Slant Six Forum
https://www.slantsix.org/forum/

1966 225 - trying to diagnose strange issues
https://www.slantsix.org/forum/viewtopic.php?f=19&t=66563
Page 1 of 1

Author:  jayman62 [ Mon May 02, 2022 6:20 am ]
Post subject:  1966 225 - trying to diagnose strange issues

Hello,

Looking for suggestions on an issue with my 1966 225 slant.

The engine has been running great but recently I've had bouts with short times when the engine bogs down and have to play with the accelerator to keep it from stalling. Then miraculously it will run great again.

Car has new gas tank, original fuel pump, new distributer and I re-built the carb, Holley 1920.

I recently switched to a electric choke and that was working well.

This weekend after a 30 minute drive, and about a few blocks from home the engine started that bogging issue and after stalling out there was a backfire through the muffler.

I limped home and parked it and stated troubleshooting.

My first thought was fuel, so I tested the fuel pump and it pumps fine, took the carb apart to re-clean it thinking something got blocked by debris. Re-assembled and the car had trouble staying running, and real bad miss, and backfired through the carb.

My next thought was timing, took out the distributor and found the point totally burn and unable to open and close without resistance. Put in new points, set the gap, and the engine fired up immediately, but not without a slight miss. Went to drive it again and it ran great again but then about a few blocks from home the hesitation/bogging returned and I limped back home again.

I'm thinking of replacing the condenser and the coil but also concerned the timing chain could be bad. Any suggestions or other things I should try?

Thanks and sorry for the long post.

Author:  Daddiojoe [ Mon May 02, 2022 7:05 am ]
Post subject:  Re: 1966 225 - trying to diagnose strange issues

Wow, Jay. FWIW, I can think of a couple of things you might look into but no single solution for your problem. Do you think that it is heat related?

A couple of heat-related possibilities:

1. Vapor lock. Does it run normally after cooling down? Can you see an absence of gas in your fuel filter?

2. Coil. I was convinced my problem w/ shutting down while hot was due to fuel, but turned out my coil was fried from heat.

Best of luck,

Joe

Author:  jayman62 [ Mon May 02, 2022 7:22 am ]
Post subject:  Re: 1966 225 - trying to diagnose strange issues

Thanks Joe.

Don't think it's vapor lock, there is fuel in the fuel filter. I'm also leaning towards coil as it's newer and these days new parts are suspect. I have the original coil from the car and will check it's resistance when I get home to see if it's still good.

Jay

Author:  Jase [ Mon May 02, 2022 8:47 am ]
Post subject:  Re: 1966 225 - trying to diagnose strange issues

Not sure where you got a new points distributor...

But I would suspect the condenser. I've heard reliable reports saying that new ones are even bad out of the box.. Maybe someone here can chime in about how to test a condenser... that way you could identify if the new one is any good as well..

Doubtful that the timing chain went, as a new set of points solved the problem for a few blocks. If the condenser is bad, the new points may now be burned as well...

Author:  jayman62 [ Mon May 02, 2022 9:58 am ]
Post subject:  Re: 1966 225 - trying to diagnose strange issues

I have a new condenser as well, I will try that first since it's easy to do and check the new points. I should have changed the condenser when I changed the points, rookie mistake.

Jay

Author:  wjajr [ Mon May 02, 2022 10:45 am ]
Post subject:  Re: 1966 225 - trying to diagnose strange issues

Check the new points, and install the new condenser. The condenser reduces sparking each time the points open & close preventing burning.

As mentioned previously the coil may be failing once it heats up. Coils should be good to go at or below 90* centigrade or about 194* F. Swap in a known good coil if you have one and see if it solves the problem. Make sure (-) terminal is connected to wire from distributor. Reversing coil polarity will shorten it life. Why that is, I'm not sure.

Checking resistance of a coil usually won't detect a heat related short.

Author:  SlantSixDan [ Mon May 02, 2022 11:20 am ]
Post subject:  Re: 1966 225 - trying to diagnose strange issues

I am guessing your new distributor is actually a "remanufactured" item; these are of notoriously cruddy quality and can make problems. Check to make sure your distributor isn't throwing oil on the points.

The condenser should always be replaced together with the points, especially with the poor quality of today's points and condensers (or, better, have done with it and ditch the points altogether). If you're sticking with points, the coil shouldn't be replaced at random; they seldom go bad. Randomly throwing parts at a car is a better way to empty your wallet than to make the car run well.

Quote:
but also concerned the timing chain could be bad


It could be; check for a slack T-chain like this. Not a match for your symptoms, though, so don't get sidetracked.

Quote:
Any suggestions or other things I should try?


Valve adjustment.

(Tune-up parts and technique suggestions are in this post; carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download.)

Author:  jayman62 [ Mon May 02, 2022 1:29 pm ]
Post subject:  Re: 1966 225 - trying to diagnose strange issues

SlantSixDan wrote:
I am guessing your new distributor is actually a "remanufactured" item; these are of notoriously cruddy quality and can make problems. Check to make sure your distributor isn't throwing oil on the points.

Yes probably and the inside of the distro was clean Dan

The condenser should always be replaced together with the points, especially with the poor quality of today's points and condensers (or, better, have done with it and ditch the points altogether). If you're sticking with points, the coil shouldn't be replaced at random; they seldom go bad. Randomly throwing parts at a car is a better way to empty your wallet than to make the car run well.

Agree, I would have done the condenser at the same time but only had a spare set of points, and to be honest I didn't realize the condenser could cause the points to degrade. Also I bought the car with many engine parts missing (someone used it as a parts store) so I was kind of forced to replace the parts I mentioned. I didn't buy new parts to try and fix this issue. It's been running awesome since I got it running over a year ago. I suspect crappy new parts.

Quote:
but also concerned the timing chain could be bad


It could be; check for a slack T-chain like this. Not a match for your symptoms, though, so don't get sidetracked.

That's good to hear,

Quote:
Any suggestions or other things I should try?


Valve adjustment. Vales were done, hot and running a little while ago. I'm pretty religious following the shop manual and other posts before posting a new topic, it was just the randomness of this issue when the engine was really running well and reliable previousely.

(Tune-up parts and technique suggestions are in this post; carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download.)

Author:  jayman62 [ Tue May 03, 2022 5:23 am ]
Post subject:  Re: 1966 225 - trying to diagnose strange issues

Thanks for the suggestions, looks like it probably was the condenser, replaced and drove it around about 20 minutes and it did quit on me. Taking the car for a longer drive tonight.

One observation with trying to do points on a slant six is it much easier to do with the distributor out of the engine, whomever designed the placement of the distributor should have thought it out better. Add insult to injury, it's right next to the oil filter making it impossible to clip the rear cap clip.

Anyone have an opinion on a good brand of points and condensers, caps and rotor? I want to carry a spare of each in the trunk from now on.

Back on the road . . .

Author:  THOR [ Thu May 05, 2022 12:27 pm ]
Post subject:  Re: 1966 225 - trying to diagnose strange issues

jayman62 wrote:
One observation with trying to do points on a slant six is it much easier to do with the distributor out of the engine, whomever designed the placement of the distributor should have thought it out better. Add insult to injury, it's right next to the oil filter making it impossible to clip the rear cap clip.


While a bit of a pain on occasion I have found that tilting the cap in the direction of the rear clip to snap it on first helps vs. snapping the other first.

jayman62 wrote:
Anyone have an opinion on a good brand of points and condensers, caps and rotor? I want to carry a spare of each in the trunk from now on.


I'm sure you will get lots of opinions, so I'll just toss out my experience: Blue Streak/Standard Motor Products caps, rotors, points and condenser have been the best I've used available off the shelf from your local auto parts store. They are more expensive, but my suggestion would be to avoid any store brand items.

~THOR~

Page 1 of 1 All times are UTC-07:00
Powered by phpBB® Forum Software © phpBB Limited
https://www.phpbb.com/