Exhaust manifolds gasket removal techniques & gasket installation process

[Senatorpack@xxxx]

This is a difficult procedure. If you feel that this repair is over and 
beyond you capabilities, make an appointment with your specialists. Do not 
attempt this without the correct tools and replacements parts.

Lift the DeLorean and remove the rear tires. If you are not able to 
utilize a lift, back your DeLorean up onto good quality ramps. Chock the 
front wheels and apply parking brake. Either with the car in the air, or 
with the rear tires on ramps, this will give you room to work at eye level. 

I recommend disconnecting the battery and removing the starter and the 
alternator on the right side to give you plenty of working room.

On the left of the car, to gain adequate access (my hands & arms are big) 
remove the muffler and if you still do not have room, you could have to 
remove catalytic convertor. On the left side of the engine, the 11 mm nuts & 
studs are hard to reach with the catalytic convertor attached.

Soak the exhaust manifolds in LIQUID WRENCH. By far this is one of the 
best rust eaters and penetrating oils in spray form. The trick is to keep 
spraying liberally on the nuts & stud WHILE your are removing. When you feel 
the stud or nut tighten and start to get stiff, STOP. Spray the area again 
and TIGHTEN the stud or bolt slightly to get the Liquid Wrench into the 
engine block threads. (This works well for water pump bolt removal too) Then 
proceed again to remove the stud or bolt. (DO NOT BREATHE THE FUMES FROM THE 
SPRAY) 

Keep this slow and steady process until the studs are removed. In some 
cases the nut rusts so bad that it "welds" itself to the stud. If you are 
lucky the nut & stud will come out together. (Dont worry if the stud breaks 
off, you will have room to remove it later when the entire manifold is off)

IF the stud remains in the block & the nut was removed, AFTER removing 
the entire left or right manifold, spray the studs again and using a pair of 
vise grips or channel locks, GENTLY lock them onto the middle of the stud and 
loosen. The stud will come out, just work slowly and with adequate space, 
spraying the stud with liquid wrench. 

When you have all of the studs and hardware removed clean the old gasket 
material that has rotted off with a small brush. You must inspect the 
manifolds for warpage. You should take them to a machine shop and have them 
leveled off to give the manifold a true, even, flat, surface to the gasket 
and block.

An optional step is to FED/Ex the manifolds to JETHOT ceramic coatings 
INC.

http://www.jet-hot.com/

The coating is applied inside and outside of the manifold. It really 
reduces the engine compartment temp, and improving the aesthetic appearance 
of the engine compartment & manifolds. If you have the JETHOT ceramic coating 
applied, make sure that the manifolds are level BEFORE sending them off. The 
cost to clean and apply the ceramic coating from JETHOT for the DeLorean 
exhaust manifolds in 1998 was $240.00.

Purchase one of the manifold kits from a DeLorean vendor. I installed the 
entire PJ Grady kit on my 1981...very simple and easy to install. PJ Grady 
includes brass hardware replacements in the exhaust manifold kit. The gasket 
that they sell is a one piece item, which is thicker than the Volvo or 
Renault OEM parts.

I recommend cleaning out the rust in the exhaust manifolds with a tap & 
die. This will give you a better area to attach the 4 studs that secure the 
manifold to the crossover pipe. Apply some anti-seize compound to the studs 
that secure the cross over pipe.

When installing new studs into the block, apply a small amount of 
anti-seize compound to the tip that is inserted into the block. After 
installing the studs into the block, holding the manifold in place, attach 
the nut that secures the manifold to the stud & apply a small amount of 
lock-tight to the nut & stud. Be careful not to over torque the new studs and 
nuts. Use a good quality torque wrench.

Finish up the process for both sides of the manifolds, and reattach the 
remaining hardware and parts that you needed to remove during the process.

I cannot emphasize enough checking the manifolds for trueness and level. 
If your manifolds are warped have them machined down and leveled off. 
Installing warped manifolds without machining & leveling, you will have the 
same exhaust leak after all of your effort and labor.


Best Wishes,
Michael Pack