Short story- Cold weather cracked y block last winter (400sb) I took it to a guy who replaced the block. I ran it a couple runs it smoked--milky oil. Changed head gaskets,had the heads pressure tested and resurfaced. Run again and still oil and water mixing. Checked the intake, no cracks. So I took it back tothe mechanic to fix what I thought could be a cracked block. He reassembled it, cut a 1.43 60ft and ran a 6.70 1/8 th mile. But same thing water and oil mixing. He said that water was being pressured through the intake gasket and that was the source of the problem. He said that the car had high compression and a stroker cranks and what I need is a vaccum pump. Does this sound right? Should he have pulled and pressure tested the block?
Your original post says the block was replaced. Were the heads checked for cracks, warpage, etc.? Using any sealer on the head gaskets? Have you checked the timing cover for leaks? Were the heads surfaced any appreciable amount or was the new block decked a bunch? If the heads were milled a lot or the block was decked a lot, there is a possiblity there can be a mismatch with the intake that will allow water to leak and/or oil to leak. There are many possibilities left to check.
Mike, you state "400sb". are you talking about some engine other than a Buick, or a '67-'69 400 big block Buick? Devon
I'm sorry, yes its a small block chevy engine. - Running the regular Fel Pro head gaskets PN 1034 - The heads were pressure tested for cracks and achecked for warpage - Light coat of sealer was used on HG around water ports - Not sure how much the head was surfaced - Good point on the intake/block mismatch. The previous block didn't have this problem. I'll relay this to the mechanic and have him check that out. - I will also relay the timing cover info to him as well Thanks for the tips guys, we'll look into these prior to purchasing a vaccuum pump.
Are you using head studs? If so, look for leakage around the stud. Seen it more than once. Switching to bolts will solve the problem. Still never got a good answer why on that one. Also, Check for steam hole mismatch on the headgaskets. had that happen a couple times too where they don't just "line up" like they are supposed to. Couple 400sbc specific things I've run into on customer cars. May be of some help to ya.
