Rebuild Tips

[hd78half]

I restore classic and antique motorcycles and was equipped therefore to rebuild the A4 in my '69 Pearson 35. Here are a couple of tips for those of you anticipating such a venture:

- First of all, the A4 is a very simple engine and anyone with some patience and a modest tool set can do it. The only specialty tools required are: valve spring compressor (simple & inexpensive), and a torque wrench (easy to borrow, cheap to rent). Otherwise good sockets, box/open wrenches, gear puller, and electric impact wrench.
- Get on-board with a local engine shop to: measure the critical fits of pistons/cylinders, crank/rod bearings, crank/main bearings, cam/bearins and cylinder honing. This work cost me $95.
- Purchase the A4 Shop Manual from Moyer.
- Purchase a cheap automotive engine support stand . Once the flywheel and housing are removed, you can mount the engine block to the stand. From then on the block is supported at waist height (perfect for working on from a chair), and you can rotate and lock it into 6 different positions for working on the crank, the valves, etc. Much better than wrestling the engine around on the bench. Mine cost $54.99 at Harbor Freight and was worth every penny. (http://www.harborfreight.com/cpi/cta...emnumber=32916)
- I disagree with Don on one point in his manual - removing all the studs for mounting the head to the block. At 38 years old, my studs were in to stay and were not coming out w/o breaking, which I had to do to replace the two for the thermostat housing spacer for an aftermarket thermostat. If the engine is supported in the engine stand, I can't find a good reason for removing/breaking the head studs. Don?

The A4 is a simple, reliable engine that is actually fun to work on and rebuild. The total cost of my rebuild was about $850. Received parts and tips from Don for which I am very grateful.

Al Lankford
Cycle Classics

[marthur]

Thanks for the tips. Did you have an problem removing the head with the studs left in?

[jhwelch]

I had my head off years ago all but one of the studs stayed in. One
did unscrew (thank goodness none broke off). It just took a little
time to pry the head up, first from one side and then the other.

-jonathan

[Don Moyer]

If you're not planning to have the deck of the block milled or the valve seats machined, it's perfectly OK to leave the head studs installed if they appear solid.

Don

[hd78half]

I didn't have any problem getting the head off with the studs in. Tapped around the edges with a soft hammer and it slid off easily.

Boat is used in fresh water (Great Lakes) so hardly any corrosion in the engine and this may have contributed to the ease of the head removal (and other portions of the rebuild).

Al