Rebuilt 302 is overheating quickly
Postmaster
Joined: Jun 2005
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That exhaust valve looks a little cooked but it might just be the pic.
Only way to be sure is get it check at a machine shop, something is pushing the coolant out of the radiator. could even be a bad hole on the other side, get this one checked and if it's it good I'd pull the other head and it checked too.
Only way to be sure is get it check at a machine shop, something is pushing the coolant out of the radiator. could even be a bad hole on the other side, get this one checked and if it's it good I'd pull the other head and it checked too.
Postmaster
Joined: Jun 2005
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Bad sealing valves and broken piston ring wont push the coolant out, but would show low compression readings. A bent valve might seal every now and again, and so will a sticky valve or a broken spring....
To be honest I would pull the other head and get them checked and freshened up.
To be honest I would pull the other head and get them checked and freshened up.
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More Turbo
Joined: Oct 2004
Posts: 621
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From: Marana, AZ
Yeah, I was already content with doing that. I figured there was nothing slapping me in the face showing the problem so it could be on the other head.
Last edited by desertdave35; Dec 24, 2006 at 05:09 PM.
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More Turbo
Joined: Oct 2004
Posts: 621
Likes: 2
From: Marana, AZ
The thing that sucks is these are totally reconditioned heads that I bought from Clearwater Cylinder Head in Florida off of Ebay. I did get a 12 month warranty with them. I think I will call them and see what they are willing to do.
Posting Guru
Joined: Mar 2006
Posts: 1,118
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From: Williamson, NY
Just a thought, Check the spark plug hole to make sure there's not some debris or a bur preventing the compression gauge from seating correctly. Yesterday I was getting ready to install a Ford 9" carrier into my axle housing and I noticed when I rotated the yoke one way it just stopped all of sudden and when I rotated it back the other way 360 degrees it stopped again. As it turned out I had a piece of old carrier gasket stuck between a couple of teeth on the ring gear. Sometimes it can be the little things that mess you up. Good luck!
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More Turbo
Joined: Oct 2004
Posts: 621
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From: Marana, AZ
Pulled the other head off last night, but same as the other. No evidence of any cracks. I think I am going to pull the valves out and look into the bowls and see if there is any cracks there.
I only need to concentrate on the exhaust valves correct?
I only need to concentrate on the exhaust valves correct?
Postmaster
Joined: Jun 2005
Posts: 2,656
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don't waist your time, you can't see the cracks, get those heads to a machine shop and have them magnafluxed.
They will tare them down, clean them in what they call "hot tank", and then use a very strong eletromagnet and mist this colored very fine metal power all over the head. Any cracks will be seen after a light blow of air over a given area. I have done this my self one day when I went to the shop to pick up some parts. It was a BBF head I did and I looked everywhere for cracks could not see one anywhere, thought I was waisting my time. Sure enough after a light blow of air you could see a crack clear as a bell.
about 35.00 around here for a pair of empty heads......If they have to take them apart it's a little more.
They will tare them down, clean them in what they call "hot tank", and then use a very strong eletromagnet and mist this colored very fine metal power all over the head. Any cracks will be seen after a light blow of air over a given area. I have done this my self one day when I went to the shop to pick up some parts. It was a BBF head I did and I looked everywhere for cracks could not see one anywhere, thought I was waisting my time. Sure enough after a light blow of air you could see a crack clear as a bell.
about 35.00 around here for a pair of empty heads......If they have to take them apart it's a little more.
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Postmaster
Joined: Jun 2005
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Little story for ya.
The D0OE heads I ported polish cc'ed you name it. I could not get it to stop pushing coolant out of the radiator..After 1 minute of run time my hoses were hard as a rock. I thought head gaskets, well I changed them a few times before I gave it the 100psi test. and found that crack. I never had the heads magnafluxed as I should have. I had 80 hours in those heads...wish I still had them. But when I was doing all the work I never saw that crack.........
The D0OE heads I ported polish cc'ed you name it. I could not get it to stop pushing coolant out of the radiator..After 1 minute of run time my hoses were hard as a rock. I thought head gaskets, well I changed them a few times before I gave it the 100psi test. and found that crack. I never had the heads magnafluxed as I should have. I had 80 hours in those heads...wish I still had them. But when I was doing all the work I never saw that crack.........
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More Turbo
Joined: Oct 2004
Posts: 621
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From: Marana, AZ
Good idea, I still want to pull the 2 valves on #7 and see if they slide up and down with no problem. I'm pretty convinced its either a slightly bent valve or maybe some debris that got lodged in betwen the valve seat during the compression test but is gone now.
Postmaster
Joined: Jun 2005
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use some valve grinding compound on the seats and spin the valves with your fingers lightly pulling them into the seats. do this a few times and then pull the valves, clean and look at the seats on the valve you should see a line all the way around the valve. If only half the valve seat is clean on the valve it's bent.
Hotshot
Joined: May 2004
Posts: 12,170
Likes: 5
From: The hills of No. Calif.
A co-worker once showed me a method of locating cracks using Muriatic acid, but I don't recall the exact procedure he used. It wasn't anything very scientific, it mainly consisted of (carefully!) pouring a little full-strength acid on the suspected area and giving it a few moments to react. I believe he then wiped or washed away the acid leaving the crack visible as the acid etched the metal and sort of sought out the crack. I have a couple of cracked heads and some Muriatic acid, I suppose I could experiment a bit and let you know what I come up with. If you try it yourself, just be very careful working with the stuff, use rubber gloves and a respirator, it's pretty caustic stuff and produces very strong fumes.
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More Turbo
Joined: Oct 2004
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From: Marana, AZ
Originally Posted by TigerDan
I'm also wondering if you merely had the lifter preload too tight on that one cylinder. The compression had to be going somewhere...
Hotshot
Joined: May 2004
Posts: 12,170
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From: The hills of No. Calif.
Srry, brain fart on my part...I'm so used to working with the older stuff I keep forgetting about the newer non-adjustable rockers. The only newer engine I have I converted to screw-in studs with guideplates, so everything I have is adjustable...
But I still like to check the preload on those to make sure there's nothing binding anywhere, no bad lifters that won't compress or anything.
But I still like to check the preload on those to make sure there's nothing binding anywhere, no bad lifters that won't compress or anything.