tssteph

Quote from documentation on GM crate motor:
Distributor P/N 1104067 or melonized distributor gear P/N 10456413 must be used on all crate engines with steel camshafts.

Is a stock Mercruiser distributor gear ok to run on a GM crate motor with a steel camshaft?

Thanks.

rws

iTrader: (3)

If the cam is an all steel hyd roller you will have to run a Brass gear on the distributor.If this is the case then save yourself some headaches and replace the cam with one that has an Iron gear furnace brazed to end of the cam.Crane makes these and others probubly do also.It may be to your advantage to change the cam anyhow.Reversion ,broader torque curve.I plan to install this Crane hyd. Roller in a 454 that I have for a spare. http://dab7.cranecams.com/SpecCard/D...1=Display+Card


I sure that there are more knowledgeable people that will offer their advice.

Rob

mcollinstn

the billet GM cam MUST have a bronze gear on the distributor.

Some guys ARE running the billet ZZ502/502 cam in boats, but it requires some exhaust tailpipes that stay dry at long way to prevent reversion.

An aftermarket cam with 112-114 lobe center will both solve your gear issue AND keep you from rusting your piston rings.

NEVER SATISFIED

Has anyone had trouble finding a bronze gear to fit the new style GM dist.Mine is out of a 97 502mag with efi. The stock GM dist.has a .491 shaft but mine is smaller than that . I don't see one for a smaller shaft listed in any books.

tssteph

The lobe center line is 112, is reversion still a problem? Others stated that 112-114 is acceptable. Here are the complete cam specs, for obvious reasons changing the distributor gear is much easier then then changing the cam.

This steel roller is for the 502 and 454 H.O. engines. (Must use distributor gear P/N 10456413.) The duration at .050" tappet lift (intake/exhaust) is 211/230; and maximum lift with 1.7:1 rocker ratio (intake/exhaust) is 510/540. Valve lash is zero/zero and lobe centerline is 112 degrees.

Thanks

KAAMA

iTrader: (1)

When I ordered my hydraulic roller cams, they told me the cams are of billet steel and I requested the cast iron distributor gear to installed on them so that I would not have to use a bronze distributor gear which was extra $40 per cam or so. From what I have learned is the bronze distributor gears wear too quickly and will change your TIMING!!!. I believe having the cast gear installed on a billet cam is the way to go unless someone else knows something I don't.

Anyone else experience something differently regarding this issue?

tssteph

The gear that GM suggests is a Melonized gear, not a bronze gear. This would be a steel gear with some special heat treating.


Melonized show excellent
sliding and running properties: the compound layer
contributes a very low coefficient of friction and minimizes
abrasive wear.

Big Boys Toys

I would not run the old mercury distributor gear in your new motor.
Is your existing gear worn?
How many hours are on it.
They do recommend the mallonized distributor gear for the crate motors because of the load that the heavier springs place on the cam shaft and gear.
If you loose the gear , you will be in for some serious pain, broken cam, stuff floating around inside of the motor everywhere that could cause additional damage to the motor. Put in what the engineers recommend for the application.
If they are recommending something it is for a reason!!!
Post what you decide to do.
Have a good day.
Brian

mcollinstn

tssteph

If you're using your crate motor in a performance application, get a meaner cam. Sell your GM steel billet cam on Ebay and get yourself either a Crane HP500 grind or better.

If you're not worried about performance, then continue onwards, or trade somebody for a take-out 502EFI cam.

tssteph

I am going to switch the cam gear to the one GM says I need. It seems like cheap insurance to me. I would eventually like to change the cam but I know how this snowballs. I have only ran the boat once with this motor and hit 58 on a GPS with the wrong prop. Any guess on what improvement I would get with a HP500 cam? I keep telling myself that this is the family boat that speed is not that important.

Thanks for all the info and suggestions.