Wastegate Servo/diaphram for '91 350SDL
 

Does anyone know where I can find a wastegate servo/diaphragm for my '91 350SDL?

I noticed power under hard acceleration was reduced recently. Assuming there was no boost, I found that the wastegate was closed. Under further inspection, I found the wastegate servo would not actuate under vacuum.

The dealer says that the servo is part of the turbo assembly and can’t be purchased separately!

Any suggestions?

Mav

Call Garrett and buy a pressure operated wastegate valve (as opposed to a vacumn unit) and plumb it to the intake. Adjust it to 14 psi at 4000 rpms in third gear and you will be done.

PS - if you have disconnected the EGR, that will cause the turbo not to function on the 350

Hey, Maverick, just got your e-mail. My lack of boost problem turned out to be a bad vac. line from manifold to injector pump. Replaced the line and adjusted the mixture and the 79 SD is flying. My engine and yours are apparently very different. A good generation and a half seperates these beasts. I had mine next to an 87 300 SD this weekend and the two didn't even look similar. Good luck with the wastegate. Be sure to examine all hoses in play with actuating wastegate - the answer may be as simple as trimming a bit of hose.