Looking for a spare aluminum cylinder head and have been offered one which has been cracked and then welded (repaired). Does it matter or should I wait for one that was never cracked in the first place?
franc123,
Nov 30, 1:26am
Depends on the head and why its cracked, what warranty they will give, if it is a known problem and the cost and availability of a new one. A repaired one may be a cost effective option.
rosehonda,
Nov 30, 1:43am
Repaired=$100 2nd hand non cracked=$400 New=No longer available
Does a repaired one mean it will have a weak spot? Or is it irrelevant?
2get1,
Nov 30, 1:54am
alloy ? repaired properly, wont make any difference, should be fine. thats the beauty of alloy, easily repaired. You would be amazed at the state of some alloy heads in motorsport after a valve drops or some other type of major blow up. Re weld, machine, in a CNC and good as new.
Cracks in iron are abit harder to repair but can be repaired and last. Ive had some iron heads repaired and never had a problem.
Will all hinge on if it was done properly and by someone that knows what they are doing.
franc123,
Nov 30, 1:58am
What motor is it off?
rosehonda,
Nov 30, 3:11am
bmw m20
ola_bitchola1,
Nov 30, 3:26pm
yup they are expensive its it the b25 head your after ? i may have one
toyboy3,
Nov 30, 5:21pm
For the head to get hot and crack the alloy may of lost its hardness = future head gasket blowing as the head bolts may not hold their tension
sr2,
Nov 30, 5:34pm
100 % correct! (Those who claim you can successfully weld any alloy head have obviously never tried to repair a cracked Sierra Cosworth head!).
elect70,
Nov 30, 10:20pm
My experience says no > I had 2 alloy heads welded & only lasted a year or so . They must have been overheated to crack in first place . Plus the "alloy" today is full of recycled metals from scrap . ( unles its a a Ferrari made of hi silicon pure forged aluminium .
2get1,
Dec 1, 12:03am
re heat treat after welding ? Ive seen a lot of alloy heads repaired successfully in the motorsport Im involved with. some of them repaired more than once aswell.
sr2,
Dec 1, 2:16am
What type of motors are we talking about?
2get1,
Dec 1, 2:42am
drag racing, but not all of them are purely strip cars, some duel purpose street strip. so see some real miles.
sr2,
Aug 14, 6:04am
Overhead cam?
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