The current spec really doesn't say much about the cylinder head other than shaving/milling is allowed.

So what is a "stock valve job"? And should any porting and polishing be explicitly disallowed?

Anyone want to add to the "Rules change discussion timeline" thread?

As I understand, porting and polishing is prohibited.

There is no rule about how the valves are ground. I, frankly, don't know how mine are done. I have never had the head off to look at. My engine builder sends it to someone he likes and puts it back on.

Joe, is there an issue here? Should I look into what was done on the valves?

Jim

Rules for something like Spec racing are meant to keep cost down. Yes, there are ways to get around some rules from technicalities in how they are written. This violates the overall fair nature and sportsmanship, however. Overall, you are only allowed to do what the rules say you CAN. If it is not talked about in the rules, it is not allowed. This is the general and honest way to interpret.

Again, if you want to max out a 944, you can find somewhere to race it. You could also spend over $15k on an engine without blinking. Spec 944 series are for cheap and fun racing, don't complicate or cloud the issue with politics!

Just my views.

"stock valve job" is a valve job done on the head to manufacturer's specs concerning valve seat angles and shaving tolerances. As mentioned earlier, if the rules don't specifically allow a certian modification it is not allowed.

I have had good success with motors. Oil coolers on motors with spun bearings are suspect. They could be ok, but probalby are not. Be very careful.


When you teardown a junkyard motor replace the rod bearings and main bearings. Balance bearings are a good idea too, but honestly I have never done that.

New waterpump is a good idea if you don't know the history of it, but a recient waterpump is not likely to fail.

As for the head you want it brought back to or check to factory specs. Beyond factory specs is not legal. Factory heads are not ported or polished. They have just the raw cast surface on there. So it needs to stay that way.

Oil pumps tend to last a life time. Cranks often cannot be re-used after a bearing spin, but sometimes can. Have them checked. Used cranks can be found cheap if you look. You want to avoid oversized bearings if you can since these get expensive fast.

Baffling the pan is a good iead as it drilling the crank. External oil coolers are good to lower oil temps and lower water temps if you did the waterbath cooler.

Now given all that the motors can last for a long time. Sometimes they don't. One think to know is rod nuts are somewhat special. Some engines came with flat rod nuts and other with serrated nutes. There are some notes in the manual that says to always use new nuts as One version is not be used twice. If it was a rod nut failure that could have been the issue.

Also it is easy to get the lower balance shaft 180 out when pull the gear off it. Thus you can line up the mark perfect, but have it 180 out. This will cause extra vibes that you might be able to feel. If you don't you risk craking the fuel rail and a fire or braking the oil pickup tube and blowing a motor.

Joe,
It looks like the cause of failure with Richmond's engine at Nat's was a rod cap came loose on # 4.
I want to believe that the stock rod cap nuts are fine if you follow the Fact. manual. I haven't seen a failure of these. I was asked if we should consider allowing ARP brand hardware.
Thoughts?