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100k out of a 347 on street?
I keep reading about the way that the oil ring is intersected in 347's. Would this really be an issue on one that is driven on the street and won't see track time? How reliable are these kits? I am thinking of the Summit kit in particular. What do you think?
------------------ 86 GT T-tops, AOD, B&M shift kit and hammer shifter, ROH wheels, K&N, Timing,MAC headers, 2.5 off road H, 2.5 American Thunder, 87 spindles, rear disc,SS lines, BBK 1.5, poly bushings, Steeda G-trac and subs, Strut bar. "DRIVE LIKE YOU STOLE IT!" |
My 347 stroker kit is composed of an eagle cast steel crank, eagle h-beam rods, and JE SRP pistons. The piston pin is up real close to the oil ring land but it still doesn't need a spacer to support the oil control ring. I'm not sure how long a 347 stroker is designed to last, but if your talking about 6000 rpm plus action with a big roller cam, etc then I think something that is in the realm of 50 to 60,000 miles would be better.
Typically in the .600 + lift range and revs in the 8000 rpm range, the life of the engine can be measured in 1/4 mile runs. I don't think this means catastrophic failure but rather when a measurable loss in performance can be observed. |
Actually, the pistons pin intersecting the ring land ONLY matters on street driven cars. Most hardcore racers don't care too much about the small loss of oil caused by the comprimised oil control ring. A few years ago one of the big Mustang mags (either 5.0 or MM&FF) did an article in which DSS *claimed* to be able to build a 600hp 396 (351W block) that would live for 100K miles. Both DSS and CHP make kits with pistons that eliminate the oil control problem by moving the rings closer together. This fix seems to do the trick, but it could possibly cause other (smaller) problems in moving the rings too close. A 100K+ street storker isn't out of the question as long as you don't pound the sh!t out of it. You may also look into a 331 kit. A tad less power but the better rod/stroke ratio should increase longevity.
------------------ 1984 1/2 GT350 (#842 Hatchback w/ T-tops), 302HO, Comp cams Xtreme Energy cam, Carter 625cfm carb, Weiand Stealth intake, MSD distributor, MSD coil, FMS 9mm wires, 1 5/8" MAC unequal shorties, 2 1/2" MAC Prochamber H-pipe, Flowmaster 2 chambers, KYBs, 16"x8" 4 lug Cobra Rs, Falken 245/45ZR16s |
Actually the ratio isnt that bad. Better than the old big blocks. The 454 chev, and 427 ford, as well as a couple others I forget.
They'll last. Skyer ------------------ -1989 Saleen Mustang #406- TFS Heads, E-303, edelbrock intake,70MM TB, 73mm MAF, off road H, 2 1/4" exhaust, and 4.10's. 332RWHP@5500 351RWTQ@3750 Runs on 87 Octane! |
There is one minimal advantage to running a high ring pack. The closer you can shove a primary compression ring towards the top of the piston the smaller the amount of crevice volume. This nets an increase in compression and reduces a dead area in the combustion chamber. However for the most part this is for N/A motors since it is more prudent to keep a gasser or S/C motor's rings a little farther down so they are subjected to the more violent combustion events associated with chemical and mechanical super-charging.
OE components probably put the ring as high as possible (within the realm of durability) but have reached a point where they can no longer shove the ring pack up to reduce emmissions (thier primary concern) instead they are now reducing bore size to achieve the same effect. Hence the increase in strokes and the reduction in bore sizes. |
err, not subjected to more violent combustion events
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I have a Keith Kraft 347 kit in my LX. I do not think it will last 100k cannot keep my foot off the floor! 3.73 c-4, no glass hoods etc! 11.93 @ 111.4 and passes emissions!
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Dont know about 100K, but if you put the best in it, you'll get better results, Use the clevitt 77 H bearings, and get file fit rings, change oil ALOT, use a high quility filter.
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Why would you have to change your oil alot?? Just use synthetic oil and there shouldnt be a problem.
------------------ 347 Stroker Motor: Balanced, 30lb Bosch Injectors, Cobra Computer, Cobra Transmission, GT40 Ported and Polished Upper and Lower, GT40 Milled Ported and Polished Heads, B303 Cam, BBK 1 5/8 Headers, March Underdrive Pulleys, Electric Fan, Accel Performance Coil, Accel 300+ Racing Wires, NGK Plugs, Ram Air, K&N Filter, 77mm Mass Air Unit, FlowMaster Exhaust w/offroad H-Pipe, Hurst Short Throw Shifter, 3:55 Gears, Ram Clutch, Cross Drilled Rotors, High Tolerant Painted Calipers and Drums. |
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