I recently got my new motor in the vette and running. However, I'm becoming very frustrated because it is completely done except for finally adjustments. Timing and carb are tuned well enough for now but the issue is adjusting the rockers. I have modified my original block to bolt a spider hold down onto it for roller lifters. So I am using the gm roller rockers for the V6 engines and scorpion 1.6 full roller rockers. I've finally got the rockers adjusted well enough to idle in both park and in gear but barely. to get the car to idle in gear it must be atleast 750 rpm which puts the parking rpm at over 1000... and even with the higher rpm, in gear the car rocks like crazy like some full out funny car or something. Now my cam spec is 230/236 dur@.50 and something like .544/.550 lift with the 1.6 rockers and 112 lobe separation. so I am expecting a bit of lope which I would like, but I shouldn't have this crazy rocking. I know this has got to be the rockers still not being adjust properly but they are apparently very touchy. I have tried adjust them a few time with the car off. (intake 1/2 closing adjusting exhaust, exhaust a good amount open and adjust intake, tightening until there is friction when spinning the pushrod, then giving an extra 1/4 turn.) and also tried a couple times adjusting them while the car is running, loosening till they chatter, tighten until they just stop and then 1/4 turn. After all this I am where I am now, with an idle, but an incredibly rough one.

Has anyone had experience with these lifters or rockers? anyone have any good tips for a very touchy setup? It's so frustrating because I can only find a few hours a week to work on it so I have spent about 2 weeks on the rockers alone and I have been going mad wanting to drive my vette again for months.

 

that's a good bit of lift and duration. 1000 rpm is't that much for a cam like that. as far as the adjustment, hydraulic lifters take up the slack after they pump up, I'm sure you know that. Usually 3/4 turn puts the lifter plunger in the middle of the lifter where it should be. How much total timing are you running, should be between 34 and 38 degrees before tdc. Could also be a vacuum leak. I built a 350 not long ago with a 480/ 480 cam and it didn't like low rpm idle either.

 

It sounds like you have your rockers adjusted and you're chasing another problem. The idle will be rough, but you should also check all your plugs and wires and make sure you have proper combustion on all cylinders. I have seen a case where two wires were backwards and the engine loped like a top fuel car.

Carb tuning, mixture, and timing are very important at this stage in controlling that idle.

 

As was said, forget about the lifters, that's not your problem. You need a higher stall converter.

 

Plug wires being crossed would make her rock like It's in a typhoon.

 

That too.

 

good to know I should be able to leave the lifters alone.

I thought the duration was the main cause of lope or rough idle, I didn't think the lift affected the lope so much.
Now I just have to manage to get out the the heat for a couple of hours to play with the timing and mixture. I'm getting tired of these 100
+ degree days.

 

I know what ya mean, its been 99 to 102 here in south Georgia too.
Takes all the starch out of ya.

 

...progress. It seems it was several issues. first of all part of it WAS still the rockers. Did one more adjustment while running and it smoothed out the idle a bit. played with the timing and smoothed out the idle a little. It also turns out that somewhere down the line I came up with a couple big vacuum leaks, AFTER I had already went through and checked everything for leaks. so now I'm sitting a a smooth parking idle of about 950 and a rough/lopey (but much smoother than it was) in gear idle at about 650-700. The idle is slightly rougher than I was looking for but it looks like I'll have to live with it since it seems I picked out a bit more radical cam than I thought i did. I rough idle won't bother me much, just not what I was expecting. Still need to play with the idle mixture and maybe that'll smooth it out a bit more.

Issue is now that I've got the car to idle properly the damn electric fan is on the frits. after checking some connection with a voltmeter, it seems I'm getting 12 to the fan and it's just a crappy connection on the plug that I need to fix up. But atleast I got it to idle properly now