[bluesmobile]

I just got my heads back from the machine shop, had a 3-angle valve job done, hardened seats put in the exhaust, new intake valves and seals.

When I got them home on the workbench, I saw a bunch of silica sand stuck to the head in multiple places (first picture), and a pile of sand in the bottom of the bags the heads were in (machine shop bags - heavy plastic clear ones). I was disapointed, and I thought I should take the heads apart and clean out the sand.

When I got the valves out I was shocked at the rough surface of the valve seat. Please see pic #2 and let me know if this is acceptable at all to run, or if I should take the heads somewhere else for another valve job.

Heads are 6X (95cc chambers), going on a 462 with a stump puller cam and rpm intake.

thanks,
Jeremy

[frankyboy455]

About the sand, I've had a similar experience many years ago. I picked up the heads from the machine shop, and left them in the trunk of my car for a few weeks. Riding around with the car with all the shaking and bouncing, there was quite a lot of sand in the bag as well. This was not a good feeling...

[Wild Bill]

I'm not sure from the pictures you even got what you paid for. The picture of the seats does not appear to show hardened exhaust seats installed. Seat inserts are a bright stainless steel color which would contrast with the gray of the cast iron.

The "sand" is glass bead used to clean the head prior to inspection and machining. However it does not look like the head was glass-beaded because you can clearly see carbon deposits in the chamber under the glass-beads.

If the heads do have seats installed that are not appearant in the picture I would definitely disassemble them and clean them before installing them.

Yes the seats are a little rough. You may be able use lapping compound on the seats to clean them up but may need the seats recut to remove the deeper grooving.

Bill

[Schurkey]

I, too, do not see hardened inserts for the exhaust seat.

I would take them to a different machinist and ask them to vacuum-test the valves/seats.

First Guess: They won't hold vacuum; need to be kissed with a stone.

[PONTIAC DUDE]

Originally Posted by Schurkey

I, too, do not see hardened inserts for the exhaust seat.

I would take them to a different machinist and ask them to vacuum-test the valves/seats.

First Guess: They won't hold vacuum; need to be kissed with a stone.

6X already have hardened exhaust seats. I have installed 1.77 and still retain the factory area of the hardened seat and show no signs of seat wear even after 75,000 plus miles and refreshen jobs. .

I bead heads but all heads are blown completely out then put thru pressure washing steps to ensure no grit in the heads before assembly.

[bluesmobile]

Originally Posted by PONTIAC DUDE

6X already have hardened exhaust seats. I have installed 1.77 and still retain the factory area of the hardened seat and show no signs of seat wear even after 75,000 plus miles and refreshen jobs. .

I bead heads but all heads are blown completely out then put thru pressure washing steps to ensure no grit in the heads before assembly.

The only reason these heads went to the machine shop was to get hardened seats put in the exhaust due to valve recession.
See pic for exhaust valve recession after 10,000 miles. Heads were initially prepped by SD Performance.

Jeremy

[72LuxuryLeMansLa.]

Originally Posted by bluesmobile

The only reason these heads went to the machine shop was to get hardened seats put in the exhaust due to valve recession.
See pic for exhaust valve recession after 10,000 miles. Heads were initially prepped by SD Performance.

Jeremy

Any idea on the cause of this. Did you contact SD Performance about it?

[bluesmobile]

Originally Posted by 72LuxuryLeMansLa.

Any idea on the cause of this. Did you contact SD Performance about it?

Yes I called SD and they were not particularly surprised. Dave did mention that valve spring seat pressure matching the chosen cam was critical on these heads to lessen the likelihood of recession. Dave did not choose the cam for this engine. I contemplated sending them back to SD for the hardened inserts and another valve job, but I chose a local "race" machine shop. I now wish I had sent them to SD for rework.

Of note, when I dropped them off at the local "race" machine shop, the head guy did say that the valve recession was likely caused by a lean A/F ratio causing the exhaust valve to get too hot. Maybe Dave at SD would have come to the same conclusion if he had the heads to look at himself.

I've had plenty of older heads with valve recession so I did not think there was a specific problem. I figured they just cut through the hardening when the larger exhaust valves were added. Since I was changing the cam/lifters/springs all with a matched set from SD, and getting hardened seats installed, I figured my problems were in the past! Ha!

Jeremy

[455Darren]

The 6X heads have factory induction hardened exhaust seats. No need to have any installed. I would find a different shop.....

[Schurkey]

Originally Posted by 455Darren

The 6X heads have factory induction hardened exhaust seats. No need to have any installed. I would find a different shop.....

What happens if you grind through the thin hardened layer?

[Wild Bill]

Yes the 6X heads would have induction hardened seats but those look like 1.77 valves not the stock 1.66 valves. Notice how close the 2 seats are intersecting at the center. Cutting the seats large enough for the big valves should also remove all of the hardened material.

[Greg Reid]

I just got a set of heads back from my local cylinder head shop (That's all they do). I should post pics of them. Your heads look like mine did before I took them in. I would not be happy with that.

[steve25]

I see the exh seat incert, but there is a bigger problem other than the poor valve job and the bead blast remains in and on the head.
Yes, that Exh seat will expand at a faster rate than the rest of the chamber meat that the Intake seals on!

The big problem is that the exh seat incert extends into the main seat area of the Intake valve, and once the exh seat heats up and expands more than the rest of the cast iron around it the Inatke valve will then loose its seal at that portion of its seat.

If what I am seening from your pictures is true, you will have to now take the heads to a different shop and get seats installed on the Intakes also, and hopefull this shops valve seat cutting equipment will cut atleast the main seat will and not rip it up and leave the chatter marks that this current shops equipment did, total **** I am sorry to say!!!

[Cliff R]

Dull tooling (carbide cutters) or not truing up stones produce the results you are seeing.

I would remove all the springs, mark the seats with a black magic marker, and hand lap the valves in. If you don't have good contact all the way around, contact between the parts, and adequate margin, get them touched up so you do. I like stones for the touch up part of that deal rather than a cutter, as they polish at the same time and leave a seat that's easier to see when determining if you have adequate width, etc.

All the sets we get back have the valves and/or seats blued/marked where the shop doing the work checked the final product....FWIW....Cliff

[bluesmobile]

Originally Posted by Cliff R

Dull tooling (carbide cutters) or not truing up stones produce the results you are seeing.

I would remove all the springs, mark the seats with a black magic marker, and hand lap the valves in. If you don't have good contact all the way around, contact between the parts, and adequate margin, get them touched up so you do. I like stones for the touch up part of that deal rather than a cutter, as they polish at the same time and leave a seat that's easier to see when determining if you have adequate width, etc.

All the sets we get back have the valves and/or seats blued/marked where the shop doing the work checked the final product....FWIW....Cliff

What is adequate seat width, intake and exhaust?

I did spend a couple hours with a hand-lapper and some lapping compound. Seats in the head did not clean up much, but I could see the contact on the valve, and in some intake seats it was less than 1mm.

There have definitely been hardened seats installed on the exhaust side, no doubt about that. (it may have been hard to see in the pics)

Jeremy

[CROCIE JR]

Horrible. I'm curious about all the other stuff, guide fit and clearance, valve tip height, did they really get magged, seat run-out and concentricity. Just stop and start over. The most you want to lap a valve seat is about 15-20 seconds max. I usually get a pattern to work with in 3-5 seconds. Any more than this and you are creating your own seat with a wooden stick!

[bluesmobile]

Originally Posted by CROCIE JR

Horrible. I'm curious about all the other stuff, guide fit and clearance, valve tip height, did they really get magged, seat run-out and concentricity. Just stop and start over. The most you want to lap a valve seat is about 15-20 seconds max. I usually get a pattern to work with in 3-5 seconds. Any more than this and you are creating your own seat with a wooden stick!

I hear ya, thanks for your advice.

This was my 5th machine shop around here that either refused to work on Pontiac stuff (too old) or did bad work. Does anybody know of a good machine shop in the Metro Detroit area? Or Flint, or Lansing? Or Toledo? Its not a matter of cost or time, I just want it done right.

The seat widths are all over the map, from 0.040" to 0.130"...

Jeremy

[72LuxuryLeMansLa.]

Originally Posted by bluesmobile

I hear ya, thanks for your advice.

This was my 5th machine shop around here that either refused to work on Pontiac stuff (too old) or did bad work. Does anybody know of a good machine shop in the Metro Detroit area? Or Flint, or Lansing? Or Toledo? Its not a matter of cost or time, I just want it done right.

The seat widths are all over the map, from 0.040" to 0.130"...

Jeremy

It is a disgusting situation!!! Here is a man in the "Motor City" that has trouble finding a half decent machine shop! That area has been destroyed geopolitically......

I hope you find a good machinist, I just had to vent a little.

[zephyrracer]

Originally Posted by bluesmobile

I hear ya, thanks for your advice.

This was my 5th machine shop around here that either refused to work on Pontiac stuff (too old) or did bad work. Does anybody know of a good machine shop in the Metro Detroit area? Or Flint, or Lansing? Or Toledo? Its not a matter of cost or time, I just want it done right.

The seat widths are all over the map, from 0.040" to 0.130"...

Jeremy

More Power Inc 616 785-8888 not Metro Det, great machine work, Sparta Mi
Gregg

[455Grandville]

Originally Posted by Cliff R

Dull tooling (carbide cutters) or not truing up stones produce the results you are seeing.

I would remove all the springs, mark the seats with a black magic marker, and hand lap the valves in. If you don't have good contact all the way around, contact between the parts, and adequate margin, get them touched up so you do. I like stones for the touch up part of that deal rather than a cutter, as they polish at the same time and leave a seat that's easier to see when determining if you have adequate width, etc.

All the sets we get back have the valves and/or seats blued/marked where the shop doing the work checked the final product....FWIW....Cliff

Have you noticed any difference between hand lapping and someone attaching a vacuum hose to a drill to lap them ? Just curious.