Splitting "HEAD"ache - 56K beware.

[Gravityman]

Whats up Subaru Freaks!

I have a problem. I pulled my head from the ER27 and found a small crack in the valve. Give me your input as to if it is ok(within limits) and still drivable or I should just junk them?





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This thread is actually dedicated to the full deconstruction of my cracked ER27 cylinder head. I am in the midst of fully cutting the head in half in many different sections to get a full visual of how much meat there actually is in an ER27s exhaust and intake valve ports. This information will be applied to my porting job for the Twin Turbo and how far I can safely and reliably go with them. By doing I hope to gain information that has been missing and has remained a mystery about our cylinder heads.

I do not know how much of this will apply to an EA82 cylinder head but I would imagine that a substantial amount of info could be applied to your cylinder heads as well.


I want anyone and everyones input on this that has input. So what I am going to do is post a see-through FSM pic. If you desire any specific part of then cylinder head to be cut I will try my hardest to do it. Just take the original picture and put a red line through where you would like me to try to cut and a discription if needed and then repost it to this thread. Mind you I am using brut force to cut these heads (HACKSAW) so I wont be cutting the head in half long ways. Praying for a band saw for my birthday!!!



I am cutting the Right Hand head cyl's 1, 3, 5 I belive, please correct. Here is my first cut.

[Huck369]

This should be an interesting thread, that I will follow closely....


(even though I don't even own a ER27 any more )

[Gravityman]

Well the first pics are in!!! It wasnt as hard as i first thought and very fun in a sore arm kinda' way. Now that I have cut from top to bottom on the head I can now cut long ways with less resistance.

Here is something you dont see everyday.!



The cutaway-- This is cylinder #1's intake and exhaust ports



One of the reasons I wanted to do this was to see how far(deep) the cracks between the intake and exhause valves actually are. I know a lot of people junk these heads for the cracks but what if we can weld them and reuse them. In 10 years when these cars are around 30 years old we will be mad at our younger self for just tossing out a set of heads that could have been easily fixed. So here are my plans for the next cut.

[Caboobaroo]

This should be an interesting thread, that I will follow closely....


(even though I don't even own a ER27 any more )

You're a loser!

Just kidding.... I don't own one either

I saw this over on the USMB and it looks exciting!

[grossgary]

that's awesome. cool stuff scott. with a handsaw even, nice!

those cracks between the valve seats are repairable. i've mentioned it in a number of threads but the machine shop that i use in maryland is very familiary with these heads and always fixes mine. they drill and thread in a specially made insert down into the crack, then weld it in place. they have done many for me and haven't gotten one yet that was too deep to fix. but i haven't given them any that were severly overheated and beat either. if i've pulled an EA82 or ER27 head without any cracks between the valve seats, i don't remember it. it's more the norm than not.

[Gravityman]

Cut number three complete. Dont try to cut through valve seats, they suck! ALL DAY LONG!!!

Well as I took a long ponder on as to where I should cut I changed my original plan. I instead cut at an angle accross the crack with the cut starting at the edge of one side of the crack. By doing this it would let me actually dissect the crack and find out how far it goes.





This cut was actually a little harder to keep lined up then the first one because I had to start the cut on a surface that was far away from all the other metal.

Here is a picture of the 2 halfs of the cut. You can see the piece between the 2 halves which is the crack that i removed.



I took my dremel and cut below the lowest point of the crack that I could see so I could remove the entire cracked piece and to verify how deep the crack runs. Where you see the crack turn sharply to the right is where I intentionally forced it to crack the rest of the way down.



Here is a picture of the crack after it was removed. There are 2 shades on the metal; the lighter part is the part that I forced to break and darker part is the length of the original crack.



This pic shows you how deep the crack actually went. I would imagine that this crack could go down to the water line but fortunatly it didnt.



After the dissection of the piece I have noticed that there is actually quite a bit of material that can be removed around the valve guides. I am getting excited to see all my other cuts. It seems that there may be more potential in this head then I originally thought!

[kingbobdole]

That crack is kinda scary! You think it could get to the water? I think mine did long ago... dumped lots o coolant out the exhaust, but the HGs looked fine... my crack was a monster though.

[xfinrodx]

OMLOLZ!!1!! TH1S THRED IS TEH KEWL!!1!

Sorry. No really, you have my rapt interest. I think I'd scrap a head with that deep of a crack. That's why I haven't looked at mine yet. I'm sure mine are in BAD shape. You have made life happy for me!

[Gravityman]

Like Gross Gary said, the heads can be repaired by either pluging and welding or just welding, depending on the depth. Here is a block that was cracked and repaired (not subaru).

[Metzenw]

Is that a 3300 series cat engine?

[Gravityman]

Is that a 3300 series cat engine?

Que? The pic of the block or the head? The block is just a pic I found online.

[Joostvdw]

I like your hands, err, saws on approach

this is something we can all benefit from, way to go! thanks for sharing.

[crazyhorse_001]

I can hear Huck getting ideas from here!

There isn't a lot of "meat" in the runners to remove. Tho, I agree that there's a lot around the valve stems. It seems to me, that the siamesed exhaust port would benefit the most from some "massaging".

[Gravityman]

What I am thinking is; match the ports to the gasket and maybe inlarge it a little. Then grind all of the parts the intrude into the port ie bolt edges and HLA's. Then cut a small fraction of the walls to blend them into the intrusions as well as grind and smooth all cast flashing. Smooth the area around the valve seat that bulges out, and lastly grind down the valve guide. From what I can see there is a substantial amount of material around the valve guide which would allow plenty of grinding and smoothing.

I just finished my third cut but the pics will be up later tonight. This is actually a 2 part cut, the next one will be very interesting!!

[Gravityman]

Well the results on cut number 3 are in! The cut was made exactly between cylinders 3 & 5.



One thing that was pretty neat to find out on this cut is how thick the metal is between the closest part of the cylinders(where the exhaust and intake ports are the closest to each other. Also look at how far off the casting is where the 2 halves meet.



I bet you won't be able to guess where my next cut will be...or if you even care. I will try to get the 4th cut done tomorrow.