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76x94 possible combination advice.
Posted: Wed Mar 12, 2014 6:05 pm
by art.b
So far I have a dual relief case bored for 94 cylinders, 94mm p&c set A pistons, Engle 110 or scat c35, stock or I:25 rockers,dual port un ported 40x 35.heads, dual or single springs, 8 doweled lightened or stock weight 200mm flywheels, kadrons or 44 idfs and 11/2 tri-mill exhaust what would be the best possible combination for a street Baja bug? Any input on the parts combination above appreciated. I have all these laying around ready to put together. As for carbs would a single 44idf be a better choice??
Re: 76x94 possible combination advice.
Posted: Wed Mar 12, 2014 7:37 pm
by volksbugly
I would go with the dual 44 idfs.. Engle 120 ? and have the heads ported. dual springs, a 8 doweled lightened flywheel, everything else sounds fine. Actually if your going to be doing any actual BaJa with it go with a center mount single idf 48mm, 44mm if you already have it. Just cause I understand duals get out of sync when your playing on the hills.
Re: 76x94 possible combination advice.
Posted: Wed Mar 12, 2014 8:15 pm
by Chip Birks
76 stroke with A pistons will stick the pistons a good way out of the top of the cylinders. 74xAxstock rod makes for a wide motor, 76 will be worse.
I recommend keeping the heavy flywheel, its a lot easier to get the car moving when you have a heavy fw, especially when you have tall tires and a heavy vehicle to get moving. Its not like you are trying to pull out of a turn on a road course or anything where a light flywheel is actually of use. You want grunt. Rotating mass will provide added grunt.
Re: 76x94 possible combination advice.
Posted: Wed Mar 12, 2014 11:38 pm
by Marc
Chip Birks wrote:76 stroke with A pistons will stick the pistons a good way out of the top of the cylinders. 74Axstock rod makes for a wide motor, 76 will be worse...
Marc wrote:....Some folks sneer at a "mid" stroke like the 76 or 78mm because they cost about the same as an 82 or 84mm yet still require clearancing...but the 76mm avoids most of the "packaging" issues that are typical of most stroker combinations if you use longer aftermarket rods.
"A" pistons have a compression height of 39.6mm and "B"s are ~33.93-34mm. This means that the B pistons will have stock nominal deck height on a crank with a stroke of about 80.3mm - at 78/78.4 or 82/84mm there's either too much or not enough, and the overall engine width tends to become a problem (sheetmetal/manifold fit, pushrod length...even engine compartment room).
But if you use B pistons on a 76mm stroke with 5.5" rods the piston deck height comes out nearly perfect, perhaps needing .020-.030" cylinder base shims to dial in (how much the case is cut down in the process of opening up the cylinder bores is a variable, of course) and other than some fairly minor clearancing work the engine goes together nearly as easily as a stocker.
The increased rod length also keeps the "rod ratio" at 1.84, still a bit lower than the stock 1.98 but not enough to make any significant change in the cam or intake port requirements. A low rod ratio tends to "run out of breath" at a lower RPM, requiring bigger intake ports and more carburetion...
I agree on keeping the flywheel heavy (at least ~16lbs, anyway) if you'll be running tall tires w/near-stock gearing, and avoiding duals for dirt work (they
can be made to work in the rough, but it takes dry-sumping them to totally eliminate the floatlevel control issues). If you'll be driving this on the street year-round a single 2-bbl will be prone to major hesitation on acceleration - even with a "deluxe" manifold that bathes the downtubes in exhaust heat, there just isn't that much exhaust gas flow through the heatriser passages with an aftermarket exhaust - if it even
has preheat flanges. With a 2-liter there'll be pretty decent flow velocity at the low end though so the flat spot won't be as bad as it would be on a 1600.
Re: 76x94 possible combination advice.
Posted: Thu Mar 13, 2014 4:32 pm
by art.b
sounds like a stock flywheel it is. I allways wanted to to try running a single idf. I have dual 44s and wouldn't mind switching one over to a single. thinking the c35 would be the cam of the 2 I have. Thanks for the input.
Re: 76x94 possible combination advice.
Posted: Fri Mar 14, 2014 10:13 am
by Phil69
If your planing on off-road allot you might want to consider an engle vz cam. They are quite hard on the valve train and lifter bores as the ramp angles are high. They are spec'd for std ratio rockers but I would personally run bolt up shafts.