BV heads, is this valve sitting right?

sizemoremk

sizemoremk

Registered User
Hey guys, I got the heads back form the machine shop today, and I am a little worried about how this valve is sitting... I used 1.625 ex valves,and stuck with stock intake valves.

The valve is "thicker" than the stock valves, it is a Ferrea valve just FYI.

Am I gonna have to worry about piston to valve clearance??

I am also confused on how may cuts there are.
This is spose to be a 3 angle VJ, but all I see is two cuts on either surface. Does 3 angle mean 3 angles, or 3 cuts???

Take a look at the pics, and see what you think about how this valve sits, and how far towrds the edge it is.

Thanks!
 

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Impossible to tell from the pictures. Hand lap it in. That is the only way to tell the whole story.
 
What is the purpose and process for lapping the valves? Do you know of a howto on the subject?

The coating isn't there yet, just sand blasted in that pic.... but they are getting www.teclinecoatings.com thermal barrier coating (CBC1).
 
Go to the eastwood site-they have the tools needed to handlap valves.

Basically the process is simple-you place a small amount of fine-grit lapping compound on the valve face where it seats, attach a tool that has a suction cup at the end to the flat of the valve, and spin the valve back and forth between your palms. You'll want to alternate lapping, cleaning, and applying Prussian Blue to check how the valve is seating in the head. When you have a solid line all the way around the valve face, you are finished with that valve, and you can go on to the next.

That's a basic description of the process-it gets a little more involved when you are doing the real thing.
 
sizemoremk said:
What is the purpose and process for lapping the valves? Do you know of a howto on the subject?
Click to expand...

Everything you need is available at AZ or any other parts store. Purpose is to see where the valve is contacting the seat. That tells you the story of how the valve is sitting on the seat. On your setup I would consider that a "must do."
 
I had to lap my valves whenever I put my heads together. Go to NAPA and get a valve lapping tool (just ask them and they'll point it out to you) and ask for some valve lapping compound. It's a gritty liquid kind of like sandpaper without the paper. You rub it on the seat of the valve all the way around it, put the valve in. The tool is a stick with a suction cup on each side of it. Just put the suction cup on the face of the valve and twist it at any speed. Twist it like your trying to start a camp fire with a stick.
 
By the way, I dont think you can use stock seats with the 1.62 valves. Did you have bigger seats put in?
 
Can't you do the same thng with a magic marker?

I have been told in an aluminum head, lapping is not neessary, as the vlaves run at an expanded size, which will be nowhere near the cold seat position...

I always thought lapping was just to soften and match both edges to kinda pre-break-in the valves...

So once I get these lines established, where do I want them at?

Thanks!
 
That's not true. The seats aren't aluminum so they won't expand.

It's necessary because it shows you where the valve will be seating. That valve is okay, the only problem would be piston-to-valve clearence and it takes more than .539 lift to do that.

If the seat of the valve and the valve seat shows the grinding marks on the angles of the seats then you'll be okay.
 
Ok, but when I heard this I thought it was because the temps were a bit higher in aluminum heads... in general.
 
What dave said. In general you can run one full point in compression(or more boost) when using an aluminum head when compared to the typical cast iron head for a particular gas. Aluminum sheds heat better then cast iron.
 
I hope I caught this in time. DO NOT LAP THE VALVES. You CAN tell if you have a good seat with a magic marker. That IS a three angle valve job. The only way to tell if you have bad PTV clearance is with puddy. Lapping will make your valve seat/seal fatter. It takes away the ENTIRE POINT of having a valve job done. Take a magic marker, mark the valve face and bounce it. There should be a line around the valve at the seat. This will show you your contact point. It should be on the valve face half of the valve. Near the 3/4 mark.

Chris
 
seawalkersee said:
I hope I caught this in time. DO NOT LAP THE VALVES. You CAN tell if you have a good seat with a magic marker. That IS a three angle valve job. The only way to tell if you have bad PTV clearance is with puddy. Lapping will make your valve seat/seal fatter. It takes away the ENTIRE POINT of having a valve job done. Take a magic marker, mark the valve face and bounce it. There should be a line around the valve at the seat. This will show you your contact point. It should be on the valve face half of the valve. Near the 3/4 mark.

Chris
Click to expand...

Hmm... It aint too late, and I was told on the hotrodders board that you should never have to lap the valves... The marker test should give an idea where it will sit, and the pressure test should verify the seal...

I think I'll just do the marker test...
 
You can also dump sum isopropoyl alcohol down the runners. It will leak a TAD but it should not flow...Only seep. Lapping the valves would be like removing the heads to halfway weld up the runners and then add some port plates just because. Sure it would work, but thats not how you do it. It makes the seat longer/wider and you gain nothing. If they are seated you are good ta go.

Chris
 
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