Need a little help with a problem. I put in a new roller cam kit into my 400 and it ate the distributor gear. The cam gear looks good still. I am trying to find what the cam core is. Is it steel or is it iron. I need to know so I can get the right dizzy gear. If any one has any suggestions I would really appreciate it.

I got the 270HR cam if that helps.

 

Call Comp Cams and ask.

A HV oil pump or improper dist gear installation can both cause a gear failure. Some distributors have had the drive gear installed to low on the shaft. When the distributor was clamped down this bound up the distributor shaft and produced high loads on the gear drive.

 

You also need to be sure you have correct dizzy gear. Bronze is the old standby for roller cams but there is a new composite gear that last a long time.

 

I have the retro kit in my 400 , used a bronze gear and it lasted about 1000 miles. called comp and they said their cam is austempered iron and that i can use a standard cast gear. Thats what i have in now and after 1500 miles all is welll. I pulled the distributor quite a few times after putting on the cast gear onto my msd distributor and its perfect. According to msd the distance from the underside of the dist housing to the underside of the gear where it rides on the block is 3.996-4.005 here is the link. Hope this helps


http://www.msdignition.com/pdf/gear_...d_frm22770.pdf

I should add that this applies to their -8 cams only. if your part number ends with a -8 then it will accept a cast gear.

 

Thanks folks, I do indeed have a HV oil pump, but this is the first time I've had this problem. Once I had the dist. out I turned it by hand and it felt like a ratchet. I'm thinking the dist. went bad and put extra load on it thuis wearing the gear. I took my old dist. to a local shop and the guy told me it looked like I had a cast gear so we ordered one with a steel gear. Did I make a mistake in ordering the steel geared dizzy? I don't want this to happen again.

Thanks for your input for this problem.

 

If you run a steel dist gear against a -8 cam the steel gear will eat the cam.Comp has a 1-800 line you can call and they will tell you if that eases your mind. gl

Heres an article from carcraft, i found when sorting out my own distributor gear dilemma

http://www.carcraft.com/techarticles/distributor_gears/

and this i found at msd's site

http://www.msdignition.com/forum/sho...stributor+gear

 

So what did you end up doing? Did you have to replace your cam?

 

As I was looking around the net I found mention of cutting a 030 groove in the distributor housing to get more oil to the cam and dizzy gear. Does anyone know anything about how to do this?

 

Well i think that the fact that i used a bronze gear in the start helped wear off any rough edges on the cam gear,purely luck. This is mentioned in the article i linked to,though i found the article after the fact. No i didnt have to replace my cam,but when the bronze MSD $50 gear wore out in only 1000 miles,(not to mention the $60 i paid to have the gear installed) i was more than a little upset. So then i started searching for an alternative to the MSD gear and thats when i learned that the cam was austempered and took a iron gear. Since then all has been well.


Quick question, did you use a new gear when you put he new cam in? I suspect also that your HV pump may have a part to play in this as mentioned above. Make sure you look really carefully at your cam before you go any further.

When i put he new gear in i used a liberal amout of moly paste that i use exclusively on all my flat tappet cams. Moly is an extremely high pressure lube and really stays where you put it. I would suggest you do the same and when you get it running again drive it right awasy so plenty of oil finds its way to the gear. As for the mod you mentioned it sounds like a good idea,i would think a small groove directly in line with the cam gear would suffice, definelty worth investigating.

On a side note i have seen it mentioned to mock up the disty before putting on the timing cover. Next build i do ,i will definetly be doin that . Hindsight is 20/20 lol

 

To answer the quick question, nope, I used the same gear that I had used with the old cam. Is is just a good idea to change the gear with each new cam install?

 

According to the article i linked , the msd gear is a bit harder than a stock gear.As for the question of should you replace the gear with a new cam thats a tough question. I installed engines for 6 yrs avg of 20 engines a month and never saw a failure. We had 6 installers full time and the whole time i was there i saw no gear failures. Not all cams we installed were stock either. If you think of all the time spent to set up a differential to get long life , you would wonder why we just dump a distributor in and call it good.
As i said i took no chances and had a freind at a precision machine shop install my gear to exact specs. Is it possible your original gear was maybe not in the best condition? Also when i asked about he dist gear i wasnt implying it should be a new one. More wondering if maybe you had put a new one and it was not set at the correct spec. Just punching out the pin and dropping a newgear on without checking its installed height could cause an incorrect contact between the cam and distributor. I would think a new gear would be good insurance.

 

Thanks for the input. I've never had a failure of a distributor gear before, so I am just picking the brains of those that may know more than I do about this stuff. I appreciate your help.

 

Please see our technical page regarding your situation:

http://www.performancedistributors.com/technical.htm