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Re: another broken valley pan!!
[Re: hornetnut]
#1473798
07/25/13 09:21 AM
07/25/13 09:21 AM
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Joined: Jun 2003
Posts: 52,972 Romeo MI
MR_P_BODY
Master
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Master
Joined: Jun 2003
Posts: 52,972
Romeo MI
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Quote:
i dont have a way to post pics but i guess i should elaborate a bit, its a 67 440 with eddy perf rpm heads, milled down to 79cc's port matched and a perf rpm intake, 030 over bore with forged pistons, steel crank and rods, old ultradyne solid cam, all packed in a 74 amc hornet hatchback, now the first time i really stood on it it pushed the dipstick out a lil and pushed oil out on the header, so i figured at the time i must have over revved it, i went racing shortly after and it got really bad at the track and i noticed when i got it home that the valley pan was cracked, after some research i figured out that i had too much crankcase pressure and replaced the pan and added a breather to the opposite valve cover, i drove it in town for a while and thought i had it fixed, went racing again and it doesnt push the dipstick out anymore but it still cracked the valley pan
You still have way to much crankcase pressure... you need to watch some of those breather caps.. the port in the cap(the hole) on some is actually restricted alot with the stuffing in them... I had a pair of Summit ones that I had to bend open the metal tang in it and pulled out over half of the stuffing to get it to flow... just try blowing into the breather from the engine side.. it should be fairly easy... on the E-vacs.. if you run muffs you CAN run into problems.. the e-vac will pull about 5"HG and for every inch of back pressure in the muffs you decrease the vac by the same amount... until you start making pressure and blows the check valve out and starts pressurizing the crankcase with exhaust gasses.... the thing is that the higher your RPM goes it wants to make more pressure... thats why on the city driving you figured it was fixed(low rpm) and at the track you spun it up
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