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Six Star Head Gasket Prep Advise


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I'm using Six Star head gakets for the first time on a 2004 Impreza 96k miles with external oil and water leaks. On previous non Six Star head gasket jobs I got the mating surfaces on deck and heads prepped by razor blade then block sand with 250 then 400 grit sand paper. Used Felpro Perma Tourque head gaskets.Talked to local machine shop that said if I was going to have them resufaced there, they would use a milling machine rather than resurfaing machine to get the correct RA (roughness average).

 

Checked heads with machinest straight edge and heads have no warpage.

 

Is my previously mentioned head gasket prep method good enough for Six Star head gaskets, or do I need to take them to machine shop and have them milled?

Edited by steve56
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I usually have the heads resurfaced since my local machine shop also cleans them up for me. If they're flat, I use 220 grit followed by 400 on a sanding block on both the heads and block surface. Make sure you lube the head bolts for a more accurate torque and the torque procedure is different for 2005 and newer 2.5s

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Thanks for the input guys. I did drop the heads off this afternoon at my usual machine shop. I think it will be $100 well spent. 

I'll check out GDs thread on getting the correct RA for DIY head resufacing. I have an 2005 Legacy 2.5 to JDM 2.0 swap coming up as my next project and will be doing head gaskets on the 2.0.

Will also look up the new torque procedure 2005 and newer 2.5s. Didn't  know there was a differnt torque procedure for those engines.

 

One thing that I picked up from a Subaru buddy of mine that seems to reduce head bolts creaking.That is to use Permatex Ultra Slick engine assembly lube on head bolt threads and washers. Dont know if its better than using regular oil, but no bolt creaking on last head gasket job I did.

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Just curious,

 

I have heard mixed reviews about the necessity of pulling the engine for this job. Did you pull it or do the work in the car? 

 

I'm sure he pulled it. Most people do. 

 

Real simple - just find a thread of someone that's done it (raises hand) and look for their recommendations on how to do it in the car if that's what you want. 

It is possible - but cumbersome and requires more steps/work to gain the access needed and harder to properly prep the block.

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I've done HGs in the car a few times, just for the experience. Last one was an EJ22 in an OBW bc I had more room to work. It's definitely not worth it. Head bolts have to come out and go back in while pushed halfway through the head. It's just a messier process to surface prep, install, everything.

 

Our shop resurfaces heads that aren't in too bad of shape by resurfacing them on glass with sandpaper. I'm pretty sure that technique was first posted on here from my boss doing it. Personally, we use the STI head gasket for N/A applications and have never had a comeback for an external head gasket leak.

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I've done HGs in the car a few times, just for the experience. Last one was an EJ22 in an OBW bc I had more room to work. It's definitely not worth it. Head bolts have to come out and go back in while pushed halfway through the head. It's just a messier process to surface prep, install, everything.

I just finished a head gasket changeout on a 96 EJ22 in the car.  I didn't really have the space to deal with pulling the engine (and I have done it before with this car).

 

I wish I had pulled the engine this round.   The driver side head is the absolute worst to get to.....it took 6 hands to get the head back on and it was really difficult.   The head bolts are too long to remove fully from the head.  And these are the "easy" ones since they are SOHC heads.

 

My back was very sore from the ordeal.  I can't even imagine trying to do this on the DOHC engines.

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I did the headgaskets in a 2000 OBW SOHC without removing the engine.  Took some effort/time to figure out the correct angle to reinstall the drivers side head but it wasn't too bad.  I used rubber bands to hold the head bolts in while lining up the head for the reinstall.

 

I only used two hands!! The only two I had available, mine. :)

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