Head test results are in .....

[Zeuk in Oz]

The saga continues.
Testing of the head (M20 '88 525i e34 - 240,000 km) has revealed a crack which the reconditioner (reputable and highly recommended) thinks he can fix.
The head will also need 5 thou to be removed from parts of it as well as a new cam and rockers etc.
The alternative is a new head from BMA (Spanish) which will be dearer but will at least will not be repaired as long as the quality is OK.
Questions :
Can these heads be successfully repaired ?
If 5 thou is shaved off, do I need the thicker head gasket ? The reconditioner thinks not !
Has anyone any experience with the new Spanish heads at BMA ?
Any other advice ?

(Sorry to be such a pain but I am in unchartered territory here and am relying heavily on your collective wisdom ! )

[gale]

Can these heads be successfully repaired ? If 5 thou is shaved off, do I need the thicker head gasket ? The reconditioner thinks not

5 thou is trivial, I wouldn't give it a second thought -- use the stock headgasket. Welding shouldn't be a problem as long as he does proper pre-heat & post-heat which I sure he will. The portion of head material to be welded will be pretty small so shouldn't affect overall distortion. I say let him proceed with it.

If you do go with the new Spain head, I lived there for several years while working on a construction project, and I was quite impressed with their casting abilities. At the time, tarrifs were prohibitively expensive on cars/products not made in the country. Seats (Spanish Fiat clone made under license) were entirely made in Spain and were one of the more prestigeous cars at the time (late 70's). I had a Citroen which was imported into Spain from France as a bare shell with minimum French made components, and the intake manifolds, carburetors (don't know about the heads) & some of the simpler items were cast in Spain and final assembly done there, to lessen the tarrifs. It was a very reliable car and well built. Wish I could have brought it back to the States with me.

[rob101]

What i am about to say isn't 100% certain and it is only an opinion, but from my experience (I work in a maintenence yard that works on heavy vehicles, cranes and everything inbetween) I wouldn't trust anyone who wasn't a boilermaker or a proper welder by trade to go welding up cast or forged components....... I've even seen boiler makers that can't weld for ****, as for welding up cast or forged components to fix them up, in my experience this is dodgy (if it were a part that could cause a safety issue i wouldn't do it ever) and definitely won't last as long as the original. I am not say its not going to work, but its far from a sure thing. If I was in your shoes it really depends on the price, if it costs stuff all to get it welded in comparision to getting a new head and you are pretty sure the place has a quality welder then get it done but then again if you reckon you can afford the new head i'd go for that.

[R1daveg]

Success will depend on skill of the welder. A good one knows to drill at each end of the crack before welding to stop it re-occuring...
An influence in the decision will be the condition of the alloy. If it has had a lot of temp cycling it may have become soft.

[E34-520iSE]

If there's a visible crack in the head, there may be serious invisible cracking below, running off any which way. There's not many people who can do these repairs and those who do charge a lot of money for it as it takes a long time & is expensive.
If it was mine I'd be fitting my spare head but I appreciate that it may be hard for you to get a hold of a good used one...or just buy one from BMA.

HTH,

Shaun

[Bill R.]

lot of cylinder head repair then they will have a furnace to bring the head up to temp to weld and then back down to keep it from cracking. Its not a problem for shops that do a lot of it. The only concern with the 5 thous removal is how much it changes the cam timing since the tensioner takes up the slack on one side and it moves the cam around slightly. I don't think the thicker head gasket is needed though. And contrary to expectations frequently a repaired head is better than new since its already stabilized or aged. I remember rumors years ago that volvo took the basic block casting for the old 4 cylinder iron block and left them out in the weather for a couple of years before machining to let the iron stabilize.. don't know
if its true or not but those blocks sure last a long time without problems.

The saga continues.
Testing of the head (M20 '88 525i e34 - 240,000 km) has revealed a crack which the reconditioner (reputable and highly recommended) thinks he can fix.
The head will also need 5 thou to be removed from parts of it as well as a new cam and rockers etc.
The alternative is a new head from BMA (Spanish) which will be dearer but will at least will not be repaired as long as the quality is OK.
Questions :
Can these heads be successfully repaired ?
If 5 thou is shaved off, do I need the thicker head gasket ? The reconditioner thinks not !
Has anyone any experience with the new Spanish heads at BMA ?
Any other advice ?

(Sorry to be such a pain but I am in unchartered territory here and am relying heavily on your collective wisdom ! )

[winfred]

herd the same thing about the volvos, also herd the spanish heads were better then the factory from a couple places, i've not seen one so i have no experence with them

I remember rumors years ago that volvo took the basic block casting for the old 4 cylinder iron block and left them out in the weather for a couple of years before machining to let the iron stabilize.. don't know
if its true or not but those blocks sure last a long time without problems.

[Zeuk in Oz]

Wow guys, your collective wisdom is awesome.

Will go with the repair and then if that is not successful I will try the new Spanish head from BMA as I don't seem to be able to source any reconditioned heads here in Oz.

I imagine there is a certain risk with reconditioned heads where you don't know the history behind them anyway. Better the you know perhaps ?

Thanks again for the instant replies !

[rob101]

welding cast parts regardless of skill always creates an added stress concentration which means added risk of fatigue failure in a nutshell the part will have a reduced life, not to mention that some aluminium alloys they use in casting engines are an absolute bastard to weld (as they are casting aluminium alloys as opposed to wrought alumium alloys used for machining and forging and sections). Be very sure that the welder is a good welder (and no that is not a given in major cities when a good welder can goto a mine and earn $200 000 a year which is why there is a skills shortage in this country).

[632 Regal]

Im sure you could source a used head with warrantee if funds are short?

Wow guys, your collective wisdom is awesome.

Will go with the repair and then if that is not successful I will try the new Spanish head from BMA as I don't seem to be able to source any reconditioned heads here in Oz.

I imagine there is a certain risk with reconditioned heads where you don't know the history behind them anyway. Better the you know perhaps ?

Thanks again for the instant replies !