[DeTomaso] Asa Jay's 1985 built 351C Forensics

[Asa Jay Laughton]

Hi all,

For those who may not remember, I've had a 351C sitting in my garage for 
some time now waiting on a forensic analysis.  Well, that day started 
late this afternoon.  First a little background.

I built this engine while going through Automotive Technologies at 
Spokane Community College back in 1985.  The engine was an original 1973 
2V in a Ford Mustang Fastback (similar to the Mach I style but -not- a 
Mach I).  It was a pretty stock rebuild, balanced and sort of 
blueprinted.   It was bored .030 over, used a .010 under crank, a stock 
spec cam, lifters, pushrods, etc.  The heads were reconditioned by the 
students in the Automotive Machine Shop.  I used dished pistons (like 
those in it to start with), had it all balanced and put it together.

It ran great.

Within the year I transferred that engine to my present 1971 Mach I 
Mustang which had just completed bodywork and paint.  It was such a 
pleasure to drive.

A few years later, I came into a set of 4V open chamber heads.  At the 
time, I couldn't remember if the pistons were dished or flat top, but I 
talked myself into thinking they were flat top.  I picked up a Ford 
Motorsport flat tappet camshaft, new lifters, a set of bolt-down roller 
rockers and found a cast iron 4V intake.  I also found a Holley 4V carb 
from someone.

I had the heads done at a local Cylinder Head machine shop and got 
started on a parts swap.  I put the new cam, lifters, pushrods rockers, 
heads, intake and carb on.  I was a bit disappointed by the fact I found 
dished pistons, but oh well, there I was, broke and needed to get the 
engine back together by Monday so I could drive to work.

It ran sort of great.  Sort of, since I could never quite get it to idle 
very well and it had terrible off-idle (crossover) performance.  Once at 
full throttle it ran like a raped ape but getting it there was a bit 
tricky.  I fooled around with it a bit, ended up swapping the Holley for 
a Carter AFB and things got a bit better.

Eventually, I knew something was wrong and I found a couple of bent 
pushrods on one side.  Turns out I wiped two lobes off the cam and had 
dished one lifter so bad it had a hole in the middle.  In went a new cam 
and lifters, new pushrods and I tried once again to get all the 
bolt-down rockers "just right."  Have I mentioned I hate bolt-down rockers?

It ran good, for a few more years.  Eventually I drove it less and less 
until one day I lost oil pressure.  So I stopped, conveniently right at 
a gas station.  I picked up a couple quarts of oil, put them in and 
drove home with oil pressure again.  The trouble was even before that, 
it had started to pick up a bit of a knock at certain RPMs.  It wasn't a 
real bad knock, it was more of a rattle.

It idled fine without noise, but give it just a bit of throttle out of 
gear and it would start to rattle.  A bit more rpm and it would go away 
again.  It just plain didn't sound good, so I stopped driving it and 
started collecting parts for the rebuild of 2001.  That rebuild is 
documented here:
http://www.asajay.com/351rebuild/351rebuild.htm
and here:
http://www.351c.info/gallery2/v/asajay/351C_Build_2001/

In 2001 I finished putting the shiny new engine into the Mach I.  It ran 
great.  I drove it on September 11th to my friends funeral, in uniform.  
I felt like I had resurrected a dream, yet, I still didn't drive it much 
and then in early 2002 when I got deployed, it sat for for nearly a year 
before being driven again.  The old engine, well, it sat on an engine 
stand just waiting for something.

Today I began the forensics on that old engine.  I didn't find any 
severely bent pushrods or toasted lifters.  granted I've not given all 
the parts a close inspection yet.  However, I found something -very- 
interesting when I took the heads off:
http://www.351c.info/gallery2/v/asajay/1985buildforensic/
A crapload of carbon build-up on cylinder number 2.  I mean a crapload.

That's as far as I got tonight.  I'll work on getting the pistons and 
rods out later, then taking a micrometer to everything and reporting on 
my findings.

What do you think?

Asa Jay

Asa Jay Laughton, MSgt, USAFR, Retired
&  Shelley Marie
Spokane, WA
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