machine shop head screw up .. info needed ..

gorskined · 04:20 AM

So i brought my 6 original heads off my 76 row turbo motor to be rebuilt at a local northeast machine shop that came highly recommended by some local local pca zone 1 members ..It was supposed be new guides, reseat the valves and a light fly cut to freshen up the top of the heads due to broken studs on #4 .. well something went awry with the light fly cut now all 6 heads have the same groove in them and i am afraid the groves are to deep to be corrected by recutting .. so what are my options . can this be corrected? i ' m hoping the cut missed a spot and its is actually a high spot not a grove but its such a gradual transition i cant tell.
i contacted the machine shop and i have an appointment later today . but i would really appreciate some feedback prior to this appointment. i am posting this not to air dirty dirty laundry but because i would like to speak intelligently when i get to the shop . i understand accidents happen but i have a lot of time and money into this motor and i want the heads fixed correctly. what's the correct course of action if these are groves not high spots ?
i took a picture with black tape to reduce the glare so it's easier to see in the picture.
Thanks in advance
Regards Ned

gorskined · 01-03-2020, 04:03 AM

gorskined · 01-03-2020, 04:06 AM

cgarr · cgarr's Garage

If they are not stamped with the amount removed then ask them how much was taken off. max is .25mm or you could measure them from the top surface to the cylinder surface stock is 84.5mm

Dpmulvan · 01-03-2020, 05:42 AM

Too much holiday eggnog perhaps? That's a shame that someone let those out the door.

Prsh356 · 01-03-2020, 06:10 AM

Highly recommended ?

gorskined · 01-03-2020, 08:10 AM

So i just met with the machine shop
The deepest discrepancy ( gouge ) is .039mm they originally took .050mm off so it can be fixed with room to spare
Craig thanks for the info on the tolerances, my heartburn is slowly starting to subside .

Regards Ned

cmcfaul · cmcfaul's Garage

What will that do to compression? A ROW motor I believe has about as high a CR as pump gas will allow. Machining that off the heads will increase the CR. May want to think about slightly thicker base gaskets to offset.

Chris

Trackrash · Trackrash's Garage

Quote:

Originally Posted by gorskined

So i just met with the machine shop
The deepest discrepancy ( gouge ) is .039mm they originally took .050mm off so it can be fixed with room to spare
Craig thanks for the info on the tolerances, my heartburn is slowly starting to subside .

Regards Ned

Are you sure about those measurements? .039mm equals about .001". That would hardly be noticeable.

gorskined · 01-03-2020, 11:21 AM

Quote:

Originally Posted by cmcfaul

What will that do to compression? A ROW motor I believe has about as high a CR as pump gas will allow. Machining that off the heads will increase the CR. May want to think about slightly thicker base gaskets to offset.

Chris

the 76 turbo row motor is stupid low compression like 6.4 to 1

gorskined · 01-03-2020, 11:31 AM

Quote:

Originally Posted by Trackrash

Are you sure about those measurements? .039mm equals about .001". That would hardly be noticeable.

they were all between .0015 and .0017" the owner assured me there was nothing over .002 he was measuring and writing down i didn't have my glasses. what made it noticeable was that it was a clean line not gradual and the black mat tape really showed it ( old trick i learned long ago electrical tape will really make any imperfection pop ).. i guess we will see once i get the final #s back. fingers crossed.