V2Rocket

Been searching but only come up with snippets and dead picture links.
What's the story with dual cam gears, on the 16v cars?
Custom jobs of course, but is a hood bump really necessary, or could small enough gears or a lowered engine get the needed clearance?

alxdgr8

I'm more curious as to why the need? Plenty of high HP DOHC platforms out there with a single belt gear and interlink chain.

V2Rocket

In case I run out of projects
Advancing the cam did great on my NA engine...I have an adjustable gear for the 16v head as well, but since the cams are tied together, there may be more power on the table by phasing the cams differently to eachother.

944crazy

Definitely benefits to having independently adjustable cam gears. On my brothers Rb26, advancing the intake and retarding the exhaust made a noticeable difference to low and mid range torque, and got the turbos spooling a lot earlier too. I would say you can benefit from the same ability to fine tune with the 16V head as well.

AlphaOmegaPower

Mine is getting built with dual cam gears. Michael Mount, Chris White( got mine from him for a good deal) and a few others who actually make and have used them would be a good source.

Adonay

The biggest problem with the 16 valve engines are that chain assembly between the two cams. That's were most s2\s engines get bent valves but sure you could open it up every now an then to check it. I would like to only check a belt if it was my 500hp engine

V2Rocket

You know what's kind of weird about the chain setup, is that the 928S4/GT/GTS use the exact same chain and tensioner assembly, and they almost never have issues with theirs.

AFAIK they don't have the oil restrictor to the heads, and while they may be putting out less power (heat) per head, it's close...(GTS is 350hp so 175/head, close to 944S)

Wondering if oil flow is an issue.

Voith

Those adjustable chain gears made by MM look good.

I think the problem is with chain, it stretches over time and eats away gear teeth which in turn leads to catastrophic failure.

V2Rocket

So what about the hood bump?
Might have found something that could work...anybody know how to cut a woodruff key slot in a pulley

Raceboy

Woodruff key slot is cut on a lathe.

Dave W.

Talk to various machine shops. The MazdaSpeed 3 doesn't have dowels on the cam gears, and no key on the crank gears, so those guys upgrade to dowels/key for durability.

333pg333

I may know of a spare set if anyone is interested. I just don't know the specs though.

V2Rocket

Maybe, if they can be used without bumping the hood at all... Lowering engine as much as possible via shorter mounts.

I bought a 90-01 integra (B18C) crank gear and it's shaft bore is exactly identical to the 944 crank. Needs a key slot cut to fit. 17 teeth, same profile and pitch as 944.

May require milling 3mm off the back of the balance shaft gear hub for everything to be in its correct place due to different gear width/hub vs 944...or run without balance shafts.

Adjustable cam gears (34 teeth) are readily available and cheap on eBay.