Diesel to check for head cracks?

LameHoof65

Famous Member
I want to take my welded E0 head in to check for cracks, one head guy said not to bother...Went ahead and got two more D7 heads from the yard---but for the life of me---I can't see anything that looks like a crack or warp on my E0 head. So, a friend of mine said to do a few things before I take it in and risk losing money on a cracked head.

1) Block off the intake manifold at the carb inlet (rubber seal).
2) Turn the head upside down and level it.
3) Pour diesel down the intake runners until valve bowls are full.
4) Let it sit over night and check in the morning. (If full the inlet section is not cracked).
5) If it is empty then it is cracked, so replace the diesel fuel with gas, then sprinkle the head intakes with talcum powder and it will pull it to the crack. For the exhaust side he said to do the same thing.
 
i'm not so sure it would be that easy...
it might work for cracks that will be an immediate problem, but i'm not sure if it'll grab the cracks that'll grow up and put a hurtin on ya later
 
I agree, I think he was saying that if it shows up as a crack with this type of test---then save your 50 or so bucks and don't take it in, unless you plan on saving the head by brazing or something. I was just wondering if anyone has ever heard of such a thing and if it is a worthwhile test.
 
Only two ways I ever checked a head or block for cracks. Either magna-flux or pressure check. Any good engine shop should be able to do either one.
 
1966 shop manual details how to use a similar method to find cracks.
Thoroughly clean the casting in question.
Minute cracks not visible to the naked eye may be detected by coating the suspected crack area with a mixture of 25% kerosene and 75% light motor oil and then wipe dry. Then apply a coating of zinc oxide dissolved in wood alcohol. If cracks are present, the coating will become discolored at the defective area.
Reference section 8 page 22 and 23.
FWIW
DaveP
 
Man I think it's too important to leave to guesswork. I'd rather just send it to the shop to be magnafluxed. In fact that's where mine is now, before I have any work done to it.
 
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