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Replacing Head Gaskets

by Ed Treijs

I changed a head gasket on an '87 Reliant, TBI 2.5. I did it the quick cheap way and to my surprise it's worked fine over the summer and fall, including an 8,000 km trip which hit some of the really hilly areas of Newfoundland.

Get new head bolts as well as a gasket. I think that the '85 setup used 10mm bolts. The later 11mm bolts are better, but I don't think that's a backyard conversion.

The quick cheap way:

1) Disconnect battery
2) Drain radiator (remember to open up the bleed plug on the thermostat housing)
3) Remove/disconnect items like throttle cable bracket to get the valve cover off
4) Undo head bolts. These are torque-to-yield I believe; in any case I don't think you should reuse bolts after overheating. Pitch 'em.
5) Remove cam timing sprocket. DO NOT lose timing belt registration! The factory tool is kind of an arm-and-hook device which suspends the whole lot out of the way. I lost timing registration....and had to pull apart the bottom engine covers and accessories to get everything back. You do not want to lose timing belt registration! Plan ahead--either someone to hold the sprocket/belt up, or some kind of (sturdy!) rig to hold it up.
6) With the aid of an assistant (NOT the one holding the timing sprocket up!), use reasonable persuasion to break the head loose. Lift the head up as far as it will go (takes one person at each end): this won't be very far because you haven't disconnected the exhaust pipe from the exhaust manifold. But it will be far enough to pull out the old gasket, quickly wipe down the head/block deck, and slip in the new head gasket which you have placed at hand, in the correct orientation.
7) Drop head, reattach cam timing sprocket, install bolts, torquing as specified, etc etc. (You do have a torque wrench, right?)
8) Properly bleed air from cooling system before starting.
9) Hope that this repair holds!!! :-)

The point of the cheap & nasty technique is that you bypass quite a number of steps, like disconnecting all the sensor wiring, removing fuel hoses, disconnecting exhaust system (must crawl under car for that)--all that would be required to actually remove the head from the car. If you're not going to take the head in to be checked for warped deck, then why bother?

I don't know about the older 2.2s, but on the 2.5s if you lose timing belt registration, you have to pull the crank pulley. That item is held on with Torx-head bolts. You need a Torx-head socket (not Torx-head bit!) to pull it. I've only seen ONE store (a newish Canadian Tire) which has the requisite "specialty tool" set of Torx sockets, at $30.

The 2.2 is the same. Don't use a regular socket to remove the torx nuts. I did once, and had to drill the bolt out. J.C. Whitney sells these sockets by mail-order. $14.99 for good Lisle sockets and $9.99 for sockets that are more than adequate (I have both).

So keeping the pulley with the belt, and the belt tight enough to keep it from slipping on the intermediate and crankshaft sprockets, is very much essential unless you want to change this from a 2-hour job to a weekend hobby.

I match-mark (with magic marker) the head sprocket and belt to help assure re-assembly. I have always changed the gasket with only one person (me), by wedging the head up with wooden blocks. Having 2 or 3 people makes it much easier.

Use the Mopar Performance Heavy duty head gasket. It's part number P4452005. I also agree on the new head bolts. If your dealer does not have the heavy duty head gasket, give a call to Forward Motion. They typically have the head gasket in stock. Last time I ordered, they were $14.82 each. I have no objective evidence, but I have been told that the MP gasket is a few thou thicker and much more durable. The Mopar Performance catalog description states that "These heavy duty replacement and special application head gaskets can be used on all turbo, supercharged, TBI, and carbureted 2.2 and 2.5 engines. Made of special material and designed for high performance usage..." Being that Chrysler says they are heavy duty, presumably compared to their OEM gasket, coupled with the fact that the prices are virtually identical, I go with the MP part.

In my experience, I have not encountered any warped heads, so the quick and easy method is the way to go. For a first time run, expect to take about 4 hours to do the job. With experience, it's a 2 hour job.

The main reason for head gasket failure is usually due to the gasket being over-crushed in the corners by #1 and #4. It gets over crushed because there are more openings in these places (oil/bolt passages, water jackets) than sealing surface. With less surface, but the same amount of force by the bolts, the gasket gets crushed harder and is "squirted" into the cylinder. The steel ring on the gasket gets burned by the combustion in the cylinder where it is sticking out. Once the ring has burned through, the fiber part of the gasket cannot hold back the force inside the combustion chamber, and the gasket blows towards one of those water jackets in the corner. Take a close look at your blown gasket. You'll probably see that the gasket is bent into the cylinder at one (or more) of the corners and is burned along the edge. If you lift that steel ring, you'll see that it is actually spilt in half (from being burned).

We have about 9 head gaskets hanging on a peg in the basement that tell the same tale. We measured the thickness of the used gaskets with a micrometer, and it is always crushed MUCH more at three of the four corners. The corner that isn't crushed as bad is the one that has the oil supply line to the head (#4, front corner). The copper ring there provides some support.

The way this problem is solved is to reduce the pressure at the corners or get a harder gasket that won't be crushed so much (I believe the Mopar Performance gasket is this way, but I have never seen one). The easiest way to reduce the pressure is to reduce the torque on the four corner bolts. When you do the final 1/4 torque, only torque the corners to 85 ft-lb This seems to be the most popular way to do it. We chose a different way. We made three aluminum spacers and drilled 3 1/4" holes in the gasket near the corners. I forget the exact thickness (I have it written down), but we machined them to the same thickness that the used gaskets were crushed to towards the center. So far, this has worked perfectly for us. This way, the bolts are being properly stretched (the 1/4 turn) all around the head.

I hope this info helps. I plan to update my head gasket page with the info on how to make and install the spacers. I already took some pics of the blown gasket and the new-and-improved gasket. :)

What I found works really well is using 2 tie straps to hold the timing belt onto cam sprocket. I also use a bungy cord pulled tight around the hood hinge to keep tension on the pulley. Talking to a friend who works at a Chrysler dealer, he said that if you take a jack to the catalytic convertor after all the head bolts are undone is an easy way to lift the head, making it possible for one person to do the job.

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