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View Full Version : Cracked Block 1994 MC Prostar 190 LT1 - Fix?


Mike K
10-26-2011, 04:35 PM
My dad just told me that he's found two cracks on each side of the block on his 1994 MC Prostar 190 LT1. The cracks are all the way through.

Any suggestions on the best and cheapest fix?

He's located in northern WI.

I guess he's already gotten a quote for a new block for about $4k plus another $2k for someone else to do the work.

Any advice would be appreciated.

Thanks!

Spork
10-26-2011, 05:00 PM
Check local used ads...

Complete lt-1 $1000

http://houston.craigslist.org/pts/2610008272.html

Fresh rebuild

http://houston.craigslist.org/pts/2611871382.html

Another one $450

http://houston.craigslist.org/pts/2606626424.html

Jorski
10-26-2011, 05:06 PM
How did the block get cracked?

87MCProstar
10-26-2011, 05:20 PM
Ouch thats too bad, I'd look on f-body (camaro/firebird) sites as well. As long as you have all acessories you can just switch over off a long block.

vrsc
10-26-2011, 05:25 PM
you should be able to find a short block from jaspers for 2K

1redTA
10-26-2011, 08:16 PM
you could find a used automotive block, just look on your local f-body forum, cz28 or ls1 tech even a machine shop may have one ( less than $150 ). As far as the 4 bolt versus two bolt mains it shouldn't be an issue under 600 horse power

JimN
10-26-2011, 09:37 PM
My dad just told me that he's found two cracks on each side of the block on his 1994 MC Prostar 190 LT1. The cracks are all the way through.

Any suggestions on the best and cheapest fix?

He's located in northern WI.

I guess he's already gotten a quote for a new block for about $4k plus another $2k for someone else to do the work.

Any advice would be appreciated.

Thanks!

These are in the outer water jacket or in the cylinders, too? If the latter, stick a fork in it and call around for a reman. Personally, for $4K, I'd look at the GM Performance Parts 350 Ramjet crate motor, although they specifically state that marine use isn't covered. In that case, contact Jasper for a quote. It's not hard to swap the accessories and their warranty is 18 months with no limit for how many hours it runs. Have the heads checked and if they're OK, have a machine shop clean up the mating surface. If the engine has a lot of hours on it, it may be time for a valve job but that's not terribly expensive.

Who winterized it?

JimN
10-26-2011, 09:45 PM
How did the block get cracked?

Northern Wisconsin.

Spork
10-26-2011, 09:57 PM
cheapest route imo is to use a used auto lt1 here are some in mi

http://milwaukee.craigslist.org/pts/2670869884.html

http://milwaukee.craigslist.org/pts/2611329412.html

http://wausau.craigslist.org/pts/2614076407.html

http://wausau.craigslist.org/pts/2594500813.html

http://appleton.craigslist.org/pts/2650190820.html

http://appleton.craigslist.org/pts/2617295482.html

JimN
10-26-2011, 10:09 PM
[[email protected];798699]From this ad-"the engine is all here but the distributor" Huh?

http://wausau.craigslist.org/pts/2614076407.html

Spork
10-27-2011, 03:46 PM
[[email protected];798699]From this ad-"the engine is all here but the distributor" Huh?

http://wausau.craigslist.org/pts/2614076407.html

Dunno, some peoples kids:rolleyes:

1redTA
10-27-2011, 04:05 PM
[[email protected];798699]From this ad-"the engine is all here but the distributor" Huh?

http://wausau.craigslist.org/pts/2614076407.html

You don't want the automotive distributor, it hates water. just transfer your stuff over

JimN
10-27-2011, 08:02 PM
[QUOTE=JimN;798706]

You don't want the automotive distributor, it hates water. just transfer your stuff over

I would have thought they were done with distributors on LT-1 before '93.

1redTA
10-27-2011, 08:23 PM
I would have thought they were done with distributors on LT-1 before '93.

The distributor ( opti spark ) on an automotive LT1 is behind the water pump and dampner also it is driven by the cam thru a cam drive arrangement. any time a water pump's weep hole leaks it is on the optispark and will kill it shortly

JimN
10-27-2011, 08:29 PM
The distributor ( opti spark ) on an automotive LT1 is behind the water pump and dampner also it is driven by the cam thru a cam drive arrangement. any time a water pump's weep hole leaks it is on the optispark and will kill it shortly

Good place for it.

ctjahn
10-27-2011, 09:25 PM
My dad just told me that he's found two cracks on each side of the block on his 1994 MC Prostar 190 LT1. The cracks are all the way through.

Any suggestions on the best and cheapest fix?

He's located in northern WI.

I guess he's already gotten a quote for a new block for about $4k plus another $2k for someone else to do the work.

Any advice would be appreciated.

Thanks!

I found a crack in a 4 cyl race motor and had my welder (Pauls Welding - Brookfield, Wi) weld it. He is an expert at cast iron (not many are) but as some old welders are a bit of an opinonated old codger (spelling?).

We decked it, line bored it, and squared it up using the local machine shop. Why replace the motor if it is mostly good? (Maybe I am missing somthing but it seems like a few people have cracked blocks and replace the entire motor - I dont get it?) Maybe I am a cheapskate. (Although our blocks are a bit rare but $100 weld job and some machine work was no where near $500)

cj

JimN
10-27-2011, 11:23 PM
I found a crack in a 4 cyl race motor and had my welder (Pauls Welding - Brookfield, Wi) weld it. He is an expert at cast iron (not many are) but as some old welders are a bit of an opinonated old codger (spelling?).

We decked it, line bored it, and squared it up using the local machine shop. Why replace the motor if it is mostly good? (Maybe I am missing somthing but it seems like a few people have cracked blocks and replace the entire motor - I dont get it?) Maybe I am a cheapskate. (Although our blocks are a bit rare but $100 weld job and some machine work was no where near $500)

cj

Once cast iron cracks, it's not necessarily going to stop- it depends on how well it's cooled and where the cracks are. It could be cracked only on the outside but if the casting plug doesn't come out, it could easily have at least one cracked cylinder wall. If a good machine shop gets it, they may be able to salvage it but it's not a 100% certainty that the fix will be permanent. Welding cast iron it definitely tricky and usually, it needs to be at high temperature, then cooled slowly, so the stresses can equalize. Even then, it can take a long time for the stresses to do that.

The usually replace the motor because they don't want to have to deal with it again, possibly with really bad results.