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penbroke
06-15-2004, 07:48 AM
I am in the process of changing the timing chain in my '67 289 HyPo Cobra engine. On the old setup there is an "oil slinger" paddle looking thing on the crank sprocket. The new double roller chain set does not have this and will not accomodate it. My parts guy says the roller chain does not need the extra oiling. Is this true? Any ideas?

Thanks,
Frank

penbroke
06-15-2004, 12:19 PM
Upon closer examination this appears to be a balance weight of some type??? NO timing chain set I have found has any accomodation for this. Anybody know anything??

Thanks,
Frank

penbroke
06-15-2004, 08:35 PM
Talked to an old Ford guy today. He said it is a Shelby thing. The motor has heavier rods and short skirt pistions. This weight and a special flywheel were used to improve balance. Seems to make sense.

I would still be interested if anybody has any input.

Is there any way to tell how the flywheel should be mounted? I marked it when I took it off but would like to verify that it is in the correct position.

Thanks,
Frank

Rootsy
06-15-2004, 08:47 PM
the flywheel should only go on one way... either by a dowel or by the bolt pattern... try it.. put it on and rotate it on the crankshaft... it'll only line up one way...

as far as that slinger piece... that is a first for me... nooo clue...

why not try one of the many shelby sites and forums out there??? maybe they can help ya

MOP
06-15-2004, 08:55 PM
Frank the most I have seen had one flywheel bolt slightly moved over on the pattern so it could only go back on the correct way. You can check by measuring the centers you should have one out of line or just stick it on and rotate it slowly to align the bolt holes.

Phil

penbroke
06-15-2004, 09:03 PM
There is a hole for a dowel in the crank but no hole for it in the flywheel. There is a small drill mark on the back face of the flywheel that would be "up" with the crank at #1 TDC.

There is also some extra material in the flywheel casting about the same size and shape as the weight behind the timing chain that would be positioned about 180 from the weight in the front.

I won't say I've hit em all but I have been looking at the mustang sites and haven't seen anything like this...

Frank
I love mysteries when they're not mine.

mphatc
06-15-2004, 09:12 PM
Penbroke,

The flywheel pattern only allows one position for fitment, just went thru this as I needed to fab a special spacer for my set up. You can't get it installed wrong ! :yes: Remember to replace your flywheel bolts with new ones, and seal them on install with red loctite.

as for the "counterweight"on the lower chain sprocket . . .

go back to an original style chain, EXCEPT use the solid metal upper sprocket, and don't use the roller chain set up.

As this weight is mounted to the crank it acts as a balancing force. Retain it! Not using a roller chain is not a bad thing. The original style chain will work fine as long as you don't use the plastic covered sprocket.

Mario L.

penbroke
06-15-2004, 09:21 PM
As always, you guys are correct! I just went out and measured and there is a subtle difference in the bolt spacing.

My plan was to keep the weight and lower sprocket and replace the chain and upper sprocket as Mario suggested. Picked up the parts today.

I can't begin to tell you how many "experts" said if it didn't come with the new timing set you don't need it. This is why I do my own work.

Many thanks
Frank

rayjay
06-17-2004, 08:52 AM
My plan was to keep the weight and lower sprocket and replace the chain and upper sprocket as Mario suggested. Picked up the parts today. - Many thanks Frank

Took me a bit to remember what this piece was for. All my 289's were balanced internally and I did not have any external balancing pieces. A conversation with Phil last night started jogging my memory. Have you buttoned up everything yet? If you did, did you check the play of the chain on the old lower counterweighted sprocket that you are going to re-use? If the sprocket was worn it will quickly wear the chain and upper sprocket to the same level of wear.

Unfortunately the only easy fix is to have the new lower sprocket re-balanced to match your old counterweighted sprocket. A good engine balancer should be able to take care of this, but for a price. I used to have to go through this, but the opposite of what you need to do. I had to have everything like the flywheel un-imbalanced.

You might also try a Shelby restoration shop such as Delta Bay for a replacement piece that has the bob weight.

Delta Bay Mustang (http://www.deltabaymustang.com/high.htm)

rayjay

rayjay
06-17-2004, 09:05 AM
As a "PS" to this, was there a spacer behind the cam sprocket to align it with the lower sprocket after the bob weight was mounted to the crank? Or was the lower sprocket machined to allow for this? Can you have a new lower sprocket machined the same way or a spacer made for the upper (cam) sprocket so you can run a complete new set?

rayjay :idea:

penbroke
06-17-2004, 09:20 AM
The lower sprocket is machined to allow for the weight and there is a roll pin in it to position the weight as the key in the crank does not go back far enough to catch the weight. The old sprocket is in good shape so I will use it for now and machine the new one for next time.

Frank