Double Check Cam Spray Bar Orientation
 

Need a double check on the cam spray bar orientation before I put the plugs back in the cam towers. Here are a couple of pictures from the top sidr of the cam towers. One hole sprays up the top rocker arm and 2 spray on the cam. Let me know if this looks right.
http://forums.pelicanparts.com/uploa...1147913165.jpg
http://forums.pelicanparts.com/uploa...1147913292.jpg

Looks correct from the pics...
 

but does anyone enlarge the holes? I was following an old thread where they were talking about using spraybars and center oiler cams to get as much oil to the heads as possible to help cool them and that the oil restricters were a bad idea from a thermal management standpoint.

Which then begs the question, if you have a ginormous oil pump like a GT3 on a tiny 2.0 motor, can you use that extra volume as 'coolant' (assuming a very large front mounted oil cooler so you can shed that extra heat)?

tadd

Tadd,

I didn't come across anything on this when I did a seach. If the holes were just slightly bigger there would be less chance of plugging. Would be good to know if it would work.

Thanks,

The heads are cooled by the airflow through them - I doubt that a little more oil splashing on the cams would make any noticeable difference...

-Wayne

Wayne:
In my mind it depends on how much extra oil. Case squirters are good for what, 100*C difference even though the cylinders are air cooled. The turbo squirters have bigger holes and are supposed to be an even better choice.

I am happy to agree that oil is a poor heat transfer fluid due to it's low thermal capacity, but if you use enough of it, then you could see positive results. If the oil is cooler than the metal in the head, thermodynamics will happen...

I can't see why enough oil sprayed on the tops of the cylinder heads wouldn't help things out by 10-50*C. Didn't the mighty 935 use both center lube cams and spray bars?

It would just be an extra margin in the fight against detonation and is simple to do - just use a bigger pump on rebuild.

tadd

Kind of makes one re-think the whole oil restrictor deal.

Many aircooled aircraft engines use oil flood to the heads to ensure that the exhaust valve guides stay cool. Just another data point.

From BAs book...
 

The 964 pump puts out 65L/min with 17 to the piston squirters, 35 to the crank, and 13 (restriced) to the cams. This is the only pump he gives numbers for and I have no idea how it compares with a GT3 pump.

So with 80mm cylinders vs 95(?) and area being a squared value, I would think that some of the piston oil could be redirected to the heads to take advantage of all that surface area. The limited surface area of the underside of the 80mm piston vs a 95+mm piston would limit heat transfer no matter how much oil you threw at it. In addition, the 'drain back' time for the hot oil to be replaced would be a big guess since it is not at the system flow rates but au natural...

tadd

I think you guys might be looking for a solution to a problem that doesn't really exist...

-Wayne

Got the spray bars sealed up last night and getting ready to start on the cams now. Stock is the way it is staying for now. :D Thanks to everyone.