I am in the process of replacing my cam tower and gasket... As I have been working I have been debating pulling the head and taking it to the shop to be freshened up (I get all my machine work for free). So here is my question...

Has anyone decked (skimmed) the head? If so by how much? Any drawbacks for doing this on this car?

 

I've taken 0.060" off my 951 head before. Don't know what the drawbacks are yet. Risk of valve-damage with a broken timing-belt is the same since it's an interference design. It does reduce the amount of rotation you can do with an adustable cam-gear, but you'd have to be using +/-40-degrees to notice.

Only catch is you're not going to get up to the compression-ratios of the later cars, which was done with pistons. However, other headwork can be done such as valve-seats and port & polish job while you're there.

 

Anything recommended on the valve seats? 5 angle? radious?

 

I'm pretty sure those 5 angle jobs don't last long, at least that's what I overheard - don't know from experience .. yet.

 

I took .035" off of my NA head. This was the most I could go due to the aftermarket cam I am running.

 

did you do anything to the valve seats?

 

if your 86 NA is running with no problems, smooth idle...recently tuned...good plugs, wires, air filter, belts, cleaned injectors yadda, yadda...don't bother...nobody here will tell you it is worth the time and/or money - as you won't gain much if anything...seems only 'chipping' is somewhat noticable from what I've seen

now if you need a head gasket or a valve job then that's another story

 

The most I've ever gotten out of a chip is +5hp and that requires 95+octane. Only way to make more power out of an NA is from the inside out. Larger displacement is best, then higher-compression for stock motors. If you don't fit the later or Euro pistons, you can mill your head. Compression is actually worth 10-15hp if you can get up to 10:1 or so, which is the difference between the US-spec vs. European one.

Heads are next and the 4-valve one will give you another 20% just like that! Or you can modify the existing one. I've done a D-ported head with, narrow-stem valves and a fully-radiused valve-seat. This is good for 25% more flow at the same pressure on the flow-bench. Cam comes next, but will shift your powerband up the RPM-range. If you want an agressive race-motor, the cam can be profiled for 7000-9000rpm operation along with a solid-lifter conversion and now you're looking at +20-30hp.

Tough to make significant increases in power without upgrading the technology, like going to 4-valve heads, variable-induction intakes & exhuast, hemi-heads, etc.

 

I am not doing this for a HP gain, but more for 'since I am in there'. My car has about 200k on it for miles and it is my daily driver. Since I am going to be moving soon, I want the car to be running as good as can be. Plus, I have a machine shop that does my work for free... need to use it while I can.

 

You might as well re-ring it while you're there. Once you've got the head off, it's only a couple hours to drop the pan and undo the rods. Good idea to do the rod-bearings while you're at it too...