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View Full Version : Repowering with 572 clearance issues



Jeff V
12-06-2006, 11:40 AM
Has anybody put one of these 620 hp engines into a 22 yet? They are one impressive crate engine. Wondering what issues you have with the increased height of the block with carb clearance and exhaust both in height and the transom and how you delt with them. Would you recommend increasing piston clearance for a marine application?

BUIZILLA
12-06-2006, 12:40 PM
with a big carb, your prolly going to have a problem, port injected might work without cutting things...

your gonna need closed cooling, unless it's a dedicated fresh water usage only combo.. lotsa aluminimium in those craters..

Pismo
12-06-2006, 02:02 PM
Good stuff........


http://www.offshoreonly.com/forums/showthread.php?t=61488&page=3&pp=20&highlight=zz572

http://www.offshoreonly.com/forums/showthread.php?t=107527&highlight=zz572






Looks like reversion is a problem which can be solved with a new cam, maybe new valves. Clearance debate is endless. JE says open them up some, others say merc HP motors are regular automotive clearance motors.

BigGrizzly
12-06-2006, 07:23 PM
Very familiar with this problem and the exhaust system has to have a reversion ring built in it. We actually build ours up to 700->735 without an issue ,but silent choice is an issue. You need a good 4 inch ID exhaust pipe with good tube design. EMI type don't cut it. Y my exhaust does have the ring in it too, even thoe it is a 502. As for the transom assy it is the same as a 454/502.

roadtrip se
12-10-2006, 02:19 PM
while we're talking clearance, what about the Ilmor MV625?

As far as I can tell, the height isn't the problem. Pretty comparable to the Merc 500 risers and such, but the problem is the 3 inches of additional clearance needed for the twelve quart oil pan in the bilge.

Just dreaming, but looking for informed opinions and ideas.