56ci OMC realistic power

[filthy phill]

I read that the early 56 was sandcast blocks then went to lost foam around 1988 - 1989 when the sst60 with its hand finished lost foam block was introduced.
funny how those that worked at omc building the motors would get that wrong .

be nice to know how they used a permanent mold to do the closed engine exhaust.

[Mike Wienandt]

The early 56 block was not sand cast. It was permanent mold. The surface was smooth and shaped very well. The proto type engine tested for SST 60 was made of this, but when the engine was manufactured, it came out as foam block and did not run as fast as the prototype. The permanent mold blocks were never legal as they are faster. The foam block were cheaper to manufacture and issues like the glue lines slowed them down. Ports in the foam blocks were less consistent.
Most engines that come to me are very worn out. I can rebuild with fresh good parts and make them good. But I you say I need to win, it is much harder because then only certain parts are required to do that. Those are hard to find, impossible to make.
I need a good clean block, not hard to find. I use my own special liners. All with in the rules. I can fix the bad boost ports per the rules. But you still have a missing link.

[filthy phill]

Mike Wienandt

would it be better to use the head from the oval port 56 being as its thicker material ? part no 339221 normal thickness is 0.240 (6.096mm) at thermostat area.
if machined down to sst60 spec it still leaves 0.0150 (3.81mm) at the thermostat area, not as ultra thin like some bridgeport 56 heads.
I measured at the thermostat and at the bottom area to see if both the same and they are uniform from what I could see.

[Mike Wienandt]

Yes, that sounds like good idea.

[MODIFIEDOUTBOARD]

I understand what you mean by the cowbell shape and I finally found the thread that had the inlet and outlet size specs of the sst 60 tuner barried in fast freds mod 50 secrets page 76

http://www.boatracingfacts.com/forum...hread-2/page76

inlet on exhaust base plate 1 1/2" x 1 3/4" outlet 2 3/8" x 2 3/8" what over all length works best in a long shaft mid is what I'm trying to figure out now. I've got a tig welder so welding up my own tuner isn't an issue trying to come up with ball park specs for when I finally get to tearing into my spare engine.

this is for etec 90ho - 75hp triple, looks really close..................................get gasket #6 to verify

http://www.ebay.com/itm/350538-Inner...5Yu9EG&vxp=mtr

[Mike Wienandt]

Measure the length from powerhead gasket to the end of the tuner. Make it 1" longer than the SST 60 spec for a V bottom. It will have more bottom end yet rev high enough to make you go fast.

[hupiveneilija]

Mike Wienandt

would it be better to use the head from the oval port 56 being as its thicker material ? part no 339221 normal thickness is 0.240 (6.096mm) at thermostat area.
if machined down to sst60 spec it still leaves 0.0150 (3.81mm) at the thermostat area, not as ultra thin like some bridgeport 56 heads.
I measured at the thermostat and at the bottom area to see if both the same and they are uniform from what I could see.

This is what i said somewhere else. I got one yesterday that im going to use next, modded offcourse.

Question: wich headgasket 1mm or 1.5mm? Easiest to get here is thicker sierra but wich is better for squeeze area in this engine? And how thin you can go for it, havent decked block yet.

And thanks for writing those things, really good information and very clear said!

[Mike Wienandt]

Are both head gaskets the same quality material. The really old black OMC ones were best but can't get them anymore. As far as the thickness, Check the squish clearance. Don't want less than .040" or 1mm
Does the piston stick up above the block, any amount then use the 1.5mm
Good luck
Mike

[hupiveneilija]

Thanks,
Jani

[ferdthe4]

Measure the length from powerhead gasket to the end of the tuner. Make it 1" longer than the SST 60 spec for a V bottom. It will have more bottom end yet rev high enough to make you go fast.

Thank you for the advice my issue is still how long are sst 60 exhaust tuners? Maybe I've been looking through all the wrong threads but I haven't been able to find what the length of sst60 tuners are.