200 out of balance??

A

Anonymous

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Hi guys,
I am new to this board and hope I can find some help here. I have a 66 mustang coupe with a 200-6 with a manual 3 speed and the engine feels out of balance @ 1500 rpm. ( free rev ) It is very smooth above and below that rpm and running well . The engine has never been apart and it still has the original clutch and flywheel. I have read that these engines run very smooth so I was wondering if my flywheel and/or clutch assy. may be out of balance. I believe these are neutral balanced engines...correct??Thanks in advance, Dave
 
If it were a mechanical balance problem, you would feel it at all rpm. I would suspect a misfiring cylinder since the problem is only at a specific point. Pull the plugs and inspect them, maybe do a compression test at the same time.
 
Having run a 302 before (sorry guys) with the wrong balance, I agree with Jack. A mechanically out of balance motor starts out vibrationally rough and gets exponentially WORSE as you increase RPM. I would guess a spark misfire if it's minor, possible a carb transition problem if all cylinders seem affected.
 
Thanx guys, I will verify that the balancer is accurate. It may be a lean condition (misfire) but what seems puzzling is that as it winds down from a rev (throttle closed) it will vibrate badly as it passes 1500 rpm too. It shakes the seats, dash, steering wheel etc. It idles smooth as glass and runs good with no bog or flat spots. I just got the car so I don't know if it's been like this from day one or not. It feels like something is about to come loose.
 
It turned out to be the flywheel. It was out 28 grams and is smooth as glass now. I was wondering why the flywheel has to be"clocked" if it is a zero balance? I wish my 01 mustang was as easy to work on as my 66...lol!
 
Junk-Falcon":1t1asmcx said:
the first thing i would ck is the damper up front and make shure its sayes top center right , i have seen a cpl of them slip n be off by a few deg

charlie
Click to expand...

So a 200 isn't internally balanced???
 
Cal Cobra":c3s66ce7 said:
It turned out to be the flywheel. It was out 28 grams and is smooth as glass now. I was wondering why the flywheel has to be"clocked" if it is a zero balance? I wish my 01 mustang was as easy to work on as my 66...lol!
Click to expand...


Ah, Detriot Unbalance. Firstly, what it is.This is the means that V8 makers reduced the weight cost of running a fully internally balanced crank. There are quite a few pounds to save, and when Ford made the first 221/260/289 engines in 1962, they saved a few million in keeping the engine in the 450 to 470 pound area, 90 pounds less than the Chevy small block. All becasue of this unblance. I understand It wasn't until the Romeo 4.6 engines that they were able to run fully internally balanced engines.

Why the clocking?
The reason is two fold.

1. All sixes run a V8-style 1.375" flywheel pilot, with one of the six bolts offset. The first Windosr V8's run unbalance factors of 28 or, laterly, 50 ounces, and were clocked to ensure no turkey ever got the flywheel wrong. The clocking has existed since the first 144, even though no inlinner has ever run a Detriot Unbalance.

2. The clocking allows the top dead centre to be found when machining things. It's a simple indexing tool.
 
Inline sixes are internally balanced. A six flywheel is clocked, but is still zero imbalance. Antoher reason to clock a flexplate or flywheel is to prevent you from installing it backward.

I don't know how you could have developed an imbalance like that unless you lost a bolt or a tooth.
 
Thanks for the explanation,xtaxi. Mustang Six, I didn't develop the imbalance, as far as I can tell from the previous owner it has always been like that.
 
The term 'clocked' is a new one on me.

In my simple English, and in my opinion, it is when the engineer ensures that someting ins only installed one way.

With all the Windsor and Cleveland made engines, weather six or vee-eight, one out of six of the cranksahft bolts is purposely miss-aligned, by a degree or so. That means you can only install it one way. The flywheel or flexplate is 'indexed' to fall only in one postion...where Ford intended it to be!
 
Indexing is probably a better term than clocked in this case. Anyway, with a zero balance I couldn't figure out why it had to be indexed. I was surprised how much 28 grams affected the balance.
 
Our local Napa machine shop was able to balance it on their crankshaft balancer.
 
It was the flywheel only. I don't know what adaptors he used to attatch it to the machine.
 
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