225V6 rough Idle

[MikeT]

My 225 is acting up. At idle it misses and sounds like a exh. valve is staying open on the right side of the eng. Also the exh. temp. on the right side is 250 deg. at idle and the exh. temp on the left side is 520 deg. at idle. When I rev it up and hold it for a while the temps even out but the miss is still there. I have tryed new lifters thinking one was pumping up, I also pulled the head and lapped the valves and checked for a blown head gasket but found nothing. I adjusted the carb thinking that fuel could be the problem but no change. All 6 cyl. have 150 lb. cranking comp. and 60 lb. running comp. All cyls. tested the same on a leakdown test also. Why would the left side of the eng. run fine and the other not??? Could I have an exh. valve hanging up causing the missfire?? or possibly some weak valve springs?? A vacuume check also shows a fluctuation of 4in. vac. at idle. That makes me think it's a valve. Any help would be great.!!!! Thank's.

[James P. Enderwies]

At first I would say a sticking valve or bent pushrod. but, since you've pulled the heads and lapped the valves, you "should" notice a sticking one and/or a broken valve spring. It could be that a valve is sticking only when it heat's up.

Have you checked the plugs and wires? Just a thought. A bad plug wire can cause something like this--1 cyl not fireing. Check the color of the plugs also.

HTH

[jpflat2a]

wrong distibutor(odd vs even fire),HEI module, bad timimg, incorrect firing order, crossed plug wire,check plug wires, arcing inside dist cap/rotor, leaking intake manifold or vac leak, dist off 1 tooth,
Aren't you gald you asked :D
back to basics with thorough diagnostics
most likely carb or ignition issue(s)

[jpflat2a]

with HEI, is ballast resistor bypassed ?
need 12 volts for HEI to function proerly

[jpflat2a]

thinking....... more coffee.........a little history please
just start acting up or were mods made and problem began shortly thereafter?

[James P. Enderwies]

Jim, and Mike too: I've learned the hard (very hare and :oops: ) way to start with the simplest things first.

When I was in college, my best friend had a '69 Mustang. He is no stranger to engines. He did a tune up on it and it was missing after he got done. He couldn't figure it out. At the time I was working as a mechanic at a 66 station that had a great owner/mechanic. He said bring it in and he would look at it.

Diagnosis: When my friend put in the new plugs he dropped one and closed the gap on the plug. He didn't think to re check it--he just installed it. Problem solved! :rotflmao:

[66cj5]

Check the timing of the motor. Mine was like that due to the dist become loose and having around 50 degrees of advance.

[MikeT]

Thanks for the info. A little history: I pulled the eng. downthis winter because it was missing out the exh. on the right side and because the timing chain was making a lot of noise. I put a new Cloyes True roller chain and gears in ( I rechecked that too) and installed a DUI dist. I thought the miss in the exh. was a pumped up lifter so I put new lifters in. Put it all together and it was quiet at the timing chain but it still missed at the right exh. I checked the fireing order and that was right, I changed plugs and wires and it still missed. Next I figured it MUST be a burnt or sticky valve so I tore it apart again and had a shop touch up the valves and seats but they did not do a full valve job (valve guides and seals.) Put it back together again and it still missed. Next I put the old Delco dist. back in just for the fun of it and it still missed. I even went as far as to buy shorter pushrods to see if maybe the valves were not closing all the way. Not the problem, just got ticking rockers . I changed carbs. because a local shop thought that the right side was not getting fuel but that did nothing. The plugs look the same on both sides of the eng., comp is the same on all cyls.,I just pulled the intake off again tonight on the hunch that I might have a intake leak on the bottom side of the intake gasket on the right side, but it looks like it had a good seal. I also pulled the right head again because a friend of mine who builds engs. listened to it and said that it was a sticking valve due to loose valve guides. I'll send the head in Monday and hope he finds something. A couple questions: 1) When installing the intake, I used the supplied rubber seals for the ends of the manifold, could they be too thick and keeping me from getting a good seal against the heads??. Also, could I just use a bead of silicone on the ends like I do on all Chevy engs.?? 2) Is there a kind of sealer I could put on the metal intake gaskets to make sure I don't have a vac. leak on the inside of the gasket? I'm thinking of Three Bond Sealer which is what I use when I rebuild snowmobile engs. on the two case halves. ( can be used in direct contact with fuel) Thanks again for the input,!!!!

[jpflat2a]

well, you certainly are getting very personal with that :v6:
my thoughts:
lets define the "miss"
A) dead cylinder, miss all the time
B) dead cylinder, goes away off of idle
C) engine miss, popping out of exhaust pipe at idle, goes away off idle
D) engine miss, popping out of exhaust pipe, all the time

Your compression readings looked okay, but if you were having valve problems, cylinder leakage test should show varying results on suspect cylinder (s) as the valve reseats its self.
At idle, have you pulled the plug wires off, 1 at a time, to help identify the weak or missing cylinder?
The rubber end seals for the intake can't really be the cause; they can give trouble squeezing out and causing an oil leak, but that won't cause the miss. 3 bond should work okay, I have used Copper Coat (?) in the
past.
With all of the work you have performed, nothing has changed. I assume all the valve springs and keepers are okay; keepers not starting to pull through. blah blah blah
I would try and identify the cylinder that is missing; this would help in the diagnosis, rather than just a cylinder on the right side.
When I hear comments about "sides" of the :v6: missing, this usually indicates ignition problem: timing, distributor, wires, firing order etc.
Do you have a good ground for the HEI ?
Do you run headers? Any visual discoloration (pink, blue) on any of the tubes that might be a give away as to which cylinder might be burning leaner than the others?
When it returns to running stage, if no change, then thorough diagnostics are needed; this is not to say that you aren't already, I am just saying stand back and recheck everything. Keep us posted

[Patrick]

FWIW, the exhaust sounds different on the passenger side at idle on mine, almost like the cylinders don't fire properly or completely, or one is weak. Several others have stated the same. You couldn't tell the difference with single exhaust.

[Hippo393]

Hello Mike,
What type of plugs? Also, do you have a mechanic's stethoscope?

You can use a bead of silicone on the intake ends, but wait until you're sure you won't be going back in (it's like welding the intake on). Gotta make sure none of it gets in the valley, so I use the rubber seals and a dab of gas/oil resistant RTV in the corners where the intake meets the head.
Good luck and let us know what plugs you're using. :beer:

[MikeT]

I'm running headers, the odd thing is that all three cyl's on the right side act the same when I take one plug wire off at a time. There is some diff. in the way it runs when I take the wires off but it don't change the sound at the exh. The miss is at idle and at driving rpm, but seems somewhat better when the eng. is under load, but is still there. At around 3000-3800rpm the eng pops once in a while out the right exh. when I hold it at that rpm steady for a little while. The #6 cyl looks a little cleaner on the piston top and the exh is a little darker but the plugs look the same throughout the entire eng., and the valves look the same on all the cyls. on the right side. I do have a good ground on the HEI and great spark to all cyls. I have never heard of the right side sounding diff. than the left as Patrick said. Is this a common trait of this eng. I don't remember it sounding like this when I first got it. Thanks again. :?

[jpflat2a]

The :v6: will idle rough and shake at idle. Mine will pop out the pass side once in while; at about 3000 rpm, not driving, the ehgine will also pop out the right side; maybe unburned fuel detonating in the ex pipe; it runs perfect otherwise, no problem while driving or under load.
A quick story, but did happen to me and my :v6:
Shortly after installing the :v6: it rained one night. I still had the hole in the hood from the :hurrican: I had removed. I did not have a rubber sealing washer under the air cleaner wing nut. The next morning, I went to start the Jeep; the engine turned over once and hammered to a stop.
@#$#@$# What was that? I waited a minute or two, then tried to turn it over again; it ran but was running "funny". Lots of popping out the pipes, especially passenger side; I let it warm up and took for a drive, ran great, but there was a small knocking sound. At the time I didn't think anything of it.
Over the next year, I had noticed discoloration in the header tube coming off #6 cylinder and the popping was getting worse. Compression and leakage tests showed acceptable results. Carb work, ignition work, did nothing, same results.
On a fluke I removed the intake manifold, not knowing what I was looking for. I found a very small chip of piston skirt material, lying in the lifter galley; where did this come from?
As you stand there looking at your exposed lifter galley, try to imagine a piece of piston skirt the size of a penny lying there, waiting to be discovered.
Removing my oil pan revealed a real nice, bent, #6 conn rod. This had bent when the cylinder had water enter it through the wing nut for the air cleaner. The way the engine sits, and the way it was sitting in my driveway, the lowest point for the water to go. When I tried to start the engine, water doesn't compress and the rod bent; after starting the engine, the knock I heard was one of the crank counterweights hitting the piston skirt, becuase the piston is now lower in the cylinder bore from the bent rod, resulting in the fractured piston, and the piece somehow ended up in the lifter galley, quite a ricochet !
I have that rod and piston hanging above my work bench.
FWIW, I put about 3000 miles on that engine before I found this problem; it was annoying sounding, but not enough that I could pin it down.I know this won't help you, but I know what you are going through.

[James P. Enderwies]

I put about 3000 miles on that engine before I found this problem;



Jim: Ouch! I guess it just goes to show how tough these :v6: engines really are. :)

Mike T does have a courious one here. Any bets going on? My best guess is a weak valve spring--sloppy guide--something still wrong in the ignition.

Now, if this was my engine, it would be a cloged carb jet that I only discovered after completely rebuilding the engine! :rotflmao:

[jpflat2a]

I put about 3000 miles on that engine before I found this problem;



Jim: Ouch! I guess it just goes to show how tough these :v6: engines really are. :)

Mike T does have a courious one here. Any bets going on? My best guess is a weak valve spring--sloppy guide--something still wrong in the ignition.

Now, if this was my engine, it would be a cloged carb jet that I only discovered after completely rebuilding the engine! :rotflmao:

Jim: I think we have all " been there, done that" at one time or another

If I were betting I would say ignition/distributor problem, even though dist's have been swapped out; gotta be something there
no disrespect meant to MikeT, probs like this are tough to find

[Hippo393]

Mike what kind/type/size plugs are you running???

[MikeT]

Hippo393 asked what plugs I was running: I am currently using AUTOLITE 85's but have used Champion UJ12Y 's in the past. I do have a mechs. stethoscope and listened to about everything on that eng. relating to valves, exh. at the headder tube up by the heads, I even listened to the spark plugs fireing. Everything sounds the same on both sides of the eng. Tonight I just had to pull the valves out of that head before I send it in tommorow to get checked. I found the exh. valves moved very roughly in the guides and the valves were loose in the guides. The valves had rough spots on the stems. I'm hoping that the valves are binding in the guides when there is tension on them causing my problem. I just wish the guy I had clean up the valves and seats would have noticed the loose guides and just done a complete valve job right away. Guess he was just trying to save me a buck. After hearing Jims story I might just check that too!!! I've done everything else!! :roll: Thanks again. The way this is going you would think this was some kind of a test!! :)

[Bob]

Like Patrick mentioned, mine too sounds different on the passenger side; kinda like a miss. Mostly noticeable at idle. I've never done a compression test, but I might in the near future just for the heck of it. It has about 139,000 on it and I've wondered if this "newer" gas has eaten up the valve seats. It does seem to run good though.

[71CJDave]

Just wanted to add another :v6: that does the same thing. I just converted to HEI (Cape Conversions) over the weekend and the EXACT (to the word) symptoms you are describing have become apparent. I think think it has always been this way, but with the HEI smoothing everything else out so much, this "noise" really stands out.

[James P. Enderwies]

Dave: Weird. I have an HEI that was on there when I bought it. PO put it on about a year before that. I have none of these symptoms.

At a 600 rpm idle, it purrs like a syncopated kitten. :rotflmao:

[71CJDave]

yeah, at 600 rpm you can't hear it, but at about 1000 up through maybe 2000 it sounds like a half a miss, or like one cylinder is missing every other firing. If I pull wires there is an obvious miss on that cylinder, but when everything is hooked up, I get this thing we're talking about. More like a syncopated kitten with head-cold. :roll:

[James P. Enderwies]

Dave: Never noticed that either. Runs like a Swiss Watch at each RPM range.

Well, the only noise I hear is my header leak. :evil:

[soler]

I would replace the push rods. I had the same problems left side was dead, right side worked good, I replaced the pushrods and tweaked the carb. Ran like a top. Pushrods are cheap too.

[Southtowns27]

I read that you swapped the old dist back in... Did it run correctly with the old dist or did it have a similar problem? I once had the EXACT same symptoms that you do...turns out that I had put an evenfire dist in it accidentally. The left side of the engine ran nice, but the right side had cool exhaust and just didn't sound right. It kinda sounded like it was blowing air out the exhaust...hard to describe. It also popped and backfired quite a bit. It took me awhile to figure it out. I put a different dist back in it, not knowing there was a difference between even and oddfire, and got lucky...it ran good again.

[jpflat2a]

...turns out that I had put an evenfire dist in it accidentally. The left side of the engine ran nice, but the right side had cool exhaust and just didn't sound right.

This is the point I was trying to make earlier; whenever I hear that one bank is fine and the other is acting up, this usually points to the distibutor.

MikeT: although you have found some obvious wear/problem with the valves and valve guides on the problem side, what are the odds that the wear you found is only present on the one cylinder head ? Logic would dictate both heads would have the same amount of wear and mileage. It would seem strange that just the 3 cylinders on the one head are bad.
Of course, I am assuming that both heads would have been done at the same time. Are you going to pull the other head as well?

Not trying to be a smarty pants, just trying to do an e-fix and think this through

[MikeT]

Jim, both heads are in getting done now. The eng. is a rebuild with about 3000 mi. on it. It was done by Gopher Eng. rebuilders but was a short block. Looks like the PO just put the old heads back on without having the heads done. Southtowns27 asked if it ran better with the stock dist. back in it, it ran the same as it does now. I agree with you Jim, all 3 cyls. on one side not working right is odd. And running cool on one side don't make any sense either. I am doing the heads partly because they were not done at the time of the rebuild and trying to eliminate one more thing. I did change pushrods but nothing changed. Still thinking. Thanks for the info.

[Patrick]

it's like welding the intake on).

HUH??????????

[James P. Enderwies]

it's like welding the intake on).

HUH??????????

Patrick: I've heard that too. But it is something I will NEVER expierence, since I will NEVER use RTV on any oil area in ANY engine. Hippo's use is just fine. For the rubber seal, I use Permatex High Tack, 3M Super Weatherstrip Seal or a new product that Permatex has called "Super High Tack"--it's like a gasket formula of 3M's stuff.

I know a whole lot of people use RTV for that application and get away with it fine. But, I think I mentioned this before, I've seen 2 siezed engines from cloged oil passages with small bits of RTV. :(

[MikeT]

I guess I need a little schooling on the diff of an ODD fire eng and a EVEN fire eng. I would assume there is a diff. in fireing order. When I look at the inside of my dist. cap on the HEI the cap looks like it is for an 8 cyl. eng but only uses 6 terminals., but the terminals are not evenly spaced. How does this work? Maybe a better understanding of this concept will help me solve this problem. The old point type dist. cap had evenly spaced terminals, I can understand that.

[Mcruff]

Oddfire has nothing to do with the order of the firing sequence both evenfire and oddfire use the same order, when you look at an evenfire crankshaft there are 6 different rod journals, an Oddfire motor has only 3, each set of opposing rods are tied to the same journal just like a v8 engine, a 90* v6 is the only oddfire motor really that is out there, a 60* v6 is a perfect firing motor just like any 90* v8. The problem with the Dauntless v6 is that it is a 90* block which means when one cylinder comes up and fires when the opposing cylinder in the firing order comes up to fire it is out of sequence on the ignition due to the fact that 360* /6 = 60* and (not 90* like the block), that the engine has just turned to bring the piston to the top of the bore to fire, thus the ignition point of the distributor needs to be altered so that the ignition can turn back 30*, the engine actually fires at 90*/150*/90*/150*90*/150* instead of a normal 90*/180*/90/180*/90*/180*. Your original distributor contacts were evenly spaced but if you will look at you rotor you will notice that the tip that contacts the spark plug tower was hooked by so many degrees, that way one cylinder would fire with the straight side (90*)of the rotor tip and the other would fire on the hooked end (150*) of the rotor tip alternating back and forth to make the engine fire properly.

Hope this helps!

[Warloch]

MikeT - the following link helped my son get it figured out.

http://home.off-road.com/~merls_garage/oddfire.html

:stout:

[MikeT]

Mcruff,
Thanks for the explanation, now I think I understand the concept. It also explains the hook on the old rotor.

[jpflat2a]

Mike, if you look inside your HEI dist, I think your rotor should look normal and the cap itself should have the "hooks" inside
might be worth checking

[MikeT]

Warlock, The site you recomended was great, lots of info. After reading the explaination on how to install the HEI I think that I might have put it in 1 terminal off. I will have to look when I get time but I think when I put the dist. in I was paying attention to making room for the vac. adv. and then just lined up the rotor with the closest terminal useing it for #1 because the eng. was at #1 TDC. I did not understand that there were even and odd terminals on the dist. Now that I read the article, I think I know how to set it up. Thanks for the help everone.!!

[James P. Enderwies]

Mike T: Merls article, along with this one http://www.jeepster.org/swchapter/hei-2.html
are on the reference areas of this Board. You just got to do a little searching for them among the Web Links, Tech References and V6 References.

Also try www.capeconversions.com for excellent instructions.

[71CJDave]

Ok, so soler recommended replacing pushrods... I wouldn't be opposed to trying that. Should all 12 pushrods be replaced at the same time? All on 6 one side? Pull them out and look for a single bent one? Anybody know where to get the cheapest/best? Any recommended part #?

[jpflat2a]

71CJDave; sorry, but can you tell us again what problems your having
2 troubles in 1 post, gets confusing
hey, at least we are on topic

[MikeT]

Dave, The pushrods I used are Federal Mogul/ Sealed Power part # RP-3173. I got them from Carquest. $ 1.90 ea. If you're going to replace one on a side, replace them all on that side.

[71CJDave]

jpflat2a - same trouble different guy! Sorry to confuse...didn't intend to hijack... :shock: :D

MikeT - that's the answer I was looking for, I'm going to start there...thanks!

[jpflat2a]

just can't believe that push rods are the problem
how would push rods on one side of an engine, be different than or worn more than the other side, engine history being known?
a bent one, maybe, but not all of them be bad

[71CJDave]

On mine, I don't know much history... I haven't gone nearly to the extent of testing and experimanting that MikeT has, but the symptoms that he describes are right on the money! Is there no reason to believe that a single pushrod is bent? I figured it would be worth a try...seems like a fairly inexpensive place to start. Can you tell by looking, or rolling on a flat surface, if a pushrod is bent? Would it be worth just taking them out to have a look before picking up new ones? I'm here for the thoughts of others though, so let me have it!

[jpflat2a]

yes you can roll them on a flat surface
and if you don't know very much history on the engine, then anything is possible
but once again, when did the problem start, before or after the dist swap out
I am kind of a back to basics guy, in case you couldn't tell

[71CJDave]

I like the basics...I'm all about keeping things simple.

I believe the problem has been there all along, it just wasn't so obvious prior to the conversion. There was much more popping and cackling prior to the HEI and now that everything else is smoothed out and quieter, this "half-miss" has become fairly obvious.

I also have a 500 CFM Edelbrock carb that could probably use a rejetting. Any thoughts there?

[jpflat2a]

rather than guess, here are my thoughts; back to basics
A shop with a scope can check primary and secondary ignition components and patterns; this should eliminate the ignition system, plugs, wires, etc (other than even fire dist in an odd fire engine)
do you have the ballast resistor bypassed and full 12V at HEI dist?
have you done compression and leakage tests on all cylinders? this checks the valves and rings for problems; if so, what were the results?
have you hooked up a vacuum gauge?; what is the vac at idle?
an exhaust analyzer would tell us too rich/too lean and /or possible carb problems
these are the basics and where I would start; I don't know how much of this you have already performed
guessing is good I suppose if you can afford it :D
I will say this again: anytime only one bank or side of the engine is affected, I lean towards the distributor
my 0.2 worth

[71CJDave]

hmmm... I will take a look at this list and work on it...thanks for your thoughts!

[71CJDave]

OK, I'm bringing it up again. I think I have it narrowed to the distributor, but I want your thoughts before I call Cape Conversions. I was right about "half a miss" I clipped my timing light on to all 6 plug wires just to be sure they were firing and cylinders 4 and 6 are skipping every few sparks, but doing so irradically. 6 does it more than 4.

By all visual indications suggested by Rich Motts, this is indeed an odd-fire distributor.
I am not 180 out.
I don't think the "primary sequence" is off as it still runs strong (maybe I'm wrong.)
I have a full 12+ V and a good ground at the coil.
I have swapped wires and plugs.
I have regapped plugs (.045)

Also, probably related in some manner, after the engine gets warmed up, it will not start. A check of the spark with the timing light indicates no spark at all! But, like I said, I have a full 12+ V and a good ground all the way to the coil.

Your thoughts please!!! :D

[jpflat2a]

Although the timimg light indicates voltage through the plug wire (or at least to the spot the timing light is attached), it does not mean that the spark plug is firing properly.

Other than that, everything I read in your post indicates to me distibutor problem.
Possibilities are still high: cap, rotor, coil, module, etc. The no-start condition when warm indicates this as well.
I know this is going to sound weird: I would try another known good distibutor, preferably points, for now. If you get the same results,............ I would be at a loss for words or ideas, other than wiring, batt cables, bad grounds, ign switch, etc
hth

edit: is there a way you can hook an external ground wire from the dist body to a good ground? maybe the o-ring or gasket is keeping the dist from being grounded properly; should ground through the clamp but ?

[71CJDave]

Yeah, I will try a totally independent ground to be sure, but when I was checking for 12V I was using the ground that connects right to the coil to be sure it was a good one.

I will write Cape Conversions and see if they have any ideas.

[msbweiland]

Is your dist a tooth off? Make sure it's dead on at TDC before you go too far. 8)

[James P. Enderwies]

I agree with Jim.

#1: Coil. When they get hot, they can die.

#2: Module. But when they go, they usually GO.

#3: Unseen crack or flaw in cap or rotor.

[71CJDave]

OK, remind me, how do we define "a tooth off." As long as the #1 cylinder is at TDC and I line up the rotor with the #1 terminal and can time it at 0 (before setting advance) I should be right on... correct?

[James P. Enderwies]

OK, remind me, how do we define "a tooth off." As long as the #1 cylinder is at TDC and I line up the rotor with the #1 terminal and can time it at 0 (before setting advance) I should be right on... correct?

That sounds about right. But remember you can be off by about 3/8" on the rotor to #1 alignment. Usually your advance is what accounts for that.

[Heimbig2]

MikeT- did you ever get your problem solved. I just replaced the stock distributor this weekend with the DUI one. Mine acts just like you described.

I tried to original point model and it did the same thing.

[66Tuxman]

Does the HEI really improve much in terms of engine performance? I have the stock distributor on my V6 and it runs like a champ, barely noticable shaking at idle and no popping really...well only once in a while. I see all you guys have converted to HEI but seem to be giving you guys some problems. Is it worth to upgrade to HEI?

[Patrick]

Does the HEI really improve much in terms of engine performance? I have the stock distributor on my V6 and it runs like a champ, barely noticable shaking at idle and no popping really...well only once in a while. I see all you guys have converted to HEI but seem to be giving you guys some problems. Is it worth to upgrade to HEI?
Yes, IMO, worth it. I'm using the Pertronix trigger and MSD Blaster coil, but I ran the HEI for a while. The only reason I went to the Pertronix, from HEI was just to try something different. I'd go back to HEI, but the setup I have now works well...

[Phalanxx]

was the distributor dropped or anything (maybe a contact got messed up?) when i installed hei onto my 231, my dad gave me 2 even fire dist. i didnt know the diff at the time and installed them. ran fine at idle, but died a horrid death when i gave it gas. i finally got the oddfire bought and installed and it finally got it all going. personally, i dont see how a carb can be the cause of just 1 cyl dying. if a bank or series of them (depending on intake design) was failing then i could see it being a bad side, but to only affect 1 cyl? odd for sure.
i have an oddfire 231 for sale..i am installing a buick 350 in a few months into mine and have the original t-14 behind it. all to be gone. headers, hei (bell housing stays tho.)
food for thought if someone wants it.