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Engine GT40 Heads Machine Shop Question

  • Thread starter Thread starter Justin87
  • Start date Start date May 5, 2019

Justin87

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Aug 7, 2017
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May 5, 2019
#1
  • May 5, 2019
  • #1
Hello all,

Recently I pulled the motor and transmission on my 90 GT to begin a rebuild / mild upgrade on the motor. I don't have the cash to do anything super crazy so currently I am doing a H/C/I swap with an explorer intake, GT40 heads, and a cam. (not sure of what cam yet, that's a different question all together but suggestions welcome)

Anyways, I got the heads from a shop a few hours away from my house. They were going to go on a customers explorer but the customer ended up bailing on the repair. So they have been re-manufactured and I have a receipt for the work done. (cleaned, resurfaced, 3 angle valve job, new valve seals). Because of scheduling, I was not able to pick them up in person and they were shipped to my house on Friday.

It looks like either because of rough handling from UPS or not enough packaging the heads scratched one another in transit. It's not terrible but I am not sure if the heads should be resurfaced again. They are deep enough that a finger nail / hook tool catches it but just barely. They are also not near any water ports so I am not sure how critical it is.

So my questions are:

1. Based on the photos, what do you guys think? Should the heads be resurfaced again? This wont be a 9 second drag car anytime soon so I am not sure the damage warrants it.
2. If machine work should be done, what exactly should I ask for? I have never taken anything to the machine shop before and I don't want to sound like a giant tool.
3. I know that stock explorer valve springs need/should be replaced when adding a performance cam, so should all this wait until I've selected a cam and have the machine shop install the new springs as well.

Thank you all for your time and knowledge.

(apologies for the photobucket tag on these pictures, I didn't know that would happen,

Photos:









 

jrichker

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#2
  • May 6, 2019
  • #2
The critical sealing areas are around the cylinder bore edges and water passages. Lay a head gasket on the head and see if the gouge is near or crosses one of those areas. Use that as your decision guide for whether or not the heads need to be resurfaced.
Both heads will need the same amount of metal removed to insure things align up and have the same combustion chamber volumes.
 
Last edited: May 6, 2019
Reactions: GalacticPonage, Justin87 and General karthief

CarMichael Angelo

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#3
  • May 6, 2019
  • #3
It doesn't look like you can even catch a finger nail on it. ( and if you can't, it's not a problem) Depending on where the HG overlaps, and as mentioned whether or not a cylinder seal is potentially compromised because of it, I'd consider it inconsequential. If it were me, I'd get a sanding block with some 220 grit, and just run the block over the head surface to clean it off ( not anything more forceful than what's required to get the surface clean) . If that gouge remains after a light scuff, then I'd look into a light resurface.
 

Justin87

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Aug 7, 2017
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May 6, 2019
#4
  • May 6, 2019
  • #4
CarMichael Angelo said:
It doesn't look like you can even catch a finger nail on it. ( and if you can't, it's not a problem) Depending on where the HG overlaps, and as mentioned whether or not a cylinder seal is potentially compromised because of it, I'd consider it inconsequential. If it were me, I'd get a sanding block with some 220 grit, and just run the block over the head surface to clean it off ( not anything more forceful than what's required to get the surface clean) . If that gouge remains after a light scuff, then I'd look into a light resurface.
Click to expand...

You can JUST barely catch a fingernail/hook tool in the scratches. It’s not even a catch as much as you can feel it/hear it.

That’s good advice with the sanding block, hadn’t thought of that.
 

Justin87

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Aug 7, 2017
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May 6, 2019
#5
  • May 6, 2019
  • #5
jrichker said:
The critical sealing areas are around the cylinder bore edges and water passages. Lay a head gasket on the head and see if the gouge is near or crosses one of those areas. Use that as your decision guide for whether or not the heads need to be resurfaced.
Both heads will need the same amount of metal removed to insure things align up and have the came combustion chamber volumes.
Click to expand...

That’s great advice. i have a set of standard Felpros in the garage that I’ll use to check.
 

mikestang63

SN Certified Technician
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#6
  • May 6, 2019
  • #6
run .it.
light sanding and the head gasket will seal that

a good cam for those heads is an N41 or TFS1
 

Justin87

5 Year Member
Aug 7, 2017
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48
May 6, 2019
#7
  • May 6, 2019
  • #7
mikestang63 said:
run .it.
light sanding and the head gasket will seal that

a good cam for those heads is an N41 or TFS1
Click to expand...

Got a favorite head gasket?

Does your cam recommendation change, if I tell you it’s an AOD?
 

mikestang63

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May 7, 2019
#8
  • May 7, 2019
  • #8
Justin87 said:
Got a favorite head gasket?

Does your cam recommendation change, if I tell you it’s an AOD?
Click to expand...

fel pro 9333 pt1
AOD's can be a little finicky with cams. you may need to raise the idle or get a tune ... TFS1 seems to have some idle issues with AOD's
 
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