Proper block/head finish
Thread Starter
Le Mans Master
Joined: Jul 2005
Posts: 5,752
Likes: 4
From: Austin Texas
Proper block/head finish
Fel-Pro 1142 MLS head gaskets recommend a finish of Ra 40 -50, Rmax 700, R2 500 max. Could someone shed some light on this for me? Can I achieve this finish myself or do I need to haul it all back to the machine shop?...TIA
Le Mans Master
Joined: Sep 2001
Posts: 7,739
Likes: 630
From: Unreconstructed, South Carolina
http://www.aa1car.com/library/ar996.htm
And hey ... I was asleep ... up late helping a bud's son R&I a trans in his wore-out blazer.
Racer
Joined: Apr 2004
Posts: 401
Likes: 0
From: IL
Because of different machines, cutting speeds and cutters used over the years Ra finish needed a standard measurement value. Ra is a simple measurement when it comes to surface finish, if you read through the article above it explains additional types of measurements more in depth. Now days prices of the measuring equipment has come down and the need for machineshops to have this has gone up. O.E.'s have gone MLS with coatings that need smoother finishes than composite gaskets so your machineshop is already familiar with the process.
Check with your machineshop to see if they may have recorded finish for their records during the process. Or for peace of mind take the heads back to verify the Ra range. They may have a "gage" (flat plate with different finishes) used for visual inspections that you could borrow overnight to check the finish if the block is in the car already.
The 1142 can handle finishes (on low end) normally used for composite gaskets. If the machineshop did their work correctly you should be fine.
Hope this helps,
Later.
Check with your machineshop to see if they may have recorded finish for their records during the process. Or for peace of mind take the heads back to verify the Ra range. They may have a "gage" (flat plate with different finishes) used for visual inspections that you could borrow overnight to check the finish if the block is in the car already.
The 1142 can handle finishes (on low end) normally used for composite gaskets. If the machineshop did their work correctly you should be fine.
Hope this helps,
Later.
