Tech Tips: Fall 1989

Stretched Head Studs?
Barney Jackson
Northridge, CA

During an engine rebuild, be sure and check the condition of the head studs. They should be straight, with the threads clean and tight in the block. They should not have damaged threads or be “stretched”—this occurs after being torqued and re-torqued, used and re-used (a common event in a 30-year-old engine). This stretching results in false torque readings, loose and/or un evenly torqued head, failed head gasket, over-heating and eventual failure (broken stud).

Checking for stretched studs is very simple. Thoroughly clean then lightly oil (WD40) the threads. Take a head-stud nut (also clean and oiled). “Start” it on the stud and “run” it down all the way. It should easily “spin” on for the complete distance. A stretched stud will bind the nut about 2/3 of the way down. This binding is caused by the distortion of the thread in the stretched area. During my last engine rebuild, I discovered that eight out of ten studs were stretched. Don’t take a chance—new studs are much cheaper than another tear-down.

(Be sure to clean WD40 off studs before torquing.—Ed.)

(Barney will receive a gift certificate for his contribution.)

Hidden Gasket Trick
By Larry Dussack
Friendswood, TX

This is the one that you have to experience for yourself. Everyone knows that most oil filters come with a rubber gasket. How many have of you have ever checked to see if there was an extra gasket on the pump body? I drove my TD faithfully for five years, faithfully changing the gasket each time I changed the oil filter. One day, it spilled oil all over the road. Fortunately I noticed the drop in oil pressure immediately and turned off the ignition. It didn’t take long to find the culprit. An oil filter gasket that had been in the car for who knows how many years had finally cracked. I have seen many people put in a new gasket, forget to remove the old. and end up with the same problem. This is a potential catastrophe for your car that takes seconds to avoid.

(This lip applies to all cars with cannister-type oil fillers-Ed)

(Larry will receive a gift certificate for his contribution.)

Priming the MG Engine Oil Pump
By D.P. Houser
Medina, OH

Let’s say that you’ve just put that rebuilt engine in the car, finished the wiring, and are ready to crank it over. All of the normal checks were done and all that remains Is to fire the engine and set the carburetors, and the final adjustment with the clutch. Now if this were a domestic V-8 you could prime the oil system with an electric drill and an extension through the distributor, but you’ve got a British Leyland motor (MGA, MGB, or Midget), which doesn’t allow such priming action. With the Ignition off, pull out the starter knob and allow the engine to crank until you see normal oil pressure (normally five to ten seconds). But what happens if the oil pump has lost it’s prime? The pump resides above normal oil level and once it is really dry it may not draw the oil upward. Now what? DONT PANIC! Try this trick that a B/L mechanic and ex-Midget racer suggested:

1. Remove the rearmost external engine oil connection on the right side of the engine. This will be the external oil line or oil cooler line.
2. Remove the spark plugs.
3. Place the gearbox in a forward gear and release the parking brake.
4. Jack up and support the rear of the car so the rear wheels can turn and block the front wheels (for safety’s sake).
5. Now with a helper feeding oil into the engine oil train though the rear oil hole in the block that you exposed in step 1, rotate the rear wheels in reverse. Your helper can squirt oil in the hole with an oil squirt can or through an overhead can with tubing. The object is to reprime the oil pump by back filling the gallery.
6. After feeding at least a pint of oil into the engine, reconnect the external oil line and to crank the engine (ignition off). If you still do not get any oil pressure, disconnect the oil line and again backfill the gallery.

If, after several times of backfilling the pump, you still do not get any oil pressure, good luck. You may have to drop the engine pan and remove the pump.

This trick of backfilling the oil pump worked for me after adding only one pint.

Also, be sure to check the oil level after you get the engine operating. You may need to drain some oil to reach the proper level depending on how much oil you added in the backfilling process.

(David will receive a gift certificate for his contribution.)