about to change head gaskets..

[JayLashua]

..right..

anyhow..

Im about to change the head gaskets on my recently purchased '87 GN.. and after talking with several people, I think I got everything, but i just want to make sure.. I am going to use the stock GM kind.

So far the procedure I have is as follows:

take off alternator, and bracket, headers - I probably need to remove the turbo too, then?

then I take off the intake.. someone suggested using a wetvac to drain the heads, easiest way?

now Im also going to get new head bolts..

after draining all water, and heads, im gonig to take the heads off.. will they want to come off or do i need to tap 'em off or what? they are kind of heavy so i wouldnt want to drop or create a gouge on the surface..

what is the BEST way to get the gasket material off with least risk to scratching/gouging the block/head surface? someone also said to use acetone and a good razor.. i have some stuff stronger than acetone, it will disolve plastic.. heh overkill?

At this point Id also like torque ratings for the heads, header, and intake bolts, just want to make sure the ones on Gnttype.org are right.

anything else I should know? i am planning on this probably taking 6 hours or so, or would it take me longer? Im not an idiot so i can probably figure it out easily enough, but theres always the bitch factor that kicks in at the most inconveniencing moment..

TIA

 

[Intercooler]

If this is your first time I would find a buddy or friend in your area with experience in doing it. IMO

If you want to go solo I am sure others will have the methods to display for you.

You are in Florida where it seems like many of the board people here are from. How far are you from Cal Hartline? Go pick his brain or phone him up.

 

[JayLashua]

I thikn i found some help tonight anyhow, so hopefuly we'll get it banged out in a day

 

[TurboGN]

Jay, the headers, crossover, turbo, pwr steering pump, tensioner, A/C compressor, alternator, and intake will have to be removed. I marked sandwich bags and used masking tape so I could write the location of each bolt. I put the accessory bolts in one bag, intake bolts in one, turbo bolts, header bolts, etc. in separate bags. Put antiseize on all exhaust/turbo related bolt threads or replace with stainless steel. Water will run down into the lifter valley when the heads and intake are removed unless you remove it to a lower level. Some have removed the block plugs (squarehead below the motor mounts) to accomplish this. I couldn't remove mine so removed the bottom rear head bolts (one on each side) and sucked it out with a turkey baster. This was tedious, however, if you're unsuccessful, the pan should be removed and cleaned.

The heads can be pried (to gingerly break the seal) off fairly easily. Once the seal is broken, lift and move the passenger head forward a couple of inches to gain easy access to the two ground bolts in the rear. Move the driver side forward a couple of inches to easily remove the TV cable bracket bolt. Reverse this procedure for the install and put a piece of cardboard between the gasket and head until the head is finally stabbed onto the dowels.

Use a razor scraper and try to keep material from entering any holes or the lifter valley.

Use brake cleaner for final cleaning because it leaves no residue. Spray it onto a shop rag for cleaning.

Once cleaned, check the block deck and heads for flatness using a good straightedge. This is mandatory and could save you lots of frustration. You may want to lay the bare heads on the block and try pressing down and rocking to test for uneveness. Some will lay them down then use a light to search for gaps.

ARP bolts are the preferred fasteners. Thoroughly clean the bolt holes (both intake and head) with taps. Don't forget to apply thread seal (bottom 1/4" of each bolt) and 30 wt oil on the threads. Torque the heads down in sequence to ten pounds. Use a Felpro intake gasket (the pan type) and install according to directions. Torque the intake bolts to 15#. Torque the heads, in sequence and in ten pound increments, to 80#. Torque the intake to spec. Let sit overnight. Loosen (1/4 turn) and retighten each head bolt three to five times before continuing to the next. This will allow proper mating of the threads and result in a truer torque and increased clamping. Each bolt should rotate an additional 20-25 degrees. This will also eliminate the need for retorquing after a heat cycle (contrary to what others may believe, in fact, retorquing after a heat cycle will actually cause you to loose rotation, thus, clamping force).

It will take longer than six hours but if its done right you won't have any regrets.

Good luck, Joel

 

[PaulRV6]

In my opinion, since you have to remove soo much of the engine already you might as well remove the engine and place on a stand. Much more accessible and less chance of parts/debris falling into where they shouldn't.
I can say that I done this more than once now.

paul

 

[blackbuick87]

Did mine this winter, and it would have been easier to just remove the engine, but I did not have facilities to do that so I made due.

I had changed head gaskets on one engine prior to the 3.8, and that was a 454. I did the entire project on my own (and with this BB of course) and it ran fine with no codes on startup.

Just leave the headers hang to the sides. Then when you start the motor the first time, just use the top three studs on each side since the headers have to come off for retourqing the heads.

With ARP head bolts you have three lengths of bolts as opposed to two from the factory, so be sure to use them in the right places or some of the bolts will be too short.

Getting the A/C compressor off sux azz, especially by yourself. That was probably the worst part of the whole job. Take the bottom bolt out from behind and you will be ok