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Post by Haines Garage on Oct 17, 2014 19:08:11 GMT -5
There has been some mention in other threads about grinding valves and seats. This topic could be discussed for a multitude of applications. Lets try to keep this one, and I said try!  To the L134 Engine  To Start, My assumption was to always buy new, Lap them in with compound and a lapping tool. However, I know new steel is not always the quality of vintage. Grinding Values from my understanding means, #1 that they are still in spec to be resurfaced. You are smoothing out a closing surface only, the shafts also have to be perfect! No bends. Also no burns. Lets talk about this....... |
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Post by Deleted on Oct 17, 2014 20:51:59 GMT -5
OK, #1, Install new guides. #2, Grind valve seats, this will make the seats square with the guides. #3, Grind the valves, most shops even with new valves will touch them up on the grinder just to be sure they are true. #4, Mark the valve face with a black marker, then set it in the guide and rotate it in the seat, then remove and verify contact all the way around. Lee  |
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Post by Deleted on Oct 17, 2014 21:03:05 GMT -5
I will add, with good valve grinding equipment, there is not much lapping done anymore, maybe on racing engines. Lee |
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Post by Haines Garage on Oct 17, 2014 21:13:16 GMT -5
I will be a Lapping! Love that shi#!
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Post by Haines Garage on Oct 17, 2014 21:18:09 GMT -5
How about someone stepping up to explain the process? I am not familiar with this process! This should be a good thread...In English! |
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Post by Deleted on Oct 18, 2014 7:43:26 GMT -5
Frankly when you lap a valve, you are making it seal on the seat. It isn't the best way to do it. It makes a larger flat surface and to flow/run better, you need a seat surface about the width of a dime. A 3 angle valve job is what does this. It makes a ridge on the seat. I think the seat lasts longer also. I let the machine shop do this for me. In the old days, guys would hone the cylinders, re-ring it, maybe ridge ream it to remove the ridge, then take lapping compound and clean the surface of the seat by lapping. They have a wooden handle affair with a suction cup on the end. You put the lapping/cutting compound on the valve and seat and twirl it until you get a seal surface cut. Then clean off the compund. El cheapo way of freshening up the engine. A good valve job and a cheap valve job, makes a difference. Oil
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Post by zooke581 on Oct 18, 2014 7:58:36 GMT -5
I double clutch to keep the valves from grinding too much.  |
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Post by Deleted on Oct 18, 2014 9:05:54 GMT -5
I was waiting for someone else smarter than me to confirm what I always thought...... Didn't want to look like a idiot in case I was wrong  Lapping valves works, but it's no replacement for a good valve grinding. That being said, I've lapped quite a few valves.... Like Kemosabe Oily mention, its like a in frame ring job, used to freshen up a tired but otherwise serviceable engine, used back before hardened valve seats and such, soft seats and valves wore more. I use the wooden handle suction cup affair, like Oily mentioned, put lapping compound on the valve seat, stick the cup to the valve head, and twirl between the palms of your hands, never in a continuous circle. Twirl a little bit, pick up the valve and spin in a different position and twirl again. You will hear and feel a slight change in the valve when it's lapped. Less is more in this case...just like honing the glaze for rings, remove only what you absolutely have to and no more. |
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Post by Haines Garage on Oct 18, 2014 9:52:48 GMT -5
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Post by Haines Garage on Oct 18, 2014 9:55:00 GMT -5
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Post by Deleted on Oct 18, 2014 22:35:36 GMT -5
As an old valve grinder from 'way back, I see it like this:
Valve lapping is a process for those who do not have access to the proper valve and seat grinding/cutting equipment. It can be a "used car" process, where an effective temporary repair that's not necessarily long-lasting is desired. Like knurling pistons or guides, honing worn cylinders and installing cheap rings.
It can also be used as a touch-up, after grinding the valves, to be sure there are no imperfections in the valve face or seat, but a properly ground valve and seat will not need it. Lapping valves after grinding, in my opinion, is only giving a head-start to the wear pattern that I just got done grinding away! BW
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Post by Deleted on Oct 18, 2014 23:25:26 GMT -5
As an old valve grinder from 'way back, I see it like this: Valve lapping is a process for those who do not have access to the proper valve and seat grinding/cutting equipment. It can be a "used car" process, where an effective temporary repair that's not necessarily long-lasting is desired. Like knurling pistons or guides, honing worn cylinders and installing cheap rings. It can also be used as a touch-up, after grinding the valves, to be sure there are no imperfections in the valve face or seat, but a properly ground valve and seat will not need it. Lapping valves after grinding, in my opinion, is only giving a head-start to the wear pattern that I just got done grinding away! BW X2, well said.................. Lapping is a presidential solution  |
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