Vibrations

[Belgium R/T -68]

Here we go again, it seems like my GTX is nothing but problems. Newbuild engine, 440 build to standard -69 spec but between 12  -2000 rpm in P or N the whole car vibrates.
That can't be normal and ofcourse I feel it also when I drive. Poor throttlerespons, no burnouts, simply said not a 440 I recognice. I have tried ignition and carb, looking for vacuumleaks
but start to think it's something inside. Anybody have any suggestions? 

//Per

[aifilaw]

It will do that with a bad miss, or a bad couple of misses, or an improperly balanced engine.
Find out if the balance was done, externally as well.

After that pull a valve cover, make sure your valves are all operating properly across the board.
Check that you have good spark to all your cylinders... et cetera.

[Belgium R/T -68]

What I have found out from previous omner is that internal balancing should have been done, external propably not. Timingchain was wrongly mounted, wrong zero used.
Converter is a Mopar standard, new, maybe that one? I connect this to another thread I have concerning the resonance sound I have from the exhaust. 

//Per

[aifilaw]

From what you told me, without knowing anything else, see if you can find a machine shop that will balance just the converter and harmonic balancer, and get those zero-balanced.
If the engine was internally balanced and they just slapped on something, then you may have a problem, but its doubtful since a converter and harmonic balancer are usually zero-balanced from the factory... unless they stole some off of an engine that was fully externally balanced.

Check and make sure you don't have any engine issues, like missing from one of the causes of that.
If it checks out, I would definitely be a proponent of pulling the engine, taking out the bottom end and having the whole thing fully balanced, then put it together with new seals/gaskets.
It will give you a chance to upgrade or fix anything they screwed up. Knowledge of your engine, and if you are just replacing gaskets rings and seals then you should only be out around $600 for the entire job.

[Belgium R/T -68]

Well, for my charger project I have everything new for the same driveline so I could maybe swap piece by piece before I open the engine! One thing that came to mind was
if the sparkcables could be an issue? They are "new" datecoded originals .  Engine runs otherwise very good, no missfires or anything, just kind of lazy.

//Per

[aifilaw]

I would guess you have a balance issue then

[Belgium R/T -68]

OK, will start with putting on the damper I bought for the Charger then. Summit artnr SUM-C4279. According to description it's zerobalanced like you mentioned.

//Per

[aifilaw]

I gotta say though, loss of power like you first mentioned still points to a miss, or a hard to diagnose miss, aka clogged fuel delivery, ignition doing hit and miss...

[Belgium R/T -68]

Agree, talked to the previous owner, he said the machineshop (supplier to Jegs) included damper and converter in the balancing job.
When turning the distributor I can almost get the vibrations dissapear but then the car isn't driveable.

//Per

[aifilaw]

Do a search on carb tuning, and timing tuning.
I believe there's a thread out two by chryco about how to tune a carberator from A to Z. I've posted how to recurve and set the timing on a distributer before, Sounds like both will need to be done, but timing first.

Because they are so cheap here, I just go straight to the dyno shop and pay for an hour or two and do my tuning there. Most places they are expensive though, so you will have to use the tools and know-how from the threads you can find in a search to get you very close.

[GreenMachine]

   Start with easiest possibilities first. A balance issue won't make your engine lazy. From my experience, lazy performance and shakes/vibrations would be an issue with distributor, plug wires, or plugs. Check that the spark plug wires are routed correctly, If so, I would get a new set and put them on for troubleshooting purposes. It never hurts having an extra set laying around.
  Also, if it is electronic ignition, check the 2 wires from the distributor. If they have been hooked up backwards, it will run very sluggish. The plug will only go on one way, but check the whole harness and make sure the wires haven't been spliced.

[Belgium R/T -68]

Thanks all, will do some tests tomorrow. Now it's sleeping time in Europe!

//Per

[Belgium R/T -68]

Could this be a contributing issue? Doesn't look like the sparks I normally use, also note the misformed washer. Could this be from the period when the timinggear was
3 gears wrong? The wrong zero on the crankgear was used.

//Per

[aifilaw]

Could this be a contributing issue? Doesn't look like the sparks I normally use, also note the misformed washer. Could this be from the period when the timinggear was
3 gears wrong? The wrong zero on the crankgear was used.

//Per

If the plug wasn't in there all the way, then yes...
If its a different sized washer and for some reason has some spring retention to it, as long as it was in the plug hole firmly then all is well. "keying" spark plugs is a way of eaking that last little 1 or 2 hp out of an engine by ensuring the spark plugs ground lead is perpendicular and between the valves, but its very rare.

[Belgium R/T -68]

With keying you mean that there is no cheramic around the electrode like on the new one here?

[Belgium R/T -68]

Learned it's a platinum model, it's a Bosch R6 971 WR 9FP. Would that be the correct ones for a -69 440?

//Per

[Belgium R/T -68]

Anybody knows of a referencetable from Bosch to check if the sparks are correct?

//Per

[Belgium R/T -68]

Meassured the compression, cylinder 3 gave 130 Psi and the others between 165 and 185 Psi. A valve that doesn't seal? 

[aifilaw]

Meassured the compression, cylinder 3 gave 130 Psi and the others between 165 and 185 Psi. A valve that doesn't seal? 

that's one of the options, check your two valves on that cylinder for true lift and full closing. If not, its time to pull the head and redo the cylinder wall and rings.

[Belgium R/T -68]

Do you mean it could be a wrongly honed cylinderbore? Engine has only 500 miles. 

[aifilaw]

a poor job honing usually results in an improper or bad seating of the rings, which results in loss of compression.
presuming that is in fact that cause, don't stress over it, just pop it open and have a look, maybe you have a bad head gasket, or a stuck valve, or a bad valve guide or seat.

[Belgium R/T -68]

Can a wrong breaking in of the cam cause lower compression?

//Per

[aifilaw]

worst thing tha tcan happen regarding the cam in breakin is it gets worn down, which means valves don't open, most of the time this doesn't affect the compression test reading, it only shows up when you look at your lift at the valve and notice its not moving at all, or much less than another valve.
But it is possible for the intake to not be opening properly and thus nto have enough air to compress and give you a bad/lower reading.

[Steve P.]

I would start with trying to narrow it down. Start her up in PARK. raise the idle till it just starts to shake and then pull one plug wire at a time. This will give you either THE cylinder that has the trouble or wire, plug, cap.  Another test that jumps out at me is a bad coil.. Or improper ground..

Are you using a vacuum advance distributor?? If yes, remove and plug the vac. port to see what changes you get..

[firefighter3931]

Meassured the compression, cylinder 3 gave 130 Psi and the others between 165 and 185 Psi. A valve that doesn't seal? 

PER,

Run a wet compression test on that cylinder and post the results. To do a wet test you need to squirt some oil in the sparkplug hole. If the comp stays the same it's a bad head gasket or valve issue. If the number increases the problem is with ring seal. If the engine was broken in with synthetic lube the rings might not even be seated up yet.


As for the rough running and vibration issues it could be just a matter of tuning the engine....advance curve/jetting etc...

Disconnect the vacuum advance and try advancing the timing to see if it smooths out. Get a vacuum guage on it and record the idle vacuum reading. You could have crossed plug wires or one that is dead.


On an iron head 440 i like the NGK xr5 plugs. 



Ron