Thread: spun bearings

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do you have it set to retard the timing when you start boosting.... if not you could be getting detonation which is hard on everything in the motor... also always always always check clearances.... so many factors... theres no perfect machining on anything, its close... really close but not perfect... then theres your torque wrench it could be a little off on torque.... and can get more and more off depending what depth socket and extension you're using....then there can be things such as bolt threads that can throw torque off.... that plastigauge stuff is one of the cheapest securities when building your motor...

the timming weights are removed and welded up at full advance. Runs 118 octane and normally 8 to 10 psi. he didn't want to run over 25 psi boost but the gates stuck and it boosted that high. car normally is mid 9 secs, when it over boosted it did two wheel stands in the first 60 ft then coasted to a 13 second 1/4. Spun all the bearings in that one run. The crank had just been turned and the machine shop checked all the rods and replaced 2 of them.

Originally Posted by chevydrivin

the timing weights are removed and welded up at full advance. Runs 118 octane and normally 8 to 10 psi.

Welding the timing in a fixed place isn't really the way to go. At low rpm, meaning under 4000, you need to have less timing and then as the piston speed increases, you can have more timing, thus the weights. MSD makes a wonderful distributor and it is all electronic plus it has the option of vacuum in addition as well, but it is up to you to set it to the desired performance according to the motor. But at 3000 rpm you would want say 32 degrees and by the time you hit 4000 rpm you could have the timing at 38, provided, provided, provided.

118 octance will allow you perhaps an additional 6-8 degrees of timing or 150-200 hp power adder. But it in no way can compensate for 25 lbs of boost. What should be done is to install a timing retarder that works off of the boost so when boost is added, the timing automatically retards.

I have mine set up for nos so that when I spray, the timing retards 10 degrees.

Originally Posted by pat mccarthy

hard to say R u on the same drugs as Me hey erik pass that back to me

No, but the story sounds a little fishy.

It has the boost controler in the MSD box that adv timming when boost increases.

Originally Posted by chevydrivin

It has the boost controler in the MSD box that adv timming when boost increases.

I sure hope you mean, the MSD box that retards timing when boost increases

Originally Posted by chevydrivin

It has the boost controler in the MSD box that adv timming when boost increases.

All I can really say is oh,my!!!
Advance the timing as boost increases and you will have nice little holes in your pistons..
RATTLE,RATTLE,BOOM,BOOM,GOOD BYE ENGINE!!!
DON'T TOUCH ANYTHING.L.O.L.

25lbs of boost on a small block = alcohol and 1500 hp. You're going to have a hard time keeping that engine alive no matter what you do.

Originally Posted by erik erikson

All I can really say is oh,my!!!
Advance the timing as boost increases and you will have nice little holes in your pistons..
RATTLE,RATTLE,BOOM,BOOM,GOOD BYE ENGINE!!!
DON'T TOUCH ANYTHING.L.O.L.

Ok did I say adv when I meant retard...............timming is not what I am asking about, my origanal question was, "will an over boost overcome the oil pressure"? Not what kind of fuel to run or what to set the timming at. And If you read, I said "normally runs 8 to 10 psi boost" NOT 25. The only reason it pegged out was because a gate did not open to control the boost to 10 psi.
If 25 psi boost = 1500 HP that would explain why the car did a wheel stand, got out of it and did a second wheel stand and felt like it was going to peel the tires off the rims. Car normally does not pick up the front wheels at all running 9's.

Now thats what I was thinking. But I am now expert, I can only imagine the force the bearings were seeing. They were worried about pushing the head gasket out, but...................it didn't.

Still say it detonated. No bearing or oil pressure will live with detonation. If it had adequate clearances and oil pressure, it wouldn't spin a bearing without detonation. There are cars running with twin turbo making 1000+ hp that are living fine without spinning bearings. Now if the engine isn't built right, that would be another story. I don't think that is the problem though beings the car runs 9's on 10lbs boost. If the waste gate stuck, there's no telling what the boost got to, but you could believe it needed more than 118 octane to run it. Do the piston tops or plugs show any signs of detonation? They may not show much since he let off so quick on the line but the whole engine would be toast if it had happened further down the track with the rpm up.

Sounds like it could be det......if it over boosted................

Camaro fever Where is Bayou, LA?

Across the ditch (Mississippi River) from Baton Rouge.

So you go to Capital city dragway? The car I am talking about has been there once....His cousin lives in Baton Rouge and is there all the time with his 78 camaro with the same twin turbo setup. We normally go to hub city or Lucas.

I go to Capital pretty regular. I go to No Problem in Donaldsonville more though. I'll keep a look out for the '78 Camaro. I'm interested in the twin turbo sbc setups and have been researching/developing a plan for one.