my mustang has recently (for the last couple months) been blowing smoke at high rpms, constantly if im above 3500, or if im getting on it hard. It did ok untill i started running above 10psi, now around 12psi it blows smoke hard (oil). Im guessing its the piston rings, but just wanted to see if there was a better way out of this. Anyways who sells a good rebuild kit that i can handle up to 14 psi? also what would be a good cam with stock heads and the intake i have? thanks!
blowing smoke over 3500rpm and under boost
- Thread starter davins130
- Start date
WHITE94COBRA
New Member
Check your dipstick, Sometimes the pcv system isnt up to the task and excess pressure builds up and blows the dip stick up a bit, them oil goes all over the headers and causes the smoke. Check there first.
i had thought i may have to do with the pcv system, i replaced the valve. I noticed a lot of oil on the top of the tranny behind the motor also, seemed to stop building up back there after i replaced the pcv valve. on the freeway over 80 is when the smoke comes tumbling out, its around 3500rpm i beleive but i dont think there is boost involved there, but i have never looked at the boost guage at that speed to verify. any other thoughts?
WHITE94COBRA
New Member
RPM's above 3,000 will build boost when under load, Even with a stock pully. I run a stock pulley and have even seen boost at 2,500rpm when heavily loaded up.
Oil smoke under boost more often than not = pressurized crankcase. This is a commmon problem with boosted 5.0's. Do a search on PCV and boost and you will find countless pages of remedies and advice on how to combat this nasty and often stinky problem.(especially stinky when oil blows all over your headers...lol)
i just re-read my post and it didnt relay what i wanted it to...what i mean is when im at highway speeds and my rpm's are in the 3k range (thats what i meant when i said i dont know if its making boost or not) is when the smoke constantly tumbles out....Anyways i replaces the pcv with the supercoup pcv, i replaced that filter thing under the pcv, put a breather on the thing coming off the oil fill tube and also welded in a new 02 bung so i can get a wideband in there (the old one had a dripped weld in it and was tuned with a tailpipe sniffer)...Its tornado time now so i cant test it, but i'll keep the post updated, thanks for the help
wow, that was some serious insight into the world of crankcase ventilation...i guess i'll make an oil seperator, if not for any other purpose than to save oil (synthetic is 6bucks a quart!) ....So if it still is blowing smoke is there a way to tell if the crankcase is still holding too much pressure or will i have determined that my rings are bad? i wont be suprised if they are since my original 5.0 has 115k on it, been sprayed with a 150 shot for 2 years and has seen 9-13 psi for the last 1.5
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