TaboII

Ok, here is my question for the day, on an 87 944 N/A 8 V head. Is it possibly if the head does not need machining to reseat the valves correctly using the old ways.

I was able to reseat the valves of my 72 Mustang on both the intake and exhaust with a simple process that required a mild abrasive compound and rotating the valves till there was a desired connection between the seats of the valves. Obviously I used the correct measuring tools to ensure that the valves where within spec at the time and made sure that it was not over milled during the process. The project came through with flying colors and I was able to maintain a 13/1 compression ratio with no problems at all. “Yes the motor was seriously juiced for its day” but that’s a whole other story.

Is it possible to mill the valves oneself with this simple technique and achieve a respectable outcome for daily use “not racing spec” well maybe autocross and drivers ed. If I can achieve at lest stock valve seal with this technique, what if any would be the drawbacks to doing this?

Suggestions? Recommendation?

Thanks In advance.
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Toolmaster

TaboII -

Not only that, but grind off the casting marks in the head too, and you've accomplished a stage I head job.

I did it myself too, and wound up with a LARGE HP number with all the other mods I made.

HTH!

Steve Lavigne

[quote]Originally posted by TaboII:
<strong>I was able to reseat the valves of my 72 Mustang on both the intake and exhaust with a simple process that required a mild abrasive compound and rotating the valves till there was a desired connection between the seats of the valves.</strong><hr></blockquote>

This would typically be called lapping the valves, and the abrasive typically used is a lapping compound. I've used this on static items (slider clutch pack to crankshaft taper on kart) and I am not sure how well this works in a moving scenario.

Here is a link to some usenet threads on the subject:

<a href="http://groups.google.com/groups?q=valve+lapping&ie=UTF-8&oe=UTF-8&hl=en" target="_blank">http://groups.google.com/groups?q=valve+lapping&ie=UTF-8&oe=UTF-8&hl=en</a>

thomschoon

I just rebuilt the motor for an 83 NA, the head had 3000 miles on a regrind. I lapped the valves and replaced the valve seals. The only concern is that you check the valve guides for wear and if the valves or seats have excessive wear you have them remachined. It doesnt take much time to clean and lap them, if you want your head nice and clean just run it through the dishwasher but skip the dry cycle. The wife/GF may not approve, but it works as good as any alkaline cleaner at a machine shop.

TaboII

Ok cool, so I lap the valves and replace the valve seals as well as check for ware on the valve guides.

What about the springs? Should I replace them just because?

Also I thought that the only real reason you would want to have the head machiened is if there was a problem. I do not believe that there is a problem to deal with in this area though i will check the trueness of the head itself. Any one have any recomendations to add?

thomschoon

You are right, the valve springs should be checked and shimmed/replaced.

I would have a clean up cut taken off of the gasket surface just to provide a nice clean seal. They took off .005 from mine and it is worth the $15-$35 a shop will charge. Some folks will actually have .025+ taken off to raise compression, not where I would want to get it from but a personal choice. Most decent machine shops work on aluminum (rice) heads on a regular basis so having a clean up cut should be easy to source locally.