I know this is a border line topic but bear with me. Does anyone know what type of material the oil pump drive assembly gear is made of?

Also, does anyone know what type of material the stock LT1 cam is made of?

This is why I ask. I purchased a cam from Thunder Racing during their Group Purchase. The salesman talked me into a billet cam (I guess I may be a sucker). The price was incredible. The part number for the cam is 07-000-9, specail grind. I did not even think of the material incompatibility problem with the distributor gear on the cam and the gear on the oil pump drive assembly. The plot does thicken. Comp cams has given me two different answers today from two different representative. One says bronze or polymer gear will be needed. The other says the stock oil pump drive assembly gear will work. WTF! I am at a cross roads. If someone knows anything factual I sure would appreciate it.

Thanks

Michael

 

Depends.....
If it is a true billet steel cam, you will need a bronze gear.

If it is a billet cam with a cast iron gear (cams using a stock or similar core are made with an iron gear pressed onto a billet cam core) , you can use the stock drive gear.

Is your gear on the cam shiny silver or a dull grey/black? Silver is billet steel.... black is iron.

I would not recommend a polymer distributor gear unless you are using an external oil pump (no pump load on the gear) ..... on a LT1 you could just insert the stub without a gear in this case.

 

I dont have the cam with at the moment, so I cant answer your question.

I will not be using an external oil pump on this motor. So that would be out of the question.

Anyone else.

Michael

 

If it's a "billet" cam (pn xx-xxx-9) and the gear is cut directly from the core, you shouldn't use it. I have been corresponding with someone else who was part of this GP and he got his cam, which is an -9 core. I would assume that Comp knows what they are doing and if the cam card specifies it's a cam for an LT1 that the right gear was pressed on, but it won't hurt to check.

I don't see why you would need a "billet" (-9) core for a street hydraulic roller in the first place though. 99.99+% of the LT1 cams out there from Comp gotta be the -8 "street roller" care and I have never heard of one failing.

Rich Krause

 

If you look at the oil pump dirve you can get a MSD Bronze Alloy Gear to go on there pretty easy and it should hold up just fine. It's like changing the distributor gear on a distributor, not to hard to do.

The reason I use billet cores on engines is to assure the most accurate cam timing as possible. Spring pressures and the motions of the engine play havoc on a cam and twist the cam itself and change the timing. A billet core is a great idea, especially with more spring pressure and agressive lobes. It's not needed on most street engines, but going for the last ounce requires it.

Bret

 

Bret,

Even with the oil pump drag on the gear, you think it will hold up? Any idea in terms of miles on the motor before it would require removal for inspection or replacement?

Michael

 

My only dislike of bronze gears is they are soft & will wear at a faster rate than iron ones. No big deal when you can occasionally pull the distributor to inspect it..... not easy on an LT1 unless you like enjoy removing the intake.

Steel gears are compatible with a billet cam as well. I do not recall offhand if they are available for GM distributors. Keep in mind that different diameter shafts exist for GM & you need to find the correctly sized gear to match. They're offered for Aftermarket units with .500" shafts. Most factory distributors had .491 shafts... not sure of the shaft size in the oil drive stub though.

 

I believe i recieved the final answer on my cam. A cam that is made of 8620 billet would require the use of a bronze gear. My cam is made of a 5150 billet core which is compatible with the stock oil pump drive assembly. This is directly from Gary Anderson, Chris Mays and David McCarver, who work for comp cams. They all finally got together on the phone with me and came to the same answer. How about that! Wonders never cease. And they all lived happily ever after.

Michael Kelly