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Knot 4 Me 10-06-2014 12:40 PM


Originally Posted by brian41 (Post 4198302)
Other benefits are the crank does not have to fight its way through the oil splashing on it, constant vacuum inside engine so no oil leaks and more HP. The only negative is the cost.

And if the belt falls off/breaks! :D

vintage chromoly 10-06-2014 12:45 PM


Originally Posted by Knot 4 Me (Post 4198344)
And if the belt falls off/breaks! :D

I thought of that but, the HTD belts are supposed to be the bees knees, the engine is enclosed and not subject to road debris damaging the system and ensuring good alignment should mitigate belt failure. The belt orientates itself via a "hat" washer on the crank pulley and, if aligned correctly, centers itself on the driven pulley.

But, yeah, it would suck if you lost the belt! Lol

JRider 10-06-2014 01:03 PM


Originally Posted by Knot 4 Me (Post 4198344)
And if the belt falls off/breaks! :D

Pressure switch should be all that is needed.

14 apache 10-06-2014 02:19 PM

You need the oil cooler or you will need a new engine.

vintage chromoly 10-06-2014 03:49 PM

I do have this mercruiser oil cooler. I think it's the hp502 type but I'm not certain. It has 1/2" NPT threads on the oil in and oil out. Would this suffice for flow and cooling capacity?
Pretty sure they make a 1/2"NPT to -12AN fitting.
http://i205.photobucket.com/albums/b...ps891419c0.jpg
http://i205.photobucket.com/albums/b...ps5a044178.jpg

brian41 10-06-2014 04:07 PM

You will want a thermostatic oil cooler that will handle your HP goal +20% to insure proper oil temps. Never lost a belt and proper tension will keep the belt centered, to tight they walk to the front of driven pulley. You should be able to slid the belt back and forth on the driven pulley with your fingers with moderate force. We run 4 stage pumps up to 600 CU and regulate the vacuum to 6-7 inches. No breathers on the valve covers, vent the system from the tank to your flame arrestor. If you use a vent tank you with always have a oil smell when you come to a stop after a good run.

Cole2534 10-06-2014 04:10 PM


Originally Posted by vintage chromoly (Post 4198431)
I do have this mercruiser oil cooler. I think it's the hp502 type but I'm not certain. It has 1/2" NPT threads on the oil in and oil out. Would this suffice for flow and cooling capacity?
Pretty sure they make a 1/2"NPT to -12AN fitting.

Yup, they sure do.


Originally Posted by brian41 (Post 4198444)
No breathers on the valve covers, vent the system from the tank to your flame arrestor. If you use a vent tank you with always have a oil smell when you come to a stop after a good run.

Good tip.

vintage chromoly 10-06-2014 04:28 PM

Thanks for the replies guys.

So, if I use a bypass thermostat on the oil cooler will the cooler I have work with the 1/2" NPT in and out?

Brian, how do you regulate the crankcase vacuum and what size vent hose to the flame arrestor?

Thanks, rob

lightning jet 10-06-2014 04:36 PM

Only use that used oil cooler if you know the history of it ,if a motor has ever gone bad like spun a bearing with that oil cooler it is scrap buy a new one.

brian41 10-07-2014 06:48 AM

1 Attachment(s)
I reverse engineered them from Moroso vacuum pump system and they worked great.


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