[DeTomaso] Valve Stem seal and Keeper replacement

[Asa Jay Laughton]

Based on a recommendation from Dan Jones (our favorite 351C engineer 
type), I purchased some new Comp Cams keepers for the valve stems on my 
engine.  I plan to run the engine basically stock in the Silver State 
Classic Challenge.  Dan has told me the stock valve stems and keepers 
can separate after long use, and possibly at high rpm.  I don't plan on 
any blazing speeds like Mad Dog but I do plan on triple digits.  So I 
felt it prudent to take Dan up on his suggestion.  While in there, I 
figured I'd change valve stem seals too, as I've rebuilt other 351C's 
and found nothing left of the original seals.

To do the job, I used a compression tester that had an air hose nipple.  
After removing the shrader valve from the hose and screwing the hose 
into the cylinder, I dialed my shop air to about 65 psi.  Before hooking 
the compression tester hose to shop air, I cranked the engine to TDC on 
#5 and using a wire, verified the piston was near the top.  The air 
keeps the valves seated while using a spring compressor to remove the 
springs.  I discovered higher air pressure spun the engine over, but at 
65, the piston stayed put and the valves stayed closed.

The seals and keepers are replace one valve at a time.  Do everything on 
one, then do the other.  Then move to the next cylinder.  I started on 
cylinder number 5, drivers side, front.  Both the intake and exhaust 
seals were intact and looked rather good, except they were hard as a 
rock.  I replaced them both with new seals sourced from Napa.  These are 
stock type seals, not positive lock seals.  I didn't want to mess with 
machining the guides, especially as the valves are still installed.  
After installing the new keepers, I moved on.  When I got to number 6, 
things changed.  I started finding really toasted seals.

It took a few hours, changing everything on one cylinder, then removing 
the air, rotating the engine, verifying the cylinder I was at was on 
TDC, installing air, compressing springs, changing seals and keepers, 
replacing springs and moving on.  Repeat seven times.

It was a darn worthwhile job and I'm very glad I did it.  You'll see why 
when you check out the photos and more comments here:
http://www.teampanteraracing.com/index.php?option=com_g2bridge&view=gallery&Itemid=57&g2_itemId=2951

Now I have to clean up the valve covers, do some cleaning and vacuuming 
in the heads, torque all the rockers back in place and put the valve 
covers on.  Darn near done.

Asa Jay

Asa Jay Laughton, MSgt, USAFR, Retired

& Shelley Marie
Spokane, WA

1971 Mach I Mustang  [ASA JAY]
1973 Pantera L 5533  [ASASCAT]
    
******************************     
http://www.asajay.com
http://www.teampanteraracing.com