Rebuilding the L134



I am not going to go too in depth into rebuilding the L134 since there are great instructions in the mechanics manual.  I will take photos along the way and give some pointers along the way.  I am by no means an expert, so some of you Jeepers out there may not agree with some of my techniques.

I pulled the head while the motor was in the frame because I wanted to check the valves.

To PROPERLY remove the head studs, use a stud puller like this one.  There are a few others you can use.  DON'T use vise grips.

The stud puller makes easy work out of pulling the studs

Pulling the oil pan and timing cover, I was surprised to find a chain driven timing setup.  In theory, my 3A should be gear driven.  I'll have to do some research.

Well, the engine rebuild came to a screeching halt.  The motor I have is a WWII MB engine!  The serial number is stamped on the right of the block, and the timing is gear driven.  It would be wrong to leave this motor in my 3A, so I trying to locate a good civilian L134.  In the meantime, I will continue to work on the motor until a civi motor turns up.

The early 2A engines had chain driven timing.  To my knowledge, no 3As ever has this setup.

The block is upside down on an engine stand in this photo, but with the side valve compartment cover taken off, you can see the valve springs.  At the top, is the mount for the oil pump.

With the head and studs removed, you can get a good view of the cylinders and valves.  Lots of carbon build up!

I use this vintage ZIM cylinder ridge reamer to remove the carbon ridge at the top of the cylinder.

With the reamer in the cylinder, use a ratchet to turn it.  It will safely remove the ridge so I can drop the pistons out the top once I turn the block over.

Bottom view of the motor with the crank removed.

With a dial caliper, I check the size of the main bearing journals and the connecting rod crankpins. 

Standard main bearing journals should be 2.3341" to 2.3331", mine were 2.314", a difference of .020".  Connecting rod crankpins should be 1.9383" to 1.9375", mine measure 1.908", a difference of .030"

Ahah!  It's all so clear now why I had low compression!

Using a bore gauge, I checked for out of round and taper.  The deviance can be up to .005", and mine were within spec.  Cylinder bores should measure 3.125" to 3.127", mine measured 3.155", a difference of .030.

Found the correct engine block today!  Both the casting number and serial number match for my year of 3A.  I was able to trade the old MB block for this one.

The inside of the engine looks good.  The block was painted red outside and inside - anyone ever see this before?

I measured everything on this engine and it looks like it has been rebuilt.  Here are the specs:  The cylinder bores measure 3.145", which is .020" over.  The main bearings measure 2.325", which is .010" over.  And finally, the connecting rod crankpins measure 1.918", which is .020" over.

There is always the proper tool for the job.  Here I use a valve spring compressor designed for flathead engines.

Before grinding the valves, I made a rack out of a 2x4 to keep them in order.  I also use a hand valve lapper and some grinding compound.


Coat the valve in a little grinding compound, and drop it in the seat.

Rotate the valve tool between both hands....

...and presto, a clean valve seat!  A unground valve is on the right.

Next up, I honed the cylinders with a course grit stone, and finished up with a fine stone.

It's hard to tell from this pic, but the cylinder walls are good as new!

My hands were pretty greasy, so I couldn't take too many photos!  I installed the valves and springs and adjusted the clearance, installed the crank with new bearings and rear main seal.  Next I installed the pistons with new bearings and rings, timing chain and cover, oil pump, water pump, and valve cover.

Here's what the motor looks like right now.  It's awaiting the head and oil pan.  The motor is painted the correct factory black.

The oil pan got a good steam cleaning as was painted to match the motor.

Before installing the head bolts, I cleaned out the threads with a tap.  Then each bolt was coated in anti-seize to prevent then becoming one with the block.

This is the motor awaiting installation in the chassis.

The original Fram oil filter was treated to a cleaning and repainting.  The closest color match I found to the original Fram orange was some Chevy orange engine paint.  The result was a nice smooth close to original finish.  I will ad some reproduction Fram stickers later on.

Finally!  The motor was ready to be dropped in the chassis.

Eugene is slowly coming back to life!

I threw in this before photo just for kicks.  Sure looks a lot better now!

This sweet shot shows the literally new motor and components.  The distributor got rebuilt with points, condenser, cap and rotor.  A new 6v coil was installed along with all new wires and sparkplugs.  The oil fill vent tube is original with the correct style hose clamps.  That Fram oil filter sure looks good!

Back view of the motor...

The new stickers for the Fram oil filter showed up today from Walcks.  Here's what they look like installed.

Looks pretty good!