[DeTomaso] #9321 is back on the road, vibration issue?

Thomas Tornblom Thomas.Tornblom at Hax.SE
Sun Jun 11 18:14:33 EDT 2006


Took #9321 out for the first drive with the "new" engine this evening, 
and it really appears healthy :-)

I started it up yesterday. I set the crank to 10° BTDC on #1, pulled the 
SPOUT plug, which makes the ignition revert to a fixed 10 degrees, 
turned on the ignition and twisted the distributor until I got a blink 
on the timing light and heard the fuel pump start. Locked down the 
distributor and turned the key to start, and it sprung to life 
immediately, purring at an elevated cold idle. It was just as If I was 
doing an ordinarly cold start. Gotta love EFI :-)

I'm amazed at how easy the new Centerforce clutch is, compared to the 
old stock clutch. I think I should replace the slave with a long throw 
cylinder though, as it seems I really have to push the pedal all the way.

One thing I noticed is that the engine vibrates quite a deal around 2000 
rpm, despite having had the rotating assembly balanced. Is that normal?

It is almost as if it would run on just 7 cylinders.

It smooths out above 3000 rpm, so I guess I might have to accept some 
vibration at some rpm. I just thought that it would vibrate less than 
the old factory balanced engine.

Or is this an artifact of the new aluminum flywheel? I assume the new 
after market damper shouldn't affect this.

The reciprocating assembly is balanced to within 1 g in total.

I noticed that the machine shop had drilled out the counterweights 
really deep, and tack welded quite a piece of steel to the pressure 
plate, which I found slightly odd as I thought that Fords were 
reasonably well balanced from the factory, and the forged pistons I use 
are similar in weight to the stock pistons, AFAIK, and I'm using stock rods.

Unfortunately I didn't verify that the machine shop had mounted the 
correct counterweight on the flywheel, but would they at all be able to 
balance the engine with the wrong weight on, and if so, shouldn't it be 
balanced in any case then?

The shop had punched marks into the pressure plate and the flywheel, 
which I lined up, so I don't think that would be the problem.

I'll call the machine shop tomorrow...

Now I'm only waiting to get the A/C compressor back. I have had to 
refill the A/C every other year, and this year I decided enough is 
enough. I have replaced all the hoses, with new R134a classified ones, 
and will replace the shaft seal in the compressor. Unfortunately the A/C 
guy believes he got the wrong seal when he ordered spares.

Oh well, that will give me some time to assure that I get the rings to 
seal properly. I follow Motormans advice, run it hard!


Cheers,
Thomas.


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