[DeTomaso] More time to plan

[Asa Jay Laughton]

Let me make a clarification on the Crane systems.

There are -two- distinct ways to go in order to obtain Full Roller Rockers.

One:
Non-adjustable.  Special replacement pedastals are mounted beneath the 
new full roller rocker and use a replacement bolt for the stock bolt.  
These are tightened down to torque specs, are used on stock heads, do 
-NOT- require guideplates or hardened pushrods.  I ran this style on my 
Mach I many years ago.  This method requires you to shim the pedastal to 
get the proper preload on the lifter when the bolt is torqued to spec.  
This can be a tedious process.  As I recall, they also take a full 
roller rocker designed for use with the pedestals (this may have 
changed).  Larry Finch is the latest person I know who documented this 
and I think he has photos on the POCA web gallery.

Two:
Fully adjustable full roller rockers.  This method replaces the stock 
pedastal and rocker with a fully adjustable rocker arm.  There are two 
ways to get to this point.  First way, you machine flat the pedastal 
mounts on the head, then drill and tap to accept the proper size stud.  
You add guideplates and use hardened pushrods.  This method is very 
spendy -if- you can find a machine shop to do it.  (there are other 
methods too by using a special cutter that mounts in the stud hole).  
The second way is to buy a "guideplate kit" which Crane used to sell.  
This uses individual guideplates and does not require machining the 
pedastal mounts.  It uses a stud that is sized on one end to bolt down 
the guideplate, and another size at the opposite end to use on the 
rocker.  This method does not necessarily require hardened pushrods as 
the guideplates include a replaceable (nylon or something similar) 
grommet (of sorts).  Using hardened pushrods would be recommended though.

I have some photos of when I did this last to my Mach I (the photos are 
small, taken with a 35mm camera, scanned and sized for an older web page).

Guideplates placed on pedastals:
http://www.351c.info/gallery2/v/asajay/351C_Build_2001/convkit1.jpg.html

Stud on guideplate (note the top end visible is a larger diameter than 
what's threaded into the head.  This also shows the use of a capscrew 
instead of the hex head head bolt.  This was for clearance to the 
guideplate:
http://www.351c.info/gallery2/v/asajay/351C_Build_2001/newbolt.jpg.html

Note the pushrod goes through a second piece that is actually fitted to 
the guideplate.
http://www.351c.info/gallery2/v/asajay/351C_Build_2001/rocker2.jpg.html
http://www.351c.info/gallery2/v/asajay/351C_Build_2001/rocker_ratio.jpg.html


Hope that clears up any confusion on the rockers and what is available 
to do.

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
  



JDeRyke at aol.com wrote:
> In a message dated 6/7/09 8:01:10 AM, boyd411 at gmail.com writes:
>
>   
>> I am looking for opinions on roller rockers ann the advantages or 
>> disadvantages of going with an electrical fuel pump with a carb. Is there an 
>> advantage over a simple mechanical fuel pump ?   I assume I would need a fuel 
>> regulator an a return line too. I have also been thinking about going with 
>> oversize brakes to install when I put on bigger wheels (either 17 " front and 
>> 18 " back or 18" al around) I have read mixed opinions about 6 pistons 
>> calipers vs 4 piston. Any opinions on specefic setups ...
>>
>>     
> Over the years, I've done all this to our Pantera, and these are my 
> opinions, Boyd: 
> Full roller rockers will reduce friction in the valvetrain and thus reduce 
> oil temps; one source claims up to 10 degrees F lower oil temps. The valve 
> guides may last longer, too. Any power increases come from the reduced 
> friction, but they also allow running a mechanical cam. They require guide plates, 
> hardened pushrods and rocker studs, with the heads converted (or 
> aftermarket heads) to 'Boss' spec go with them. A sort-of system is the Crane assembly 
> that uses patented guideplates with replaceable plastic grommets. With 
> this, no head swaps or machining, and stock bolts and stock pushrods can be 
> used. The Crane system sin't as strong nor as rigid as the 'Boss' stud system.
>
>