99 Cherokee Head Gasket

Subscribe
Oct 14, 2019 | 10:24 AM
  #1  

Doing a replacement on my 99's head gasket (0630 casting). Coolant loss through exhaust. No contamination of the oil system.

Obviously replacing all the gaskets (valve cover, t-stat, head, exhaust/intake, etc), cleaning the push rods, bridges and rockers as well as degreasing the head once it's off the motor. During this mess, I found out the engine ground strap was not even bolted to the stud, it was only semi-captive by the fuel injector harness retainer's plastic leg.

Going to have the head mag-particled at work tomorrow to make sure there's no cracks and then likely resurface the mating face on one of our surface grinders before reinstalling. Using a AM-814776326 gasket kit for the rebuild.
Reply 1
Oct 14, 2019 | 12:01 PM
  #2  
It's not a good idea to surface grind the head surface because it needs to be rough enough for the gasket to bite into it. A smooth mill cut is better.
Reply 0
Oct 14, 2019 | 12:29 PM
  #3  
Quote: It's not a good idea to surface grind the head surface because it needs to be rough enough for the gasket to bite into it. A smooth mill cut is better.
Somewhat false logic there. The idea of the gasket is to allow for differential expansion and contraction. The only real requisite is that is has an RA between 30-60 and a recommended between 50-60 for best performance. Since I'm using a Multi-Layered Graphite Head Gasket, a rough finish is detrimental to the process and greatly reduces the life expectancy of the unit overall. I could mill it on an old textron bridgeport, but it would be a better finish using a bryant surfacer or the P&W Surf grinder. The main sealing factor on this whole thing is the proper torque and torque pattern more than a finish.
Reply 0
Subscribe
Currently Active Users (1)