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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: Paso One on November 11, 2010, 06:39:58 PM

Title: Another jake Brake installation obsticle
Post by: Paso One on November 11, 2010, 06:39:58 PM
Well popped the valve covers off both engines today,  and the 6V71 has 2 valve heads the donor 8V 71 has  4 valve heads.

Not sure if Jacobs make bridges etc.. for the 2 valve head.

Well I am re thinking rebuilding the 8V after all it's only money :)
Title: Re: Another jake Brake installation obsticle
Post by: TomC on November 11, 2010, 10:21:02 PM
2 valve heads were very common on the 6V-71's in transit buses since they have better low end torque then the 4 valve head-meaning they work better with the 2 spd automatic.  Not much you can do to bump the horsepower-that's why Detroit came out with the 4 valve head.  I believe the Jakes were originally made for 2 valve heads, and the bridges were made to adapt to the 4 valve head-If I'm wrong, I'm sure I'll be corrected shortly.  Good Luck, TomC
Title: Re: Another jake Brake installation obsticle
Post by: luvrbus on November 12, 2010, 05:44:30 AM
The 2 valve head uses a cap on one valve each side , 6 caps (3 on ea side) hard to find may I add  


good luck
Title: Re: Another jake Brake installation obsticle
Post by: Paso One on November 12, 2010, 02:56:31 PM
Thanks for the info about the caps Clifford :)

Do you know where I might find a picture of these caps??? 

It would be nice to see what I am looking for :0

I have heard all the benifits you mentioned TomC with the 2 valve heads in a Transit who would have figured going back to a 1938 version to fix transit whoes....