96 Prostar cracked block

[96sammyd]

Hi guys,
I have a 96 prostar 205 Sammy Duvalle. I took it in to get some work done well they noticed a crack around the plug. They called wanted to make sure it was ok to hook it up run it... well now we have chocolate milk oil. So it has a 5.7 Indmar engine, what the best option??? I havn't heard good things about Jasper? Can I buy a chevy truck motor and transfer the marine parts over? I know of a Chevy truck rebuild able block, Is that an option? Or do I have to go marine block? any thoughts are welcome Thanks!

[1redTA]

yes, use the same block and exchange the marine specific parts

[CruisinGA]

Look at Michigan Motorz

[Maristar210]

Look at Michigan Motorz

^^^^^ I second

[tjrowbot]

If you can swap the block yourself 100% agree with the two above. I have heard nothing but great things and they rebuilt a neighbors 5.7 Predator.

[mikeg205]

you wrote - well now you have chocolate milkshake oil?? did you before you took it in?

[96sammyd]

Thanks for the information guys. No it was not like that before i took it in. They said when they got it the checked the oil it looked a little high on the dip stick but once they ran it, it then turned to cream color

[Cumminscj]

Was the boat properly winterized? If so and it was done before you took it in I would be looking for second opinions.

If it is truly cracked I would get a block and get everything swapped over. Use appropriate freeze plugs and gaskets. I would probably have a machine shop check the heads out a do a valve job. Or at the very least lap the valves yourself and replace the seals. I know my machine shop would build the engine for me for around $2,500. I currently have them doing a friend's engine I don't have time to build. I sourced a couple used LT1 blocks for my 205 with and LT1 for $150. Bought the boat as a project due to the cracked block. Plenty of options out there depending on your skills and how much time you want to invest

[Double D]

I had Michigan Motorz replace mine with a new long block a year ago. Good people.

[JimN]

Hi guys,
I have a 96 prostar 205 Sammy Duvalle. I took it in to get some work done well they noticed a crack around the plug. They called wanted to make sure it was ok to hook it up run it... well now we have chocolate milk oil. So it has a 5.7 Indmar engine, what the best option??? I havn't heard good things about Jasper? Can I buy a chevy truck motor and transfer the marine parts over? I know of a Chevy truck rebuild able block, Is that an option? Or do I have to go marine block? any thoughts are welcome Thanks!

I used Jasper after going through the tour of their factory- never had a problem. As long as the rest of the components are in good condition, you could search for the same engine (look behind the bell housing for the casting numbers) or find a good used engine that matches.

If the crack isn't too long, I know of people who ground a groove and applied JB Weld- never had a problem, either.

Make sure to use marine gaskets if you rebuild.

[96sammyd]

Thanks for all the help, I have dug into this issue more. So the dealer never saw a crack they just noticed I didn't leave the block drain plugs out. So they checked the oil and saw it was higher than normal. So they hooked it up and ran it, well instantly noticed chocolate milk in the oil. So I brought it home pulled the motor out this weekend. Once we pulled the heads off we found the crack in one of the water jackets. It was kinda odd to us that that the crack was on the front end of the motor (the high end of the block)? But it doesn't matter now I need a new one.

[mikeg205]

sorry to read that.

[Totem1]

Have a crack block also and looking for options. Larry at Indmar recommended buying a replacement block from Michigan motors and waiting to hear back; however, not sure of the condition of the 2000 Mastercraft Pro Star 350 C.I.D. 5.7 Liter 310 HP fuel injected engine with 270 (supposedly) original hours.
Do not have the experience or tools to rebuild and from the few places inquired at doing a rebuild commented that probably more damage than just the small freeze crack in the block.
Where did you find the replacement engine and who is Jasper?

Stay safe.

[3event]

Try here:
https://www.jasperengines.com/

Good luck and please do post back, for those of us also considering repower.....

[Totem1]

Appreciate the information and will contact Jasper. Saw several good comments on them.

Stay safe.