Duramax Q.
09-08-2004 | 05:39 PM
#11
TECH Fanatic
Joined: May 2004
Posts: 1,087
Likes: 0
From: Cibolo Tx
Originally Posted by James B.
Come to think of it, all the guys I know running Duramaxes have propane injection. That might explain the milage.
The big blocks have oil consumption issues due to intake manifold gasket sealing problems. Oil from the intake area literally gets sucked into the ports. There was also a problem with PCV (also on earlier Gen-II engines) where oil was being drawn out. The PCV issue has been addressed with orifice-type regulation, but as far as I know the intake gasket problem still plagues some new trucks.
On the subject of gaskets, GM recently introduced a new Vortec 305/350 intake manifold gasket with several design changes to help combat the failures that every one of these motors eventually experiences with these damn gaskets. You Gen-III and LS1 folks have it much better when it comes to intake gaskets! I guess I'd rather have leaks than piston slap!
The big blocks have oil consumption issues due to intake manifold gasket sealing problems. Oil from the intake area literally gets sucked into the ports. There was also a problem with PCV (also on earlier Gen-II engines) where oil was being drawn out. The PCV issue has been addressed with orifice-type regulation, but as far as I know the intake gasket problem still plagues some new trucks.
On the subject of gaskets, GM recently introduced a new Vortec 305/350 intake manifold gasket with several design changes to help combat the failures that every one of these motors eventually experiences with these damn gaskets. You Gen-III and LS1 folks have it much better when it comes to intake gaskets! I guess I'd rather have leaks than piston slap!
Your truck has a lot of mods!
09-08-2004 | 06:35 PM
#12
TECH Apprentice
Joined: May 2004
Posts: 330
Likes: 0
Yah Don't don't even consider the 8100 vortec. I am surprised it even moves the truck. It kinda gutless, has no powerband. Drinks gas even though I get 14.5 to 16 highway avg. and 13.5 to 11.5 in town hard on the gas. Thats one thing that really gets me when people say only get 8 mpg. Just because they see 8.1 liters or 496ci. And its more like a quart every 3500 miles. All in all it is worthless motor. Even though it can maintian med to high rpms all day long. Far as intake gasket problems retorque the intake bolts, done. Heck don't know why boat racers keep winning with the 8.1. 
09-10-2004 | 10:07 PM
#14
Teching In
Joined: Sep 2004
Posts: 3
Likes: 0
From: Coastal ME, NH
are you looking for a tower/grocery hauler or a 700hp daily driver? 
the fords also have the torqueshift 5 speed auto, great, if not, better tranny (in my opinion) than the allison. dodge 48re still sucks, still has a crappy converter.
put a fueling and/or pressure box with guages and tranny upgrades, and you can run 15's easy while having power to tow up the hills.
the fords also have the torqueshift 5 speed auto, great, if not, better tranny (in my opinion) than the allison. dodge 48re still sucks, still has a crappy converter.
put a fueling and/or pressure box with guages and tranny upgrades, and you can run 15's easy while having power to tow up the hills.
Thread
Thread Starter
Forum
Replies
Last Post
calsdad
8-Lug Truck Performance
34
06-14-2023 11:07 PM