L31 with LT1 bottom end

[Schurkey]

There are tons of melonized gears at Pull-A-Part on Vortec distributors. It's a five-minute swap while you have the distributor out. I put one on my TBI distributor since I'm running a roller cam.

The TBI distributors ALREADY have a melonized gear.

I went through this twenty years ago when I stuffed a '92 Caprice TBI roller-cam service-replacement "crate" long-block into my '88 K1500 TBI (flat-tappet cam) truck. I bought the crate engine from Pace Performance. They sold me a melonized distributor gear along with it because of the roller cam in the replacement engine.

The gear was for the larger distributor shaft of the coil-in-cap HEI--0.491 instead of the skinny-shaft TBI distributor (which might be 0.430 diameter?) So I call them and ask about getting a melonized gear for the skinny-shaft TBI distributor. The guy researches it for awhile, then tells me to use the distributor gear already on the distributor since the TBI distributor gears are all melonized.

I never did get a refund for the too-big gear they sold me.

 

[Erik the Awful]

Thanks! I did not know that. At least I got it cheap.

 

[Supercharged111]

The TBI distributors ALREADY have a melonized gear.

I went through this twenty years ago when I stuffed a '92 Caprice TBI roller-cam service-replacement "crate" long-block into my '88 K1500 TBI (flat-tappet cam) truck. I bought the crate engine from Pace Performance. They sold me a melonized distributor gear along with it because of the roller cam in the replacement engine.

The gear was for the larger distributor shaft of the coil-in-cap HEI--0.491 instead of the skinny-shaft TBI distributor (which might be 0.430 diameter?) So I call them and ask about getting a melonized gear for the skinny-shaft TBI distributor. The guy researches it for awhile, then tells me to use the distributor gear already on the distributor since the TBI distributor gears are all melonized.

I never did get a refund for the too-big gear they sold me.

The car motors were roller cam motors, but not the truck motors. You sure the trucks got it too?

 

[Schurkey]

What I was told by Pace Performance was that "all" the TBI distributors had melonized gears.

All those years later, I pop a head gasket between #3 and #5, torched the block and head, and wound up re-using that distributor AGAIN on the newest replacement engine--Vortec short-block, aftermarket heads and intake manifold.

What bothers me is the frequency of Vortec distributor gears going bad compared to TBI and the ancient coil-in-cap gears. I see photos and posts about the Vortec gears and they're sharp enough to shave with; I never saw a TBI distributor do that.

[Edit] Here, for example.
99 escalade won't start, replaced crank sensor
[/Edit]

 

[Supercharged111]

Oh I'm aware of the wear of the Vortec gears. Mine was so sharp I couldn't set cmpret properly, then a year after I replaced it with a GM gear the new one was showing wear.

 

[L31MaxExpress]

Oh I'm aware of the wear of the Vortec gears. Mine was so sharp I couldn't set cmpret properly, then a year after I replaced it with a GM gear the new one was showing wear.

I put a Napa Echlin gear on mine. Still looks great. It is now mated to its 3rd cam in a 2nd engine.

 

[Supercharged111]

I put a Napa Echlin gear on mine. Still looks great. It is now mated to its 3rd cam in a 2nd engine.

Noted.

 

[Crazydavez28]

Why? Are the pushrods you have so long that you don't get proper sweep at the valve tip?

I used Comp 7.300" Pushrods on PRW 1.6 Rockers (they were used and free to me). The heads had 7/16 screw in studs + guide plates and I didn't get too much thread engagement on the polylocks. The geometry looked good but I think the stock 7.195 pushrods would still work. I honestly don't plan to touch them until my first oil change. Has 300miles on the clock now. Runs damn good and fuel trims are around +11-12%

I will post an update of the cam gear and distributor stem size tomorrow. I got some new intake gaskets that have the steel load limiters...maybe I won't crack them this time.

I actually think the oil pressure is good but the gauge on the dash is reading incorrect as it seems a little jumpy (1/4 sweep movements) at times. Didn't find anything concerning at all in the oil filter.

I am having a weird stumbling issue at start-up. Engine fires right up then rumbles at 4-500rpm for 5-7 seconds and them smooths out and idles fine. No issues after start-up. Injectors are new MPFI Spider. Is this fuel pump, IAC, or oil pressure related?

 

[Supercharged111]

Marine cam uses stock pushrods. Why did you go with different pushrods?

 

[Schurkey]

I used Comp 7.300" Pushrods on PRW 1.6 Rockers (they were used and free to me). The heads had 7/16 screw in studs + guide plates and I didn't get too much thread engagement on the polylocks. The geometry looked good

If the geometry is good like you say, you don't need shorter pushrods. You need longer rocker studs.

I am having a weird stumbling issue at start-up. Engine fires right up then rumbles at 4-500rpm for 5-7 seconds and them smooths out and idles fine. No issues after start-up. Injectors are new MPFI Spider. Is this fuel pump, IAC, or oil pressure related?

Check the fuel pressure, connect a scan tool to see what the IAC is being commanded to do. Wouldn't hurt to verify that the IAC passage is clear of carbon/varnish/sludge, and the EGR is seating.

I don't know how this could be related to oil pressure since you should have "plenty" of pressure when the engine is cold.