buicks are engines that need the close tolerances on the bearings to live . .0008-.0015 are the accepted clearances for a Buickou: ou:
Just what I wanted to hear. My first clue that these guys were'nt up on Buicks was when they didn't even know what a Nailhead was. One guy told me to put a little shim stock under the bearing caps, but I don't think that would be a good idea. Anybody got some suggestions or should I just fire up the impact?o No:
I wish there was a way to avoid that. I'd have to get it re-ground and balanced and it's hard to do that with the pistons in the engine and the engine in the car. That's a lot of work, and it would be expensive. It's a shame they don't just make .011" or .012" undersized main bearings.:ball:
It's a Fram. I filled it with oil before installing it the last time I changed my oil but it still knocked a little until it filled up all the way. :bglasses:
Anyone who tells you to use shim stock under a bearing should be hit in the head repeatedly with a hammer:af: Your only alternative at this point would be getting the crank cut again or build another short block and switch them when you have time. After what you said about the heads, maybe another engine that hasn't been touched by an incompetent rebuilder is the way to go. I've been burned before, so I know how you feel, but after all was said and done all I could do was call it an expensive lesson. Being that I'm the vengeful type it wound up being an expensive lesson for the other party involved as well(medical bills, loss of property, etc.:grin: ). I can give you an email address for someone who has a good 425 core(may even be runnable as is) if you're interested, I think he wanted $450 for it obo. Artie
This motor was a 80,000 mile virgin. The valve guides are OK now, I had him cut them down to exactly where they should be. He did a real good 3 angle job on the seats, and all the stems are sticking up within .015 of each other and are below the max. 1.540" as it says in the book. These were virgin heads, and I had the guides sleeved so as to follow the center of the originals. That keeps the seats concentric and that way you only have to cut a little to true them up. (I replaced the whole guides in my old heads and that screwed them up and they were never the same since. The original guides are not all concentric. Some of the seats were sunk down very deep in order to clean up. That makes the stem height too high and you have to add more shims under the springs to compensate, and the spring seats are no longer concentric with the new valve guides.) The block is only bored .020 over, and I am very happy with it. It made 220HP at the rear wheels on the dyno. It runs strong, doesn't burn oil, and like I said the only time it makes objectionable noises is when I change the oil. That is something I can live with I guess, but I'm a perfectionist. :bglasses: I wonder if it would be possible to have a set of .012" undersize main bearings custom made?
I'd zip that Fram filter off from your engine and put an AC or Purolator filter on there!!:TU: There has been MANY a thread on poor quality Fram filters all over the 'net!!:rant: :rant: Ticking noises are one of the issues. I believe the bypass valve was one of the Fram's problems. It would be nice if that was all that was causing your ticking.:grin: What kind of oil pressure are you getting? I know you mentioned it was good.
I'll take your advice. The only filter that I could find around here that fits is either a NAPA generic filter or the fram. I'm going to order an AC for it as soon as I find a place around here that sells those. The noise I have is not ticking, it is the mains knocking for a few seconds when I install the new oil filter before the galleries fill up with oil. The pressure is good. I haven't checked it with lighter oil though, I'm running 10w-50 synthetic.:bglasses:
Ahh.....got it!!ou: So...you effectively have a BRAND NEW 'high mileage' crank.:eek2: Unless you can get the machine shop to grind and balance another crank....you don't have too many options (except maybe align boring/honing). Only thing I can think of that might help (and not require you to pull the engine) is some kind of Pre-Luber. That would give you full oil pressure before you fire it up. I'd also be curious to know if switching to a 10w-30 oil might help at all.o No:
All I know is that NAPA's machine shop will never have the chance again to ever screw up another motor of mine. They told me the spec in their book is .0008" to as loose as .0034" and I should be OK. I don't feel like taking it all apart, or else I would have stuck that crankshaft in his ear and made them do it over again. I thought I was talking about being only 1 thousandth undersized, but 2 is much too loose for me, and 1 year later I doubt if I could get anywhere with them anyway. I should make them pay for the labor, gaskets, balancing, and new bearings. I'm really pissed!:rant:
I was so pissed I caled them. The spec is now .0007" to .0038".:Brow: After a lengthy conversation, I got him to argee to re-grinding my crank .009" or so smaller to the next undersize. He wanted to line bore the mains (blameing them for not enough crush) and said the noise I'm hearing is probably normal. He claims that 3 or even 3-1/2 thousandths is really all not that much clearance. That may be ok on something else, but not on my car. Buick motors are more precision than that. He's going to check out having a set of mains custom made .0115" undersize to save me all the work, but I will have to pay for the bearings myself. I'll go for that just to save myself a lot of work even though I think this whole thing is all their fault. Somehow I think that is all too good to be true.:af:
boy you have been thur a lot. this is what i do when i build a buick engine I check the algin bore first and make sure it is on the small end of spec if it is i then put my bearings in and TQ up the main bolts i measuer my crank then the inside of my bearings fiquer out the clearance i want and give this to my crank grinder doing it this way i have found no problems in getting the clearance wright. mike
Joe! I was just on the Egge Machine web site (egge.com) and they DO list .001 and .002 undersized main bearings! $127 for the set, pn MS2664-001. Hope these work out for you! And Mike....have you worked on nailheads??.....I'm right up the road from you. I'll be in touch about my present build..... And have you ever seen my GS cruisin' the 'boro??.....I miss those days! Where do they hang out these days?
Great! glad I got to you in time! I had trouble with the site too....it took a few tries... goto 'new online catalog'.... enter year....wait....enter buick....wait.....enter engine size....wait.....click on 'search'....the parts list page should come up. This should get you to the search page: http://www.parts123.com/PartFrame.asp?ZTM=cadegiia&GHOME=www.egge.com&TITLE=Egge It must use frames or something, so I can't find the 'address' of the parts listing... If you still have trouble, I'll scan the page I printed out and e-mail it to you...
Walt, thanks for the thought. I just checked out the site. My crank has been ground .010 undersize, I need .012" undersized bearings to fix my problem. The .001" and .002" undersize are for a standard sized crank and would give me .011" or .012" clearance. Custom made bearings would cost over $500 to make so it looks like I'm going to have to pull the crank and have it re-ground if I want to fix this problem.
