Jump to content
Ultimate Subaru Message Board

Cracked head, can it be repaired?


Recommended Posts

Someone has offerd to sell me a mpfi intake, turbo heads and u turbo up pipe:brow:

This is perfect timing cos i wanna megasquirt my carbed wagon:banana:

 

one of the heads has a crack in the exhaust port which leaks coolant, it is fixable? will it be reliable and is it worth it???

Link to comment
Share on other sites

Is it fixable? Yes, if you find the right shop and they are willing to do it. Is it reliable? It should be, as long as you find the right shop. :rolleyes:

 

There are a couple rebuilders in my region that do this. However, most people around here don't bother with repair and just find another head.

Link to comment
Share on other sites

Find someone with a TIG welder... Should be relatively easy, since it's in the exhaust port. The ones in the combustion chamber are a pain, but this one woild prolly just need to have the ends of the cracks drilled. the crack V'd, and TIG welded (Could also be welded with Oxyacetylene, but that is not somethign a lot of people know how to do...)

Link to comment
Share on other sites

thanks, but would getting it welded be cheaper and easier than buying a new head?

 

its a turbo head, so what is the difference in CR ratio between it and a mpfi head?

NEW head would be very expensive. A rebuilt head can be had in my region for around US$150 (with rebuildable core). Repair cost depends on who does it.

 

At least for US-spec (and I believe JDM) there is no difference in CR or any other significant feature between MPFI and turbo heads. The CR difference is in the pistons. The turbo heads have fittings on the right-side (driver's perspective) head for turbo oil; these fittings are cast into MPFI heads but not drilled/etc.

Link to comment
Share on other sites

when i said new, i didnt mean NEW, just meant one is working order

 

What would have caused it to crack?

 

Because it cracked once, does this mean it is now a weak spot or an indication that there is a problem?

 

Thanks for your advice.:cool:

Link to comment
Share on other sites

I would replace the head because the weld would be a different material than the cast aluminum, thus a different expansion rate. It's in the exhaust port on a turbo motor, it will probably crack again. The only time I weld a head is to replace corroded head gasket water passages and to add extra material in areas that get ported beyond the outside of the casting.

It's not worth your time and money to weld the exhaust port just to take it back apart and buy a replacement head anyway.

-Chuck-

Link to comment
Share on other sites

...What would have caused it to crack?...

It being a right-side EA82T head. :grin: There seems to be 2 types of right-side EA82T heads: Those that have cracked and those that haven't cracked yet. There are a lot of opinions and conjectures as to why they crack; most that I have heard don't make much sense to me, and I have my own opinions.

 

A proper repair job should be reliable. Yes, it is in the exhaust port but there is water just on the other side constraining the temperature rise. (Sort of like boiling water in a paper cup over an open flame.) An improper repair job will likely fail, just as any improper repair.

Link to comment
Share on other sites

It being a right-side EA82T head. :grin:... There are a lot of opinions and conjectures as to why they crack; most that I have heard don't make much sense to me, and I have my own opinions.

 

I'm in total agreement, and have a few ideas too... we should talk sometime. :-p

 

Gary

Link to comment
Share on other sites

I'm in total agreement, and have a few ideas too... we should talk sometime. :-p

 

Gary

*mini hijack*

(I thought of putting a joking "we never talk anymore" line or two in here, but figured someone/somewhere would not think that it was meant to be funny.)

 

I have some thoughts about exhaust port temps that would require EGT sensors, and also thought that while I was at it I would stick in EGOs for each cylinder. (This latter for those in the "lean cylinder" camp.) Also a pressure transducer in each exhaust port. So, each exhaust port would be a very busy place with sensors: 2 EGTs, 2 EGOs, and a pressure transducer/port.

 

I would also like a temp sensor (in each head?) for drainback oil... the turbo dumps its spent oil right into the head, draining back not that far from the crack point. Consider the temp of it, especially if low on coolant...

 

Just some thoughts on how to track down the culprit(s).

 

*End mini hijack*

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...