Eightbanger

Hi guys,

When I removed my heads first time round I had not known about Valve Lapping, so this time I have bought some course and fine lapping paste and a tool which fits on my cordless drill to do the job...
my question is this, should I keep on lapping the valve and seat that you see in the picture as its quite badly pitted? my concern is that the valve seems to be softer than the seat as its already smooth, and I dont want to take to much of the valve while triyng to gt the pitting out of the seat...can I go too far?

redoldsman

Nigel:

I would take the heads to a machine shop and have a valve job done. They will cut the seats with a stone and cut the valves in a lath. You may have some valve seats that need replacing.

Eightbanger

Thanks Red, I had a gut feeling that's what it would need, but that's for the future when time and especially money allows for a proper engine rebuild, for now I just need her running as well as I can manage.

Sugar Bear

See if a machine shop would grind only the seat or seats needed, not clean the whole head etc. it should be rather inexpensive. Continuing may ruin the valve. The seat pictured really needs to be ground not just lapped. The sealing edge on the valve is getting wide.

Eightbanger

Thanks for that SB, I've never done this before but had a rough idea that there may be a point were you can't keep on Lapping.

Eightbanger

Perhaps I could do it myself, but which one of these valve seat grinding stones would I need to get? (see link)

https://www.goodson.com/Valve-Seat-Stones/

Sugar Bear

Sorry, I don't know which stones would be needed as the angle that the seat needs to be ground to needs to be known first. Then the valve needs to be ground at a different specific angle. A pilot to keep the stone in line with the seat is also needed. Then the valve is chucked into another machine to hold it at the correct angle for the valve face. There isn't much room for error due to equipment in this procedure.

It would probably cost a great deal more to buy the equipment than to have it done. Ask some machine shops or old school mechanics in your region if they would grind that one seat and valve. It may cost way less than you expect.

Good luck!!!

redoldsman

Nigel, since you have the heads off, I would wait until you can have the heads done by a good machine shop. When my 54 got here, it smoked so much it looked like it was fogging machine. The problem was worn valve guides. There was so much slop in them you could wiggle the valve stems from side to side. We had the heads rebuilt and I am still driving the car without touching the bottom end of the engine. There is no smoke (I do have a pretty bad oil leak). Why I am telling you this is there is more to rebuilding heads than grinding the valves. I would take your heads to a machine shop and get them to give you an estimate. I think you will be glad you did.

MDchanic

Whoa! Those valve seats are BAD.

If you haven't, guys, open that picture in a separate page and have a close look. It looks like the lunar surface.

And your valves are badly worn, and probably beyond re-grinding.

You need to have someone with a valve grinding setup do a job on all of those seats, and, ideally, replace the valves (I wouldn't expect them to be very expensive).

You'll be glad you did, and will probably gain power that you didn't even know you were missing.

- Eric

Tedd Thompson

X2 on this. The margin on that valve appears to be to thin now .You could just replace the valves (probably only the exhaust will be too bad) and touch up the seats for a temporary fix. but there are many things that need to be checked for your heads to last a very long time.... Tedd

Andreas.Johansson

Hi Nigel


As many of the guys wrote the most proper way to do this is go to a machine shop.
But I understand the situation your in just want to something that is good enough...
I have done a few valve jobs with similar conditions as on the picture and by just lapping them you will get something that is way much better on what you had but not as good as a professional valve job.
Worth a try a try to do this in a "quick and dirty" way.