At What Point Is A Valve Job Necessary?

hoopty5.0

mechanicus terribilis
15 Year Member
Dec 14, 2010
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To say that the budget for my fox is tight is an understatement at the moment. I snagged some P heads last week for $100 and need to buy the $105 spring kit from Alex parts.

The question is, how do I know if I absolutely have to have the seats re-cut? I have a right angle die grinder with scotch brite pads and cleaned everything up, nothing seems obviously wrong. Since they are just P heads and I am not trying to set any records, I could probably just roll with it, correct? What should I look for?
 
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If the valves are seating all the way around, the next thing to look for is valve guide wear. If the guides are good, slap some new seals and springs on them and run them. You can always fill the ports with fluid and look to see if any fluid leaks past the seat. If it holds fluid you are good to go.
 
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^^Good advice. If they fail the fluid test you can reseat them with clover lapping compound and an elctric drill..

Works in a pinch.
 
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If the valves are seating all the way around, the next thing to look for is valve guide wear. If the guides are good, slap some new seals and springs on them and run them. You can always fill the ports with fluid and look to see if any fluid leaks past the seat. If it holds fluid you are good to go.

That's another thing - I have always thought heads had bronze guides. These do not, it's just part of the head.

But yes, I will check the deck on them.
 
That's another thing - I have always thought heads had bronze guides. These do not, it's just part of the head.

But yes, I will check the deck on them.

I'm pretty sure bronze are installed and reamed to size when a shop refinishes them. Factory reams the cast iron to size.
 
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So I'd assume if the guides are too worn, there would be slop and the valve would move around in the guide? They all seemed very tight as I removed them.

If that's the case, set them with the chambers facing up and fill them with water. If they hold, install new seals and run em.
 
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Yes, they'd move and air would get around the stem. I'm just going to say this because we'd all say this to any noob asking, save your $$ and get those dang heads hot tanked, magged, new valves, 3 angle, along with the new springs etc. Once you install these heads they're likely not coming off for a long time. It's worth the extra couple hundred bucks or so. :hide:
 
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Yes, they'd move and air would get around the stem. I'm just going to say this because we'd all say this to any noob asking, save your $$ and get those dang heads hot tanked, magged, new valves, 3 angle, along with the new springs etc. Once you install these heads they're likely not coming off for a long time. It's worth the extra couple hundred bucks or so. :hide:
Well, before I take them anywhere or buy anything, I'm going to do a little port work. The EGR bump is going to be removed in the exhaust port and a couple of areas in the intake port will get massaged. From what I've read, those 3-4 small changes net large results in the mid range lift flow numbers.

I will get the heads checked, but I don't want to spend money on processes that aren't necessary.
 
Did you go to the gt-40 website that documented the porting process and flow benched each step of the porting process and documented where the flow was improved at a certain lift point and what areas where hurt during the porting process?
 
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That was really cool how they did that. I absolutely will not get that advanced, but I will pick the low-hanging fruit. I may get 5 hp out of it, but anything that helps the mid range is a win in my book.
 
The extra HP from porting plus a smaller combustion chamber with the P's should give you some fun butt dyno time. What else are you doing when you replace the heads? Explorer intake? Ported? Cam?
 
Im going to pull the whole motor apart and see what kind of shape it's in. But the end game is an 'explorer' top end and a small cam of some sort. This car is grossly underpowered. Im ashamed to admit I had trouble passing a Mazda SUV the other day getting on the freeway going to work.