cracked magnum heads
- Thread starter 93ragtop
- Start date
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Also, below, the seal on the right is the one installed on the heads. I have the ones on the left from my rebuild kit.... Would it be better to replace them. In addition, the last picture shows one of the kit seals intalled. It does not quite bottom out. Is this a problem?
pishta
I know I'm right....
You up to some smoothing on that exhaust port wall? Couldn't hurt while they are off. Probably a non issue on a stock motor.
pishta
I know I'm right....
Understood. Start the tool after you clear the seat for safety.
as many cracked Magnum heads as I have run across, the cracks between the valves can't be thru, as the engines they were off of all ran when pulled...… I never have, once they have been deemed cracked, but they were fine before eyes got laid on them..... couldn't you just cut them for new seats and get rid of the cracked material in so doing?
I have 2 sets of Magnum heads at the machine shop now that are headed for their junk pile as a result. One of which came off of a 200K mile engine in a 1 owner truck, that had been known for sure to have never overheated, from new.
the guy replaced them with aluminum "just because" he made a 408 out of it. NOT because of any issues.
I have 2 sets of Magnum heads at the machine shop now that are headed for their junk pile as a result. One of which came off of a 200K mile engine in a 1 owner truck, that had been known for sure to have never overheated, from new.
the guy replaced them with aluminum "just because" he made a 408 out of it. NOT because of any issues.
replicaracer43
Grumpy Old Man
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@volaredon this is a magnum 360 head I cut in half. You can see the crack goes straight into the water jacket. Now I suppose you could "pin" this head, then re machine the seats, possibly install seat inserts in both, but it becomes unpractical from a money standpoint really fast. Especially when the "EQ" heads were available.
I posted the pictures to give others a chance to consider another option for a replacement head. I can take more pictures if you tell me what you want to see.
I went with these for this simple reason. They cost, shipped $579.00 plus tax. My machinist looked at my 185,000 mile heads and said on on one, there is at least 2 cracks. Guides are worn, seats are bad, valves are wore out. He did not charge me anything. Just told me, repair is iffy, and would cost more then they are worth.
Does anyone have an opinion on the seals, should I switch them or use what came on the heads?
I went with these for this simple reason. They cost, shipped $579.00 plus tax. My machinist looked at my 185,000 mile heads and said on on one, there is at least 2 cracks. Guides are worn, seats are bad, valves are wore out. He did not charge me anything. Just told me, repair is iffy, and would cost more then they are worth.
Does anyone have an opinion on the seals, should I switch them or use what came on the heads?
Wyrmrider
Well-Known Member
are the positive seals viton? need the clearence run them
otherwise?
I do ot like teflon positie seals, can work on od honed HARD chrome stems not for stainless, stock, ot decorative flash chrome
flash chrome keeps non stainless from rusting and for break in, notice that it is worn off on used valves
otherwise?
I do ot like teflon positie seals, can work on od honed HARD chrome stems not for stainless, stock, ot decorative flash chrome
flash chrome keeps non stainless from rusting and for break in, notice that it is worn off on used valves
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