Slant got me stumped

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GAMoparMan

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Hey guys, I have a 225 here giving me a fit and I can't for the life of me figure this gremlin out.

Started with a 73 225 single barrel..... won't idle below 1800rpm. Runs rough.iming showing like 30+Before. At first I thought it was timing because I couldn't get it to set and it would just bounce around. Inspected and replaced worn timing chain."slap the chain sides together"

Got timing not bouncing, but still acting the same. Rotated it to TDC and stuck the Dis back in....Won't run unless timing is high 25+....Rough

Same....Checked for wiped lobe and set the hot valve lash..That was fun at 1800+RPM...

Same...thought it was a bad cylinder or something..all checked out at 140psi +-5 and no bubbles in the coolant..so headgasket is good.....

Same..changed distributor,coil, and ECU with a known good

Same..verified fuel pump was pumping good.

Starting to look towards a vacuum leak/issue

Completely changed over to a Super Six 2bbl setup, verfied carb, and a remflex gasket..All ports plugged except vent

Same!......Gawr!

Autolite plugs look good..alittle on the black side..I caulk that up to it running like crap..They still have the washers on them.Head has tubes..But I think that would cause this......?

Only thing I haven't changed is the ballast...But I just can't see that being the root cause...could it?

Any other idea's?

Thanks
 
GAMoparMan said:
They still have the washers on them.Head has tubes..But I think that would cause this......?


Thanks
Click to expand...

Since you mention the head has drool tubes, you need to remove the washers from the plugs. It may or may not cure your issue but it's a start.
 
Some ideas and questions roughly grouped in ignition and fuel/carb categories. The compression seems to be good.

IGNITION:
The wrong ballast surely won't help but it is unlikely to cause this problem. Put in a BWD RU19; that will be close to the stock resistances; it'll run better at cold starts in cold weather in any case. Just get this remote possibility out of the way.

Measure the voltage on the blue wire connection to the ballast and make sure it is around 12v.

Find TDC accuately and check to see if the timing mark on the damper is accurate.

Pull the spark wire from the coil; place 1/4" from metal and crank to see if you get a good blue spark. Repeat for a plug wire from the distributor. Don't test across just a spark plug.

Did you change the condenser when you changed the distributor or re-use the same one? That could do this.

Clean the grounding for the ECU very thoroughly, and make sure the ground jumper from the rear of the block tot he firewall is present, is in good condition, and the connections are clean.

What is the plug brand/number? The spark plug tubes should not be any issue unless they are not sealing; I think this year uses the tapered seat plugs with the tube; someone should speak up and verify that; or, you can search this forum for that info.

CARB/FUEL:
What vacuum reading are you getting? Even at this high idle, it ought to be pretty high: 18-22 or so. Does the car have power brakes? If so, has the vacuum hose to that brake booster been plugged to see if that helps?

When you say 'verified carb', what do you mean? What carb is on there now?

What is the choke plate doing? If closed when you start, it should open about 1/8" to 3/16" in the moment the engine starts. Have you tried opening the choke plate by hand
to see if that helps? This will detect an over-rich cold mixture.

How many turns out from fully closed is the idle adjust screw? Usually will be around 1-1/2 turns out.

This possibly acts like the idle and progressive circuits are not working right, and the car only runs well on the mains. But this would be a lean condition, and the plugs would not be blackened by carbon soot.

What specific tests were done to the fuel pump?

Recheck the float setting; does not seem likely for the symptoms, but it needs to be very close. Wet float can be set for the Holley 1920 to see the bowl's fuel level while running (and perhaps others).

How old is the fuel? Bad gas can cause these symptoms.

OTHER:

Watch the valves when running; do some of them seem to be closing more slowly or lazily than others? Sticking valve guides is not uncommon for the /6 and will cause rough running, and can screw up your feel for hot lash settings when running. If you check lash settings when not running (hot or cold) and any are way off, this can indicate sticky valves.
 
Thanks for the comments nm9stheham,

I haven't volted any wires yet to see what their show, But I did clean all the grounds for the ignition and battery systems.

TDC and balancer are lined up good

haven't checked the spark yet....I check that this afternoon

different condensers

Autolite 66's if I remember correctly

I'll check vac reading this afternoon, I assume its good as the carb top could have stucked in a dog when it was running.

verified carb...good carb pulled from a running motor.

Tried playing with the choke plate setting...

tested pump with just the starter motor spinning the fuel into a bucket and also with a 5psi regulator on it. no issue detected.

Gas is good.

no valves sticking.
 
This brings back some frustrating memories. Mine did soemthing similiar when I bought my dart. The distributor ended up being one tooth off. I marked where the #1 position was on the body of the distributor and pulled the cap with the pulley mark at TDC. Once I found it, it was very obvious but something I previously overlooked while tracking down what seemed to be a vacuum leak.
 
Two things come to mind. And nm9 mentioned one already,
1)to verify true TDC. And then re-time the ignition, as may be required. And,
2) reset the valves the traditional way;with engine off, but warm, one cylinder at a time with the valves on the base-circle. And
3)while the cover is off, verify spit-overlap is within a couple of degrees of true TDC.
Oh wait, thats three.
Until these three are known to be correct,you could be going down all kinds of frustrating rabbit-trails.
After that you cant go wrong following post #3.

I should also mention that,based solely on my experience with just my several slantys, their valves can be tricky to set.It seems the valve-tips like to wear grooves in the rockerarm pads right where the valves contact them. Using regular width feeler gauges, makes accuracy impossible. I had a set in my toolbox, left over from my motorcycle days, that was just about the same width as the stems. These worked great.
 
couple of thoughts:
Check to make sure the distributor cap has no cracks in it.

Plug all vacuum lines and check for leaks.

Spray a healthy amount of carb medic in the Carb bowl while running.

Good luck
 
GAMoparMan said:
... Only thing I haven't changed is the ballast...But I just can't see that being the root cause...could it?
...
Click to expand...
It could, or the associated wiring. Easy to check. Measure from BATT- to Coil+. Should be ~8 V while running (kind of guessing). If <5 V, it definitely won't run well. Bottom line is whether you see a strong spark on a spark tester.
 
Just my two cents worth...

Timing on my slant went south one day acting pretty rude, the distributor hold down bracket under the distributor loosened up an the distributor turned some. This is not the bolt you see but underneath the distributor on the oil pump side.

Also the head gasket can be bad with no bubbles in the radiator. The gasket can blow between the cylinders or into an oil drain hole.

Honestly It sounds like a vacuum leak to me. Possible leaking from intake to head, but when you changed the intake that should had solved that. If brake booster hose or check valve or diaphragm was leaking that would do it also. Throttle cable sticking or kick down linkage hanging up??

In 73' they are kind of still very basic. After 25years of turning wrenches for a living ALWAYS go back to the basics.
Good luck!
Joe

Joe
 
Yeah, pull the distributor and look at the adjustment bolt underneath the bracket. Mine was set all the way to advance, so I had 30 degrees at idle, and it wouldn't idle below 1000. The distributor could also be a tooth off, but probably not, because that's a huge amount -- there are only 13 teeth. When correct, at TDC the rotor should be pointing more or less at #1, which would be almost aligned with the vac advance pot -- down and to the right.
 
Update:

I cold lashed the valves to .010 and .020

Brought the motor back around to TDC and stabbed the Dis back in and made sure it was pointed to the right area and started the firing order. I have the under side adjustment bolt a hair bit loose some I can move the timing around more. I checked the air-gap while I was in there... .008 and good....

I got it to fire up and run ..of course only at a high RPM

no Power Brakes..and all vac ports are capped.

I'll spray around and look for vacuum leaks tomorrow but I would think the remflex gasket would of took care of that issue....let alone, the motor was acting the same with the 1bbl intake carb setup...
I'm wondering if the reluctor has moved...like rotated abit...That would throw timing off..It dark here..So I check that tomorrow also...

Thanks for the idea's..I'll keep ya'll posted as I go on the hunt for this gremlin.
 
Distributor felt tight..I took it apart and changed the springs/advance plate for a custom tune....But to rule it out, I swapped in another known good distributor and the same issue occured.... Will continue the hunt hopefully tonight when I get home. Chance of rain pending....might go hardcore with a tarp.
 
"TDC and balancer are lined up good" is not an answer.Its an opinion.
"gas is good" is not an answer. Its an opinion.
I see lots of opinions.
Nobody, from hundreds of miles away, cant build a diagnoses on opinions.

And, since you didnt mention verifying the TDC mark, nor checking the split overlap, I'm gonna assume you're waaay smarter than me, so, theres no sense in me hanging around.
 
AJ/FormS said:
"TDC and balancer are lined up good" is not an answer.Its an opinion.
"gas is good" is not an answer. Its an opinion.
I see lots of opinions.
Nobody, from hundreds of miles away, cant build a diagnoses on opinions.

And, since you didnt mention verifying the TDC mark, nor checking the split overlap, I'm gonna assume you're waaay smarter than me, so, theres no sense in me hanging around.
Click to expand...

Sorry AJ, I thought it when I changed the timing chain..and the dots are lined up.. and the balancer lined up with its mark, and that both valves are resting on base after the intake valve has come up that it should be good...

if the gas is good enough for my lawn mower and my truck.....I would think its fine...
 
Just a thought, when you turn down the idle, does it just start to run rough till it dies or does it die right away? Torque Converter, if it just dies right away, JUST a thought. MT
 
Mopar Tim said:
Just a thought, when you turn down the idle, does it just start to run rough till it dies or does it die right away? Torque Converter, if it just dies right away, JUST a thought. MT
Click to expand...

It pretty much dies like right away....the only way to keep it running without my foot in it is to set it on the fast idle cam...... to me, its like a ignition or vacuum leak.....I'm going to do some spraying tonight and look for a possible vac leak.

Thanks for the questions MT.
 
Don't look for vacuum leak with starting fluid unless you want to catch on fire. Best way is to use smoke. MT
 
GAMoparMan said:
Sorry AJ, I thought it when I changed the timing chain..and the dots are lined up.. and the balancer lined up with its mark, and that both valves are resting on base after the intake valve has come up that it should be good...
Click to expand...
Hmmmm, when the chain sprocket dots are lined up, the TDC mark on the damper should NOT be lined up with 0 on the timing scale; it will be about 10 to 15 degrees retarded. So if the damper was lined up at 0 with the dots perfectly aligned, then the damper is off. I really encourage you to carefully check the damper versus true TDC; based on the info provided, it appears to be a significant problem.

I also have to wonder if the chain is off one link; if you went by the damper mark aligned to 0 then it could well be. These engines are quite touchy about cam timing; just 4 degrees will make them behave quite differently, and a whole link is a lot more than 4 degrees. Sounds like a careful and thorough cam timing check is in order if nothing else works.
 
Now I'm doubting the alignment in the timing.....

and yes, the balancer is old and the rubber ring was looking sortof bad...

Thank you nm9....This makes the most sense.....

lol....I don't want to go back in....
 
nm9, After thinking on the drive home...When I changed the chain, I lined up the timing marks and installed the cover. I remember the balancer mark being as you said about 15 degree's before and I shrugged and rotated the engine around with my finger in cylinder 1 until I felt pressure build after the intake circled around and then brought it to TDC on the balancer....
 
I think I should get a new balancer and then go back in and verify the marks and work my way out

Thoughts?
 
Find TDC on cylinder 1 by removing the spark plug and turning the engine til it stops hissing at you then stick a pencil in there and turn back and forth to find tdc, and check to see if the timing mark on the balancer lines up with Zero on the the timing scale. If it doesn't make a new mark and set your timing and move on.
 
GAMoparMan said:
nm9, After thinking on the drive home...When I changed the chain, I lined up the timing marks and installed the cover. I remember the balancer mark being as you said about 15 degree's before and I shrugged and rotated the engine around with my finger in cylinder 1 until I felt pressure build after the intake circled around and then brought it to TDC on the balancer....
Click to expand...
Well the damper mark should have been 15 degrees AFTER the 0 mark (towards the driver's side), not BEFORE, if everything is right. On the /6 timing scale, 15 degrees AFTER is not even on the scale markings; the scale usually runs maybe 5 degrees AFTER to 15 degrees BEFORE. So if you saw the damper mark at the 15 degree mark, it can only be 15 degrees BEFORE........

So if the dots were really lined up right and the damper mark was at 15 degrees BEFORE, then it sounds like the damper is about 30 degrees too far advanced and is showing far more advanced timing than it actually is. All this is based on what you are telling us of course.....but it could sure would explain why you need what looks to be so much excessively advanced timing....

Soooo, that gets me back to thinking if it was me, I very soon would take the time to check the damper mark versus true TDC, and not be 2nd guessing myself. And I'd also look very carefully at cam (valve) timing versus true TDC. When you actually do find TDC, the intake and exhausts on #1 or #6 should be about equally open. (This is just a rough method; just a check before tearing the cover off.... which I agree would suck.)

Trying to find true TDC with you finger in the hole is a good way to be off by 20-30 degrees either way; please don't waste your time or ours. Use a solid stop; it is not hard to make with a spark plug if you break/drill out the guts and thread the inside for a long carriage bolt, and use that to carefully find TDC. The pencil method is too rough also, when one is trying to really get the damper mark nailed within 1-2 degrees. The piston motion is very small per crank degree near TDC or BDC.

Other possibilities still remain, and I would also keep on those (LIKE CHECKING SPARK STRENGTH AND TAKING VACUUM NUMBERS; THOSE ARE FUNDAMENTAL TESTS THAT SHOULD HAVE BEEN DONE ALREADY..... which makes this a great statement: "In 73' they are kind of still very basic. After 25years of turning wrenches for a living ALWAYS go back to the basics.") But from your symptoms, this damper mark issue needs addressing. Personally, I would do the checks on the present damper so I would know waht is actually going on before getting a new damper. Of course, if you have another damper, it would not be much effort to compare the 2 as a start.
 
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