Any thoughts on this engine issue

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Abodee,

Taking it one step at a time. This weekend going to pull rockers and do a leak down test on all cylinders. Just the push air and listen variety. Then if I get no leaks the rockers go back on and I look for lash variances. Not knowing what cam this is makes it a bit hard to guess on lash. But I will stay on the safe side and start with at least .0030 when cold and then recheck when hot. If vacuum settles down then I can see how it runs. Not looking forward to the chain issue. But that will likely be next. Oh and with the rockers out I figure I will be able to see how much lift I am getting at the pushrod. No lash to figure in. Then I may be able to idnetify the cam since the mechanic I spoke too remembers it being as Isky. There are only a few solid lift cams Isky makes for this engine.
 
crackedback said:
If you have a vacuum gauge, set the idle mix screws using it.

Have you set the float levels? Checked if fuel was dripping from the boosters?

I'd start over on tuning it. Set initial to 16 BTDC, Re-baseline the idle mix screw settings, 1.5 turns out, set float level and trying tuning it. Highest idle vacuum, leanest setting.
Click to expand...

We did try most of this, we actually reference your post while doing so. We put the vacuum gauge on the carb and then tuned the carb to the 12-14 like you mentioned before... Still have the bucking issue... We looked down the carb and YES it was dripping some... So we swapped it out...

The 2nd carb we took from Mopar Al's running truck. No dripping, adjusted and the best vacuum we could get out of it was around 10... still no better...

At that point it was late, we were frustrated and tired, so we did the compression check, cycled the valve train and then put Al's truck back together.... scratched our heads and quit for the night.

When I get another chance to head up there we will definitely try starting over from scratch on the timing... maybe over the weekend.... Hopefully the engine builder will have gotten back to me by then as well...

Thanks everyone for the ideas and the help... I'm looking forward to posting a video someday of the engine running smoothly!!!
 
Demon,

So that pretty much eliminates another source for fuel. So now the question is. Why is it running so rich? Or is it not running rich but just fouling because the timing is messing up. Is this an auto or manual. Not that it has anything to do with the problem, but at least you could move the idle up until you were out of the idle circuit. Say 1500 RPM and then drive it. Of course that is not a good option if this is an Auto. If you do not know for sure if the engine is really running well above idle you could chase this forever. Do you see my point. You need to see how it reacts under load.
 
spinman1949 said:
Demon,

So that pretty much eliminates another source for fuel. So now the question is. Why is it running so rich? Or is it not running rich but just fouling because the timing is messing up. Is this an auto or manual. Not that it has anything to do with the problem, but at least you could move the idle up until you were out of the idle circuit. Say 1500 RPM and then drive it. Of course that is not a good option if this is an Auto. If you do not know for sure if the engine is really running well above idle you could chase this forever. Do you see my point. You need to see how it reacts under load.
Click to expand...


I totally understand what your saying, that's the confusing part. The bucking goes away when you on the throttle. I can sit there all day and rev the motor at the carb up to 2000rpm or 3000rpm and it smooths out. Drop it to idle and the bucking shows up....we have also turned the idle screw up to as high as 1400rpm and the engine smooths out... so its definitely only showing up at idle.

Car is an automatic, so I'm not okay with turning the idle up that high and trying to road test it... a least not unless I trailer it to a parking lot. Don't need the thing launch and going squirrely on me...

I have a few things to try here. Maybe I will make it up to Al's this weekend or early next week for a 3rd day of guessing..

Thanks again!... I seem to have a few folks here scratching there heads on this one too..
 
73AbodEE said:
if it is out of time, increasing the rpms will sometimes make it sound like it is running better and it will smooth out because the pistons that are firing are working faster.
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if it is out of time, the cylinders are not firing efficiently or all the time, allowing unspent fuel into the combustion chambers without burning it , thus the rich condition and carboned up plugs.

my theory anyways.....
 
73AbodEE said:
if it is out of time, the cylinders are not firing efficiently or all the time, allowing unspent fuel into the combustion chambers without burning it , thus the rich condition and carboned up plugs.

my theory anyways.....
Click to expand...


I agree with him, just because the parts new doesnt mean its good anymore.
 
73AbodEE said:
if it is out of time, the cylinders are not firing efficiently or all the time, allowing unspent fuel into the combustion chambers without burning it , thus the rich condition and carboned up plugs.

my theory anyways.....
Click to expand...

I agre with this logic. That why I called the original builder to see if he has the notes on what the engine was built with exactly. I have some pieces of the puzzle from my notes.... but I am showing we had it narrowed down to (2) different Comp Cams.... I am hoping he can verify which one went in the motor since all that is on my receipts is Comp Cam kit - cam, lifters, springs, chain.

Game plan is to start from scratch.
1) Put my distributor, ECU, and Coil back on in -- Since there was no change with the swap
2) Pull all the plugs and clean them so we will be able to read them again
3) Set the initial timing -- Base on finding out the CAM Specs and engine build details.
4) Vacuum test -- And retune carb to vacuum gauge
5) Put more gas in the tank.... Maybe this should be step #3 -- I gotta laugh at this point
6) Drink beer and ponder why this didn't change or drink beer to celebrate
7) Read the plugs again -- clean and adjust accordingly...
8) Repeat step #7 till the plugs read good.... If the bucking continues drink more beer and develop a game plan from there.
 
LMAO.... maybe i missed it, but please check tdc with a piston stop against the balancer and rotor / number one on the cap, then time it with the vacuum advance plugged off.

THEN drink beer LOL
 
73AbodEE said:
LMAO.... maybe i missed it, but please check tdc with a piston stop against the balancer and rotor / number one on the cap, then time it with the vacuum advance plugged off.

THEN drink beer LOL
Click to expand...

Its on the list of things to try the next time I get up there...its on page (2) or (3) here somewhere.... Good thing I work for myself... I spent most of the day posting on here... LOL... I'm sure me and Al will have a couple more beers before we figure this all out... Hey Al, hope your enjoy all the readying when you get home from work.... If all else fails we can always light it fire and roast marsh mellows like we talked last night. HAHAHAHAH
 
73Abodee left out a few steps so I fixed his post..

73AbodEE said:
Drink Beer.

please check tdc with a piston stop against the balancer and rotor / number one on the cap, Drink another beer, then time it with the vacuum advance plugged off.

THEN drink more beer
Click to expand...
 
Very interesting,

I just fixed a similar issue on a friends 72 Chevelle, fouled plugs & all (I am the Hot Rod Chevy & Ford Mechanic out my small group where I live)

I may be new to Mopar, but a 4 cycle motor motor is a 4 cycle motor regardless of who the manufacturer is, & I completely understand how a Chrysler engine works with it's minute differences from the other two of the big three. I stated the last sentance so we don't get into an argument of the brands & whats different from Demon's 340.

Long story short, doing all of the same checks as mentioned so far in this thread, here's what I did on his engine: (Chevy 350 with very similar cam)

Pulled the intake manifold (Eddy Performer RPM), pulled the lifters, then installed Rhodes lifters. Then installed an Eddy Performer RPM air gap intake with high quality Fel-Pro gaskets, not the cheapos. (the change of intake is irrelevant to subject at hand but thats what went back on)
Then pulled the distributer apart, eliminated the vacuum advance mechanism & installed heavier springs / weights, then reinstalled the distributer. Installed a new Holley 750 CFM carbeurator with electric choke, then set initial timing at 18 degrees. Eliminated the PCV valve & installed crankcase vents. The idling issue was gone & it performed much better across the RPM range.

I'm not saying to do this to yours & yes it was a different motor, but maybe there's something in there I did that you havent tried yet. Hope it helps.

Good luck,
Rob
 
UPDATE:

Well I went up last Sunday and spent the day with Al working on the issues:

Original Engine Builder thinks its a dead spark issue. And mentioned like many to check the electrical aspects of the engine:

So here is what we did:
-Cleaned the spark plugs
-Changed the cap to a new cap
-Tried to change the plug wires but the didn't go so well since I picked up the wrong plug wires. But we did pull each wire while it was running and checked them for spark -- ALL GOOD
-Put my original parts back on the motor since we ruled them out as being bad (as you can read in previous pages) Found the distributor intermediate shaft was off (prob from all the dist swaps we did) so we set that back correct.
-Started from scratch on everything again:
-set initial time and then fine tuned everything -- see video
-set vacuum best we could -- see video
-tac is reading around 900-950 -- see video
-STILL SHACKING AT LOWER RPM RANGE -- see video
- WE also fixed a bad red hot wire in the dash bulk head connector -- we think it was arcing -- fixing this helped.
-I did find out the cam is a COMP CAM XE274H Hyd cam

So this IS THE BEST IT HAS RUN, but I think it is still having electrical issues on the hot side of the ignition (somewhere in the dash harness possible at the column to dash connector. it isn't really strong there, so that may need see some attention.

Next Step -- drain the transmission and fill it back up with clean fluid and then we think we need to see what it does under load. Since the motor seems to live nice at 900-950rpm at idle (least amount of shake) I think we need to see if the shake reappears under load...

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Are the idle mix screws out an equal amount on both sides?

I'd put the initial at around 20*, see if it starts when warm ok.

Check the gap on reluctor wheel and pickup, .008 with a brass feeler.

You might try hot wiring the ignition, see if that changes anything. One thing with wiring being underwater, if there are any breaks in the insulation, it's common for corrosion to start.
 
Yeah its definitely an odd situation I have going on here. Even crazier, when its running and you pull a plug wire (and I mean any plug wire) it doesn't really make it run any worse....

So we will try it under load next week and see what happens..
 
crackedback said:
Are the idle mix screws out an equal amount on both sides?

I'd put the initial at around 20*, see if it starts when warm ok.

Check the gap on reluctor wheel and pickup, .008 with a brass feeler.

You might try hot wiring the ignition, see if that changes anything. One thing with wiring being underwater, if there are any breaks in the insulation, it's common for corrosion to start.
Click to expand...

idel mix screws -- yes they are -- Al turns them exactly the same when he adjusts them..

Gap on the reflector -- yep we checked that too... its ..008 with a brass feeler

We have not hot wired the car --- I'm not quite sure how to do that??

At this point I am thinking that the wiring is the culprit in this.... Then engine harness and forward lamp harness were both new from Year One, but the dash harness was original with the car... I'm still searching my parts for a GOOD unmolested dash harness to swap out to see if that helps... Till the the search for smooth idle will continue at a nice slow pace. Good thing we always have beer in the fridge at Al's garage.
 
demon34071 said:
Yeah its definitely an odd situation I have going on here. Even crazier, when its running and you pull a plug wire (and I mean any plug wire) it doesn't really make it run any worse....

So we will try it under load next week and see what happens..
Click to expand...


if you are pulling wires and it is not doing anything i will still say that somewhere between the cam timing and the ignition source lies the problem. did you bring it up BTDC with a piston stop to verify that the balancer and the rotor are almost dead nuts at #1 ?
 
73AbodEE said:
if you are pulling wires and it is not doing anything i will still say that somewhere between the cam timing and the ignition source lies the problem. did you bring it up BTDC with a piston stop to verify that the balancer and the rotor are almost dead nuts at #1 ?
Click to expand...

Yes---but not with a piston stop --- did n't have one... so we did it the old fashion way. Put you finger over the plug hole and rotor the engine till it blows your finger off. When we did this the rotor lined right up with #1
 
Well, with the idle set at 1000 rpm, it sounds and seems like an intermittent electrical arcing/grounding that I had to chase in one of my former cars. I waited until dark and then started it up and observed the light show of faulty plug wires which were brand new at the time. I replaced those and then saw one of my coil leads would arc near the intake manifold. It turned out that the wire had dried out and developed a crack. Just remembered that this was on a big block and so the coil wires run along the head from the firewall, which is not the same layout as a small block.

But you say that you have replaced the wire harness from the bulkhead connector on the firewall.

Dang! This is puzzling.
 
lol, I kinda have the same motto. I used to live near Pittsburg, too bad I'm not still in the area, I would gladly drop by to lend a hand. We just moved here a little under a year ago, I was there when all the flooding happened, talk about terrible. I helped get quite a few vehicles dried out & running again.

I'm with 73Abodee on this one now. Good idea to go ahead & find a good dash harness just because of possible corrosion issues.

It may sound odd as you don't have any miles on that motor, though I have watched this happen while breaking a cam in, but the very last thing I would rule out is a flat lobe on the cam. Very unlikely, but have seen it happen a few times with a new cam.

That aside, I will agree on bypassing everything & hot wiring the ignition to see what happens. Let me do some review before telling you how to Hotwire it, I'd hate to tell you how to fry your ignition lol

DFX brought up a good idea too that I didn't think about. Fire it up, then turn all the lights out to see if anything is arcing anywhere maybe
 
I read through the entire thread but have lost track of what you have done.
#1 when you had the #1 @ TDC did you check/Mark the balancer?
#2 either something is wrong with your timing light or there is an ignition problem. The light SHOULD NOT skip like that try another light - if the same there is definatly an ignition problem.
3# do you have the vacuum advance hooked up to the ported vacuum on the side of the car? If so get rid of it for now.
#4 Make sure your ignition Box has an EXCELENT ground - the box case should be grounded - clean off the paint behind one of the bolts.
#5 if you think it could be a mechanical distributor problem you can drill some holes in the top of the cap @ #1 terminal - big ones - then you use your timing light to watch the position of the ignition rotor - this assumes you get a nice steady flash from the timing light.
 
run a wire directly from the battery + to the ballast.
 
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