Surging at higher rpm

[Turbosl2]

First off I want to thank everyone for helping me get this car back in great running shape. I almost have everything figured out. One last thing

 

I feel as if the timing is jumping to advance and retard at higher Rpms under heavy load. The car has a slight surge. Power-Less power. No pinging, no backfiring. Still smooth just feels like timing Going up and back down while my foot is heavy on the throttle. Around town all is good. Seems to happen when I am at 50mph going up a hill. Doesn’t seem like a misfire. Cap, rotor, plugs, wires all new. Those didn’t fix the problem like I was hoping. 
 

1941 straight 8 smaller engine. 

[Matt Harwood]

Is your vacuum advance working properly (it's technically a vacuum retard, but same function)? Take off the distributor cap and apply vacuum to the vacuum canister and see if it moves. If it doesn't move, it's bad, if it does, then check your base timing. I had all kinds of minor drivability problems because I had advanced the timing a bit too far. Also make sure your plugs are gapped correctly, somewhere around .025-.027". What type of plugs are you using?

 

 

Edited May 3, 2020 by Matt Harwood (see edit history)

[Turbosl2]

3 minutes ago, Matt Harwood said:

Is your vacuum advance working properly (it's technically a vacuum retard, but same function)? Take off the distributor cap and apply vacuum to the vacuum canister and see if it moves. If it doesn't move, it's bad, if it does, then check your base timing. I had all kinds of minor drivability problems because I had advanced the timing a bit too far. Also make sure your plugs are gapped correctly, somewhere around .025-.027". What type of plugs are you using?

 

 

Thanks Matt I will check this tomorrow. I am using the AC 46 oem plug gapped to what you stated above. 

[pont35cpe]

Also if the vac. advance checks out to be good. The points plate it attaches to, pivots on 3 ball bearings, these get worn or dirty and will not let the plate move freely with the vac advance, affecting the timing.

[Turbosl2]

1 hour ago, pont35cpe said:

Also if the vac. advance checks out to be good. The points plate it attaches to, pivots on 3 ball bearings, these get worn or dirty and will not let the plate move freely with the vac advance, affecting the timing.

I am just nervous to move any of this stuff as I am unfamiliar with how to use a dwell meter...etc. I actually don’t even know how to set the base timing on this car. I have done it on SBF or SBC. Would pertronix be a good upgrade Or does the distributor still need to use the advance/retard with those too.

[Turbosl2]

Pertronix

?? worth it. I don’t have all the tools to set dwell, timing...etc. vacuum retard of broken will this solve the problem

[Matt Harwood]

Don't worry about dwell--as long as your point gap is correct it should be OK. I would not recommend Pertronix, either. I've not had a lot of success using them on 6V cars. Besides, points and condenser are reliable and will work even in failure mode. Pertronix will fail in a millisecond poof of smoke. Just get the timing and point gap correct and it'll run just fine.

 

Checking timing is very easy. There's a window in the bellhousing on the passenger side of the block and you can aim your timing light in there (many of them work on 6V). You should see the mark pretty easily and tweak the distributor to set it to 0.

 

Here's a description with a [poor] video showing it:

 

 

 

[Turbosl2]

12 minutes ago, Matt Harwood said:

Don't worry about dwell--as long as your point gap is correct it should be OK. I would not recommend Pertronix, either. I've not had a lot of success using them on 6V cars. Besides, points and condenser are reliable and will work even in failure mode. Pertronix will fail in a millisecond poof of smoke. Just get the timing and point gap correct and it'll run just fine.

 

Checking timing is very easy. There's a window in the bellhousing on the passenger side of the block and you can aim your timing light in there (many of them work on 6V). You should see the mark pretty easily and tweak the distributor to set it to 0.

 

Here's a description with a [poor] video showing it:

 

 

 

Wow you have all the info in that post, found it. Page 15 of 19. I am excited. Lots to do tomorrow  . Thanks for the help I will report back tomorrow. 

[Turbosl2]

Here is my sophisticated timing light, lol

[pont35cpe]

That light takes me way back, i had one just like it, 50+yr ago. It always got the job done. Sounds like you`ve got a plan for tomorrow, working on the distributor. I still have a feeling, with the surge happening at high RPMs, that your problem might be fuel/carbureator related.

[Matt Harwood]

90% of fuel problems are ignition.

[Ben Bruce aka First Born]

1 hour ago, Matt Harwood said:

90% of fuel problems are ignition.

 

 You are beginning to sound like Jon.

 

  Ben

[Turbosl2]

2 hours ago, pont35cpe said:

That light takes me way back, i had one just like it, 50+yr ago. It always got the job done. Sounds like you`ve got a plan for tomorrow, working on the distributor. I still have a feeling, with the surge happening at high RPMs, that your problem might be fuel/carbureator related.

It’s highly possible I am wasting my time. Overall I have no idea where the base timing is set or if the vacuum retard is working 

[edinmass]

10 hours ago, Matt Harwood said:

90% of fuel problems are ignition.

 

So are the other 10 percent!

[Turbosl2]

I spent a few hours today working on the timing. Well I could not see the marks at first with my crap timing light so I spun it over with a breaker bar until I saw some yellow paint and added some white to the hashed area. Prior to this I was turning the distributor to try and get the mark to show up. So I can’t say if the engine was timed or not prior to me moving it. It is in time now between 0-2deg. I can’t say I see much of a difference with idle speed. It’s def smooth and low but it was like that before to. I took it for a 6 mile trip and it runs much better that’s for sure. It still has the slightest surge when WOT on the highway climbing a hill, but it’s so minimal...or the engine just wasn’t hot enough most of the time I feel this. Either way so far it seems better. I never go WOT but that’s the easiest way to make this problem present itself
 

I also checked the vacuum retard and here is what I found. When I apply vacuum I can push the plunger in with a screwdriver but without vacuum it’s to hard. Seems like I am pushing against a 10lb spring...with the vacuum it feels like a 1lb spring. No vacuum your barely moving it. This was with the plate connected and disconnected.  The vacuum comes from the carb and I am surprised it actually is enough to move the distributor at all or carb can even draw much vacuum. 

[pont35cpe]

Breaker plate should pivot freely. Remove the breaker plate, clean the ball bearing groove, if the groove shows wear, here is a fix for the groove, "Spark-O-Liner" ebay #401490880855  or the 3 ball bearings can be up dated with the plastic pivots(if you can find them) i don`t have that Delco #, someone on here may know it.. Another option is to update the breaker plate with a Dyna-Flyte model-880, another hard to find item, these are an excellent replacement if you can find one.  Good luck, Tom

[Turbosl2]

30 minutes ago, pont35cpe said:

Breaker plate should pivot freely. Remove the breaker plate, clean the ball bearing groove, if the groove shows wear, here is a fix for the groove, "Spark-O-Liner" ebay #401490880855  or the 3 ball bearings can be up dated with the plastic pivots(if you can find them) i don`t have that Delco #, someone on here may know it.. Another option is to update the breaker plate with a Dyna-Flyte model-880, another hard to find item, these are an excellent replacement if you can find one.  Good luck, Tom

The plate did move freely but I could tell it had some where. What does it take to remove the plate? Can I leave the points and condenser connected just pull the wires that connect to the distributor housing? I never set points so I am worried about messing with it

[Turbosl2]

39 minutes ago, pont35cpe said:

Breaker plate should pivot freely. Remove the breaker plate, clean the ball bearing groove, if the groove shows wear, here is a fix for the groove, "Spark-O-Liner" ebay #401490880855  or the 3 ball bearings can be up dated with the plastic pivots(if you can find them) i don`t have that Delco #, someone on here may know it.. Another option is to update the breaker plate with a Dyna-Flyte model-880, another hard to find item, these are an excellent replacement if you can find one.  Good luck, Tom

I ordered that part just to have in case, maybe I need it maybe I don’t but scared to pull the plate out 

[pont35cpe]

2 hours ago, Turbosl2 said:

The plate did move freely but I could tell it had some where. What does it take to remove the plate? Can I leave the points and condenser connected just pull the wires that connect to the distributor housing? I never set points so I am worried about messing with it

You might be able to do it with the distributor still in the car, i`ve always removed the dist. from the engine and took it to the work bench. Vac. advance will have to be removed and the rotor, then remove the 2 screws that hold the cap clips(these 2 screws also anchor the breaker plate in place). Now take notice here, looking at the inside where the cap sits on the dist. housing, there are 3 vertical grooves down to the groove the ball-bearings roll(pivot)in, turn the plate to where the ball bearings line up with the vertical grooves, then plate should pull upward and out(the bakelite piece which the points wire hooks to on the inside, and coil wire attaches to on the outside, will have to be removed before breaker plate will lift out). Clean the groove, put the Spark-O-Liner in the groove, the gap in the liner is clocked where (bakelite piece) passes thru the housing. Then reassemble in reverse of removal. Also put a small amount of lube on the 3 ball bearings before dropping breaker plate in place. Not that it helps, but you may use some 4 letter words in this process.  Good luck, Tom