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Eds56
08-28-2016, 09:01 AM
Hello Guys,

Working on my 56 BA & I'm trying to eliminate a "slight" intermittent miss / stutter while cruising 55mph @ 2100 rpm and would like your input. It doesn't do it all the time and sometimes you have to really feel for it.

Specs -- 1968 327 with 461 heads, TRW Forged Flat tops, Crane 284 cam, set 4 degree advanced with 1.60 roller tip rockers, NEW 600 Holley Carb, with MSD 6A, Pro Billet 85551 dist. (NO Vacuum Adv.) Blaster 2 coil, NGK V-power xr5 spark plugs (heat range 5) gapped to 45 per MSD. dist. is running the 18 degree bushing with light blue springs & 16 initial timing to put me @ 34 total and all in around 2800--3000 rpm. I ONLY run BP 93 & Car starts great, hot or cold and i don't have any pinging at high rpm. 4- speed tranny, manual Disc brakes, 160 thermostat, 1 5/8" Headers.

Things i have already done--


lowered timing, seem to make it worse so i put it back.
changed spark plugs from AC 43 --- the NGK's did seem to do better, also bumped gap UP to 45.
marked, pulled & inspected plugs, the lower side (closest to piston) is a white/vanillaish clean color.....however, the top side (closest to valves) is dark, black, wettish color.
Replaced pick up modue, dist. cap and rotor button.
set air fuel mixture. both are turned OUT 1 turn to get a maximum vacuum of 12-13 inches.
looked for stray sparks under hood at Night with engine rev'd up pretty good. - none found.
Checked for vacuum leaks -- none found.
Checked with timing light, while rev'n up the rpm's.....occasionally the timing line will fluctuate, indicating the miss.....BUT not noticeable by ear, just sitting at idle.


On the to do list--


GOING to change dist. springs from blue to Silver (the lightest to allow to come in sooner)
Pulling plugs back out for one more review -- NOTE these have been Fouled Once and were cleaned and re-used.
Verify line on Harmonic balancer is correct for TDC


This complete MSD 6A ignition system (likely now out dated) was purchased a long time ago and then suddenly the project came to halt, (family reasons). Originally i had planned to just take it drag strip as a race "toy" hence the NO Vacuum Dist. BUT not now, as my intentions are to just DRIVE IT / Cruise around and enjoy..... NO drag strip.... just an "occasional Heavy FOOT between red lights" while the boys in Blue are having doughnuts.

So here are my questions--

Considering this is now more of a weekend driver and less WOT --- would a vacuum advanced type dist. be a better option? the one i'm looking at is MSD 8361 as this will plug right into my current box.
Do i even need a MSD box, in other words perhaps go to a small cap version distributor with a Pertronix unit or something similar? I do NOT want points and need a dist. with small style cap to clear firewall.
increase or decrease spark Plug -- HEAT Range and or GAP??
could it still be a spark plug wire breaking down, even though i don't see any sparks under hood? The reason i ask, is these are OLD and have a couple nics on them.
Increased or decrease timing


Sorry for the Lengthy post, but had to get it ALL out there.

Thanks in Advance,
Ed

markm
08-28-2016, 09:13 AM
When I have a miss usually at upper RPM on a SBC especially one with Headeraches I change plug wires and usually find the problem.

Rick_L
08-28-2016, 09:18 AM
I would suspect the plug wires given what you've done already. You can have a problem without seeing sparks jump in the dark. Actually if you were able to see that, you'd probably have a full time miss, not a part time one.

Another possibility is the MSD box itself. Personally if it's that, I'd repair the MSD box rather than switch to something else.

Another possibility is bad fuel, especially if you don't drive the car often. 10% ethanol in the gas is an additive problem if you don't drive it often.

A vacuum advance distributor is something you should look into, it will give you driveability and fuel mileage, but it's not likely part of your current problem. However the extra timing under a cruise situation may help, especially with the cam you have, which is a touch big for cruising.

I don't think the spark plugs are a problem, except that you should stay away from the cold ones. Big plug gaps when new result in even bigger gaps after some miles - and that can be a problem. I'd go with .040" or so with an MSD.

55 Rescue Dog
08-28-2016, 09:26 AM
Definitely need a vac distributor, and I would check vacuum when the problem occurs. Could be pulling open the power valve.

Eds56
08-28-2016, 09:57 AM
Guys,

I really do appreciate your time and input, THANK YOU. I will look into getting a new set of wires in the next week or so and probably a set of plugs too. Would you stay with the heat 5 NGK's or jump back to the AC's? Maybe i just had a bad batch on last AC go around? But the V-power did seem better when new.

I'll also be looking into a vacuum dist. -- i was kinda leaning that way, but wanted to try all the other cost effective options first.

I drive it at least once a week and most of the time more and try to keep fresh gas in it. But i understand your point about today's ethanol blend of gas.

55 Rescue Dog
08-28-2016, 01:16 PM
Guys,

I really do appreciate your time and input, THANK YOU. I will look into getting a new set of wires in the next week or so and probably a set of plugs too. Would you stay with the heat 5 NGK's or jump back to the AC's? Maybe i just had a bad batch on last AC go around? But the V-power did seem better when new.

I'll also be looking into a vacuum dist. -- i was kinda leaning that way, but wanted to try all the other cost effective options first.

I drive it at least once a week and most of the time more and try to keep fresh gas in it. But i understand your point about today's ethanol blend of gas.
I run the MSD ready to run vacuum distributor on a standard coil. It has a built in rev limiter, and fully adjustable. Works perfect.

markm
08-29-2016, 06:10 AM
I have had great success with Autolite 85swith those heads. if not them AC plugs.

Eds56
08-29-2016, 09:38 AM
I have had great success with Autolite 85swith those heads. if not them AC plugs. ------ Thanks markm


Would the "extended / projected" Tip spark plug be the Prefered Version VS. non ext. tip?

55 Rescue Dog
08-29-2016, 12:15 PM
Light throttle at 2100rpm, with no vacuum advance I think your timing is retarded quite a bit, which will make your plugs run colder too. That's one of the reasons for vacuum advance to keep the plug tips hot at idle, and light throttle. Figured that out from 40 years ago running a 427 with no vac advance. Couldn't get a set of plugs to last a month in town.

markm
08-29-2016, 12:30 PM
Summit Racing Part Number:
ATL-85
UPC:
00009100000859
Shorty Spark Plug:
No
Resistor:
Yes
Manufacturer Heat Range:
5
Electrode Core Material:
Copper
Electrode Tip Material:
Copper
Insulator Type:
Projected
Spark Plug Thread Size:
14mm
Spark Plug Reach:
0.375 in.
Spark Plug Seat Style:
Gasket
Wrench Diameter:
13/16 in.
Ground Strap Quantity:
One

markm
08-30-2016, 07:29 AM
Light throttle at 2100rpm, with no vacuum advance I think your timing is retarded quite a bit, which will make your plugs run colder too. That's one of the reasons for vacuum advance to keep the plug tips hot at idle, and light throttle. Figured that out from 40 years ago running a 427 with no vac advance. Couldn't get a set of plugs to last a month in town.
Could you expand on this a little because I have never experienced this I have 3 cars running Mallory Unilites without vac advance on street. A couple have 10 years on plugs.

Rick_L
08-30-2016, 08:10 AM
While vacuum advance is a good thing for a street engine, it really doesn't have much to do with fouling plugs.

chevynut
08-30-2016, 08:18 AM
I suspect plug wires. Looking for sparks under the hood is different than when driving under a load where cylinder pressure is higher. Also you say they're old and nicked so it wouldn't hurt to replce them considering eveything else you've replaced.

55 Rescue Dog
08-30-2016, 01:03 PM
Could you expand on this a little because I have never experienced this I have 3 cars running Mallory Unilites without vac advance on street. A couple have 10 years on plugs.
There is zero reason to run a mechanical only advance on the street. The vacuum advance has been around on everything since 1930 for good reason, that the computer does now. Mechanical advance is controlled strictly by RPM, whereas vacuum advance adjusts for engine load, adding advance during light loads, adding heat to the plugs to help save, and burn off excess fuel. Plug tips get hundreds of degrees hotter with every degree of advance, and last longer. If you drive WFO all the time, then that would be the only reason not to have vac advance, but it wouldn't hurt anyway, because there is no vac advance at full throttle. A computer controlled engine operates basically the same, but better.

markm
08-30-2016, 01:34 PM
There is zero reason to run a mechanical advance on the street. The vacuum advance has been around on everything since 1930 for good reason, that the computer does now. Mechanical advance is controlled strictly by RPM, whereas vacuum advance adjusts for engine load, adding advance during light loads, adding heat to the plugs to help save, and burn off excess fuel. Plug tips get hundreds of degrees hotter with every degree of advance, and last longer.

I have to run these distributers to run my Jones/ Moroso mechanical tachs on my 55 & 67 Camaro. My BBC with a tunnel ram and two Holley 600 knocks down high teens in MPG on the highway. I doubt I can improve that much if at all. I have a Vac advance equipped Unilite I bought for my 56 that sits on the shelf. I probably have to remove the wiper motor and rear two barrel to install. I am not convinced that it worth the effort.

55 Rescue Dog
08-30-2016, 03:58 PM
I have to run these distributers to run my Jones/ Moroso mechanical tachs on my 55 & 67 Camaro. My BBC with a tunnel ram and two Holley 600 knocks down high teens in MPG on the highway. I doubt I can improve that much if at all. I have a Vac advance equipped Unilite I bought for my 56 that sits on the shelf. I probably have to remove the wiper motor and rear two barrel to install. I am not convinced that it worth the effort.
I have an Accel dual point, mechanical tach drive with a SW, or Moroso mechanical tach I would love to sell! I'ts been in a box for 30 years. I love mechanical tachs, but only with vac advance. Other than the cable, I loved the old school mechanical tachs. You could see each cylinder firing at idle.

markm
08-31-2016, 07:06 AM
There is no sound sweeter than SBC with headers, 2.5 exhaust and turbo mufflers idling with a 30-30 Diuntov. as long as the plug wires are fresh.

Eds56
08-31-2016, 10:09 AM
I suspect plug wires. Looking for sparks under the hood is different than when driving under a load where cylinder pressure is higher. Also you say they're old and nicked so it wouldn't hurt to replace them considering everything else you've replaced.

Thanks for all the responses, New wires are now on order....should have them in a few days. When i pulled the old wires off, i also found a burnt place on #6 wire, which is routed underneath.....so i couldn't see it before.

Now for the spark plugs, I have read countless articles and honestly just came out more confused, as apparently there is no "specific best plug" and a TON of opinions going in all different directions. I do appreciate the input, but the thought of an Autolite (FORD to me) plug in a Chevy borders sacrilegious...lol ;) -- If these are indeed the best plug...then YES I will run them. And i probably will not notice much difference between them and if not that's ok too. This may be FOOLISH of me but to help me determine what works best for ME.... i ordered a couple to try along with a couple more R45s & NGK's. The thing i liked about the NGK 3332 is they are about 1/8"-to-1/4" Shorter in length than the R45s i had and a couple of my Header tubes are VERY-VERY close to the SP boot, so this shorter plug seemed nice. NOW i know that's not much, but Hey every-little bit helps. And i refuse to pay ACCELLs ridiculous shorty price $$$

markm
08-31-2016, 03:29 PM
Lets see Autplites a US company is problem and NGK is ok, I don't get it.

Rick_L
08-31-2016, 05:21 PM
Autolite hasn't been part of Ford for 30 years or more. Motorcraft is their brand for that stuff now.

At one time I ran NGK plugs in my stuff because they gave them away. Then I got a whole case of them where 1 or 2 plugs in 10 was dead right out of the box. I switched to Autolite and never had a problem again. Prior to all that, I ran Champion and AC with no problems either.

The NGK debacle was fixed I'm sure, just left a bad taste. I would take them the bad plugs at the races, they would say that can't happen but they'd hand me another box of bad plugs as they said that. It was too much of a hassle to find the bad ones.

Spark plugs are not magic. There's no silver bullet.

Eds56
08-31-2016, 05:51 PM
Lets see Autplites a US company is problem and NGK is ok, I don't get it.

Well mark, I did order, the specific plug you recommended, and also an autolite platinum version too. In fairness, i intend to give them a try. Nothing to do with USA, instead more of the Ford vs. Chevy mindset. The name Autolite makes me think of That nasty 4 letter word beginning with F. The plus on the NGK for me is header clearance.

Thanks Rick, didn't realize it's been 30 years since the ford split, guess I just get hung up in the past too much.

markm
09-01-2016, 06:12 AM
Spark plugs are not magic. There's no silver bullet.

Been my experience too, I do have an interesting story about the Autolite 85s that I ran in my 67 Camaro years ago they ended up in my Farmall A tractor replacing the 7/8 thread plugs that were wore out. My buddy at machine shop put 1/2 inch pipe plugs in head and drilled and tapped them for 14mm gasket style plugs. Those bracket car fresh Autolites have been mowing grass for 25 years. Today I see that heli-coils are available and this would not be necessary, but at the time we could not find anything.

Eds56
09-08-2016, 05:12 AM
Good Morning All,

Just thought i would give an update and ask follow up questions--

1.) Replaced plug wires and now runs much better. Note: there were more bad places on the wires that i thought.
2.) Trying different spark plugs, as stated by others, there is no silver bullet. Nothing noticeable at this point from my trials, No biggie.
3.) Marks point above, about using a car plug in a mower got me to thinking, Anyone out there ever went the other direction and used a small engine (SHORT) spark plug, such as, lawnmower/chainsaw? Obviously one with the correct 14mm thread, .375 reach, heat range, etc. (such as Champion RCJ6Y)
4.) I've always used resistor plugs, but the only modern electronics in my car are radio & MSD. Are resistors a Must??
5.) I read online that it's best to have ALL the initial timing the engine can stand and the balance from dist. to get the 34--36 total. What i currently have is 16 initial + 18 dist with light blue & silver springs for my 34/35 total all in by 2800--3000 rpm. NOW that i'm going to the msd 8361 (vacuum) distributor, What dist. spring / bushing set up would you use?

Gotta get to work, Have a Blessed Day.

Rick_L
09-08-2016, 05:31 AM
You can go too far on timing without having audible pinging, but with most small blocks it's pretty rare.

On initial timing, 16 may be a bit much. But if it's not pinging or kicking back against the starter when the engine is warm, it's probably OK. Your mechanical advance setup is pretty good (again provided there's no pinging).

When you install the vacuum advance distributor, don't change anything and monitor for pinging. I don't recall if the MSD distributor has adjustable vacuum advance or not? May want to limit how much.

chevynut
09-08-2016, 05:54 AM
My BBC with a tunnel ram and two Holley 600 knocks down high teens in MPG on the highway.

At 30 MPH? :) :) No way imo are you going to get "high teens" MPG at highway speeds (70-75) with a tunnel ram, dual quads, no overdrive, and what rear gears? You better have your speedo calibrated. ;)

markm
09-08-2016, 06:11 AM
What speedo don't need them on hotrod, especially some aftermarket ugly POS based on brother in laws Garmin on a 125 trip. Who said I didn't have OD, TKO -600 with a 3.54 Dana. You are the engineer you figure it out.

markm
09-08-2016, 06:17 AM
Good Morning All,

Just thought i would give an update and ask follow up questions--

1.) Replaced plug wires and now runs much better. Note: there were more bad places on the wires that i thought.
2.) Trying different spark plugs, as stated by others, there is no silver bullet. Nothing noticeable at this point from my trials, No biggie.
3.) Marks point above, about using a car plug in a mower got me to thinking, Anyone out there ever went the other direction and used a small engine (SHORT) spark plug, such as, lawnmower/chainsaw? Obviously one with the correct 14mm thread, .375 reach, heat range, etc. (such as Champion RCJ6Y)
4.) I've always used resistor plugs, but the only modern electronics in my car are radio & MSD. Are resistors a Must??
5.) I read online that it's best to have ALL the initial timing the engine can stand and the balance from dist. to get the 34--36 total. What i currently have is 16 initial + 18 dist with light blue & silver springs for my 34/35 total all in by 2800--3000 rpm. NOW that i'm going to the msd 8361 (vacuum) distributor, What dist. spring / bushing set up would you use?

Gotta get to work, Have a Blessed Day.

A Farmall A is actually a small farm tractor with a 113 now 123 CI four cylinder liquid cooled engine. I don't think lawn mower plugs would be a good plan.

55 Rescue Dog
09-08-2016, 07:30 AM
Good Morning All,

Just thought i would give an update and ask follow up questions--

1.) Replaced plug wires and now runs much better. Note: there were more bad places on the wires that i thought.
2.) Trying different spark plugs, as stated by others, there is no silver bullet. Nothing noticeable at this point from my trials, No biggie.
3.) Marks point above, about using a car plug in a mower got me to thinking, Anyone out there ever went the other direction and used a small engine (SHORT) spark plug, such as, lawnmower/chainsaw? Obviously one with the correct 14mm thread, .375 reach, heat range, etc. (such as Champion RCJ6Y)
4.) I've always used resistor plugs, but the only modern electronics in my car are radio & MSD. Are resistors a Must??
5.) I read online that it's best to have ALL the initial timing the engine can stand and the balance from dist. to get the 34--36 total. What i currently have is 16 initial + 18 dist with light blue & silver springs for my 34/35 total all in by 2800--3000 rpm. NOW that i'm going to the msd 8361 (vacuum) distributor, What dist. spring / bushing set up would you use?

Gotta get to work, Have a Blessed Day.
The new distributor will come with the charts. I'm currently running the silver 25 degree bushing with 1 heavy silver, and 1 light silver. 10 degrees initial, and slower mech advance ramping from 1500 to all in at 4500 for a total of 35 degrees at redline. Runs great.

chevynut
09-08-2016, 11:17 AM
What speedo don't need them on hotrod, especially some aftermarket ugly POS based on brother in laws Garmin on a 125 trip. Who said I didn't have OD, TKO -600 with a 3.54 Dana. You are the engineer you figure it out.

If you think you can get "high teens" on the highway (70-75 MPH) with a 454, dual 600 Holleys, tunnel ram, 3.54 rear (which OD ratio?), standard distributor, and the radical cam you talk about, I should be able to hit mid 20's with my 502, EFI, 410 rear, .50 overdrive, and relatively mild cam. :)

125 miles isn't enough distance to determine mileage very accurately. I'm not buying it. :)

55 Rescue Dog
09-08-2016, 01:43 PM
With a engine built for fun and speed, MPG's doesn't really matter. But getting them to run the best you can with old fashion tuning is fun. Like with your new distributor you can do a lot off things using the vacuum advance. Try full vacuum, or ported to see how it works. I prefer full vacuum advance, if the engine likes it, because you can back the idle screws off a bunch, and run a little less initial advance. Seems to help combustion at idle.

markm
09-09-2016, 06:27 AM
If you think you can get "high teens" on the highway (70-75 MPH) with a 454, dual 600 Holleys, tunnel ram, 3.54 rear (which OD ratio?), standard distributor, and the radical cam you talk about, I should be able to hit mid 20's with my 502, EFI, 410 rear, .50 overdrive, and relatively mild cam. :)

125 miles isn't enough distance to determine mileage very accurately. I'm not buying it. :)

Your pompous and arrogance is really showing through here. Please show ne where I stated that I had a radical cam and a 454 in my 55. I have always freely stated its a 1965 Impala 396 with a 425hp 427 solid cam. The only racial cam equipped 454 I own is in a Camaro and is not capable of a 125 mile road trip. The 8 gallon fuel cell would be empty before I got to the county line. Your final drive ratio is about the same as mine so why don't you quit pontificating and get to work and prove something.

55 Rescue Dog
09-09-2016, 05:15 PM
It really doesn't matter whatever engine/gear/car/truck you have. 9 MPG or less is where the fun happens!!! Until you have to refuel, or repair/replace something.

markm
09-11-2016, 07:53 AM
It really doesn't matter whatever engine/gear/car/truck you have. 9 MPG or less is where the fun happens!!! Until you have to refuel, or repair/replace something.

Actually that is about were I was at with a BW Super T10. Actually launches better with 5 speed due to lower 1st gear, No other changes so I kinda got the best o both worlds.

chevynut
09-11-2016, 08:16 AM
Actually that is about were I was at with a BW Super T10.....No other changes so I kinda got the best o both worlds.

So you were at 9 MPG and made no other changes other than the TKO600? If that's the case your .64 overdrive got you to 14 MPG. That's more believable. Certainly not "high teens".

chevynut
09-11-2016, 08:23 AM
Please show ne where I stated that I had a radical cam and a 454 in my 55. I have always freely stated its a 1965 Impala 396 with a 425hp 427 solid cam. The only racial cam equipped 454 I own is in a Camaro and is not capable of a 125 mile road trip. The 8 gallon fuel cell would be empty before I got to the county line. Your final drive ratio is about the same as mine so why don't you quit pontificating and get to work and prove something.

Well since you talk so much about your 454 and your big cam, one would assume it's in a tri5 since that's what this forum is about. I didn't know you had such a small big block in it :). But nobody really knows what your car is because you have never posted any pics of it. In fact, you've never proven to anyone here that you even own one. :D

And since you're apparently a little math challenged, 0.5 isn't nearly "the same" as 0.64....it's a 28% difference. In other words, if I'm cruising at 75 MPH at 1800 RPM, you would be at 2304 RPM...that's quite a difference.

markm
09-12-2016, 06:00 AM
You only hear what you want to hear. I have posted pictures and U-Tube links to ne a drags, since you are so smart find them. Most guys with running cars have a 4.10 with a 6 speed. Therefore I figure 3.54 x .68 about the same result.

Eds56
09-12-2016, 10:09 AM
You can go too far on timing without having audible pinging, but with most small blocks it's pretty rare.

On initial timing, 16 may be a bit much. But if it's not pinging or kicking back against the starter when the engine is warm, it's probably OK. Your mechanical advance setup is pretty good (again provided there's no pinging).

When you install the vacuum advance distributor, don't change anything and monitor for pinging. I don't recall if the MSD distributor has adjustable vacuum advance or not? May want to limit how much.

I installed the MSD 8361 dist. this weekend, as listed below, i do NOT think this vacuum can is adjustable. Now have more questions--
I set the total timing @ 34/35 & all in by 3k rpm. initial 16 degree + 18 mech. (using the same spring / bushing combo) with vacuum hose disconnected and plugged. Then hooked up vacuum line to manifold vacuum. I then had to back DOWN my curb idle. Rechecked @ idle with vacuum connected and the timing is now at 36. I increased the RPM's to 3k+ and it seems to max out around 52 degrees. Does this sound correct?
I still do NOT hear any pinging, rattling, etc... I only drove it 4 or 5 miles, but it still started right back up, without any starter drag. Had plenty of power & Actually seemed to run a bit cooler. Before this, at idle my temp would always creep up a tad above stat level when just sitting at idle.....But it didn't yesterday and it was mid 90's outside like usual.

I hope to put a few more miles on her this weekend to better judge the results. It just doesn't seem right to see that much advance. I'm sure there is a big difference between 3 or 4k RPM in neutral VS. under load. I suspect that under load that number will drop.

Rick_L
09-12-2016, 11:19 AM
It all sounds good, normal, and what's expected. The cooler running is something that wasn't discussed that I recall, but it's also expected.

markm
09-12-2016, 01:01 PM
Sounds like you won all the way around.

55 Rescue Dog
09-12-2016, 02:35 PM
Seems like a lot of advance at idle with that much initial advance. With that much initial, you could see how it runs with ported vacuum. Or, put in the
25 degree bushing and back the initial down to 11,or so, which would give you 36 total, and idle vacuum timing would drop 7 degrees too. Just need to experiment a little, to see if you can improve it, one thing at a time. It would also be good to adjust your idle mixture screws too. Or, if it runs the way you want, don't mess with it.

Eds56
09-13-2016, 04:50 AM
Thanks Guys for all the info / feedback. Guess, now i just need to put some miles on her and see the results.