: Changing '96 head gaskets....What else?



BIGGUN
05-14-04, 05:36 AM
Seem to have found my over heating problem.
If I expose the overflow hose and brake torque the motor a little I blow coolant all over my driveway. This would explain my level going down without being able to find any leaks or steam in the exhaust. It also explains why I'm out of coolant alot faster if I jump on it at all.

So now I'm planning on changing the head gaskets next week. I have the gaskets and shop manuals ordered.

What else should I do while I have it apart?........Keeping in mind I'm on an ever tightening budget. Any easy performance mods that can be done?

Thanks for the input,
Kevin

growe3
05-14-04, 12:24 PM
When you work on these engine don't "cheap out".

That doesn't mean be wasteful, but trying to do it for the least amount will usually haunt you later. Replace the hard to get at items, if at all questionable, it can save you many hours of frustration and cussing later.

See link to thread, for a previous parts list. Project was from one of my 93 STS's.

http://www.cadillacforums.com/forums/showthread.php?t=12328

-George

86caddtwithflows
05-15-04, 12:41 AM
and take the heads to a machine shop, get new head bolts, u dont wanna do it twice

BIGGUN
05-15-04, 05:03 AM
the gaskets come with new bolts so that won't be a problem.

How much can the heads be decked without causing problems? And will there be a performance increase with decking? Should I deck them even if they are true just to be safe?

Oh, and do you always need timeserts when changing head gaskets?

Thanks again,
Kevin

growe3
05-15-04, 12:04 PM
How much can the heads be decked without causing problems? And will there be a performance increase with decking? Should I deck them even if they are true just to be safe?

Oh, and do you always need timeserts when changing head gaskets?
If heads are within .002 or less of being flat there is no need to resurface.


I have never heard of a Northstar that needed any head machine work. These engines are very solid; with the noted exception of the head bolts stretching the block bolt holes. The heads are likely just fine.

You will not get any appreciable power gains by decking. The Northstar operates with an already high 10.3:1 compression ratio; any material removed from the heads will make the already high compression higher, bring the valves closer to the pistons and is completely unnecessary. The valves and seals are also very robust, and barring any interference damage are most likely just fine.

Use spray gasket remover, a plastic scrapper and patience. Do not gouge or scar the soft aluminum heads or block.

Clean the outer surfaces and the EGR tunnels carefully, and without any disassembly (do not remove the cams either), and put them back on.

For cleaning I use paint thinner first, then strong detergent and water to thoroughly flush all of the head including the intake and exhaust ports. Blow the heads dry with compressed air. Apply engine assembly lube to all of the cam lobes and they are done.

Yes, the TimeSert thread repair must be done to all of the head bolt holes!

If the threads arenít already damaged when you remove the bolts, they will strip out when you torque the new ones in. Get the TimeSert kit and ten additional inserts so you can do all twenty bolt holes. You will need a good drill motor, vacuum cleaner and compressed air for the drilling and tapping. Use spray brake cleaner and compressed air to clean each hole prior to placing the TimeSert. The hole needs to be clean and bone dry, for the thread locking application to work correctly.

The four head alignment dowels will need to be removed to do the TimeSert repair. I use a little WD40 at the base of them then grip them firmly with large channel lock pliers. Rotate them and lift outwards at the same time. Be careful to not damage the block surface, i.e., do not pry from the block deck, it will dent the surface and may cause the new gasket to fail.

You can either carefully grind tool marks from the dowels and reuse them, or preferably get new ones for replacement.

Perhaps the single most important thing to do/get is a set of Helms service manuals. While they are not cheap they are vital to doing the repair job in a correct manner. There are numerous important methods of assembly and dissassembly techniques that must be followed. Tightening the head bolts properly is a critical point.

If you don't want to buy a set, spend time at your local library copying lots of the pages for reference. In my opinion the manuals pay for themselves in short order as they cover the whole car, not just the engine, they will save money and time on future repairs or modifications.


-George

BIGGUN
05-15-04, 03:31 PM
I already have the GM service manuals. Are the Helms manuals better?

That's a bummer about the Timeserts. That's a few hundred dollars I didn't expect to spend. Were's the best place to get them?

Thanks again,
Kevin

growe3
05-15-04, 06:34 PM
Gm and Helms manuals should be the same.

www.timesert.com (http://www.timesert.com)
-George

zonie77
05-15-04, 07:28 PM
For the timeserts check Ebay. Some one on the forums may want to sell a set...See if anyone posts in the next day or two. You will probably find some of the threads pulled. It's pretty common if you blew the headgaskets. Timesert all of them. It's good insurance.