Slant Six Missing

[Deemo]

i know this topic has probably been beat to death, but here it is. 65' valiant signet 100 (smaller /6 with carter 1 bbl carb 3 speed manual) has a miss that I can't for the life of me get out. I've changed:
Plugs
Points
Distributer cap
Wires
Valve adjustment while idle if .10-.20 to spec
New carb
Fuel filter and hard line and tank
Carb tuned within reason

So this morning, fire up my daily and it purrs like it never has before. Light throttle it's great. Little more gas, she sputters like a cylinder is down. Now, my local MOPAR guy says bad valve. I adjusted the valves and when I'd hit the throttle linkage I could hear number two hiss like blow by. Compression test is also within spec so my question is this:

If I have a bad valve, why does it every so often sound great? I thought bad valves don't care what rpm or throttle you have, Bad is bad right? I'm not knocking the local MOPAR guy, I just want it to run right. Timing is set at 13 degrees. Why is it still missing???

 

[whitepunkonnitro]

Your problem is ignition load related. First, bypass your ballast resistor with a jumper wire. See if that helps.
If no, jump out the entire electrical system by hot wiring the coil directly to the battery.
If that doesn't work, change the coil.
This is predicated on assuming you have a good condenser in there...you mentioned changing points, but said nothing about the condenser

 

[slantsixdan]

13° initial timing is too much for a stock or near-stock '65 170, and can cause a variable miss and sputtering. Try setting your timing to 3° BTDC (at 650 idle rpm, vacuum advance hose removed from the distributor and plugged). Then reattach the vacuum advance hose and readjust your idle settings as described in this post.

"New carb" is very possibly a step backwards, depending on what you bought -- the "remanufactured" items you can buy off the shelf of a real or virtual parts store today are garbage.

"When I'd hit the throttle linkage I could hear number two hiss like blow by" doesn't make sense in any way I can read it; where did you hear this hissing seeming to come from? Usually cylinder leakage of the kind you have in mind isn't audible with the engine running, but only with a static leakdown test, so the hissing you heard might have been a normal engine-with-valve-cover-removed noise.

What spark plugs did you use, how are they gapped, and did you remember to remove the metal ring washers before installing them?

It's just as hard to buy good-quality points these days as it is (see here, read whole thread) to buy a good distributor cap. Do yourself a favour and put in electronic ignition of one kind or another. I like the HEI upgrade, though it requires more parts-buying than putting a Pertronix kit in the existing distributor.

 

[Deemo]

I changed the vacuum advance so n the distributer as well. Forgot that. I'll turn back the timing and try that.

As for the hiss, it as if a valve isn't sealing and I can hear the valve not closing. I dunno. But I have literally tried everything I know. I have a dwell meter from way back when I used to help my grandpa and it's set right. I used over the counter plug from a local parts store. Champions. I gaped them and put them in. They are all perfect except the #2 doesn't look as worn as the others. So obviously it's that cylinder. I used msd plug wires that you cut to length and crimp. Checked those. Same thing happens.

As for the carb, I have checked around and have a Holley on the way to make sure it isn't the carb. I have literally tried everything I know of to get this miss out. Light throttle car runs great. Piddling around town it's fine. But try to give it more gas and and it accelerates but sputters. It's fuel or fire. So I'll try and completely rule out the fuel with the carb. Last resort is a head swap but over a miss??? That's extreme to me. I'll work on the ignition and bypass the stuff I can and go get a new coil. I have rewired the engine bay from the firewall to the engine and headlights. No change and the car sat for 20 years before that. I haven't been able to get the miss out since the day I drove it out of the barn from where it sat. 27k original miles so plenty of life left. I just hate the miss

 

[whitepunkonnitro]

An intake valve that is not sealing will give you a pop through the carb if it is bad enough to actually cause an issue.
Fuel problems will manifest themselves with a soft miss and will be more related to throttle position than load.
Ignition problems will give you a sharp, abrupt miss, and be more load related.

 

[brian6pac]

Valve adjustment to tight? How are you adjusting the valves, I had a motor that they were adjusted to tight, putting around ran o.k. as soon as you put a load on it the misfires started then popping backfiring when it got hot.

 

[slantsixdan]

As for the hiss, it as if a valve isn't sealing and I can hear the valve not closing.

I'm still dubious on this count.

I used over the counter plug from a local parts store. Champions.

Not very good spark plugs, but they're usually not bad enough to cause a miss. Next time, buy NGK № 3459 (that's the stock number; plug number is ZFR5N) which is the "hot ticket" plug for stock or near-stock pre-1975 Slant-6s. It has an extended electrode pair that moves the spark point away from the quenchout zone for more reliable light-off.

And (again)...what did you gap your plugs at, and did you remember to leave off the metal ring washers before installing them?

As for the carb, I have checked around and have a Holley on the way to make sure it isn't the carb.

Previous comment about "remanufactured" carbs still applies. They're often junk no matter which brand they are. Did you keep the original carburetor, or is it gone forever (traded in as a core to be destroyed by a
"remanufacturer")?

Last resort is a head swap

No, last resort is systematic diagnosis...not just swapping the head on a guess.

I'll work on the ignition and bypass the stuff I can and go get a new coil

I don't see or hear any evidence that your coil is faulty. Don't just guess and throw parts at it.

 

[slantsixdan]

As for the hiss, it as if a valve isn't sealing and I can hear the valve not closing.

I'm still dubious on this count.

I used over the counter plug from a local parts store. Champions.

Not very good spark plugs, but they're usually not bad enough to cause a miss. Next time, buy NGK № 3459 (that's the stock number; plug number is ZFR5N) which is the "hot ticket" plug for stock or near-stock pre-1975 Slant-6s. It has an extended electrode pair that moves the spark point away from the quenchout zone for more reliable light-off.

And (again)...what did you gap your plugs at, and did you remember to leave off the metal ring washers before installing them?

As for the carb, I have checked around and have a Holley on the way to make sure it isn't the carb.

Previous comment about "remanufactured" carbs still applies. They're often junk no matter which brand they are. Did you keep the original carburetor, or is it gone forever (traded in as a core to be destroyed by a
"remanufacturer")?

Last resort is a head swap

No, last resort is systematic diagnosis...not just swapping the head on a guess. I don't think it's a good guess, either -- if you had a stuck or otherwise faulty valve, you wouldn't have a smooth idle, which it sounds like you do.

I'll work on the ignition and bypass the stuff I can and go get a new coil

I don't see or hear any evidence that your coil is faulty, which it probably is not. Don't just guess and throw parts at it -- a nice original 27k mile car like that gets a little less original with every replacement part you put on it, plus the waste of money, time, and effort replacing parts that don't need it.

Start at the start: set up the engine so it's running at a speed that makes it miss, then go listen at the tailpipe. Is the miss a rhythmic "chuff-chuff-chuff" type of sound (one or more specific cylinder/s always missing) or is it irregular spluttering and popping (multiple cylinders misfiring at random)?

One item I don't see on your "tried it" list: intake manifold gasket. The original shim-type gasket worked okeh for a lot of years, but I have often enough seen them fail on (or soon after) resurrecting a car that's been sitting for a long period of time that this is worth considering.

 

[rustycowll69]

are you absolutely sure the rotor is phased correctly. Most people don't like installing points on a slant. It is easy to get a tooth off on the gear, if the dist. is removed to install new points

 

[Deemo]

Dan, well, I do not remember the gap, and I set the valve lash per your instructions!!!! .10 and .20 per this thread: Slant Six Forum, :: View topic - What type wrench for valve lash?

Did it while the car was running and hot and was way easy. I did not have any trouble at all. Remembered that it went exhaust -intake- then two in the middle were intake then back out to exhaust. I checked, rechecked, and checked again three times to make sure I had this correct. When I set the lash, the car really came to life. Ran like garbage, did that and I was astounded at how well it ran. Like driving a vw bug and then getting into a sports car.

Yes I do still have the original carb, and I will rebuild it once I get this straight. I found two more at the junk yard, just need to pull them. One is a halfway tore up 64 dart which I nabbed the bumper, distributor, and other parts from just to have.

I tell you what I'll do, I'll take a video tomorrow and post it up of the hiss I'm hearing and one driving.

Spark plugs: Got it. I'll go get a new fresh set in the morning first thing and never get any other types.

Distributor: Yes I took it out, I'm almost 100% sure I hit it dead on the mark going back in. I'll tdc it and recheck the cap/timing when I change plugs in the morning.

Intake gasket: haven't looked there. I drive this thing daily, so it can't be down for more than a few hours as I have to pick the kids up from school.

I also have a radiator swap that looks factory that I need to post up a how to. Looks great, fits nicely and just need to chang one hose out when it comes in and it's from a Dakota and fit nicely. Looks mint

Anyhow, video tomorrow so I can get more eyes and ears on it. Local mechanics and the dodge dealer won't touch it.

 

[slantsixdan]

Video's a good idea. Please make sure to show not just the engine from an underhood view, but also take the camera back to the tailpipe so we can hear that, too.

Plug gap needs to be 0.035" with a points-type ignition system.

You don't necessarily need to tear stuff apart to check the manifold gasket. Get a can of carburetor cleaner and spray it at the manifold/head junction, at each runner, from multiple angles. If you have one cylinder (№ 2, you said) giving a "different than the rest" spark plug appearance, focus on that one. You're listening/watching for the idle to change noticeably immediately after a squirt from the carb cleaner -- that would indicate an intake leak near where you squirted. And then you hafta take stuff apart to fix it!

 

[KosmicKuda]

If there is any doubt about the valves seating then go to a local big chain auto parts store and rent a compression gauge for free. Remove all the plugs and crank the engine so you get 3-5 hits on each cylinder. Record the numbers and compare them. If changing the plugs anyway, this would be a perfect time to do it. If nothing else you will be able to cross this off your list.

If you have a low or zero cylinder and with this car sitting so long, I wouldn't be surprised if the oil holes in the rockershaft feeding the rockers may be plugged and a valve is hanging up. Another cause could be a burned valve.

 

[rustycowll69]

I must have missed the point that it has been sitting for a long time. I agree with previous poster. Very common for valves, and/or rockers to "stick" due to rust. Strongly advise some rust penetrant on rockers and valve stems.

 

[Deemo]

First video. Went and got new plug per Dan, now gonna take valve cover off and try to do the second video. This video you can clearly hear the miss. It'll go from smooth to miss smooth miss and so on.

 

[slantsixdan]

You've got a rhythmic miss at idle (that SputSputSput sound), and you've got random spluttering. I agree with you it's probably not a valve, and while I'm now voting a second time for an intake manifold gasket vacuum leak, this kind of "comes and goes" miss can also be due to a problem in the distributor.

(…and where's that at-the-tailpipe footage?)

 

[Deemo]

Well lol it had a newer muffler on it and there's a rust hole in it. No smoke what so ever from the car. Doesn't use a drop of any fluid. Figured that the sound was sufficient from there. New plugs are in gapped to where you said. I'll yank the distributor here in a minute and fiddle with it. If I change to a pertronix kit how much and will that be a good solution for the long run? Never had to mess with points before as I've always had ford fairlanes (64,65,66s) and they all had Clevelands or 5.0s I'd swap in with msd boxes. That was the first thing I did always. I'll do the carb cleaner trick and see.

 

[slantsixdan]

Pertronix is a quick and dependable drop-in upgrade, yes. You're going to want to look for evidence of sparks jumping around where they shouldn't be jumping in the distributor. Sometimes there's no evidence.

Did you put in a new condenser when you changed the points?

 

[Deemo]

Yes sir sure did. Cap rotor condenser points plugs wires. The normal things even the o ring on it.

 

[slantsixdan]

Was this video taken before or after readjusting the timing as per post № 3 in this thread?

 

[Deemo]

Alright. Fixed. Almost should I say. So I went and bought the pertronix kit. Installed it. Slapped the distributor back in it after finding top dead center fired it up and boom. This thing does a one wheel peel, accelerates like a champ and idles nice and smoothly almost now. When I hit the gas it has a sputter and then comes to life. I guess there was something wrong with the points or condenser. I have no clue. Because I double checked that the dist. Was in right and on the right gear alignment. Checked timing. And still missed. Pertronix kit fixed most of my issue, I think what's left is to check the intake gasket which I ordered anyways when I got the pertronix and get a new valve cover gasket. Thanks for the help guys. I just didn't know where to start and didn't want to go through the valve replacement

 

[slantsixdan]

Good deal! Your stumble on acceleration sounds like a probable accelerator pump issue. With the engine off, remove the air cleaner and peer down the carb while you operate the throttle lever. Every time you open the throttle you should get a strong shot of gasoline squirted in from the carb throat sidewall. If it's weak and piddly, your accelerator pump plunger is worn (common on old carbs) or the pump was not properly put together (common on "remanufactured" carbs). If it's a strong but very short shot, move the accelerator pump link outward by one hole. Take a look at the lower passenger-side corner of the throttle lever and you'll see three holes, one of which has the accel pump link in it. Innermost hole = smallest accel pump shot. Outermost = largest shot. If you make this adjustment, also adjust the bowl vent setting -- there are three slots on the accelerator pump stem for the clip that lifts the bowl vent cap. Lowermost slot for outermost link hole, middle for middle, uppermost slot for innermost link hole.

If you turn out to need a manifold gasket, it is very much worth your while (like, "do it once instead of multiple times") to get the good gaskets for the manifolds-to-head and intake-to-exhaust junctions rather than the cruddy parts store items.

 

[Killer6]

are you absolutely sure the rotor is phased correctly. Most people don't like installing points on a slant. It is easy to get a tooth off on the gear, if the dist. is removed to install new points

Setting in the dizzy a tooth off will not affect the phasing one bit, only the timing.................

 

[Killer6]

Alright. Fixed. Almost should I say. So I went and bought the pertronix kit. Installed it. Slapped the distributor back in it after finding top dead center fired it up and boom. This thing does a one wheel peel, accelerates like a champ and idles nice and smoothly almost now. When I hit the gas it has a sputter and then comes to life. I guess there was something wrong with the points or condenser. I have no clue. Because I double checked that the dist. Was in right and on the right gear alignment. Checked timing. And still missed. Pertronix kit fixed most of my issue, I think what's left is to check the intake gasket which I ordered anyways when I got the pertronix and get a new valve cover gasket. Thanks for the help guys. I just didn't know where to start and didn't want to go through the valve replacement

Love the fuzzy dice! I think once You've set the valve lash, You're home free if the valves are still good. I'm 100% w/Dan on the carb stuff, send him a close-up of the carb #'s,
& He can tell You if it's the correct one. If so, definitely re-do it Yourself or send it to a reputable specialist, God knows what You'll get or get into otherwise.

 

[Deemo]

Love the fuzzy dice! I think once You've set the valve lash, You're home free if the valves are still good. I'm 100% w/Dan on the carb stuff, send him a close-up of the carb #'s,
& He can tell You if it's the correct one. If so, definitely re-do it Yourself or send it to a reputable specialist, God knows what You'll get or get into otherwise.

I agree. I bought a brand new reman"d carter. Can't remember which but the slight miss it has I agree, Gonna be carb related. I can rebuild them no issues there, just getting the parts and time to do it. I'll post up a pic of the tag tomorrow.


Thanks again for the help. I learned a few things today. I've read tons and tons of posts about slants and the a bodies. Trying this and that but nothing worked. Appreciate all the help

 

[slantsixdan]

To be clear: post a pic of the tag on your original carb, not the "reman".