DeTomaso Mailing List: May 2000, Message #24

Don:
1. I have seen the results of a twisted crank once on a very large slow
speed Diesel. This engine was an inline 8 cylinder, an attempt had been made
at starting it while there was some liquid in cylinder 7, as these cranks
are built up of several segments shrink-fitted together, this crank was able
to twist 5 degrees without breaking. The twist caused very low compression
pressures before ignition in 7 and 8 but very high peak pressures as
ignition in those two cylinders happened 5 degrees "early" (severe
vibration)
I'm not sure how the cylinders are numbered on your engine, but from what
you describe, 4 and 8 are the rearmost cylinders I.E. on the same journal on
the crank, in that case the problem could possibly be a twisted crank
however if that is the case, I can't see how they could be next to each
other in firing order as one would be on it's compression stroke and the
other on it's exhaust stroke I.E. 360 degrees apart.
2. I have recently received a recording of a performance test on a V16
engine where on one bank, the performance of the cylinders gradually
decreased as they got further from the driven end of the camshaft. Again,
this camshaft was made up of 8 individual segments dowelled together, a
lifter jaqmmed on cylinder 8 furthest from the driven end, causing the
dowels at each segment to bend, this caused the cam timing to be more and
more retarded as we moved back from the driven end, resulting in very poor
performance for the last couple of cylinders. Maybe some food for thought.

Lars
Longchamp GTS #3215

----- Original Message -----
From: Franck DJ (Don) <DJFranck@equilon.com>
To: Multiple recipients of list <detomaso@realbig.com>
Sent: Tuesday, 2 May 2000 1:19
Subject: The persistent miss problem with 351 Windsor


> Okay,  We have done compression test with a low of 140 high of 150.
> Done a Leakdown and it is okay.
> Changes heads
> Changes distributor
> Changed Intake manifold
> Changed Coil
> Changed spark plugs and wires
> Triple checked the firing order IT IS CORRECT
> Changed the Spark plug wires around.
>
> After each of these steps, I get the same results.  It now seems to me
that
> the problem must lie in the short block.
>
> I still have a very bad miss at idle  If I pull the plus wires on 4 and 8,
> there is no difference at idle.  This is a 351 Windsor and 4 and 8 are
next
> to each other in the firing order so I get a VERY BAD vibration at idle.
>
> It does seem to me the I get the most power from 1 and 5 with
progressively
> less power from both sides as I work my way to the back of the engine.
>
> My vacuum is about 19 with a wobble.
>
> I have had two suggestions.
>
> One - the crank is twisted????
> Two - I have a bad cam????
>
> I figure I can change the cam for around a hundred bucks.  The crank is a
> different story.
>
> WHAT SHOULD I DO???????
>
> Don Franck
> DJFranck@equilon.com
> 1971 Pantera #1777 /  1969 Mustang Mach 1
> Wk 713-346-3211 / Wk Fax  713-241-8234
> HM 281-856-8049 / Hm Fax  281-859-9531
> http://www.geocities.com/MotorCity/Downs/9415
> "Some people said it couldn't be done.  What they meant was "They couldn't
> do it".
>
>
>
>