Jake Brake Install

[richard5933]

!974 was the last year those heads were used and at a rebuild at Detroit they tossed those and replaced with the newer style lol 45 years of service is not too shabby

What difference is there between these heads and the newer ones?

[luvrbus]

What difference is there between these heads and the newer ones?

the new style have larger water jackets,2 lbs more metal and easier hookups for the water cooled manifolds in marine use those heads were the pits, they will not withstand much heat in any application

[richard5933]

Guess that means I'd better keep a close eye on the temp gauge...

Does using the Jakes build engine heat?

[buswarrior]

Does using the Jakes build engine heat?

No fire in the cylinder...

Happy coaching!
Buswarrior

[chessie4905]

That's ok. When you crack them on a long grade out west in the summer@ +100° without a good mister system, you can upgrade to the newer style.

[thomasinnv]

Yes jake use does produce heat, but not near as much as an engine under load. When the jakes are operating you still get heat from friction and compressed air. Compare temps running down the same hill with and without jakes on and you will find the engine cools down much faster when the jakes are off.

[Geoff]

How can Jakes make the engine run hotter than just coasting?  Jakes prevent combustion, coasting means you still are firing each cylinder.

[richard5933]

If I understand correctly, the Jakes turn the engine into a big air compressor. Air compressors get hot when running. Got to be less heat than when firing, but still more heat than coasting.

[buswarrior]

Physics.

Compressing a gas (air) will raise its temperature.

Also how you get compression ignition.

Happy coaching!
Buswarrior

[chessie4905]

I was talking about CLIMBING a hill, not descending one. Although I can see where some may be confused.

[muldoonman]

You Guys are gonna make Cliff get out his pole vaulting stick again.

[richard5933]

After a 45-minute drive home from the shop, I can say that the Jakes work. Not 'through the windshield' work, but they definitely provide braking action. On flat ground obviously they are more pronounced, but on a downgrade they certainly help hold speed.

Only problem with the install I noticed is that the valve cover rubs the bump, but it was easily fixed. The valve covers I was able to get had breathers on top of them, which were pulled and replaced with the DD blank plate/gasket. They sit flat, but do stick up about 3/8" higher than the surrounding vavle cover. To remedy things, I just adjusted the bumps stops and striker plates on the engine bay tailgate so that it doesn't close quite as far. From two feet away it's not possible to tell it's not sitting where it was before.