65 fuelie oil leak

[John H.]

Re: 65 fuelie oil leak

Anyhow John I was right when I said you need a Melling M55 oil pump. Plain M55 with no suffix after the number. JD

I'll add that as of yesterday, the Tech guys at Melling told me that they stopped using the GM-designed "weak" lightweight casting for the M-series pumps about two years ago that they used to warn not to use for performance applications; both the current M-series and "Select" pumps use the same durable casting now that we all grew up with.

[John S.]

Re: 65 fuelie oil leak

I know anything is possible, but I do net believe the engine has been apart. .018 steel head gaskets still in place. That is why I am thinking it is a stuck relief valve. I am going to give it a couple hundred miles and see if it changes. Actually going to Cardiff by the sea event to observer judge. Thinking about driving the fuelie. 140 miles each way. I will see what happens the drive. If nothing changes I will drop the pan and check it out.

On a side note, I replaced the old N11 mufflers with new ones and it sounds a ton better. Old mufflers had multiple holes in them. They were not original to the car as they were clamped at the back. Actually went quiet well. I believe the pipes to the back are original as they are flat in all the right places.

[Timothy B.]

Re: 65 fuelie oil leak

John,

Keep in mind that removing a oil pan on a C2 corvette only requires removing the idler arm to frame bolts and lowering the drag link. After removing the oil filter, starter and rear bellhousing cover it's all oil pan bolts so correcting the oil pump issue is not a big deal. How many miles on the engine? IMO, I would look for a nice used or NOS GM oil pump and order the high pressure (60lb) relief spring and install.

[Joe C.]

Re: 65 fuelie oil leak

WHOA!!! Please hold-up on the oil pump replacement!

First, since you have recently bought this car, you have no prior history base. You couldn't have noticed whether or not the oil pressure has increased suddenly??? Have you checked the pump pressure with a verified correct gauge? If not, then do so before you go after the pump!!!

Oil pressure gauges are frequently re-faced (from 60 pounds to 80 pounds, and vice versa) without being correctly re-calibrated. It is highly unlikely that your pump pressure relief spring has become stuck, and even if that is the case, I seriously doubt that an old engine with an old worn-in pump and probably larger than spec journal clearances would be capable of generating 80 psi!

Next, check the viscosity, and if you can't verify, then replace with CJ 10W-40..............although I doubt that in the event that 20W-50 was used, that 80 psi would be generated if the oil was fully warmed up to it's operating temp of 180-220 degrees.

If you eventually have to replace an oil pump some day, then be advised that the M55 with the beefed-up neck is the way to go. The pump that you want to use was sold as a "Melling Select" at one time, although John H seems to have found that the situation has been corrected with the standard pump. There's no need to replace your pump unless trash was somehow picked up if the screen fell off. You should check the clearance between the gears and the cover plate. The cover plate and gear ends should be surface ground (easily done with wet-dry paper, a flat plate, and some WD-40 or similar) so that the end play is between .0015 and .0025. Install a new spring:

http://www.melling.com/LinkClick.aspx?fileticket=nn2s4R4eSHI%3d&tabid=221

Use the 55058, or the 55070 if you take your engine past 6000 RPM occasionally.

Be advised that if you remove the idler arm from the frame you will have to reset the toe and steering wheel center. Better to use a pickling fork and separate the idler ball.

[Jerry G.]

Re: 65 fuelie oil leak

I agree with Joe, but this thread is getting a little goofy. oil pooling around the adaptor plate on front of the motor is the problem this thread started out to discuss. Has that source been found and corrected, if not then why would someone take it for a couple hundred mile drive or be thinking about dropping pans and changing oil pumps. Several good areas to investigate have been suggested, have these been resolved?

[John S.]

Re: 65 fuelie oil leak

Jerry,

I have checked just abou everything. Oil pump rod bolt is in place. Although old and hard, I do not believe any oil is coming from the base plate front seal. I checked the PVC system and it is clear with the proper size hole in the 90 degree fitting. Taped up the oil fill tube as the oil cap cork gasket seems to be original and is hard as a rock. Took car on a short drive and did not see any more leaking. I purchased a mechanical oil pressure gage and will be testing to double check the gage pressure Sunday. As for originality of the car I already stated that it is an original 65 fuelie with 35k original miles. Documentation includes the POP. The car has been in Jim Gessner's survey as an original low mile car for many years now. Yes I want to fix the oil leak, but I also want to track down the reason and fix the high oil pressure before any damage is done.

[Jerry G.]

Re: 65 fuelie oil leak

Did you check the main engine vent flame arrestor coming into the FI air meter adaptor. Be sure this is open and free or motor will build pressure in crankcase.

[John S.]

Re: 65 fuelie oil leak

Jerry,

yes I did and it is fine. One question you may know the answer. Can I pick up the oil pressure with the shop gage off of the fitting at the front top pf the block. You can see the 1/8 plug in one of my pictures up above. Thanks for the help!

[William C.]

Re: 65 fuelie oil leak

Yes, that will work.

[Joe C.]

Re: 65 fuelie oil leak

Jerry,

yes I did and it is fine. One question you may know the answer. Can I pick up the oil pressure with the shop gage off of the fitting at the front top pf the block. You can see the 1/8 plug in one of my pictures up above. Thanks for the help!

It will read pressure but probably won't be the same as the 1/8" NPT tap at the back of the block. Pressurized oil comes out of the pump, and up the back of the block where the rear tap reads full pump pressure before feeding main and tappet galleries. The front tap reads residual pressure after the main gallery, and possibly the tappet galleries have been fed.

[John S.]

Re: 65 fuelie oil leak

Joe,

that was why I asked. We will see what the difference is.

[John S.]

Re: 65 fuelie oil leak

Update on leak issues. Cleaned up the whole engine compartment and ran the car around a bit. Main leaks on both side from the valve cover gaskets. Picture shows driver side valve cover with the gasket not even in place on the top rail. Bubba or previous owner had the gasket slide down on the when installing and did not catch it. Passenger side just had a leak at bottom left corner from age and over tightening.

One note that maybe John D. can comment on. I had to remove the air horn or meter assy to get the valve cover off. Is that the normal procedure?

On the oil pressure deal. I think the Rislone is starting to work. Hot oil pressure is now down to 40 at idle and just under 80 at speed. Previously it was 60 at idle and pegging over 80 at speed. I think I am going to give it a few hundred miles of driving to see if it drops more.

Going to adjust the valves per Duke W. and John H. procedure and put everything back together in the next day or two. Thanks to all for your help.

[Dan H.]

Re: 65 fuelie oil leak

John, put the new gaskets on with contact cement to hold in place.
Dan

[John S.]

Re: 65 fuelie oil leak

Dan,

Already done!

[Michael H.]

Re: 65 fuelie oil leak

One note that maybe John D. can comment on. I had to remove the air horn or meter assy to get the valve cover off. Is that the normal procedure?

On the oil pressure deal. I think the Rislone is starting to work. Hot oil pressure is now down to 40 at idle and just under 80 at speed. Previously it was 60 at idle and pegging over 80 at speed. I think I am going to give it a few hundred miles of driving to see if it drops more.

Going to adjust the valves per Duke W. and John H. procedure and put everything back together in the next day or two. Thanks to all for your help.

John,

The valve adjusting method recommended is spot on. I would definitely stick with the factory recommended lash specs of .030-.030" though.

You may find it easier/faster to remove the left valve cover if you only remove the FI choke cone and pizometer ring instead of removing the entire air meter.