clearification on jake head model numbers

[Larry B]

 The engine I am working with is an 8-71. The information I got by downloading Jake Brake maintenance manual  from Jacobs web site and from a great deal of help from individuals on this site. The Jacobs book talks of a 71A/92A housing and to set clearance at .059 (with large rocker arm pads). The number on my Jake housing is 71/92A. The letter A after 71 is not present on mine. Are my Jake housings considered one of the other combinations that the Jacobs manual refers to? These are set at .064 clearance. I set mine at .064 until I had a chance to ask this question.  Second question is:  if mine should be set at .059 and I left them set at .064  am I really going to notice that much difference in effective braking?  Thanks as always  Larry B

[johns4104]

Larry,
The manual that I have states the 71/92 are to be set at .064. and says " The .064 (1.6mm) replaces all adjustments used in the past. All previous Model 71 installations can be adjusted to this new .064 (1.6mm) adjustment."

I hope this helps,
John

[luvrbus]

Jakes require a different setting for "A" timing  you need to be careful out there in Jake world lol

[johns4104]

Clifford,
My manual from Jacobs, says .064 for the A timed and standard timed engines.
Has this changed?

thanks,
John

[luvrbus]

I have no idea what manuals you have but mine call for 0.59 for standard timing and 0.64 for "A"  timed 71 series works for me, Don sets all at 0.55 he has done that for years on a 71 series with both type housings works for him also

good luck

[johns4104]

http://www.jacobsvehiclesystems.com/files/support/docs-pdfs/003879.pdf

This is the latest I can find on the Jacobs web site. See page 4.
It depends on small or large contact patch of actuator. .059 or .064

Good luck
John

[bevans6]

I set mine at .062", because thats the gauge I had when I did them.  Considering they had been set at 1/8", and the oil bridges were backed off by an equal 1/8", I suspect when I finally get to test them they will work astoundingly well compare to how they did work...   

Brian

[Larry B]

 When I started the Jake install one of my heads had large rocker arm support pads and the other head had small support pads.,so I changed one set of pads so both heads have large supports. In my Jacobs manual the only thing determining the clearance setting was the size of the rocker arm support pads and the model # stamped in the Jake housing. My engine has "A" timing so with that noted Clifford I am going to leave setting at.064   Brian when you mention the oil bridge having an 1/8" space, I am surprised the oil pressure didn't blow the small oil ring seal out between main Jake head and the drone. If it wasn't missing ,it must have been leaking  really good. Once again thanks for all the feedback and guidance..
             Larry B

[luvrbus]

Jake gives you that setting to cover all before people start playing with Jake setting they need to know what cam and valves they have in the engine all things are not created equal I notice the section is gone about adjusting while running to many bent valves I guess lol