Distributor drive gear on a Windsor engine

[Wayne]

Last Sunday following a Show & Shine in Ballina in NSW Australia, my GT40 came to an abrupt stop while in the process of passing a number of trucks.
We were in a convoy with a number of GT40'S and Cobras and luckly I was able to cut back onto the side of the road without mishap.

The first things to check was for spark and fuel.. Fuel was ok but no spark. Removed the Distributor cap and with the starter motor turning the distributor rotor was not.

I have S/B Windsor with EFI - Built my own engine with heaps of advise from all the so called experts in the land. It has completed just over 3000 Kms

Billet camshaft with EFI you need a bronze gear drive on your distributor. Sounds good and thats what I fitted. Not sure if I mentioned that I was fitting a high flow oil Pump, but no one asked.

The bronze gear had worn the lobes to a sharp point, weakening and stripping the gear.

Talking to the Ford Performance guys they smiled and said this was a common mistake made by people not in the know. --- ME ---Cost $$$$$

There is a steel alloy gear listed in the Ford Performance Parts suitably made for my type of engine build

This weekend my engine comes out and the clean up and removal of all those little fillings will have to be made.

Hope this helps no one else makes the same mistake.

I still wonder if a high volume oil pump is necessary??

Thanks to the guys who stopped and offered to assist. I drive an RF GT40 and the two guys who stopped to console me drive DRB Gt40s.

Wayne

 

[Jac Mac]

How far the bronze particles have travelled thru your oiling system will depend on how good your oil filter paper was & also in the bypass area. If you remove & check the Number 1 and 8 rod bearing caps you should get an indication of how much & how far it has travelled ( these two bearings being @ each end of the gallery & being individually fed from the front & rear main brgs tend to get the major share of debris in this sort of situation)

My own thoughts would be ditch the Hi Vo pump, but I dont know what clearances you have used in your engine build.

Jac Mac

 

[Scott]

I would ditch the pump and go back to a good stock pump unless you are spending a lot of time on the track. You could always dry sump it and remove the load on the disti gear completely.

 

[Wayne]

Thanks for the reply and will check all the bearings.
Whats your thoughts on the steel gear?

 

[Sandy]

I just saw the same warning on the Crower site -

"Warning: If 8620 steel billet cam core, bronze gear is mandatory. If
cast iron cam or cast iron gear, Crower recommends factory gear.
Crower does not recommend high volume oil pumps when running
aluminum/bronze distributor gears."

I also recall for some reason that some Hydro-roller had the an iron cam side gears and they did not require the bronze.

The high volume pump and bronze gear story is news to me. Now I will wait for the failure but my saving grace might be that the engine is getting loose and the extra oil is just squirting in the pan...

Sandy

 

[Jac Mac]

Thanks for the reply and will check all the bearings.
Whats your thoughts on the steel gear?

If you have your Roller cam ground on a 'Ford' blank core then use the designated 'Ford' distributer gear with this . Where using an aftermarket Steel Billet cam use the gear recommended by that manufacturer and make sure you tell them that you are using wet sump etc. There are some characters out there trying to sell dizzy gears that are made from the wrong type of bronze so stick to the well known brands.

Comp Cams for example are now making Steel roller cams where the gear & rear /front journal are made from different material and pressed onto the camshaft after heat treat etc. They also make a 'Carbon ultra poly composite Distributor gear for Ford-Chevy application which is supposed to be the answer to all these problems - I have not tried one of these yet, maybe someone else has.

Jac Mac

 

[Sandy]

I saw the 'plastic' gears but I would definitly want to let someone else run them for a while, seems just a little scary, but who knows might be the next thing since sliced bread.

Sandy

 

[Ron Earp]

I've got one in my motor, I'll let you know how it turns out.

R

 

[David Briggs]

I run the steel Ford gear on the Crower Hydralic roller cams in both my Tiger and the GT 40, I used a high volume pump in the Tiger build and it did wear a steel gear to the point of causing the timing to be erratic, in the GT I used a stock, blue printed pump, no problems.

 

[Jim]

I found this, hope it may help.
Cobra Lads - building a JBL ford 427 shelby cobra kitcar: Why SB Ford Distributor Gears Fail

 

Excellant find Jim.Very interesting article.I think we all learned something today.

 

[Ron Earp]

I agree, thanks for posting that. Mine is tight and it was already on my list of things to look at because it seemed odd. It was set at what the tag had on it which is in that article. When I went to put the dizzy in and lock it down it wouldn't seat in the block well, and, if you tried to make it seat it'd require a lot of force. Good stuff.

Ron

 

[Wayne]

Jim Thanks for your contribution
I reassembled the old broken gear to the distributor shaft and with four teeth still in place I reinserted the distributor and engaged the camshaft.
With the clamp is in place there is a feeling of resistance or slight binding.
A shim would have probably eleviated my problem

I have the new steel gear and will drill the locating hole for the roll pin tomorrow and carry out more tests

Wayne

 

[Lynn Larsen]

I am glad this was brought up as well. All along, I thought the only issue was with mismatching the material (hardness of the metals) of the cam shaft with the distributor gear. I have an MSD also, so you can bet I'll be checking it closely.

Thanks again to everyone!

 

[Jac Mac]

One way of checking this critical dimension is to fit & clamp your distributor in place in a bare cylinder block and verify that you can measure vertical clearance between the gear thrust face & block ( 0.015" approx ) by lifting the shaft with pliers and also the gear thrust face should contact the block with light downward pressure ( 0.000" ). Now measure the distance in the block from the recess that the dist clamping ring sets on to the thrust face the gear runs against with a set of vernier calipers and compare it to the cyl block in your car ( they should be the same, if they are not you may have to configure your dist to 'your' block only ).

If you perform this vital step at engine build time & every time you swap/ borrow a distributor you can eliminate this particular cause.

Jac Mac

 

[Sandy]

I found this, hope it may help.
Cobra Lads - building a JBL ford 427 shelby cobra kitcar: Why SB Ford Distributor Gears Fail

He is an interesting cat, day trader, cobra builder, etc. I have watch the build of his Cobra for a long time and he has had some bad things happen to a couple of engines (oil lines backwards on external filter), but has some interesting things he did to the motor and build of his car. Not sure how much of it really worked but dig to the older articles and you will find some interesting photos and entertaining stories from the 'Butcher'.

Sandy

 

[Wayne]

Jac Mac
The filter has held all the bronze as the bearings showed no signs of any gold particles. Cut open the filter and YES! There they were.
Draining the sump into a round container and them swirling the oil, showed me there was a small present of goldern particles sitting at the bottom of the sump.
I have fitted the steel gear and shimed the distributor.

Ran out of time to kick it over today but hope to during the week.

I did contact my camshaft manufacturer "Crow Cams" and he is aware of these problems with the distributor drive gear. A comment he made "was I using a certain brand of oil" and yes I was.

This oil is very well known in the competition engine fraternity.
He commented that a majority of distributor gear failures occured with this brand of oil.

Interesting or a coincidence?

I will be changing brands

 

What brand?

 

[chuck smith]

I would think a thinner synthetic oil with a lot of zinc in it would be best to prevent gear wear--Royal purple,Red Line,ect maybe 5w-40

 

I know they are taking the zinc out of reg. car oils,does anybody know if they are doing it to synthetics to?