Blown Head—how to repair?

[GLImages]

You may have to pull the valve cover to see them if they are there.

Good reading on the Hoffman Site about the crack repair.

https://newsite.hamheads.com/porsche/alt-m96/m9697-986996-crack-repair/


Here's a snippet.

"—Some radiate from one of the coolant expansion plugs over toward the nearest spark plug well.
-Others migrate from a valve guide bore across the machined spring well and end at the nearest spark plug well.
–Most cracks occur on the outer cylinder positions, but on occasion the center cylinder produce a crack that runs from a spark plug well across an exhaust spring well and end in a valve guide bore.
—Occasionally the plug well to spring well crack will continue from the spring well****on to the nearest head bolt bore. These are the worst examples, but we can repair them too.
–Most of the cracks that gravitate toward a valve guide bore head toward an exhaust guide. However, the 3.4 heads that have just 2 coolant expansion plugs beneath the lifter housing will sometimes crack from a spark plug well to an intake guide bore. I have not yet seen this on a 3 expansion plug head.
With over 25 years of cast aluminum crack repair to draw upon I have developed routine repairs for every type of crack that we see with these heads.********The type that run into a guide bore are much more involved than the type that don’t and are therefore more expensive to repair. ****
Crack repair requires a ****very****specific series of processes to end up with a reliable repair. And the cracks that run through the valve guide area are the most demanding. ****Even shops that say they can repair cracks will often shy away from these challenging repairs, or worse do a poor “repair” that will get through the warranty period but fail down the road."



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[Gilles]

Hello McSpooney,

If you are sending the head to Hoffman Engineering, you may want to consider sending both sides for a head repair and porting..

Regarding the removal/installation, if you use a brace between the strut towers, you will be able to hang the engine from above (the bottom will be clear to move yourself around) and after removing the transmission mounts, you would be able to lower the engine several inches to clear the frame rails, just be careful not to stress the engine harness (better to disconnect it).

For a brace, I used a home made (4x4) with a long treaded 'J' hook through the 4x4 that allowed me to lower or raise the engine smoothly with a nut and a couple of washers.. I can search for a picture if you want, good luck!

[McSpooney]

Originally Posted by Gilles

Hello McSpooney,

If you are sending the head to Hoffman Engineering, you may want to consider sending both sides for a head repair and porting..

Regarding the removal/installation, if you use a brace between the strut towers, you will be able to hang the engine from above (the bottom will be clear to move yourself around) and after removing the transmission mounts, you would be able to lower the engine several inches to clear the frame rails, just be careful not to stress the engine harness (better to disconnect it).

For a brace, I used a home made (4x4) with a long treaded 'J' hook through the 4x4 that allowed me to lower or raise the engine smoothly with a nut and a couple of washers.. I can search for a picture if you want, good luck!

Hah I don't know about spending all that extra time and money to get the other head off. Sends a chill down my spine considering going thru all this again for the other head.

Buuuuuut. I really like your idea of lowering the engine a bit. I happen to have one of those strut tower bridges from working on a honda earlier this year. I'll take a look and see what it takes to fit it.

[Gilles]

Originally Posted by McSpooney

Buuuuuut. I really like your idea of lowering the engine a bit. I happen to have one of those strut tower bridges from working on a honda earlier this year. I'll take a look and see what it takes to fit it.

McSpooney, I found the picture of my beaner shade tree mechanic tool, it is actually a 2x4 but it was strong and stable enough to lower and raise the engine/gearbox assy.

The treaded rod allows you to fine tune the position, if I remember correctly, I put a bit of anti seize on the treads to make it work pretty smooth.. :-)

PS:Sorry for the picture not sure what happen... :-(

[McSpooney]

Originally Posted by Gilles

McSpooney, I found the picture of my beaner shade tree mechanic tool, it is actually a 2x4 but it was strong and stable enough to lower and raise the engine/gearbox assy.

The treaded rod allows you to fine tune the position, if I remember correctly, I put a bit of anti seize on the treads to make it work pretty smooth.. :-)

PS:Sorry for the picture not sure what happen... :-(

Beautiful! I was going to ask what part of the motor you hooked it up to, but I get it now

[McSpooney]

So I read thru the hoffman site... I am thinking of just sending them the head and asking them to inspect and refurb it accordingly. I'll probably call them Monday. Thanks again for all your guys' input.

I just inspected again and am seeing nothing. No cracks on the tops of the heads, no cracks in the exhaust or intake ports.
The ports are a little crummy though, so its hard to tell. My rotary tool broke, otherwise I would be wire brushing the insides to see if it helps me see a crack.

I mean maybe there's no crack and this was all a head gasket issue??
Incoming image bomb... I am bad at taking pics...

[BYprodriver]

Originally Posted by McSpooney

So I read thru the hoffman site... I am thinking of just sending them the head and asking them to inspect and refurb it accordingly. I'll probably call them Monday. Thanks again for all your guys' input.

I just inspected again and am seeing nothing. No cracks on the tops of the heads, no cracks in the exhaust or intake ports.
The ports are a little crummy though, so its hard to tell. My rotary tool broke, otherwise I would be wire brushing the insides to see if it helps me see a crack.

I mean maybe there's no crack and this was all a head gasket issue??
Incoming image bomb... I am bad at taking pics...

Head gaskets never fail if properly installed, they are little more than steel shims. Send both heads to Hoffman they can make the heads stronger to prevent cracks & a great valve job. You don't want to do this twice.