I pulled the pan on this L-76 this afternoon and I noticed the two bolt mains had regular bolts except for one close to the oil pump. This main bolt was the extended kind that allowed a windage tray to be attached. Did these cars even come with windage trays? Did the engine builder on this car run out of regular bolts and substitute a long main bolt? I haven't messed with cars for many years but I remember unbuttoning these small blocks and finding something like four or five long bolts for windage trays or something like that. Just curious and I thought I would ask you guys that have seen a lot more of the insides of these babies than me. Also I know what the purpose of windage trays are for. But do they really add any noticeable performance to a steet engine? :confused:

 

Yup, '64-'65 L-76 and L-84 (F.I.) used a windage tray; must have disappeared during the rebuild; not big deal on a street engine. :thumbs:

 

All L-76 SHP and L-84 FI engines had a flat windage tray secured to five special main bolts that had stud extensions to secure the tray and the "big" oil pan that provided six quarts total system oil capacity. This pan also had build-in baffles around the oil pickup and a trap door to keep the oil from sloshing forward on heavy braking. From the exterior the big pan is recognizeable by its deep section, which extends forward for about 3/4 the length of the pan as opposed to about half for the standard pan on medium performance engines. This long deep section precluded the use of the steering damper of power steering boost cylinder.

At 6000 revs the crankshaft is spinning around 100 times per second and creates a virtual hurricane in the crankcase. The windage tray helps keep the oil from being whipped up into foam, which would cause power loss and potentially uncover the pickup.

These were very well engineered engines and could be raced as is in SCCA competition with very little prep. Lack of the windage tray is not going to have much effect on the street, but if you drive hard on occasion they increase the reliability of the oil system to maintain a steady flow of oil to the engine's vital parts.

Duke

 

I believe this is what it looks like.
Andy B

 

Was there any design in the windage tray that helped in extreme cornering?

When I had my oil pan off I inspected the setup with some interest. I had never seen a system like this and was a little baffled when I saw the tray bolted to the bottom of the main caps. When I had the oil pan off I was going to glass blast it but decided not to when I saw the complexity of the internal tray configuration. Lots of areas to trap media.

I used the regular style gasket. I used the spray RTV on the side gaskets to tack them to the pan. I used copper RTV on the front and rear along with the gaskets and let it cure for about 3 months. (Winter project). No leaks.

Mark

 

The tray just kept crank windage from whipping up the oil Fill up an old pan with oil and stick a leaf blower into it to see the effect.

The baffling in the pan was designed to keep the pickup covered in spite of dynamic loading, but remember that the best street tires of that era would probably not even generate 0.75g cornerning braking, and period racing tire might generate 0.9g.

Duke

P. S. Nice photo of a 327 SHP bottom end. The LT-1 had a curved windage tray, often referred to as "semicircular", but it wasn't really a half circle - just curved to follow the contour of the rotating parts.

 

Just for info, here is a C3 L-82 windage tray set-up.






[Modified by paul67, 7:24 AM 8/10/2003]

 

Yeah I had one of those long bolts ( closest one to the pump per Andy B's pic). Someone had added p/s to this car so the larger pan was not on the car and maybe this is why the tray is history or they just left it out. In any case I appreciate the information. That photo from Paul 76 has a windage tray that looked like the one I had in an old Z-28 in high school.

 

Duke - Re you comment "This long deep section precluded the use of the steering damper of power steering boost cylinder." - I have a 66 L72 427/425 with power steering and an original "big" oil pan that you describe. Did they create this pan just in 65/66 to accommodate both ?

Peter

 

My comment just referred to small blocks. Somehow Chevrolet managed to design a five quart pan (six quart system) for the BB that could accomodate the damper or PS boost cylinder. It would be interesting to compare the SB SHP and and BB pan side by side to see how they accomplished this.

I suspect the BB pan is wider, so it would hold more oil in a (lengthwise) shorter deep section.

Duke

 

Oil pan trivia:

My Cosworth Vega (and all 140 vegas) has a baffle/windage tray sandwiched between the oil pan and the case. It completely isolates the pan from the crankcase except for an opening at the very rear of the tray. The Porsche Boxter engine has a similar setup and is sometimes referred to as a "semi-dry sump".

The interesting feature of the Vega tray is that it's primary purpose is to keep the oil from flooding the front of the engine when the cars were tipped on there nose and installed in special rail cars. It was called "Vert-a-Pac." The battery fill ports were on the rear of the battery and the coolant overflow tank and windshield wiper reservoirs and fuel tank were also designed with the fill port on the rear so they wouldn't spill when the car was rotated to the vertical position.

I designed an auxillary baffle to be welded to the top of the deep section to keep the oil from sloshing forward under heavy braking (I run it on racetracks), and another CV owner who is a structural engineer did a modal analysis using the ANSYS finite element program to insure that the baffle's natural frequency was above the 250 Hz second order unbalance vertical shaking force frequency at 7500 revs so the baffle would not go into resonance and fail! My original design required a bit of modifcation in the form of stiffening ribs (as in the prior photos in theis thread) rolled into the flat section to pass muster.

Duke




[Modified by SWCDuke, 9:39 AM 8/10/2003]

 

Here's the Verti-Pak shipping method Duke mentioned - shipped hundreds of thousands of Vegas this way. We installed four sockets in slots in the underbody, which engaged four hooks in the rail car doors when the cars rolled forward on the doors as the door was raised into the closed position.

:cheers: