Head Rebuild Questions

[CBLEGUY]

I have started a build thread, and have torn the top end down already. I am concerned about my head. I know I had the head resurfaced once, and I know that it was done once before. I am not sure about the total amount of material that has been removed already. I have inspected the head for cracks, and there are none visible. Is there any way to measure the head for a new MHG? I want to make sure that the compression remains lower as I am going to be running a bigger turbo. The problem I see is that buying another head poses the same problem, you don't know where it's been. I am going to take my block(never been touched) and head to the machine shop that Liberty 1's performance in Ft Myers uses (not the same one that did a shitty job last time) in the next week because they are a couple weeks out. I need some advice on what to do, becasue I am ready to order my other parts as well.

Thanks

 

[starscream5000]

I'd take the head up there also to be inspected for straightness and RA spec for the MHG of your choice. They will be able to tell you if they can take any more material off of not. The best thing to do to compensate should be to get a thicker MHG (you shouldn't need anything thicker than a 2mm gasket I would think, but the numbers will tell you. BTW, how thick was the old HG?

 

[CBLEGUY]

I used a composite with arp hardware to 80 lbft. I was going to use this motor while I built another, but after 6weeks it was a no-go so I pulled the motor and am just going to use it for my rebuild.

 

[starscream5000]

I would take it all to the machine shop so they can tell you what needs to be done to the head, block, and bearings (if you're using aftermarket pistons and rods, take it all up there at the same time).

 

[jdub]

Standard head height is 116mm (4.567 in).

 

[CBLEGUY]

That standard height would be measured from the bottom of the head to the top lip? I am not sure, but I will measure it tonight. I know when I had the head done last time, he said there was warpage, but only small amount, and the head was not a total banana.

 

[jdub]

From the deck to where the cam covers sit.

You have a set of vernier calipers?...that's what you will need to get an accurate measurement.

 

[CBLEGUY]

yes I have a set of calipers.

 

[jdub]

Outstanding :icon_razz
You don't see many people here that have a set of those

 

[CBLEGUY]

I have waaayyy to many tools that I only use once in a great grea while... I have a big problem with Obsession Compulsion. I cannot proceed with things unless I know it is perfect. I cannot stand to have to take things apart once I put them together, I have to do it right the first time. It drives my friends nutz..

 

[jdub]

I have to do it right the first time. It drives my friends nutz..

Trust me...concerning the 7M, that's not a bad thing

 

[CBLEGUY]

Trust me...concerning the 7M, that's not a bad thing

This is why I am having concerns about the head. It failed on my, and I am not trying to rebuild this whole motor, and have it take a shit on me again for a while.

 

[starscream5000]

Like mentioned earlier, just take your time and pay attention to the fine details and don't cut corners and you should have no worries .

 

[CBLEGUY]

I make sure to get it spec'd out, and the purchase the right MHG. I have read so many thread about the "right" HG to use. I know that I will buy the most reliable, but if you balance the opinions on the two main types, people seem to be split on either the Cometic or HKS. I am looking to hit around the 400 to 500 hp mark reliable. About taking time, I always do, I never cut corners.

 

[jdub]

This is a good read:

http://www.supramania.com/forums/showpost.php?p=216396&postcount=5

I'm using a Cometic myself...sized to my cylinder/piston diameter. Cometic will make you any thickness or cylinder diameter you need.

The Cometic is a bead type MHG; it's just as good as the others out there (Greddy, HKS)...you're just not paying for the name. The Cometic also requires a 50 RA spec for the block/head decks...the HKS and Greddy requires a 30 RA. The Cometic does have a couple of rivets that need to be removed.

If you're going for the high HP numbers, the HKS Stopper is the best...no doubt.

 

[saxman47]

About taking time, I always do, I never cut corners.

you know what they always say, do it once, do it right, then you don't have to worry.

good luck with your build :icon_bigg