The contact bands should be in the middle of the seat, .050 solid band all the way around, if the contact is closer to the rim of the valve that's fine, at this point your machinist is out to lunch, find a independent garage that has a valve grinder or if there is a speed shop by you talk to them.

Oh man, I feel for you.  He might not be dressing the grinding stones often enough...I don't know. You're right, The seats on some of those intakes look too wide. Also the contact should be more towards, but not at, the outer edges of the valves. In a perfect world that is. If this isn't a high performance engine and as long as the contact isn't too narrow and the valves seat and seal you'll be OK
Nothing more to offer but best wishes!

"FREE SAMPLE"

I took all the valves back and asked for the 3 intake valves to be re-ground. I also took up 4 spare intake valves Incase there was an issue with the 3 valves.

So the machinist ground those 3 valves and also ground the spare 4 as back up spares. I get home and drop those 3 valves in for a lap (280grit) and check the result.... slightly better but not perfect. I pulled out one of the “good ground” valves to reference it against the newly ground valves and he has gone and re-ground all 16 valves + the 4 spare and made them worse than before. I was furious to say the least as I only asked for the 3 valves with issues to be ground.

I really need some expert advice on what a freshly ground valve should look like after lapping including recommended seat width, seat angle and back cut with angle.

This will be the 3rd time I have had to return for corrective work and just want some additional information so I know how to steer the conversation the correct direction. I have searched online but can’t pin down and useful information.

These are some of the valves, some look ok with a consistent contact band but others have 2 or 3 pronounced bands, others look like they have lots of broken bands where the compound was rubbing on high spots. From what I have read, the seat contact ‘band’ shouldn’t be too thick and should be consistent all the way through the seat contact.

Any feed back would be very much appreciated.











Thanks, Dennis.

56 F100 - 272 Y Block
NSW, Australia.

Cliff, lord Gaga-

Yep I’ll take it back an have him fix those issues.

There are only 2 machinists in my area and the other guy takes months to do anything and Ive also had bad results using him. Unfortunately I’d have to travel 1 hour north or south from town for another machinist but wouldn’t even know where to look or who is good. Hence the fact I’m using this guy, I was recommended to him by a reputable mechanic.

3rd time lucky I hope🤞🤦‍♂️




Thanks, Dennis.

56 F100 - 272 Y Block
NSW, Australia.

On that second photo....looks like the valve or seat was ground at the wrong angle....who IS this guy?! I'd go somewhere else.

"FREE SAMPLE"

Take it back

Thanks Lord Gaga,

I did notice an inconsistency in the grey lapping markings on 2 intake valves. I’m wondering if I should have the machinist address these issues or if they are ok to leave? What do you guys think?

Good intake valve lap


Suspicious intake valve lap (I have done this one 3 times to see it it would come good)





Thanks, Dennis.

56 F100 - 272 Y Block
NSW, Australia.

Nice work Dennis!

"FREE SAMPLE"

Small update-

The machinist fixed the valve seat in an hour and was fairly embarrassed that the head left his shop like that.

This afternoon I cleaned the remaining gasket material from the head surface and dissembled the valves for lapping.

I have one head done and I’ll do the other head tomorrow then give them a good clean.

Thanks for all the help and information fellas. Hopefully this will be the last time I have the heads off for a while🤞😅





Exhaust valve before


Exhaust valve after


Exhaust seat before


Exhaust seat after


Looks like the machinist didn’t want to make the same mistake twice



Thanks, Dennis.

56 F100 - 272 Y Block
NSW, Australia.