windage tray for a 1966 L72.

[Mark F.]

Hello All. Was hoping for some thoughts and confirmation I am going about this the correct way. Have an oil pressure problem that required me to pull the oil pump and when I dropped the pan noticed no windage tray so want to put one back on before I button it up. I do not have a stock oil pan, it is a later model without the timing cover bolt, so I figured the common windage tray and main cap bolts with the stud on it is the way to go.
Just about every vendor out there has the 4 mounting bolts with studs and the corresponding windage tray. It appears the windage tray also has a hole for mounting on the oil pump. Is this oil pump bolt with stud not required as if so would they not come with the the 4 other mounting bolt/stud hardware? i know chevy part # 3866604 is an oil pump bolt with a stud on it, but not easy to get and maybe you can get one by Christmas, if your luck. If I have to wait to Christmas to get this done right, I will, but if it not required, I could get back on the road this week.

1966, 427/425HP, 4 bolt mains

Anyway, all thoughts are appreciated. Happy Holidays to all. Mark

[Patrick B.]

Re: windage tray for a 1966 L72.

I think the flat GM windage tray is attached in the rear directly with the oil pump bolt. There is no oil pump bolt with a stud on a stock engine.

[Mark F.]

Re: windage tray for a 1966 L72.

I think the flat GM windage tray is attached in the rear directly with the oil pump bolt. There is no oil pump bolt with a stud on a stock engine.

Hey Patrick. Thanks for the response. So it was installed the oil pump against the block, then windage tray then oil pump washer and bolt? I guess when I get the parts if the windage tray lines up right with the oil pump that's the way it was. Maybe that is why there was no windage tray on the car? There was a high-volume oil pump on the car which is a little bit larger (top to bottom) due to the oil pump gears being longer, which would maybe not let the windage tray line up properly? I removed that HV pump and replacing it with a standard volume with the blue high-pressure spring mellings 77 which hopefully everything will line up copesetic. Thanks for your input. Holiday Cheers. Mark

[Joe L.]

Re: windage tray for a 1966 L72.

Hello All. Was hoping for some thoughts and confirmation I am going about this the correct way. Have an oil pressure problem that required me to pull the oil pump and when I dropped the pan noticed no windage tray so want to put one back on before I button it up. I do not have a stock oil pan, it is a later model without the timing cover bolt, so I figured the common windage tray and main cap bolts with the stud on it is the way to go.
Just about every vendor out there has the 4 mounting bolts with studs and the corresponding windage tray. It appears the windage tray also has a hole for mounting on the oil pump. Is this oil pump bolt with stud not required as if so would they not come with the the 4 other mounting bolt/stud hardware? i know chevy part # 3866604 is an oil pump bolt with a stud on it, but not easy to get and maybe you can get one by Christmas, if your luck. If I have to wait to Christmas to get this done right, I will, but if it not required, I could get back on the road this week.

1966, 427/425HP, 4 bolt mains

Anyway, all thoughts are appreciated. Happy Holidays to all. Mark

Mark------


All original Corvette big block engines were equipped with an external oil baffle ("windage tray"). So, yours has been removed. This may have been done in your case when the pan was replaced. If you have a much later GM #14091356 oil pan it will not work with an original 1966 oil baffle. A later GM #3967854 baffle must be used. A 14091356 pan can be identified by internal baffle upper spot welds being located 4-1/8" below the bottom of the oil pan rail surface.

All Corvette big block external oil baffles used 5-point retention----the four main bearing cap studs + oil pump stud GM #3866604. The latter is still available from GM although it might be back-ordered.

All original Corvette big block oil pumps were standard volume pumps EXCEPT ZL-1 and LS-7. Hydraulic lifter big blocks were standard pressure; mechanical lifter used high pressure. So, the pumps were the same except for the installed pressure relief spring.

[Patrick B.]

Re: windage tray for a 1966 L72.

Sorry Mark, I guess my memory failed me.

[Mark F.]

Re: windage tray for a 1966 L72.

Mark------


All original Corvette big block engines were equipped with an external oil baffle ("windage tray"). So, yours has been removed. This may have been done in your case when the pan was replaced. If you have a much later GM #14091356 oil pan it will not work with an original 1966 oil baffle. A later GM #3967854 baffle must be used. A 14091356 pan can be identified by internal baffle upper spot welds being located 4-1/8" below the bottom of the oil pan rail surface.

All Corvette big block external oil baffles used 5-point retention----the four main bearing cap studs + oil pump stud GM #3866604. The latter is still available from GM although it might be back-ordered.

All original Corvette big block oil pumps were standard volume pumps EXCEPT ZL-1 and LS-7. Hydraulic lifter big blocks were standard pressure; mechanical lifter used high pressure. So, the pumps were the same except for the installed pressure relief spring.

Thanks Joe. Great information. Just ran out and measured my oil pan and sure enough internal baffle spot welds are 4 1/8" below the pan rail. So now just waiting for the later #3967854 baffle to come in along with the NOS main cap studs. Ordered the oil pump stud from a different source. Just waiting on parts.

Thanks for putting it all together. Cheers Mark

[Mark F.]

Re: windage tray for a 1966 L72.

Sorry Mark, I guess my memory failed me.

No worries Pat. I just hope I remember how to put all the pieces back together. Thanks Mark

[Joe L.]

Re: windage tray for a 1966 L72.

Thanks Joe. Great information. Just ran out and measured my oil pan and sure enough internal baffle spot welds are 4 1/8" below the pan rail. So now just waiting for the later #3967854 baffle to come in along with the NOS main cap studs. Ordered the oil pump stud from a different source. Just waiting on parts.

Thanks for putting it all together. Cheers Mark

Mark------

One other thought I had is this: are you sure this is an original Corvette engine? The configuration of no external baffle, no main cap studs, and a bolt rather than a stud for the oil pump is actually typical of most NON-Corvette big blocks. Those non-Corvette engines would also have used a different oil pan, presumably necessitating the installation of a Corvette oil pan.

One big clue here: the main cap bolts all appear to be genuine GM bolts. If this were a Corvette engine and somebody wanted to eliminate the external baffle, there would have been absolutely no necessity to replace the main cap studs with bolts----the studs could have been left in place even though no baffle was installed.

[Mark F.]

Re: windage tray for a 1966 L72.

Mark------

One other thought I had is this: are you sure this is an original Corvette engine? The configuration of no external baffle, no main cap studs, and a bolt rather than a stud for the oil pump is actually typical of most NON-Corvette big blocks. Those non-Corvette engines would also have used a different oil pan, presumably necessitating the installation of a Corvette oil pan.

One big clue here: the main cap bolts all appear to be genuine GM bolts. If this were a Corvette engine and somebody wanted to eliminate the external baffle, there would have been absolutely no necessity to replace the main cap studs with bolts----the studs could have been left in place even though no baffle was installed.

Good question Joe: It is not a numbers matching car. It is a3869942 block and was cast Sept 65. (My car is an April 66 car) I purchased the car in March this year. I was having oil pump pressure problem, as I revved the engine the oil pressure dropped. Put a test gauge on it same thing. So dropped the pan. Could not find anything obvious, put plastic gauge on two main bearing journals and well within tolerance. Oil pump was a high volume Mellings 77, so putting a standard Mellings 77 with the blue (HP)spring in it. Thought maybe all that crank churning and windage could have something to do with the oil pressure problem and the original corvette L72 had them for a reason so though it would be a good idea to put a windage tray in while I had it opened up.....Do you think I am making a mistake here? Thanks Mark

[Joe L.]

Re: windage tray for a 1966 L72.

Good question Joe: It is not a numbers matching car. It is a3869942 block and was cast Sept 65. (My car is an April 66 car) I purchased the car in March this year. I was having oil pump pressure problem, as I revved the engine the oil pressure dropped. Put a test gauge on it same thing. So dropped the pan. Could not find anything obvious, put plastic gauge on two main bearing journals and well within tolerance. Oil pump was a high volume Mellings 77, so putting a standard Mellings 77 with the blue (HP)spring in it. Thought maybe all that crank churning and windage could have something to do with the oil pressure problem and the original corvette L72 had them for a reason so though it would be a good idea to put a windage tray in while I had it opened up.....Do you think I am making a mistake here? Thanks Mark

Mark------


No, I don't think you are making a mistake adding the baffle. It cannot do any harm to install the baffle especially since you do have a Corvette oil pan. However, I'm a bit skeptical that it will solve your oil pressure problem. Many non-Corvette big blocks were built as yours is currently configured save for the oil pan and they had no reputation for the sort of problem you are experiencing. I do not see how the oil pan you have could, installed on a non-Corvette engine, account for the problem.

Are there any stampings on the engine stamp pad that might identify the original application of this engine?

[Mark F.]

Re: windage tray for a 1966 L72.

Mark------


No, I don't think you are making a mistake adding the baffle. It cannot do any harm to install the baffle especially since you do have a Corvette oil pan. However, I'm a bit skeptical that it will solve your oil pressure problem. Many non-Corvette big blocks were built as yours is currently configured save for the oil pan and they had no reputation for the sort of problem you are experiencing. I do not see how the oil pan you have could, installed on a non-Corvette engine, account for the problem.

Are there any stampings on the engine stamp pad that might identify the original application of this engine?

Hey Joe. Yea, I am at a loss for why it is losing oil pressure as you increase rpm. Its like it is running out of oil in the pan, but the old HV pump was set at 1/4 inch from the bottom. Since I am this far into it thought I would put the windage tray in couldn't hurt (Thanks for confiming that). I will try to add some photos of my engine pad stamping. The previous owner tried to make it look like a numbers matching car and the engine stamp pad is ridiculous. If you want others let me know.

[Joe L.]

Re: windage tray for a 1966 L72.

Hey Joe. Yea, I am at a loss for why it is losing oil pressure as you increase rpm. Its like it is running out of oil in the pan, but the old HV pump was set at 1/4 inch from the bottom. Since I am this far into it thought I would put the windage tray in couldn't hurt (Thanks for confiming that). I will try to add some photos of my engine pad stamping. The previous owner tried to make it look like a numbers matching car and the engine stamp pad is ridiculous. If you want others let me know.

Mark------


There's no way that engine code stamping is original. In fact, it's a very crude re-stamp. It looks like it was done with individual dies, not a gang stamp. So, now we don't know what this engine is or in what application it originally resided. All we know is that it was an application that originally used a 3869942 block. That includes most 1966-67 Chevrolet 427's but, based on the bottom end, it was very unlikely a Corvette application.

[Mark F.]

[Mark F.]

Re: windage tray for a 1966 L72.

Just put everything back together last night and did a quick road test. Oil pressure was fine, not as high at the old High Volume pump but did not fall off at high RPM. Used a one-piece blue felpro gasket on the pan and torqued it to felpro specs and had a leak at the tail end of the pan. Torqued it a little more and now no leak.

Looking at lessons learned on this and trying to find out how I fixed the problem of losing pressure as the engine gained RPM and to say it was one thing I cannot. I did remove a HV Mellings 77 pump and replaced it with a standard Mellings 77 pump with the high-pressure spring, in hope of keeping more oil in the sump. I did add a windage tray in hope that it will stabilize the oil as it sits in the wet sump and the car came with one anyway.

I would like to thank everyone for their help and comments over the past couple of weeks, I could not have done this without you guys.

Holiday cheers. Mark