Built my engine 2 years ago. Built 383, Pertronix HEI distributor, Pertronix Digital HP box..... Car still isnt on road, hoping soon here (been driving up and down street to adjust wheels, etc)...Anyways, from day one engine was a little weird timing wise. Also heard a noise once in a while. Few weeks back changed springs to lighter ones. Lately noise has been more noticeable. Yesterday i had enough and jacked car up to pull shield off tranny cause it seemed to be coming from there, Nothing. Here is what i have going on....

1) Engine had a stumble off idle. Went through carb twice - nothing wrong there. Changed plug types twice - no change. Adjust HP box - no difference.
2) Engine idles a bit rough (to be expected with cam,etc) but would pull 20" vacuum at idle steady.
3) Plugs all even. Seems to run rich and then not so rich.
4) Would start perfect one time, then labor the next. Had nothing to do with heat. Was totally random.
5) On 2 different guns, the timing said it was 44 degrees at idle (impossible)
6) Noise seemed to be coming from distributor, but figured that wasnt likely.

So after inspecting tranny and a few other things, i pulled distributor to check the gear - was perfect. So now im like WTF is going on here. Then i noticed this...

Never would i have though this could be the issue. The center weight is upside down. The weights just flop around.

Im putting back together today, and hope my stumble-noise-timing is fixed. I wrote to Pertronix this AM, but dont think anything will come of it. I just want people to be aware of this.

I didnt see this when i changed the springs a few weeks back - i should have. But in my defense, im a Marine Tech, and boats dont use HEIs, or mechanical weights (not anymore at least). So i overlooked it. No excuse for not following the KISS rule.

Im done. I feel better now. Couldnt sleep last night was so pissed. Ill post an update later.

Thanks for reading!

 

Hope it clears out the noise!

 

Hope it clears it too.

Also, my boat has HEI and most I've worked on have too lol. All the ones I touched were 03 an older though.

 

Good catch!

 

Boats do use an HEI, but not a vac/mechanical advance with a coil attached. They use the remote coil setup with electronic advance boxes. A mechanical advance hasnt been used since the points days. The mechanical would always corrode and stay that way. And boat engines have no vac ports (except EFI engines)
All Volvo/Mercruiser/PCM/ETC used the remote coil setups. Unless some low volume MFG used them i dont know. But if i popped the hood on a boat and saw a HEI with vac advance and a coil on top there, i would know bubba installed one.

 

UPDATE.
Noise still there but not as loud (actually i should say noticeable). The one weight still can move around a little and rattle. The other one is fine.
Stumble still there. Gotta still play around. But idle timing is now 22 and advances and starts fine everytime.
When or if Pertronix gets ahold of me im gonna tell them i want new weights and go from there.
In hind-site had i know i was gonna run a CD box, i would have gotten a small cap dist and remote coil. Oh well.

 

What good would it be to have a vacuum advance in a boat, when your almost always running at about 5" vacuum??

 

Well finally got around to calling Pertronix. I wanted a new set of bushings, but they said they dont have parts like that around. But they did offer to replace the unit, which was good. I just ran the engine again last night, and noise is there once it starts to build heat. But no skip or anything. Id hate to replace dist to have same noise. Maybe ill pull coil tonite to see if anything is going on. The noise is weird - almost sounds like a shuttering noise, or weights flopping around. Does sound like spark scatter, but no trace of it in the cap area. Cant tell if the noise goes away higher rpm as i cant hear it over the engine. This crap only happens to my stuff. I build and work on over 250 engines a year, and NEVER heard this noise.

Let me tell you another story that only happens to me....In 1993 i blew up my 305 in my mint condition 83 Z28. I was happy lol. So i was gonna build a 350 for it, but my mom sold our house so we had to move. She ended up buying me a longblock from Summit. Put the engine together and installed in my Camaro. Well, right from day one i had a noise. Sounded like ball bearings rattling around). At the time i was a good mechanic, but wet behind the ears at 19 years old. I had over 20 master mechanics, and 5 machinists look at it - all baffled. Plenty of power (330 hp i believe it was)..... Comp good - spark - fuel - oil stayed fairly clean - no metal - etc. EVERYTHING possible was checked. Tore engine down in my friends driveway, new lifters and gaskets - no avail. After a year of this, we took engine out and i got new bearings, rings, etc for a rebuild (had 500 miles or so). Well checking the gap on rings i had way too much clearance. So i called NAPA and they said maybe they were packaged wrong (2nd set same measurement). So now NAPA thinks they have a problem. Well, the machinist let me borrow a bore gauge. On the tag of the engine, it said "bore .030 over, crank std, rods std" Turned out the engine was bored over .040, and they installed .030 pistons. Pistons were not even scuffed up. Amazing....So the owner of Summit called me to apologize, and set me a 350 engine with trick flow heads as compensation (360 hp i believe) and a Summit racing jacket i still have and never wore that says 1993 on it. I loved that engine. Thats the crap that happens to me....

Thanks for letting me vent.

On a good note, Pertronix and there tech team was great FYI.

 

having a similar issue with Summits msd system I got 60 mi on it and developed a nice misfire I cant track down. At that time their system was made by msd..."sorry sir but its 8 yrs old so we cant warranty it". Dist needed rebuilding right off the bat, coil failed few weeks back etc. Cant get a consistent timing reading. About to throw it in the trash and put an HEI in. I got Charlie Brown luck too...lol
If this dist gear is good Im done with it.

Keep us posted.

 

I am glad you are getting the problem sorted out. Never seen the weight problem before and worked on many a mechanical advance distributor back in the day. I would assume that the company does not run and test their distributors before shipping. I was fortunate to have access to a distributor machine and it was a blessing setting them up.

I think you deserve to be driving your car and getting that permanent smile on your face.

 

Somehow, I don't know how the weights of a distributor could rattle around to make a sound that can be heard over a running engine. Can you just put a stock vacuum hei distributor in to compare?

 

Yeah originally when i found the plate upside down and weights flopping around, it seemed like that was my noise. Fixed it and seemed fine for a few minutes, then re-appeared. So, here is the symptoms...

- Noise in dist after it starts to get warm.
- Still running rich. Ive been through carb 3 times.750 VS that i milled choke tower off, 6.5 powervalve, #31 shooter, #70 primary jets, #75 secondary (added rear metering block, and jet extensions all 4)
- Stumble off idle, no matter timing and carb, still does it. Rich when i rev it up.


I have the digital HP box from Pertronix as well. I set the voltage to the lower setting, and no different. MDS is on. I asked if they had any issues using an HEI with the box and they said shouldnt be an issue.

It dosent sound like an arching coil, as thats usually a snapping sound. This is a shuttering sound. I have video but sounds nothing like real life.

I know its a PITA trying to see whats up when i cant even drive it but im reaching....If i can get both bumpers soon ill get plates on it so i can drive it at least into the huge school parking lot across from me.

Thanks everyone.

 

Pulled cover and coil last night. No arching or anything else wrong.......