[DeTomaso] Valve Stem seal and Keeper replacement

[Asa Jay Laughton]

I run teflon seals on all my rebuilt heads.  The valve stem needs to be 
out of the say to machine for them, which is why I didn't install them 
on the Pantera yet.  I have a good set, new in the box, but couldn't put 
them on because the head needs machining to to do it.  I like them 
personally.

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
  



Tomas Gunnarsson wrote:
> Asa Jay,
>
> I've done this a couple of times myself when changing springs and/or seals. I never bothered bringing the engine to TDC, instead I let it turn over to BDC which is a stable position. Like you I found my seals very hard though not quite as messed up as yours. Allmost all of the exhaust seals had cracked IIRC, some of the intakes had too. I went with teflon seals that require machining when I had the heads refurbished, it'll be interesting to see how they hold up.
>
> Tomas
>
> ----- Original Message ----- 
> From: "Asa Jay Laughton" <asajay at asajay.com>
> To: <detomaso at realbig.com>
> Sent: Sunday, August 09, 2009 2:39 AM
> Subject: [DeTomaso] Valve Stem seal and Keeper replacement
>
>
>   
>> 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
>>  
>>
>>
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