New distributor gear from Comp Cams

[fxbill]

After voicing a concerned opinion to Comp Cams about abnormal distributor gear wear with the last two cams from them I was told about a new gear made by them that is claimed to last as much as 100,000 miles with no significant wear. Although I felt the staggering $100 cost was more than I wanted to pay I purchased one anyway...( tired of having to pull the distributor every 1,000 miles to see how soon I'd need the next gear..).
It arrived today...along with my new cam. WOW... What a shock.... It's PLASTIC!!!..A composite, but plastic, nevertheless. ( guess you don't heat this one to press it on..... )
The cam gear is also different than the past two cams. No more razor edges... they've been factory smoothed out and are actually a bit rounded on the edges. Sure hope this setup lasts....

[Jack21]

I hope so too, because I'm about to spring for the same expensive plastic gear for the same reason.

Using FMS steel roller cam gear now. It's got 16,000 miles on it now, but should have been replaced at 12,000.

[Anthony]

I heard from a ford engine builder that the 351W block is hard on gears, the way the block is designed, with maybe inadequate oiling.

[fxbill]

Comp also told me the same thing about the wear, but to be honest I've had a number of stock 351's in the past that never had problems...even my 85 Van with the same motor has over 100,000 miles....same original gear. I've read that high volume pumps are a problem and I do know that the last two cams I bought from comp came with very sharp gear edges. You can almost see where the gear has shaved off the distributor gear teeth. This last cam is totally different though....You can't feel a sharp edge anywhere.
Anyway...Good luck Jack...Hope it works for you. I won't know for another couple of weeks. My new motor arrives this week and I still have to change the cam, lifters and valve springs before I install it in the car. I also have to pull the T5z, install the TKO600, change rear end gears, install upper and lower tubular A Arms. Man...I feel like I'm starting all over again!
Let me know how it looks to you .... feels really light and weak to me.

[Jack21]

Don Scott did a writeup on why the dist gears go out. It's the cam blanks used on aftermarket cams, and 351W's seem to be one of the worst offenders. A little work with a bench wire brush seems to clean it up as you can tell with your new CC cam. Had I known this, I'd have reworked the cam gear before I installed it.

CC has a new retrofit hydraulic roller. 224/232. Seen it? Mine is the 224/224. New one seems to have a slightly wider power range, but less lift. Let me know how yours works out.

I'll let you know what I think of gear.

[fxbill]

The cam I got is a special grind taken from the specs that Don uses for his 351's, but has a slight change and higher lift because of it being a roller and because my new engine is a 446 Dart block stroker ( the 100 extra cubes requires more lift to do the same thing according to Comp). I think it's a 232-236 with .566-.571 lift. Comp says it'll hit really hard before 2,000 RPM and run out around 5,500 with the peak torque at 3,500 and peak HP at 4,000-4,500 RPM. I'm excited to see what it will do. It's quite a change from the last cam in my 393. I'm not sure what configuration the Iron Eagle block has. I was hoping to run stock Ford roller lifters, but couldn't in my last engine....the lifter bores were too low and short. I had to run crane lifters with connecting link bars. I still have them if needed, but like the ease of the Fords with the valley pan.
I plan on using the brush with the cam as Don suggested the other day on the phone even though Comp seems to have cleaned up their act quite a bit with the new gears.

[jeffko]

Does it help to change the distributor gear? I am just about to purchase a MSD 8479 which has an iron gear. I also have a Comp Cam but really did not notice a sharp gear. Not in favor of pulling the cam at all. Any thoughts?

[Ford of France]

Someone over a year or two ago on this forum mentioned that by burnishing the cam gear on a wire wheel took care of most of the problem they were having with 351W cams. He indicated that they had built 36 engines and had not had a problem after taking off the sharp edges on the cam gear.

[dscott]

That was me talking about burnishing the gear. I called Comp Cams I don't know how many times to tell them about the problem and they said no way. They always blamed the way the gear was installed, using the high volume oil pump, or whatever else they could come up with. I think it's funny they came up with a new gear to take care of a problem that's so easy to fix. It's been several years since I started burnishing the cam gear and I have not had 1 failure.
Don

[jeffko]

I also called Comp Cams and Msd and one pointed at the other. I was told that the roller cams required the stock iron gear from MSD and that burnishing the cam gear "if done right" was acceptable practice. Problem for me is that my cam is installed and degree'd. Any ideas?

[MidOHasp]

I don't think it has much to do with extra crap on the grear. It's a metal vs. metal (which is harder) fight.

Roller cams are steel, and will munch an iron gear pretty quickly. Steel cam needs a steel gear, and amazingly enough, MSD and Comp Cams don't make the distributor gear required to mate an MSD distributor to a steel cam!! I guess you're saying COMP does now, in the "plastic" variety.

Crane Cams make a steel gear for the steel cam. I think the bore is .531", but I really don't remember. Doesn't matter who makes it, you just need the right distributor shaft diameter, and to replace the stock iron gear with a steel gear.

That's what I did. Don't have enough miles yet to tell you how it has worked (5,000 miles), but will be pulling the distributor soon, and if I remember, I will let you know - my guess is it is fine, from what I've heard and read in many other places.

Hope this helps.

[fxbill]

Jefco.... The roller cam requires a steel or bronze gear....not the cast iron gear that comes on the distributor when you first buy it. Ignorance and using the cast gear with a roller cam cost me a motor a few years back!..( Did I misread your post?)

[jeffko]

Here is what I have learned...

* bronze gears will wear faster than any other
* an hv oil pump will add load to the dist shaft/gear
* sharp edges cause gauling and shavings
* close tolerances need better lubrication
* most of the adverse wear is oil pump related
* you can't argue with real life xperiences if accurately portrayed.

I have a melling pump that is blueprinted and has a base that includes a seat for the bottom of the pump shaft which stabilizes the shaft from lateral loads. It seems this has a great deal to do with it. So for my case I have to decide if it is such a concern to remove the cam, burnish it and reinstall. The only other thing I could do is have the gear moly coated.

Any other suggestions?

[RICK LAKE]

Rick Lakefxbill The gear you are talking about is made by Greg Depree. 803-730-7574. As long as you are not a nascar builder, he will sell you one for $80.00. He makes them for comp cams. They are the gears they use in the nascar motors ford and that other makes. 3 thing are causing gears to wear out, no or poor oiling to the 2 gears where they meet. Too much end play on the camshaft, causing the gears to rub again each other. The distributor shaft not being square with the block and cam gear. A high pressure, high volume oil pump will help wear out the gear but not in 5k miles. You need more than oil splash to keep those gears with proper lube. There is a trick to put a .030 groove in the lower distrib housing so the oil pours onto where the gears meet. The gears are not plastic, they are a polymer with carbon for strenght. The more carbon the strong the gear but the gear gets brittle also. I think that a geo gear pump like titan has less drag than a gear to gear pump. A titan pump is $700.00. For this knid of money I would go with an external oil pump setup that works off the crank. Avivaid makes a kit for FE motors. More volume and pressure, and will not wear put a distributor gear. My thoughts Rick Lake

[jeffko]

Rick, I would like to hear more about the .030 oiling trick.

Jeff

[ItBites]

Don't any of the cam manufacturers make billet steel cams with Iron Gears (distributor drive gear) for your Ford engines?

I've run roller cams in Chevys for years (>13 years on the same roller cam and dist gear in my BBC Vette) with standard distributor gears (that don't wear out like bronze). The key is to order the version of the steel cam that has an Iron distributor drive gear. As I recall the Crane cams simply need an "IG" designation at the end of the standard steel cam part number.

This returns the cam gear/dist gear configuration to the same long-life, high reliability combination as used in factory engines for forty or so years...

Just thought you guys might want to check with your cam vendors. Simple solution. No "special" dist gears required. No issues with extreme wear...

Now the oiling issue is something us Chevy guys know how to solve in our engines easily also. Usually a small (.030 or so) groove in the lower ring of the dist housing where it passes thru the aft cam oiling galley. This basically squirts oil onto the cam gear. I am not certain this is necessary in Chevys, but I've always done it.

[Jack21]

The correct distributor gear for roller cams (up until now) is a Ford performance part that Ford used on their late 351W roller motors. At now 16,000 miles, the installed steel gear from Ford shows excessive wear and needs to be replaced. Might try your suggestion of polymer coating the replacement gear, or just installing the plastic (carbon fiber) gear instead.

Thanks for Greg Depree's phone #

[fxbill]

Yes.....my thanks too for the number. I hope I won't need it, but nice to have just in case!

[RICK LAKE]

jeffko Itbites has it right for the chevys. I used the same thing for my first motor in my car. I am running a 100 psi spring for the oil pump. Harded shaft for the drive. This is oiled by splash and drain off coming from the oil valley. If you slot the lower housing on the distributor so the oil drips on the meeting spot of the 2 gears, this helps to lube this location better. Cuts the wear, heating, and helps better lube the spot. If you want to get fancy, run a line to the location with air craft line and a very small oriface to spray the oil on the gears. This is an old racer trick. Rick Lake

[jeffko]

Well guys I have a solution given to me by Russ at LAM machine shop. I had to pull the cam sprocket, but I believe it to be well worth the effort. If you look at the front of your block, unfortunately with the timing cover off, you will see the right bank lifter galley plug straight behind where the distributor shaft and gear would be. Pull that plug and drill with a #60 drill bit and replace. This little trick will provide a continuous stream of oil right on the problem. Besides the poor oiling of this area you need the correct gear. Comps roller cams are all cast blanks and therefore use the stock cast gear that comes on all MSD distributors. If you have a Ford Racing cam it is a billet blank and therefore requires a steel gear. You can get a Ford Racing steel gear at Summit for about $27 that is .531 which is the same gear bore as the $68 MSD gear. If you follow these 2 steps, according to Russ you should be trouble free even with a high volume pump, which by the way is the single most contributor to this whole problem.

Jeff