help!cracked heads
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Tuned
Joined: Jul 2003
Posts: 359
Likes: 0
From: ga
help!cracked heads
heres the deal,thermostat went bad causing motor to run hot.i pulled the heads and they are cracked.$800 to replace them. should i go through the bottom end also?what kind of money will i wind up spending in the bottom end?the trucks not very nice so i hate to sink alot into it.i thought about buying a used motor but i dont know if that is a good idea or not.(money is tight!).how do you know what your getting?has anyone got any advice for me?i dont expect to get 300,000 miles out of it, 50,000 would be fine. i dont drive it very often.money is short so im looking for the cheapest alternative.thanks guys,Kevin.
Hotshot
Joined: Feb 2004
Posts: 11,697
Likes: 3
From: Marengo, Iowa
cheap and diesel repair don't go in the same sentance very well, I am afraid. If you had no problems before with the bottom end, you should be fine to just put the heads on it. Thje bottom ends on these will go for a long time if you take care of them. If there is no scoring in the cylinders, they should be ok. A full overhaul will easily run another $1000.
Post Fiend
Joined: Nov 2004
Posts: 5,638
Likes: 1
From: Manitoba
How did you remove the heads, did you untorque in reverse sequence 1/4 turn at a time for several sequences. I hate to say but you may have cracked them if not...
I have a set from Diesel cast welding.... see their web page and email them.
http://www.dieselcastwelding.com/
I have a set from Diesel cast welding.... see their web page and email them.
http://www.dieselcastwelding.com/
Senior User
Joined: Mar 2003
Posts: 235
Likes: 1
When I pulled my heads off last month, I tried to follow that unbolting sequence. However I found that as soon as the head bolts were turned 1/4 turn, they were already loose as can be. Don't know what happened there. I have not inspected them yet, but it all adds up ($$$)
I am in the process of doing a rebuild on my 7.3L, and I have to agree, it is NOT CHEAP.
If I didn't have so many trucks already, I would have just went out and bought another cheap used F250/350 in that era (88 to 94) to replace what I had broke. I have seen '90s F250 SuperCabs diesel go at auction for about $1000 to 1500 CDN (running).
Once you get into it (rebuild), there are alot of places to spend money that you didn't notice before...
I am finding that gaskets alone will cost me $500 CDN. And that is just to put it back together.... Let alone the price of the parts that will need replacing.
I am in the process of doing a rebuild on my 7.3L, and I have to agree, it is NOT CHEAP.
If I didn't have so many trucks already, I would have just went out and bought another cheap used F250/350 in that era (88 to 94) to replace what I had broke. I have seen '90s F250 SuperCabs diesel go at auction for about $1000 to 1500 CDN (running).
Once you get into it (rebuild), there are alot of places to spend money that you didn't notice before...
I am finding that gaskets alone will cost me $500 CDN. And that is just to put it back together.... Let alone the price of the parts that will need replacing.
Freshman User
Joined: Sep 2004
Posts: 46
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Where are the cracks? I had a crack on my 1983 heads fixed and it seems to be fine. Had both heads done and repared for $400.00 locally. Just a thought. There is some skill involved in doing it properly, but it may be possible depending on where the cracks are.
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Tuned
Joined: Jul 2003
Posts: 359
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From: ga
thats just great!i didnt know anything about the unbolting sequence so its very possible i crackerd them myself! @#$%^^!as far as the bottom end goes ,how do you know if you have problems with cavitartion or not?
yall really think im safe with my bottom end?
and finally............is there anything else i can screw up by my ignorance about diesels?!?tips or tricks?thanks guys,Kevin.
yall really think im safe with my bottom end?
and finally............is there anything else i can screw up by my ignorance about diesels?!?tips or tricks?thanks guys,Kevin.
Hotshot
Joined: Feb 2004
Posts: 11,697
Likes: 3
From: Marengo, Iowa
Were the head gaskets blown, or was it blowing out somewhere, and that why you are believing the heads were cracked? I just want to know why exactly you pulled them to start with, and we can go from there. I myself was unaware of the unbolting problem, so I can't comment on that, as I have pulled 7.3 heads before, and not cracked them by that, and have some difficulty understanding and accepting it, but I won't argue anything until I hear more, but I do know that overheating them will crack them, if severe enough, but usually dry heating, like a leak or burst hose is the cause. Cavitation is a pinhole leak into the cylinder through the wall, and if were that, you would either have to sleeve the block or trash it. You would find one cylinder that washed the piston clean.
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Senior User
Joined: Nov 2004
Posts: 305
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From: Bothell, WA
I noted the same thing as Ironpants when I unbolted my heads. Thebolts were loose as soon as I gave them the first first 1/4 turn. Mine was a rebuild and judging from the rest of the quality I'm wondering if they were torqued correctly when the heads were bolted on the first time. They seem to have held just fine though but I've never run more than about 8 lbs of boost from the aftermarket turbo. 4X4man, I had my heads reconditioned and bought a new gasket set before learning my block was toast. I'm considering a long block replacement in which case my heads and the gasket set might be available. I hate the thought of only getting a core credit out of the reconditioned heads. They are pressure checked and ground, have all new valve springs and guides, and the bad valves were replaced and the good valves reconditioned. The good cylinders were holding 440 to 480 before I pulled the heads.
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Post Fiend
Joined: Nov 2004
Posts: 5,638
Likes: 1
From: Manitoba
tdford
"" I had my heads reconditioned"" and to what extent were they milled/re surfaced/dressed regarding the head deck to valve cover surface. There is a minimum head thickness from Ford, IH and AERA that being......... 4.795"
"" I had my heads reconditioned"" and to what extent were they milled/re surfaced/dressed regarding the head deck to valve cover surface. There is a minimum head thickness from Ford, IH and AERA that being......... 4.795"
Senior User
Joined: Nov 2004
Posts: 305
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From: Bothell, WA
PLC7.3, I wish I had a good micrometer but the best I could do was check with my dial caliper. I hadn't unpackaged the heads yet but I unwrapped them just a few minutes ago and checked each head 3 places and got consistent readings of 4.796 for the first head and 4.798 for the second. That's so close to the tolerance you listed that I wouldn't want to let anyone have them without checking them again with a micrometer. Sounds like it might be time for another tool. What was the deck thickness on new factory heads?
Last edited by tdford; Jan 25, 2005 at 11:10 PM. Reason: correct posting mistake
Freshman User
Joined: Sep 2004
Posts: 46
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Originally Posted by PLC7.3
New factory heads were:
New Thickness 4.7950-4.8050"
Minimum Thickness 4.7950"
Warp Spec .006" overall
Yours heads sound fine.........
New Thickness 4.7950-4.8050"
Minimum Thickness 4.7950"
Warp Spec .006" overall
Yours heads sound fine.........
Re: Crack checking: Cracks are very hard to see, so I would suggest having the heads magnafluxed to ensure all the cracks are found.
Freshman User
Joined: Sep 2004
Posts: 46
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Originally Posted by PLC7.3
Point to remember is the piston comes above the block .010 to .031", recessing valves and trimming stem height come into play..............
Thread Starter
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Tuned
Joined: Jul 2003
Posts: 359
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From: ga
the reason i pulled the heads is pressure in the coolant system,water in the oil and white smoke at start up.once the motor was hydrolocked from the coolant in the cylinders.all this happened after i replaced the thermostat.
if the factory specs are 4.7950 - 4.8050 and tdfords heads are 4.796 then do they rewally need to be checked for clearances?
tdford, what all comes with the gasket set you have and how much are you asking for it all?also,where are you at?
i think im gonna take my chances with my bottom end.i really dont want to sink alot into this truck .if that doesnt do it ,then ill get rid of the truck and start over.the body is just not nice enough to spend alot on.
if the factory specs are 4.7950 - 4.8050 and tdfords heads are 4.796 then do they rewally need to be checked for clearances?
tdford, what all comes with the gasket set you have and how much are you asking for it all?also,where are you at?
i think im gonna take my chances with my bottom end.i really dont want to sink alot into this truck .if that doesnt do it ,then ill get rid of the truck and start over.the body is just not nice enough to spend alot on.