Well, I think I found the suspect. The MSD Billet Distributor advance mechanism is sticking. It get's stuck advanced, then I adjust the timing to look good at idle, but then there is no advance at higher RPMs. I think the difference between 15 and 35 degrees BTDC would probably explain the 100HP and 100 lb-ft of torque I lose every so often.

DUI, looking even more appealing. This is about the 6th problem I've had with MSD stuff. The dizzy probably has a whole 5000 miles on it, if that.

Anybody had experinece with the MSD Billet Dizzy advance sticking? Maybe, since it is sticking open, I should go with the stronger springs to help bring it back, no? I'll try that and post back.

Right now, it's running the 2 light-weight silver springs to get the steepest advance ramp.

 

So the weights are sticking in the out position? Why dont you try a little light grease or some oil to see if you cant free it up. It sounds like the mechanism isnt worn and loose yet from manufacturing.

(insert sarchasm)

Worst comes to worst you could always go back to points and a stock distributor!

(end sarchasm)

Sorry, I had to.

 

I put in a blue spring (slightly stiffer) on one side. It seems to be advancing now. But it still felt like it was intermittent power monster on the road test.

Initial advance is in the teens ~15 and max is around 35 BTDC. Seems good to me.

Anybody wanna fly down here and tune/troublsheet this beast for me? :-)

I think I should buy a Dynomometer and A/F meter. Think the wife would notice?

 

Worst comes to worst, you can always spend $60 on a Duraspark dizz and call it good.....

BTW, the wife will not notice if you get the unit that installs under the floor (I've seen others that don't)

Good luck man, I think you're on to something --Mike

 

Cool, I got one right. Sounded like advance when you first described it.

You should be able to use the light springs. Don't change you desired curve just to get the weights to come back. Find the problem and fix it. Disassembly may be required, maybe a little polishing or lubrication, who knows. Don't give up on the dizzy just yet.

After all:

1 good dizzy + Gtex's luck = sticky advance.

Sorry, I couln't resist either.

-Scouder

 

We'll see. It still seems to be intermittent on the Wahoo!

I took out the in-cab gas tank, allowing me to plumb the monster tank straight to the filter and pump. It was going through the tank switch (probably very restrictive).


I've had a busy day:

1. replaced the power brake booster with reman unit

2. replaced the master cylinder with reman unit, bled brakes, probably needs a bit more, but is seems better already.

3. removed, heater assembly, removed 20lbs of leaves from the vent. no wonder the heater wasn't working well. replaced the heater core, not sure it needed it. replaced heater control valve and some plumbing. (If you're ever driving my truck, pull heat for defrost and vice versa :-) Oops.

4. placed sheet of rubber between the fuel pump and the frame C channel to quiet things down. It worked.

5. reinstalled subwoofer (main reason for removing the tank :-) must have tunes...

6. removed 20 or so reciepts from behind seat ..most all from the local auto parts store :-)

7. remove dthat pld fire extinguisher and those wood trays.

All this while in the worst Texas weather I've seen in a year. It's our week of winter I guess. It actually sleeted earlier today and their talking snow/sleet/wintry mix for tonight....

I may sleep well tonight.

Maybe, I'll do that $300 worth of fuel plumbing next week. I still have not ordered the parts.

 

You have some crappy luck Greg. My MSD is cooking with crisco. I love it. It does sound like the creature comforts are coming along well anyway. You need to get to the dragstrip and see how intermittent this stuff is. I would send the dizzy back if its sticking. That may turn into a bigger problem. I think the DUI stuff is real nice but it is pretty expensive. An MSD working correctly should work just as good.

 

Dang Greg,

If you get that timing fixed, along with your fuel system you'll be stylin' big time. Not only that, but now that you've removed all the agriculture from your ventilation system you'll have better weight transfer and probably knock a tenth off your quarter mile times!

-Scouder

 

Leaves? You're complaining about leaves? I had to remove about 20lbs worth of mouse nests from my under dash air conditioner. You're lucky it was just leaves, trust me, mouse nests are NO fun.

Seriously though, glad it's coming along good. If it was me that distributor would be on the big brown truck back to where ever it came from. In the meantime until you get the exchange, I'm sure you have a stock distributor laying around.

 

Mouse nests? Huh. That's nothin'. I have to keep diggin Chevys out of my fenderwells. And those things can really get wedged up in there too. And you thought mice had diseases. Sheeesh!

-Scouder

 

Still messing with te timing. I pulled the dizzy and cleaned things, moved up to the stiffest springs and the biggest advacne stoip bushing. It seems to be returning now, and I like the overall timing. It's not as rapid an advance rate as I would like, but it's full in by 3500 rpm according to the MSD paperwork. Should be good.

The Carb is making me angry. I've pulled the entire electric choke assembly off, because it acted like the carb was messing with the idle. Sometimes after I rev it up good, it doesn't come bcak down all the way. Like it's at a high idle. But, this after I've been running and through several revs. ???? I may never get this choke assembly reinstalled. Now the high idle speed adjustment screw/cam is just laying there???? I can usually push the throttle with my hand (or pull up on the pedal) to a normal idle.


Now, DUI and Projection are looking appealing :-)

Any ideas out there?

 

I don't know how long you've had the dizzy but you could possibly get a replacement from MSD.

Does your throttle return to idle if the pedal linkage is unhooked? Is it the linkage causing the resistance?

Also, you said the fast idle cam is no longer an issue, correct?

Sounds simple, but do you have enough return spring? Is it pulling at an angle that gives it good leverage?

The reason I ask is that the only other options are not good. Bent butterfly shaft, vacuum leak?

-Scouder

 

Could a vacuum leak come about after revving the motor, and be intermittent?

I do need to make sure it's not linkage, but it's not suspect at a glance.


I don't like the slower advance curve. It's stumbling a bit off-idle.


It sems like the truck is making substantial power when I first get into it, but by the time the tires hook up and I'm going into 2nd it's just above average. It still runs and pulls pretty good until I shift around 5K rpm. But, it just feels like somethings not quite right.

 

A vacuum leak can definately be inconsistent. In the past I have had good luck testing with starting fluid. With the engine running shoot starting fluid around the base gasket, and the vacuum lines, if any, as well as the butterfly shafts. Any change in engine rpm would indicate a leak.

As to the linkage. If its not a vacuum leak. Disconnect it at the carb and see if the high idle problem continues. If it doesn't then we have a linkage problem. Either a binding or sticky linkage or inadequate return spring. If it does continue with the linkage disconnected then the problem obviously comes back to the carb.

-Scouder

 

Also, for any type of performance 3500 is about 1000 rpm too late for your timing to hit maximum. I think those lighter springs will be the ticket. For inital startup and breakin I have mine set to come in at about 2800 and limited to 34 total. I will set my initial at 14 and adjust once the engine comes to temp. Ultimately I expect my initial to go 16-20 and my total to go 36-40 all in by 2500, but only time will tell.

-Scouder