420A Cylinder Head Gasket Installation

[Skyline-Tweak]

So this is my 5th head gasket I'm going through this year. I believe there is something that I'm doing wrong. So far we've tried just a normal head gasket and we've tried putting a very thin bead of Red High Temp RTV and then laying the gasket on top. That seemed to have worked the best but then the belt slipped off and bent valves. I got a new head to put on but I would like to know if theres a better way to seal it off. I heard about the one head bolt not being right too. Could that be an issue? Any help is appreciated.

 

[tec_41]

5 in a year?! I think after the 3rd you should start doing a little research

It's a pretty simple process, but there isn't much room for error. What exactly is happening when they fail? Leaks, oil burning, mixing with coolant? Have you replaced all of the timing components (belt, hydraulic tensioner, pulleys)?

The head needs to be checked. You should take it in to a machine shop to have it checked for leaks and have it decked so it's perfectly flat. This is especially true if the car has ever overheated since aluminum heads are more prone to warping.

The torquing of the head bolts is a very important process. You need to dip them in oil, and torque them down in the exact order/stages that a repair manual suggests. If you don't have one already, I'd suggest following the steps in a Haynes manual. I followed this step by step my first time on a 420a and had no issues.

 

[darknezz7]

Head MUST be cleaned and decked, only costs $80 at my machine shop.

Block must be totally clean and flat as well.

DO NOT USE ANY SEALERS ON THE HEAD GASKET

are you using a composite or mls gasket?
Stick with a felpro composite.

USE NEW HEAD BOLTS, lightly oiled.

Torque in 3 steps in the correct pattern up to factory specs.

If the belt "slipped off" you have some other issues...

 

[2slow4now]

You need to check the head surfaces for being flat. How did you remove the old gasket material? Used head bolts? Are you blowing the head or is it just leaking oil or coolant?

We need more details of what you have done to prep the head and block to know what you have been doing wrong. It shouldn't take a sealant to seal a head gasket. Look up some of bogusSvo tech articles on heads. Look up jafros you tube vids.