I'm looking at building a 62 389 tripower motor for my 62 tempest. One of the problems with doing this is the high compression ratio. From what I understand E-85 works better in high compression engines so it would be a perfect fuel to use. Has anyone modified their tripower setup to operate with e-85?
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You need to talk to AlkyGTO. He runs his on alcohol, and knows all the ins and outs. You will need huge jets and you'll need to richen the mixture way up.
You might want to double-check your numbers. I ran that motor through my spreadsheet, and also through Wallace's calculator and found a +.060 389 with otherwise "nominal" dimensions (.020 deck, .042 gasket, 6 cc's in the valve pockets) and 68cc heads. Both came out with a shade over 10.3:1
Be sure you actually cc the heads instead of just using the factory number of 68cc's. Pontiac heads have been known to vary in volume and it doesn't take much variance to have an effect on compression ratio.
When I did the calculation the deck height was already set at 0 and gasket was .41. I assumed using a virgin block deck height was 0. Not sure where I went wrong?
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some may say i have too many projects
.020 won't make that much difference in compression. Pontiacs are almost always .020 down unless the block has been cut to bring them to .000. The operation is referred to as 'zero-decking' the block. It's a good thing to do to help avoid detonation by promoting cylinder turbulence via 'quench pad' and "covering" the sharp cylinder edges to prevent hot spots. If I rerun the numbers and assume the block is zero-decked, that's still just 10.87:1
What I want to do is build a 389 super duty motor (with 538177 heads). So if I use stock crank, forged rods, standard bore 400 forged flat top pistons, with a head and deck surface I should be ok on 91 octane fuel?
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some may say i have too many projects
Personally, on 91 octane I wouldn't attempt to build an engine with iron heads that had any more than 9.1:1 or 9.2:1 static compression. Some folks have successfully gotten away with pushing it past that a bit, but you have to really know what you're doing and select the right parts, stay dead-nuts on top of the tune up, cooling system has to be perfect, etc.
I'm looking at building a 62 389 tripower motor for my 62 tempest. One of the problems with doing this is the high compression ratio. From what I understand E-85 works better in high compression engines so it would be a perfect fuel to use. Has anyone modified their tripower setup to operate with e-85?
Quote:
Originally Posted by geeteeohguy
You need to talk to AlkyGTO. He runs his on alcohol, and knows all the ins and outs. You will need huge jets and you'll need to richen the mixture way up.
I run straight Methanol in my car but E85 is similar in that it is a corrosive fuel. That means no rubber hose and all aluminum parts need to be anodized to protect against corrosion.
Your fuel system needs to be set up to flow at least 30% (if not more) volume. More than bigger jets, the internal passages of the carbs will need to be opened up and I would recommend 1/2" fuel line up to the carbs and a high flow pump.
I would recommend calling Quick Fuel or even Cliff's to see if they have ever done this conversion on a tripower. I would think that one of the BG tri power systems would be more easily adapted to E85 than the stock setup.
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