Discussion in 'Race 400/430/455' started by Staged70Lark, Aug 31, 2005.
Well don't hold your breath.
Well heres another one done, can you believe this was only good for about 700 10-second passes, or about 15 years? (# 4 main)
Wait! Let me catch my breath! YOU broke something? Mr. pump gas? Mr. No stress? I just can't believe it! :laugh:
Yea, this racing thing sucks, breaking stuff all the time, I hope the next one lasts 15 years, :laugh:
P.S. Doug,Its hard to be king! :3gears:
You took the words RIGHT out of my mouth!!!
What.... Your not going to try gorilla glue?:grin:
John, was your engine internally balanced or externally balanced? Any block filler? What RPM did you turn it to? Yours is not the first to break #4, I don't buy the engine mount theory. I know olds pulls the side of the block off but I think Dave is right, girdle or no girdle, motor mounts or mid plate it don't matter there just weak. The block is thin at the bottom of the bores and around the webbing, well for that matter its thin everywhere's but anyways, the crank is very heavy and to boot its hanging way out the bottom. With crank in using main studs and no girdle you can take a screw driver between the crank and main caps and move the caps with hardly any force, I wonder what is moving around in there at 6400 rpm:eek2: #2 and #4 are longer, mine broke the pass side not the driver's side, and to boot the pass side of the webbing is the short side, the mount pushes on the block on that side not like the drivers side that pulls. It seems they break all over the place mostly just do to being weak. I was looking at a DRC engine in pieces all over the bench the other night and I couldn't stopping think man if only it said buick on it instead of olds, the only thing to worry about there is valve springs and traction, it makes 1200 relieable HP. One of the rich locals here past away this winter and the family is selling his collection of prostock stuff off. How about a Jerry Haas 1200HP 500ci complete with 4 stage oil system, vacuum pump, sheet metal intake, 2 carbs, a bunch of extra's etc $8500, its hard to stay loyal to buicks when theres stuff like this floating around ou: ........Chris
Yeah, there is no fixing it a weak block. :idea2: We can just bandage it and try to milk a little more out of it. The #2 main is a combination of things. I'm sure the #4,3 together (which tend to be two lean cylinders) in the firing order don't help but change the firing order and the problem just moves to another spot. As long as you address issues that can to reduce block fatigue, it all helps. Solid mounts isn't the sole cause of the breaks in the #2 but if I can take stress off that area, I am.
Solid mounts I can see causing a big problem. I use stock mounts with tie downs that bolt to the front and back of the driver's side head and are fully adjustable. Solid mounts sould not be used on these things. When you were talking about mounts Rick I didn't realize you were reffering to solid mounts. Sorry......Chris
so solid mounts are the ons that are causing this?
i guess i had it backwards.
Anyway, ill tell you my (new) plan and see if you guys think it will help.
first some background, 430 bored .027 over (custom forged pistons) ta sportsmans rods, girdle, .002 clearances all around (.0025 on the rear), sfi harmonic balancer and JB the wheel flexplate, main studs, head studs, no block filler ou:, 10.75 CR, expecting 750 hp.
Plan is to run stock motor mounts, and a custom made bracket that goes from driver side frame up to head, bolts to the head in spare bolt holes, goes across top of timing cover, bolts to passenger side head, down to passenger side frame, front and back made of steel.
what do you think?
Your mount plan should be OK but I personally hate those clearances on a 750horse application.
Chris, It was still externally balanced, no filler at all, I try to shift at 6,000, puts me thru the traps at 6,200, but I do have a 6,400 "chip" in it, which I bounce off of pretty regularly in the water box. Ask Bobb how "stock" this engine really was, nothing exotic at all, stock rods, iron heads, dished pistons, run on 92-93 octane gas, best run of 10.31 @ 3,200lbs. I did have solid mounts on both sides with a cable to the drivers side head, the crank and rod bearings looked great, so..........all of the internals, as well as the top end has already been put into another block that I had, this one does have block filler to the bottom of the water pump passages, I did decide to use a rubber mount on the pass side, but still used the solid on the drivers as well as the cable. I made a couple passes down the road this evening, seemed ok, so, it'll be loaded up for the trip to Bowling Green to try and defend my win last year in the S16.
Rob, I decided against the Gorilla glue.
I'd add a thou to those clearances too. But I think Steven will see closer to 600 hp when its all done.
:ball: at least 700 (hoping)
I'd be hoping for as much as possible too Steven, just trying to be realistic. :TU:
But you know a dyno printout will lay all the speculation to rest.
John, explain how this failure gets noticed, with the engine still buttoned up...you said you noticed it when you were changing the oil. I would like to be able to see this coming before the crank goes thru the oil pan...Thanks!!!
And good luck at BG!!!
how about if its girdled, wouldnt it not let it move away enough?
this foum sucks
someone not reading all the tips in here than can possibly prevent you from losing a block?
maybe if you could spell the it would make more sense....:bla: