Help with 351W timing chain gears

[1973grandeklar]

I have a 1969 351W from a Mustang. It is the 4V version and everything is still OEM. So I go to change the timing gear set as the OEM an aluminum gear with plastic nylon teeth. Everything looks very good, but the plastic must be getting brittle and could crack.



I had a brand new Autozone OEM timing set for a 302. I checked and it is the same part number as the one for the 351W. I installed it, put the fuel pump eccentric on, then installed the timing cover. The timing cover hits the fuel pump eccentric and there is gap at the block. The gear hub is too thick.

So I go online and check out Summit Racing and Jegs for a double roller timing set. I try to be very careful and select a set specifically for a 1969 351W mustang motor. I get the new set and install it same issue.



I need help with the 1969 timing cam gear. The crankshaft gear matches perfectly. However, the top gear has a thicker center hub and when I mount the fuel pump eccentric onto the front, it hits the timing cover!

I measure the hub heights:

Original gear hub = 0.780"

roller gear hub = 0.931"

Autozone OEM gear = 0.930"

fuel pump eccentric = 0.937"

The original stack-up is 1.717"

The new gear stack-up is 1.868"

The timing cover clearance is 1.790"

That means the original gear had 0.073" of clearance.

The new gear has 0.071 of interference







How can I fix this? Is a new fuel pump eccentric thinner (currently I have a one piece design)? Can I machine the front face of new gear?

It appears that the distance from the gear face to the back hub is identical on all three. It is the front mounting face that is different on the three gears. The second picture is an edge shot of three gears lined up, you can see the taller center behind the original gear. I tried to take pictures and show the differences. I would prefer not to machine the gear, but I can if that is the only good option. Changing the cover is not a good option.

Here is the gears with a photo taken on edge. You can see it is the center hub on the fuel pump eccentric side. The cam side is the same on all three.

 

[jbojo]

A machine shop should be able to mill off the extra height (0.151) in the face of the gear. As long as the rear has the same spacing you should be fine. I had to mill the front of my timing gear to get a proper fit but mine is a 351C but that should not make a difference. The machine shop should be able to duplicate the overall thickness of the OEM to the new one. There may be a reason why this can't be done so someone else may chime in with why it can't be done. I am curious too.

thx

 

[c9zx]

This may help. http://www.compcams.com/Technical/Instructions/Files/179.pdfhttp://www.compcams.com/Technical/Instructions/Files/179.pdf

It sounds like the two piece eccentric is required, it is shorter I believe. It has been a long time so don't trust my memory, verify please. Chuck

 

[1973grandeklar]

This may help. http://www.compcams.com/Technical/Instructions/Files/179.pdfhttp://www.compcams.com/Technical/Instructions/Files/179.pdf

It sounds like the two piece eccentric is required, it is shorter I believe. It has been a long time so don't trust my memory, verify please. Chuck

Link does not seem to work, but I found that document. I think you are correct, I need the 2-piece eccentric. I also found by intensive internet searching (means I had to wad through a lot of crap), the one piece eccentric is thicker than the two peice eccentric. To use the two peice the gear has to have a mounting pad, which the roller gear has, so the inner part will secure it to the cam and the outer ring will rotate freely. I also have to put in a shorter dowel as the two piece has a finger tang that locates in the dowel hole and must not hit the dowel. If the dowel is too long, the eccentric will not mount flush to the cam.

I ordered a two piece eccentric and should get that before the weekend (if the one day expected delivery is correct).

 

[Jeff73Mach1]

I haven't had a Windsor motor apart in over 20 years, so I'm not likely to be much help.

The 2 piece eccentric is preferred for reducing friction, but the one piece may be more durable.

The oil slinger you have mounted in front of the crank gear may cause some interference with the front cover-if it does, it is not necessary and can be left out of the assembly.

Elgin and Cloyes both make timing chain sets that would probably be a more direct fit and are probably under 50 bucks-if you can't swap your current set, then you can compare that to the cost of machining.

 

[Don C]

This may help. http://www.compcams.com/Technical/Instructions/Files/179.pdfhttp://www.compcams.com/Technical/Instructions/Files/179.pdf

It sounds like the two piece eccentric is required, it is shorter I believe. It has been a long time so don't trust my memory, verify please. Chuck

+1, the 2 piece should solve the problem.

 

[jbojo]

I just looked at the comp cam site and there are two gears available for the 351W. They made a change over in 1972. Comp Cam #3220 appears to have a flat face that is what you need. Cost is $29.86 for the set. Their part #3230 has the raised front which appears to be what your new part has.

Here is the link to probably what you need:

http://www.compperformancegroupstores.com/store/merchant.mvc?Screen=PROD&Store_Code=CC&Product_Code=3220&Category_Code=

 

[1973grandeklar]

Got it installed correctly!

The two piece eccentric is thinner:

It measures 0.690" combined with the thicker hub height, this easily clears the timing cover. the timing gear has a mounting pad that the center part of the eccentric mounts to. The outer part of the eccentric freely spins underneath the inner ring and the gear. It specifically fits over the mounting pad (I know most know this, but for reference to anyone searching for this same issue).

The roller timing chain and the new eccentric are now on the motor.

 

[c9zx]

Got it installed correctly!

The two piece eccentric is thinner:

It measures 0.690" combined with the thicker hub height, this easily clears the timing cover. the timing gear has a mounting pad that the center part of the eccentric mounts to. The outer part of the eccentric freely spins underneath the inner ring and the gear. It specifically fits over the mounting pad (I know most know this, but for reference to anyone searching for this same issue).

The roller timing chain and the new eccentric are now on the motor.

I'm glad you got the problem solved. Chuck