Valve lapping questions

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prorac1

prorac1

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We received the new exhaust valves with the Higher grooves to get our spring Heights correct the other day.

I'm lapping them in today. Below is pictures of the first new valve lapped. I don't think I can do anything about it, but the pattern looks wide, very wide. Is this going to cause a problem?

I know it's probably not optimal for performance, which were really not too concerned about right now, we're more concerned about them sealing. I think we will be ok, just figured I'd ask.

Thanks. Eric


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Too wide. Needs the valves and seats ground properly.
 
Mine were like that from sealed power. I lapped them, cleaned the seat/valve with rubbing alcohol and then I poured rubbing alcohol in the exhaust ports to check for leaking. I also shined a flash light through the exhaust port in a dark room to see if they leaked. None leaked from either test.
Compression was within a couple of pounds of each other across all 8 cylinders, being 140 -142.
 
That's plenty wide. If you had stones you could use a 60* stone to narrow the seat up from the bottom. Then take a 30* stone and top cut it. Then take your 45* stone and cut the seat. I ,Ike .040-.060 wide and on the outside edge of the valve face.
 
Yeah, I can guarantee this thing probably needs a valve job done properly. LOL. What we're going for is getting the valves to seal so that it doesn't pop through the exhaust while idling. LOL.

We're definitely sacrificing power with the seat that wide and essentially a single angle valve job. But we're planning on replacing the heads in a couple of years. I would like to find a Nother set of 318 heads and over the winter let Jason port them, and learn a little bit about flow characteristics. Etc.

Like 318 will run was saying. That's kind of what we're going for here. The same thing he did.
 
yellow rose said:
That's plenty wide. If you had stones you could use a 60* stone to narrow the seat up from the bottom. Then take a 30* stone and top cut it. Then take your 45* stone and cut the seat. I ,Ike .040-.060 wide and on the outside edge of the valve face.
Click to expand...

My concern is it's too wide. Which it is. LOL. But what problems could this cause other than lack of flow due to the wide single angle. Drivability wise I think will be OK
 
Flow characteristics aside, I think the main concern is the wider the face the more opportunity for a bit of something to land on it and hold the valve off its seat and cause a burnt valve.
 
Well, let's see if the valves even seal. LOL.

Springs and retainers and valves are in on that cylinder and a spark plug is there to fill the hole. The chamber is filled with mineral spirits. Let's see what happens



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Originally you were going to just lap in the used stuff and put it together. The intended future of this pair of heads was just "make it run". It'll run.
 
prorac1 said:
Well, let's see if the valves even seal. LOL.

Springs and retainers and valves are in on that cylinder and a spark plug is there to fill the hole. The chamber is filled with mineral spirits. Let's see what happens



View attachment 1715136570
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Can i give a tip? pour the alcohol into the port, you'll get more "gravity" pressure to challenge the sealing of the valve/seat due to more volume of alcohol overall and it will all be resting on the seat.
 
Max1196 said:
Originally you were going to just lap in the used stuff and put it together. The intended future of this pair of heads was just "make it run". It'll run.
Click to expand...

You are absolutely correct sir. But, the rotator style exhaust valves would not work with the valve springs we have. So buying new exhaust valves was a must. Just trying to get them to lap in and see which it looks like they are.

I just figure it doesn't hurt to check while I'm going through the process so that we know exactly where we sit with this pair of hands. And I think we sit OK. Thank you again everyone for the help. We greatly appreciate it.
 
318willrun said:
Can i give a tip? pour the alcohol into the port, you'll get more "gravity" pressure to challenge the sealing of the valve/seat due to more volume of alcohol overall and it will all be resting on the seat.
Click to expand...

Thank you for the advice. Since I already have the mineral spirits in the chamber, I took the airgun hooked to the air compressor and blew through the intake and exhaust port. We got no bubbles at all. I think we're seated
 
318willrun said:
Can i give a tip? pour the alcohol into the port, you'll get more "gravity" pressure to challenge the sealing of the valve/seat due to more volume of alcohol overall and it will all be resting on the seat.
Click to expand...

Alcohol will find a leak easier also, due to it's viscosity compared to mineral spirits. (not like it matters that much in this case)
One thing for sure is those valves will transfer the heat off.:D
 
TrailBeast said:
Alcohol will find a leak easier also, due to it's viscosity compared to mineral spirits.
One thing for sure is those valves will transfer the heat off.:D
Click to expand...
Agree. I always use rubbing alcohol.
 
Unfortunately I didn't have rubbing alcohol handy. All I had was mineral spirits so we went with it. But the 120 PSI from the airgun seals the deal. LOL
 
Just for reference, here is a before and after to show the poor state of affairs that these heads were in before we started. LOL



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prorac1 said:
Just for reference, here is a before and after to show the poor state of affairs that these heads were in before we started. LOL
Click to expand...

Oh heck that aint bad.:D
You should have seen the valves that were in my factory magnum heads.
They only sealed if the valve was in just the right place, because the valve face and seats were so out of round you could literally see the egg shape.
If you turned the valve 180 degrees and set it back on the seat you could almost throw a cat though the gaps.
 
It's an exhaust valve. They are supposed to be wider than the intake. This ain't no 20K race motor. Lap um, slap um and run um.
 
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RustyRatRod said:
It's an exhaust valve. They are supposed to be wider than the intake. This ain't no 20K race motor. Lap, slap um and run um.
Click to expand...

HEY MISTER!!!!

Its a $20,000 race motor on Craigslist. Lol. It's going in a Hurst Valiant ya know. Lol

Our motto on this engine has kinda turned into……

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