My Bad Luck, Should I order a new Block??

Discussion in 'Race 400/430/455' started by badbuik, Sep 5, 2005.

  1. gs455david

    gs455david Well-Known Member

    Forged shortblock perhaps

    Gary,
    I have a .30 over TRW forged piston shortblock with a stock crank that has only been polished and not yet turned. It will need new rings and bearings, but it is a balanced assembly that was good for me. It also has a Hemi Killer cam that goes with it. ARP bolts are in it, Stage one oil pick up, etc. $400. 1-619-516-6631 David
     
  2. jmccart

    jmccart John McCarthy

    I am about 3 hours away, I have 3 455 blocks, 2 are standard. Need one? PM me if so.
     
  3. Staged70Lark

    Staged70Lark Well-Known Member

    Gary,

    When you say the bearings were bad are you talking rods or mains or both? What solid camshaft were you running? Its been my experience that a 12.8:1 464 with aluminum heads needs a minimum of 268 degrees of duration on the intake side with 110 lobe seperation to keep the intake valve open long enough to not build too much pressure. This is for naturally aspirated engines. I dont know enough about nitrous to say how it will effect cylinder pressure and therefore its effects on the bearings.

    The intake valve closes a certain amount of degrees after bottom dead center. At that point it will start to build cylinder pressure. The art of cam timing is to find the ideal time for that intake valve to close and begin to build pressure. If it closes to late then your engine doesn't make the kind of power it should. If it closes to early then it make too much pressure and litterally trys to push the piston back down. I have also heard that a nitrous engine needs an additional 10 degrees of exhaust duration than a normally aspirated engine. Did you have this??

    If your crankshaft was cracked in that many places then you definately had something going on. Was is the cracks in the block that caused it?? or something else??? For you to go 9.31 at 3600 lbs takes around 900 hp :Do No: So you were definately making some big HP.

    Gary thanks for taking the time to answer my questions. I am a real advocate of this main oiling mod and want to make sure it isn't causing any problems for us.

    Thanks
     
  4. badbuik

    badbuik Well-Known Member

    John, I think that the crank cracked due to just being weak after being turned .010 on the rods and .020 on the mains, and the offset grind, that or just detonation while "squeezing" it. Or just bad luck....Which came first, crack in block or crack in crank?????? Light weight JE pistons & GRP aluminum rods, have to be "easy" on the crankshaft. The bearings if I remember right, the #3 Main was badly worn, not "spun" but pretty close, #4 main worn bad,no bearing material and showing alot of the copper backing material, and I think that the # 5 & 7 rod bearings were gone. I have thought about this alot, did all this happen in that one instance, or was something else going on prior. I know that I never reved the motor until oil temp was at least 100 deg. The cam I run is basically a TA 408s ground on a 110 lode center, cam card says to "deg. intake lobe to 108". I run 1.7 roller rockers, lift is .654 Int, and .671 Ex, at the cam it's .385 I, .395 E, dur. at .050 is 274 I, 288 E, I was running .024 lash, and I always degree the cams in to what the cam card says, card says "Int opens 48 deg. BTDC, Exh closes 50 deg ATDC, Int closes 84 deg ABDC, and Exh opens 94 deg. BBDC" There is different info. for degreeing, "Int opens 29 deg. BTDC, Exh. closes 32 deg ATDC, Int. closes 65 deg. ABDC, Exh opens 76 deg. BBDC." Is this enough overlap to keep cylinder pressure down?? It's like 36 / 44 deg. of overlap, right?? No, more like 98 deg., right???
    I'm just starting to think that I've just had some bad luck, I would still do all the same oil mods. I think I have been pushing this pretty hard, and something had to give. Like I said before did all this happen crossing the finish line @ 6800 rpm and running for 1 min. + without oil press., or was something else going wrong prior, maybe, seems like it's just open for speculation. I really appreciate the input John and others.
    Gary G.
     
  5. Dan Gerber

    Dan Gerber Founders Club Member

    Hi Gary,

    Sorry to hear about the engine damage. I've always been impressed by what you've accomplished, and I hate to see you experience such set backs.

    Believe it or not, I may actually be able to help you with your block. I'm enrolled in an engine blueprinting class at Cypress College, which just happens to be touching on the subject of cast iron engine block repair methods this week. The instructor, Mike Dighera (owner of Mike's Speed & Machine, Santa Fe Springs, CA) specializes in this type of service. He and his partner have repaired a number of cracked cast iron 1000+ HP Chevy aftermarket blocks successfully utilizing certain brazing procedures.

    Anyway, I forwarded your story and photos to him so he can at least get an idea of the extent of the damage. When I go to class tonight I'll ask him what his thoughts are. Of course, he'll have to examine the block in person to give a final answer, but he may be able to at least determine if it's worth going any further.

    Judging from our initial telephone conversation regarding the damage, I suspect that the crack that extends into the cylinder bore is the "kiss of death".

    Good luck.
     
  6. badbuik

    badbuik Well-Known Member

    Hey Dan Good to hear from you. I really appreciate the info. If you need to call me, here's my cell # (858) 531 -2963, or anyone else. I'll actually be going up to Long Beach on Sunday for the swap meet. Just let me know if he'd like to see the block or whatever.
    Gary G.
     
  7. Dan Gerber

    Dan Gerber Founders Club Member

    Well Gary... I can honestly say that the next dose of nitrous your engine sees (repaired or not), will be its' last. Actually, I suspect that the next low-10 second run it sees will be its' last (repaired of not).

    My instructor advised against trying to repair it... primarily because of the crack that extends up the cylinder wall. He doesn't feel that a repair in that area will survive, especially at the power levels your engine is producing.

    He's confident that he can repair all of the other cracks "as good as new", but the cylinder wall is another story. A contributing factor, by the way, is the hardblock. Grinding the crack out of the cylinder wall will expose the hardblock, which probably will contaminate the subsequent weld or braze.

    You may want to contact him regarding the possiblilty of him checking it out in person and possibly repairing it for use as, say... a low-11 second street/strip motor. His business number, by the way, is 562-522-2878.

    Frankly, speaking as an overly cautious novice, I advise ordering a new block. When you consider all the $$$ you have invested in parts that attach to, or are installed in the engine block, and how fast all those parts could become scrap metal if the block destroys itself in some spectacular fashion, it makes good economical sense to start with a bullet-proof block.

    Of course, if you take all the advise that overly cautious people hand out, you'll never have any fun. Will you? :)

    Anyway, good luck and let us know how this all plays out.
     
  8. got rice?

    got rice? Well-Known Member

    mabey if all else fails,just sell what you can,and just buy a entire big cube engine from world if you race all the time.i know its not a buick,but hey,it didnt come from a chevy factory either.
     
  9. leo455

    leo455 LAB MAN

    Ok , I have not built a motor to this extent,but it sounds to me the motor was starving for oil before the belt thing happen. I have seen this same problem on 450-500 hp motors.Not to the extent of cracking up the clynder wall, but other wize , Yes. I am not pointing fingers at T/A but something had to be plugging up the oil passage. The belt coming off just finished it off. Find a 75-76 block and go on!
     
  10. badbuik

    badbuik Well-Known Member

    John Z. are you out there???Just wondering what ya think, haven't heard from ya after I posted the info.you requested..
    Gary G.
     
  11. Staged70Lark

    Staged70Lark Well-Known Member

    Gary,

    Lets start by saying I know nothing about the effects of nitrous on an engine!!

    But... the camshaft numbers you gave should be fine for an iron or aluminum headed naturally aspirated 470 CID combination. With the program I have your dynamic compression ratio is fine and comes in around 8.6:1. If you use the same cam with your new crankshaft and say its the same compression then your dynamic compression ration will be around 9.8:1. Thats wayyyy to high even for a naturally aspirated combination. Everything changes when you change the crankshaft stroke!!!!!

    I wish I knew more about using nitrous and how that effects the camshaft that you use. From what I have heard you CANT build a naturally aspirated engine and then put massive amounts of nitrous to it..... it simply will not last. The guys that I know have there Engines and Cars setup up for nitrous. There isn't a dual purpose setup here!!!! When the car runs without nitrous its a pig. But with nitrous lookout. From what I have read with your combo, you tried to set the engine up for a naturally aspirated combo then put nitrous to it. And your results were not that good. What I dont want to see you do is put this thing back together the way it is and with or without the new block you have the same results.

    Here is factual information that I can give you. My 535 Buick with 14:1 compression has a 286/296 duration at .050 camshaft its ground on a 113 LCA and installed at 111. Most people in the Buick community say this cam is wayyyyyyyy to big. When it was first suggested to me by an Oldsmobile friend to run this cam I just couldn't believe it. I of course said the cam was wayyyyy to big. Then Scott Brown at Straightline Performance (Very knowledgable Buick guy) suggested the same cam, I just kind of shrugde my shoulders and said... OK.... lets have it done. The Olds guy said when installed you should have around 210 psi of cranking compression. Waaaallllaaa.... its right at 210. This engine has many passes and knock on wood.... its been good thus far. However I am having a problem with the oiling system sucking in the bottom of the oil pan.... I gotta figure this one out!!

    In conclusion... I think your engine would have been fine if you ran it without the nitrous. The addition of the nitrous and the extra cylinder pressure that the nitrous has to give probably caused some problems. TALK TO SOME N20 EXPERTS to find out what cam to run in your engine. The one you have is more than likely too small. Give Scott a call along with other knowledgable N20 guys. Also make sure that oil pan isn't sucking up in against the pickup.... Crazy stuff truly happens.

    If you want to talk more about this just PM me your phone number and we can chat. I am horrible at typing LOL.

    Later
     
  12. gymracer01

    gymracer01 Well-Known Member

    Mains!

    I'm not sure if someone touched on this in another post as I didn't take time to read all of them. But I have been told to never tighten the studs in the block, just screw them in by hand, they say that if you tighten them the block will crack. Also, the type of lube determines the torque. I think for the ARP studs I just put in my engine it was 90 lb.ft. with their lube. I would never waste the money on trying to weld it. Just me.
    Jim Netherland
     

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