If so can the oil passages be welded up and the covers removed and still be legal?

If the rules do not say it is an allowed mod, then the mod cannot be made.

Can I suggest a rule change for the following reasons?
1. We all know about the issues with 944 rod bearings. The top balance shaft oil feed is directly fed from the #2 main bearing. Plugging the oil feed passages increases the oil pressure throughout the system, something needed for these engines.
2. One less area to leak on an engine that is prone to oil leaks
3. No competitive advantage. The couple of HP gained is marginal and can easily be found elsewhere to meet the limit.
4. There is no way to inspect who is running without the balance shafts unless you remove the belt cover. I suspect many are running without the belt which does nothing to improve the oiling, but cannot be inspected regardless.

I think this is a smart move for all 944 racers to make, and it would be great to see adopted.
Hope you agree.
John

Thanks for the suggestion. Will consider for 2012.

We did some testing of belt on and off for the balance shafts and found that with the belt off the engine gains a small amount down low and then loses compared to having the belt on at the top end. When I have run without the belts it is like a game to see if I can keep up with the parts, nuts, bolts, etc flying off every session as well as the mysterious cracks that occur in fuel rails and such. If you want to fix the oiling put a 50% restriction in the #1 feed hole and you will be amazed how even the oil distribution becomes. Greg F

Overall sounds like deleting the balance shaft isnt worth it.

I would have to disagree about things breaking and coming loose all the time. I have not run a balance shaft belt since my car was built 4 years ago and have had no such issues. The shafts are in my car but no belt as that is completely legal. The balance shafts are to help the engine between 3000 and 4000 rpm for regular street driving, not at the rpm we run. Other then idle and when we are under caution you can't tell I don't have balance shafts. My engine was also built for SP1/Spec so it was not even balanced by a machine shop.

Ask 10 different engine builders how to solve the oiling issue 944's have and you will get 10 different answers.

I think that the only thing that should be changed about this rule is to state if the shafts need to be in the car or not, not that we have to run them. The belt removal rule goes back to the old PCA rules and has been around for years. The real advantage of removing the shafts completely would be removing weight from over the front axle.

For some of us, that range is frequented more in our race cars then street cars, and not to discount the amount of idling time on the race car. Seems the Porsche engineers went to a lot of trouble to include balance shafts, and for good reason.




And not all engine builders are the same in their abilities or experience. In this case, Greg is at or near the very top of the list for race engines, with 944's being a specialty. Something to be considered.




The rules already are clear as to balance shafts.

The harmonics dampener were intended for mid rpm vibration reduction on street vehicles. A range lower the what we typically see racing. As for things rattling loose, not a chance. 20 year old car that hasn't been properly gone through is always the case. Every 500+ turbo race motor i built had properly deleted balance shafts. Never an issue And never a spun bearing even without dry sump.

Not everyone may agree but I think we should make it an option for those that wish to do it this way. I think we can all agree there is no measurable completive advantage.

I've been running a 924S in SCCA ITS for 5 seasons, and many engines. I ran 3 of those seasons without driving the countershafts. Found it necessary to carry spare fuel rails, spare alternator pivot bolts, and a few other small items which would regularly fail or fall off. The engine was running on the stock DME with stock rev limit, and I tried to limit peak rpms to 6300 to avoid RUD (rapid unscheduled disassembly). I had been wanting to enter in endurance race series being run in this area, but the engine life expectancy was not up to it. I put some serious study into this over winter months and returned to "the books" from my engineering student days. The basics of reciprocating engine layouts show one of the inherent issues with inline 4 cyl. is the secondary vibrations caused by the flat (180 deg) crankshaft layout, where all reciprocating mass is reversing direction at the same time in the cycle. Without getting into the dynamic analysis here, all inline 4 cyl. engines suffer the issue, but the degree to which it becomes an issue is related to the reciprocating mass ratio to the non-dynamic components (everything else in the engine that is standing still). The reciprocating mass of the M44 engine is relatively high (one cause of the rod bearing problems I believe). So, armed with a theory (not much else to occupy oneself during the northeast winter months), and reasonably sure the HP loss due to those shafts was minimal, and really wanting to gain enough drivetrain life to dare enter an endurance race, (and understanding that the design engineers on that project were probably intellegent enough to have done a cost benefit analysis of the added countershaft system), I built an engine with the shafts operating as designed. The result of the experiment was I have not failed a component due to material fatigue since (2 seasons, many races). I have used a repaired fuel rail without a failure. Have not replaced the alternator bolt since.
So, believe what you will, I will run the countershafts as designed.