No5 Main Bearing

Having trouble keeping No 5 main bearing alive 120 lb oil presure on run, what crankshaft clearances would you normaly run B/E and mains. Car runs AA/FC PSI 72% overdrive 6.1 sec at 232 mph

 

Rolme,
The normal causes for #5 Main problems are; Not enough oil in the pan (#5 starves first and even after you take your foot off the loud peddle, it has to carry that clutch), line bore problems (either alignment or clearance), or out of balance clutch (if it's been certified and reassembled properly, that shouldn't be it).
The easy thing to check is if it's running out of oil too early (we have to run 17 quarts to keep ours from getting thirsty).
Good luck,
Marty

 

Our team had problems with this last year when we stepped up to a better roots blower than we had run the year previous. We finally ended up (after destroying two or three motors) running what Marty said (17 qts) as well as installing one of those Moroso Accusumps on the car which holds 3 extra qts of oil under pressure.

Seemed to work really well, we did not hurt one part after that...oh, and has anyone ever watched the oil pressure gauge when you throw the chutes out, or just after and seen the needle buried in the 0 area? Well, once we put the accusump on i noticed that when I pulled the chutes the needle didn’t go so far now, staying at around 15-20 psi (approx)...which to me I really liked because then we could tell that the bearings weren’t going absolutely dry at the end of the run.

 

Thanks for the input guy's.I have just had the tunnel line honed (not bored) B4 the last meet the engine has a P & P Fabrication's dual oil pump on it and we use Lucas Oil in it 2.5 Gal in the engine and 2.5 Gal in the oil tank. The clutch is new from Crower this meet. Any thoughts on what BE and Main bearing clearance you like to see?