EGR system

REDNECKENGINEER

MEMBER
1997 CHEVROLET CHEYENNE
5.7L
V8
4WD
AUTOMATIC
175,000 MILES

I have recently thrown out the factory 4.3L Vortec out of my truck it is the K1500 model and replaced it with the 5.7L Vortec out of my 1999 Cadillac Escalade. Engine has previously been slightly bored and has RV/towing cam all done when I rebuilt it in the Escalade. During the swap I deleted A/C (stupid move on my part) and got rid of the fuel injection along with pretty much everything that was computer controlled and replaced it with a Jegs dual plane intake and a 750cfm Edelbrock along with a Accel super-coil HEI distributor with MSD cap and rotor. Before the swap. Obviously, it had an EGR system. Now, since intake is not EGR compatible, I just capped off the hole on the exhaust manifold. The engine runs excellent and has no problem lighting up the 35/12.50/R18 procomp mud terrains and gets better fuel mileage than any full size 4x4 I have ever owned. My question is, if not running the EGR system will eventually cause failure? Also a lot of guys talked about the melonized gear on distributor and having to use only that but original distributor did not have a melonized gear, but replacement I put in last year did. Accel HEI does not. Will this be an issue? Any input at all will be helpful because it is my daily driver but also my constant project so I am always looking for the next idea.

1997 Cheyenne 4x4.
5.7 SBC vortec heads 750 Edelbrock.
True dual exhaust, hollowed cats, w/Flowmaster dual-in/dual-in muffler.
4L60E with no computer control what-so-ever.
NP241.
3" torsion key lift.
35-12.50-R18 procomp mud terrains.

1 Reply

STEVE W.

MECHANIC
13,443 POSTS

Not sure how you run the 4L60-E without the computer as they will not even shift without the TCM because all internal pressures and shifts are solenoid controlled. The 700R-4 might work as it has the TV cable but then you still lose torque converter lock-up.

But your asking about EGR, EGR lowers combustion temperatures to lower NOX production. Running without it should not hurt anything but the air.

In the "old" days cams were iron and the cam gears were as well. Those were very good for wear as iron is a very good bearing surface. Then along came steel camshafts. A steel camshaft drive gear will destroy a common iron distributor gear. GM and Ford started using steel cams when they switched to roller lifters. They also started using heat treated (melonized) iron distributor gears.

Which driven gear you need is based on what the cam is made of and what type of cam it is. Generally a flat tappet style cam will be a cast iron core and gear so an iron gear is fine on the distributor. Roller tappet cams are pretty much ductile iron or steel core cams and those require either a hardened distributor drive or for short term (like drag racing) a bronze gear. The bronze gear will get eaten up very fast so is not something you want in a street vehicle.

A melonized gear however can be run with all of the cam materials without any real worries. When I build an engine for street use they are what I use. Never had an issue with them. Keep in mind that with a new cam you should install a new gear, and if you pull the distributor and discover that the driven gear is worn or damaged, you also need to change the cam as it will have that damage worn into it as well and any new gear you install will have a very short life.