C1 59 Valve covers

[Rob M.]

Fellow restorers,

I often see valve covers been sold on e-Bay claming to be for a '59 Corvette (e.g. see items 2448853774, 2449191274, 2448290916, 2449327009). To my believe these are all not correct covers for a 1959 Corvette. I've been able to find item 2446202127 which is to my believe a correct set. Am I right or wrong on this one ?

greetings,
Rob.




The C1 1959 Corvette Restoration Project

[William C.]

Re: C1 59 Valve covers

What HP and what is the serial # or date of build? All factor into the "correct" answer for a '59

[Rob M.]

Re: C1 59 Valve covers

Bill,

My car sadely doesn't has an original engine (Camero '83 300 HP) but I'll mount a 1x4 Carter Carburator to make it look more authentic. So it would have to resemble a 230 horse power engine.

Rob Musquetier
The Netherlands




The C1 1959 Corvette Restoration Project

[John M.]

Re: C1 59 Valve covers

Rob,
All of the valve covers that you are looking at could be the correct valvecovers for your car. The Cast aluminum covers were used on the optional engines, and the stamped steel covers were used on the base 230hp engine.
In both styles of covers, you also have different mounting holes that were used in 1959 depending on when the car was built. Late 59 cars had the straight across bolt holes while early 59 car used the staggered mounting of eariler year models. There are two different stamped steel covers and only one is correct for a corvette. The passenger cars used a cover that was sloped on the end while the Corvette cover's end was straight up and down. With the late model 305 in your car, either the stamped steel or cast cover could be used, but you could not use the staggered mounting cover.

Regards, John mcGraw

[Rob M.]

Re: C1 59 Valve covers

John,

Thanks for your response, but I can't work out what staggered mounting is. Could you please explain what is ment with this method of mounting.

greetings,
Rob Musquetier.




The C1 1959 Corvette Restoration Project

[William C.]

Re: C1 59 Valve covers

late '59 heads, (and all others up until the mid-80's used an arrangment where the valve cover hold-down bolts are located in a direct alignment with each other top and bottom. The '55-early '59 valve covers used an arrangement where the mounting holes on the top of the valve covers were closer together than the bottom holes. thus the holes were not aligned top and bottom, but "staggered"

[Mike McKown]

Re: C1 59 Valve covers

If you look at your last picture of the engine, straight down on the left valve cover, you will see that the lower attaching bolts have the same fore/aft spread as the top two. On the early '59's the top holes are maybe 1 inch closer spread than the bottom.

You didn't ask but I am curious if you are blowing oil out your fill pipe? I don't see any "loop" for the crankcase vent system. The '83 blocks didn't have any provision at the back for a breather.

[Rob M.]

Re: C1 59 Valve covers

Thanks both for explaining the staggered bit.

I must admit that, since I have the car since September this year, I haven't been able to drive around with it a lot but no oil traces were found when I have drove appr. 2x 60 km. with it. I know big blocks should have a vent hole in the valve covers but this is a 305 block (5.0 L for us Europeans) and therefor I was persuming I don't need the ventilation from the valve cover provisioning. I hope that I'm right about this...

greetings,
Rob.




The C1 1959 Corvette Restoration Project

[John M.]

Re: C1 59 Valve covers

Rob,
The original engine for your car had a vent that came out of the rear of the block and relieved any pressure in the crankcase out through a road draft tube that ran down behind the engine. This was connected to an oil trap which was mounted under the manifold and connected to this vent. On your late model block,
the method to vent the block was through a PCV valve which was inserted in the valvecover and connected to the vaccuum of the intake. This means that if you desire to use original style covers on your late model engine, that there is no available opening to allow venting of the crankcase other than the oil fill opening. If you use an original style ventilated fill cap, it will ventilate the crancase but will probably push out a little oil as well on to the intake manifold. This is however, preferable to using a tight oil fill cap and blowing oil out around some gaskets.

Regards, John McGraw

[Rob M.]

Re: C1 59 Valve covers

John,

Thanks for noticing this shortcomming. I wonder if the extra outlet near the oil-cap is doing this job (see picture underneath on the left).

greetings,
Rob.




The C1 1959 Corvette Restoration Project

[Christopher R.]

Re: C1 59 Valve covers

I can't see "the extra outlet near the oil-cap" to which you refer in the photo.

You really can't use those original valve covers on a later model engine. The later model engine is designed for a positive crankcase ventilation (PCV) system using the valve covers. The crankcase is ventilated by taking in fresh air on one side and sucking out fumes on the other. One valve cover is the inlet. The other the outlet. Air goes in 1 valve cover, down through the crankcase, and out the other valve cover. The inlet air is filtered by the carb air filter. The outlet is to manifold vacuum and is controlled by the PCV valve. See diagrams of 1967 and up PCV systems.

Your valve covers have no openings in them. They are sealed. Later model valve covers have holes in them for the PCV system. The later model valve covers also have baffles underneath the holes for oil control. See pictures of 1967 and up valve covers. There are some nice finned aluminum ones from those years.

Your original 1959 motor would have had the air inlet at the oil fill and the outlet at the road draft tube at the back of the block. Your motor doesn't have an outlet at the back of the block. From your photo, it appears that there is only one opening to the crankcase - the oil fill tube. It appears that the oil fill tube is both the inlet and the outlet.

That's not ideal. But it may work OK for you. You're not getting the benefit of flushing the air in the crankcase, so you should change your oil often. But you probably do that anyway. You're not venting blow by gases out of the crankcase, but in a newer motor, there may not be much. Test will be after a long drive at highway speeds. See how much oil mist forms in the engine compartment. If it's really dirty in there after a long drive, you'll know you should do something.

This is a common problem. Many people have later model engines in their C1s, and wish to use the original valve covers (like yours) for appearance sake. Some people have cut holes in the original covers for a PCV system, but have reported problems with sucking in oil. Maybe that could be solved by constructing a baffle such as the later model ones. But wouldn't it break your heart to cut up such pretty valve covers. Usual solution is to use the later model covers with the holes already in them. They're not too expensive. They are finned aluminum, similar in appearance to the original ones. That's what I did.

[John H.]

Re: C1 59 Valve covers

Here's an example of a solution to a proper PCV system on a later block - it's on a C2, but it's the same type of situation you have. The owner drilled a hole near the rear of the driver's side valve cover, installed a baffle inside the cover to avoid oil pullover, and connected that hole to the air cleaner with the usual large-diameter intake hose. The exhaust side is typical, with a sealed cap on the oil fill tube and a PCV valve on the tube with a hose to the PCV port on the carb base.

[John M.]

Re: C1 59 Valve covers

Rob,
Keep in mind that not all C1 corvettes had a vent at the front of the manifold.
Some optional engines used a non-ventilated filler cap and only had the draft tube for ventialtion. Now granted, oil blow-out is much less objectional out of the draft tube than it is at the front of the manifold, but it only illustrates that a second vent is absolutely necessary. If you don't run your engine to high rev's on a regular basis, and your rings are in good condition, you may not have a real problem with oil blow-out. I would drive the car for a while and see if you can live it before drilling holes in a set of original covers. If you just use your car for leisurely weekend drives, You may find that all that is necessary is to wipe the breather off after a long drive.

Regards, John McGraw