Sweating Horsepower
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Senior User
Joined: Feb 2002
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From: Breckenridge, Minn.
Sweating Horsepower
My oldest son told me a year ago that the leaky rear main seal was just the truck sweating horsepower. I wish I would have done something a year ago about it. Prior to purchasing the truck someone had done a valve job to the engine and cobbled the engine together. When torquing the head bolts down they torqued the lower bolts first then the upper ones and now the heads are cracked and have to be replaced. All I was going to do was split the engine from the tranny and replace the rear main seal. Yah, right. Both heads are cracked in the same place and I get to qualify out another set of heads. Can I go to the auto lot and present them with my findings? The local machinist says he believes the heads were torqued in the wrong sequence and drawn down to the final setting instead of steps as it was suppose to be done. Whats your thoughts?
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Joined: Jan 2004
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From: Albany NY
I don't think its likely that you could break a head by tightening it down wrong. You could end up with a leak. In the worst case maybe warp the head a little.
I think something rather catistropic happenned to the engine. Kinda sounds like a potato in the exhaut pipe. It might of seriously overheated when all the water leaked through the head gasket. Be sure to inspect the block throughly before buying new parts.
I think something rather catistropic happenned to the engine. Kinda sounds like a potato in the exhaut pipe. It might of seriously overheated when all the water leaked through the head gasket. Be sure to inspect the block throughly before buying new parts.
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Joined: Feb 2001
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From: Iowa
Higly unlikely a head would actually crack from incorrect order and such. Not sure what kind of engine, but in my opinion most of the manufacturers took a a two decade vacation from making quality head and block castings. Lighter and lighter they got. Busted V-8 heads and blocks was a very rare thing in 1970, you usually had to do something really stupid. They crack for no apparent reason in 1985. (and many other years)
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From: Breckenridge, Minn.
Castings on the heads indicate they are from 1985 and the block is from at least 79. They supposedly went to the external rear main seal in 82 and this has the split variety in the main cap. Numbers indicate that they are of proper vintage for the truck. I was told that if you torque the lower bolts before the upper bolts that the head gasket will compress more easily and then when the upper bolt tightens it pulls on the lower one and acts like it is teatering over a fulrum point. The other possibility was that the person assembling the engine used air tools instead of the torque wrench. In any case there are five cracks where ford heads are not suppose to be subject to cracks. Thanks for the feed back.
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