Questions I Should Ask at the Head Shop?
07-21-2010 | 07:22 PM
#1
Thread Starter
Man of many SIGs
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From: Florida, USA
Questions I Should Ask at the Head Shop?
No, not THAT type of head shop 
I'm getting ready to send my US 4.5L heads down to have them refurbished before they go on. Is there any questions in particular I should be asking to be sure they are competent?
I plan on deviating from stock parts. They will be getting 951 springs and exhaust valves along with "Euro S" intake valves.
I'm getting ready to send my US 4.5L heads down to have them refurbished before they go on. Is there any questions in particular I should be asking to be sure they are competent?
I plan on deviating from stock parts. They will be getting 951 springs and exhaust valves along with "Euro S" intake valves.
07-21-2010 | 09:28 PM
#4
Burning Brakes
Joined: Nov 2008
Posts: 908
Likes: 2
From: West Vancouver B.C.
Make sure they understand the heads need the corect valve spring / stem height , and change the seats , not just machine them out . Valve guides would be a good idea too . Ask them how much seat margine they plan on ( valve contact area ), are they back cutting the valves ? what about porting ? Terry
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07-22-2010 | 09:36 AM
#13
Three Wheelin'
Joined: Aug 2006
Posts: 1,765
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From: Atlanta
Some random tips for finding out if the shop cares about quality:
First look around and see if any of the heads in their shop have signs of a power rotary scotchbrite. If so, walk right out and forget them. That will tell you if they are careless, lazy and will screw up your parts for their own convenience.
After that first level you can ask them how close they hold the seat to stem runout and how they can measure it and how they check seal. The answer itself is less important than their attitude and enthusiasm in answering it and this can root out carelessness again.
Ask how they will handle the transition of the seat to the chamber. If there's a blank look it means they plan on keeping whatever cutter is in the machine and sinking away until the seat cleans up whether that leaves a funky step or not.
First look around and see if any of the heads in their shop have signs of a power rotary scotchbrite. If so, walk right out and forget them. That will tell you if they are careless, lazy and will screw up your parts for their own convenience.
After that first level you can ask them how close they hold the seat to stem runout and how they can measure it and how they check seal. The answer itself is less important than their attitude and enthusiasm in answering it and this can root out carelessness again.
Ask how they will handle the transition of the seat to the chamber. If there's a blank look it means they plan on keeping whatever cutter is in the machine and sinking away until the seat cleans up whether that leaves a funky step or not.
07-22-2010 | 10:04 AM
#14
Thread Starter
Man of many SIGs
Rennlist Member
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Joined: May 2005
Posts: 8,722
Likes: 11
From: Florida, USA
Make sure they understand the heads need the corect valve spring / stem height , and change the seats , not just machine them out . Valve guides would be a good idea too . Ask them how much seat margine they plan on ( valve contact area ), are they back cutting the valves ? what about porting ? Terry
Some random tips for finding out if the shop cares about quality:
First look around and see if any of the heads in their shop have signs of a power rotary scotchbrite. If so, walk right out and forget them. That will tell you if they are careless, lazy and will screw up your parts for their own convenience.
After that first level you can ask them how close they hold the seat to stem runout and how they can measure it and how they check seal. The answer itself is less important than their attitude and enthusiasm in answering it and this can root out carelessness again.
Ask how they will handle the transition of the seat to the chamber. If there's a blank look it means they plan on keeping whatever cutter is in the machine and sinking away until the seat cleans up whether that leaves a funky step or not.
First look around and see if any of the heads in their shop have signs of a power rotary scotchbrite. If so, walk right out and forget them. That will tell you if they are careless, lazy and will screw up your parts for their own convenience.
After that first level you can ask them how close they hold the seat to stem runout and how they can measure it and how they check seal. The answer itself is less important than their attitude and enthusiasm in answering it and this can root out carelessness again.
Ask how they will handle the transition of the seat to the chamber. If there's a blank look it means they plan on keeping whatever cutter is in the machine and sinking away until the seat cleans up whether that leaves a funky step or not.
Hopefully now I won't be posting a "the machine shop f@cked up my heads" thread.
