7M cylinder head opinions needed, please

[the t3d]

I'm currently in the market for a cylinder for my mildly built 7MGTE shortblock. I have a few different routes I can go, so I wanted to know what you guys thought. The first option is I can have a local head shop rebuild me one for about $700 out the door. I can snag one off ebay for about $400 used but recently rebuilt, but I would still need to get it looked at for another couple hundred to make sure it's bolt on ready. OR I just found a local deal of rebuilt longblock done back in 2008, that has yet to be installed, for about $700. So, with that deal, I would get a rebuilt head and shortblock. I would just keep the rebuilt shortblock as a spare. But I would still take it apart and make sure the head surface is smooth enough for a metal headgasket. I am curious as to what you guys think about the situation, and what you think you would do? Thanks in advance!


-Ted

 

[Enraged]

Honestly, I would get the machine shop to build a known good (ie not overheated, get it checked for hardness) head. That way you know the complete history of the head that's going into your car. What's included in that $700 price? You can save some money if you do your own valve shims. It's not hard, just takes time and patience.

Even if you are doing a mild build, I would look at upgraded cams, and add adjustable gears. If you want to rev it, you can also do shimless buckets (search, there's lots of info about them.)

 

[the t3d]

The machine shop build pretty much gives a bolt-on ready head prepped for a metal head gasket. All new seals and guides, along with valve seating. This is the route I'm leaning towards, but the older rebuilt longblock looks to be in such good shape, it's hard to pass up. I would love to be able to afford upgraded cams, but at the moment I cannot. In the future I probably will, and I will have a good head to work with finally. Thanks for your input!

 

[adampecush]

Caution regarding heads. Have them checked carefully for cracking. I went through three separate heads before I found one that was at least marginally suitable. Common locations for cracking are around the exhaust valve seats and into the water jacket.

 

[RacerXJ220]

I wonder if the heads are softer than JZ, as well as other castings. I think Quake on Supraforums mentioned the 7M heads need clamping help on the exhaust side.

That is very coincidental and correlates with his suggestions to fix it.

 

[the t3d]

Yea my head has a lot of irreparable scoring on the head and cam surfaces. I'm leaning towards the $700 rebuilt longblock, because I'm not in a major hurry to work on it because school doesn't allow me to. The deal is almost too hard to pass up. And it looks well taken care of. I'll just still have to get it looked at just to make sure she's ready for a mhg application. Man, I went through a period where I couldn't acquire a head for under $900, and now I have too many options. I do better with structure.

 

[adampecush]

I wonder if the heads are softer than JZ, as well as other castings. I think Quake on Supraforums mentioned the 7M heads need clamping help on the exhaust side.

That is very coincidental and correlates with his suggestions to fix it.

I have a feeling that it is a case of more 7M heads experiencing overheating than the 2JZ counterparts.