'87-ish V8 issues

[1971s2av8]

Hi, I've got a late 80's, carburated, 3.5l Rover V8 (sits in a Series now). Was rebuilt around '03, and just now getting a run-in as I've finished my Series Rebuild.

Problem is: Last year, was running great, then under load (up hill) lost all power, ran very rough, and died. Would restart after a bit of 'rest', but couldn't handle any throttle at all.

I replaced the Coil, Accumulator, and Points (made adjustments, etc) and got it running again. Ran great for about 50 miles, then exact thing happened as before (all power cut out under load).

It will start and run great for a few minutes, then cuts out again... Almost as if it's heat related.

I've checked the vacuum advance is advancing the timing, I've tried new dizzy cap and HT/Plug leads.

I've noticed that when it's cutting out, the (after market) tachometer seems to cut down to zero as the engine is missing, sputtering, and backfiring. Again, after a bit of a 'rest', it starts and runs again, cutting out (or dying at idle) after a couple minutes.

I'm not sure if I can rule out vapor lock, but it really seems electrical. I don't have a scope to look at the coil voltages, etc... so any advice is appreciated!

Shawn

 

[joey]

I would check fuel pressure or at least try to hook up an electric fuel pump and test off of a small can a fuel....

 

[1971s2av8]

Good thought. Existing electric fuel pump is clicking away and is circulating fuel so far as I can tell... but I may devise a way of checking the circulation is still happening as expected when it's refusing to run. Thanks for the input.

 

[Moose]

Carb out of whack? Sounds almost like a choke-flood situation. It's been years since I've owned a carbed auto, but my motorcycles do that, where they bog down under load due to running overly rich.

 

[roverman]

I had a Jeep with a stuck choke before, same symptoms. That'd be too easy though

 

[1971s2av8]

Latest update... I decided to check everything from the start (again), and noticed that the plastic arm on the points was slightly cracked, and would likely cause the points to not open under high rpms. This may also explain the warmth issues as it would likely be more bendy when warm.

In any case, I changed to my last spare set of points, but wanted to check something:

There are 2 black wires that bolt to the points. One from the Accumulator (capacitor), and the other from inside the dizzy (I think it goes out and back to the coil, but I haven't checked)...

How is that supposed to be connected? The spring end of the points arm is isolated from the post by plastic spacers. Which one of these wires goes where? Are both supposed to be together? Are they supposed to be attached to the post, or touching the points arm? Is it meant to be one on top, one on bottom?

Any further help is appreciated!

Shawn