Blowed Up (The Post I never wanted to make)

[woody45]

Well last Sunday I pushed the 455 in my 71 GS to far. Getting on I-575 I wound it out to far it went up in a cloud of smoke. Towed it home found #5 spark plug smashed & antifreeze poured out,also found the crankcase full of antifreeze.
Today with high hopes I dissembled it(oh no). Found the piston in pieces with parts all over and a big crack in the cylinder wall What to do:It seems that the pistons are Speed pro Hypereutectic. #1 & 8 are H392NCP-.030/125-04-09-A and all the rest are H392NCP-.030/125-04-09-B (whats the diff between A & B)?
The block is a 1231738 block (1/2) oil pick up/Code TA,heads #1231786/intake #8-1236403/ painted in white under the timimg cover (1708930?) All points to a 71 Riv GS engine. Questions are: 1.Can the block be sleeved when its .030 over. 2.What is the difference between #1&8 pistons stamped (A) and the rest stamped(B) 3.the only marking on the cam seems to be cast #1231304 (stock?)3. why these pistons with 4 valve receses if the rest is stock? 4. Is there a machine shop in the Atlanta area that I could trust to do this repair if it's possible.Guess this is the time to detail the engine bay. Thanks, Woody

[Yardley]

Ouch. Sorry, Woody.

Why would you want to repair this block? Is it a numbers matching block? If not, I'd just find a good 455 core and start from scratch and build a 500HP beast.

A 455 block w/ forged slugs. Hot cam. Roller rockers. TA Aluminum heads and SPX should get you there.

[woody45]

Hey Yardley, Begining to wonder myself, It's not a number matching engine,but it's the one I cruise around in. Its a 71 GS 455 convertible. I'm not sure what it came off the line as. I was just wanting to find out if could be done and approx cost.
I also have a red 72 GS 455 convertible,the engine in it has a block girdle,cam & solid lifters & roller rockers it's pretty stout. Don't know why it has a 650 holly,but with parts from Greg Gressler I'm putting together a 800 quad for it. To this point I had not dissembled either engine to see whats in them. It was a suprise to find this one was .030 over. I'll see which way is the most cost effective. Woody

[TheFly]

How far did you push it, what RPM did it let lose???

yea a 650 sounds small.

[woody45]

I'm guessing here but I'd say about 5500 it caught me by suprise happened quick. Iguess I'll put the 800 quad on the other GS for now to see how it does. I've only run it several times, on street tires & the 650 needless to say wouldn't hook up. I think my best was low 13@99mph. Pulled the cam out of the one that came apart the markings on the back are TA 212 39406 m 232069 haven't reserched it yet anyone familure with it. Still hashing over what to do. Woody

[TheFly]

Sounds low but I don't know 455's, sucks though.
Sorry for your wallet ;)

[LARRY70GS]

You may have detonated the engine. Hyper pistons do not like detonation. It doesn't sound like you know how high it was spun. How was your oil pressure?

[greatscat]

I'm guessing here but I'd say about 5500 it caught me by suprise happened quick. Iguess I'll put the 800 quad on the other GS for now to see how it does. I've only run it several times, on street tires & the 650 needless to say wouldn't hook up. I think my best was low 13@99mph. Pulled the cam out of the one that came apart the markings on the back are TA 212 39406 m 232069 haven't reserched it yet anyone familure with it. Still hashing over what to do. Woody

Use the block as a planter,the pistons will make good wheel chocks and start over with a 71 or later block so the oil mods are done,do it right and go have some fun in the 12's
gary

[woody45]

Well I got the block out of the GS. On the side of the block is a metal remanufactured tag with the # 703537 on it. Also got the cam out found it is a TA 212 camshaft (25hp increase over stock), As I said the pistons are Speed Pro Hyperectectic .030.
Curious about what company the reman is from. From what Iv'e found from a repidal machine shop I should be able to sleeve it for Approx $120. and if I go back with the same piston $50. + gaskets it may not be to bad. It would be a cruise night & driver for fun.

Woody

[woody45]

Ok got the block out of the GS yesterday,as I said before it was my fault I think. I'm sure the problem came from detonation and I was running alot of initnal to get the idle I wanted and had not had the time to recurve the dist for the max of 36 degrees. The dist is a rebuilt also with alot of shaft end play I'll address that later. Also both of my GS's are still running the restistor wire with 9 volts at the coil running, both have been converted but I don't know what kit they have (any ideas in this area,conversion kits,rebuilt dist,or parts)
The engine I found out is a remanufactured engine (metal tag on the block no name) the pistons are Speed Pro Hypereutectic .030,the crank has been turned .010,and the cam is a TA212, and the block has 1 sleeve in it now.
Looking at some of the other pistons there appears to be some cracks around the pin areas. Comparing these pistons with the stock they almost appear to have to high compression ratio> Has anyone had experience with these pistons in these engines.
I dropped of the engine at the machine shop that does some work for Then & Now for inspection trying to save$$$$$$$$$$$$$$$$
This GS will be a driver fun car for the weekends & cruises any information on any of this would be helpful.
Woody

[TheFly]

Id get Dave to fix ya up, chep and he knows his Dizzys.

http://www.davessmallbodyheis.com/

Id just make sure and doc all you do well so if they car is ever sold least maybe the first few owner will know not to push it hard.

[V8s4ever]

Those pistons are junk.I would rather have stock cast pistons than hypers.For any performance engine forged is the way to go.

[greatscat]

Ok got the block out of the GS yesterday,as I said before it was my fault I think. I'm sure the problem came from detonation and I was running alot of initnal to get the idle I wanted and had not had the time to recurve the dist for the max of 36 degrees. The dist is a rebuilt also with alot of shaft end play I'll address that later. Also both of my GS's are still running the restistor wire with 9 volts at the coil running, both have been converted but I don't know what kit they have (any ideas in this area,conversion kits,rebuilt dist,or parts)
The engine I found out is a remanufactured engine (metal tag on the block no name) the pistons are Speed Pro Hypereutectic .030,the crank has been turned .010,and the cam is a TA212, and the block has 1 sleeve in it now.
Looking at some of the other pistons there appears to be some cracks around the pin areas. Comparing these pistons with the stock they almost appear to have to high compression ratio> Has anyone had experience with these pistons in these engines.
I dropped of the engine at the machine shop that does some work for Then & Now for inspection trying to save$$$$$$$$$$$$$$$$
This GS will be a driver fun car for the weekends & cruises any information on any of this would be helpful.
Woody

As I said before,use the pistons as wheel chocks,there are problems around the pins with these,the piston to wall clearance is so tight they tend to fail there.I've seen several motors with this problem.
gary

[nick rabi]

Dump those hypers!!

[woody45]

I know where there are 7 -.030 over Hypers avalible.
Woody