Ken
The 1275 engine in your Midget is light years away from the one in a Spitfire.
Although, the engines in the rubber bumper Midgets are a bored out version of
the Spit engine. Spitfires (I believe in '74 and up) came with 1500cc engines,
which is the same as the RB Midgets.
The biggest thing to be aware of with this engine is end play in the crank.
Here's how to check:
This article was written for a TR6, but the procedure for checking the 1500 is
only with clearances of .006-.014 inches for the 1500.
TR6 Thrust Washer Check & Installationby James Davis,
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TR6 thrust washers tend to wear themselves out in short order, and sometimes
require replacement even after as few as 50,000 miles. A common problem with
them is that they can easily be installed backwards, in which case they wear
out VERY fast, even in as little as a few thousand miles.
This article describes first how to quickly check to see if your thrust
washers may need replacement, and then how to make sure they are installed
the right way 'round. Checking the Thrust Washers
Checking the condition of the thrust washers is quite straightforward, and
doesn't even require opening up anything on the engine! This is a good check
to repeat every few thousand miles, as letting worn thrust washers continue
to wear away can require a different crankshaft and block if the condition
is severe enough.
To check, simply push the crankshaft pulley rearward as hard as you can,
then have an assistant sit in the car. Now, use your hand to span the space
between the crank pulley and the front of the engine, and inform your
assistant to lightly step on the clutch pedal. You'll feel the crank pulley
move forward slightly, and this will reveal the condition of the thrustwashers.
The allowable axial play for the crankshaft is .007-.013 If the distance
seems greater than say, the thickness of your fingernail, you should bargain
for a lower price, knowing that you'll have to be into the lower end of the
motor soon. If the distance approaches 1/8", you can bet that the thrust
washers have fallen into the oil pan, and the connecting rod bearings are
short to fail. In this case, a different engine may be in order.
Installing the Thrust Washers the Right Way 'Round
Since I've replaced these, and my oil pan contains nothing more than Castrol
20w-50 and my crank doesn't move about unnecessarily, I'll quote from page
36, Chapter 1, sec. 45, par. 8 of the Haynes' manual:
Rotate the crankshaft in the direction toward the main bearing tabs(so that
the main bearing shells don't slide out). At the same time feed the thrust
washers into their locations with their oil grooves outwards away from the
bearing (photo). [bold type added for emphasis]
The photo shows a thrust washer half being inserted with the oil grooves
facing toward the inside of the engine.
Now for the confusion: Page 132 of the Bentley manual has an illustration
(of a photo on page 36 of the Haynes manual) which shows the grooves facing
toward the outside of the engine. The illustration is obviously in error, as
the original photo has no oil grooves showing and the text in the Bentley
manual reads as follows:
Insert the thrust bearings into the grooves in the cylinder block ensuring
that the oil grooves face towards the sides of the crankshaft journal.
This is a very good example of why I prefer the Haynes book, but use the
Bentley manual as a reference.
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