C2 427 valve cover drippers?

[Ted Koehner (24972)]

Just bought a 427-425 1966, numbers matching roadster. It has aluminum aftermarket valve covers, I want to replace them with painted, correct valve covers. I have a set without the drippers. If I use valve covers without drippers can I do damage to engine. I assume they are there for a purpose. What application does valve covers without drippers have? Can I safely use the valve covers without drippers?

[Joe Lucia (12484)]

Re: C2 427 valve cover drippers?

Ted------

The drippers were used on high performance and special high performance engines in order to provide extra drip lubrication to the rocker arm pivots. If you drive your car in a normal, "street legal" manner, I don't think that the lack of drippers will cause any problem, at all. However, there are options for you:

1) Obtain a set of reproduction valve covers that have the drippers. The US made examples are expensive. However, the foreign-made pieces, while not being exactly correct, are very nice pieces. You can get the C2 style, unpainted big block covers WITH drippers for less than $100 per set. Noah Performance is one source;

2) Obtain a set of drippers and install them yourself. This can be done with epoxy if you do it correctly. I've developed a method for this and I'm VERY confident that it will be as durable as the original sspot-welded system. In fact, that's exactly what I plan to do with my "ZL-1" if I end up using stock-type rocker arms. The epoxied-in drippers avoid the marring of the external valve cover surface caused by the spot welds used to attach the originals. Dripper rails can be purchased from Cranes Corvette of San Diego. They can also sell you very fine, American made, exact reproductions of the original covers, but the cost is about $500 per pair;

3) Install roller rocker arms. Then you don't need (or want) dripper rails in the covers.

[Clem Zahrobsky (45134)]

Re: C2 427 valve cover drippers?

no problem with well broken in rocker balls,just do not do that with new rockers and balls because the oil from the pushrod over shots the rocker arm pivot point.

[Craig Schultz (29385)]

Re: C2 427 valve cover drippers?

Joe - just curious on the Noah Perf covers and what is different from the originals....I have a set for my 66 with drippers. When I called, they indicated they had the original tooling, but did have them stamped offshore. It sounds like that may not be the case based on your observations...althought they do seem to be of high quality. Thx..Craig

[Joe Lucia (12484)]

Re: C2 427 valve cover drippers?

Craig-----

The covers, themselves, are identical. However, I'm not sure that the configuration of the attached bracketry (wire stands, etc.) is exactly the same as original. There were so many different configurations of these attached components that there were a "zillion" different big block valve cover part numbers. I'm not sure if the Noah covers are true to the configuration used on the other Chevrolet cars (undoubtedly, their biggest market) or the Corvette configuration. I expect the former, though. They do not have any covers that are Corvette-specific, as far as I know. And, they don't have the late 68+ left side cover.

If they are using the original tooling, somebody must have spent a million bucks having it refurbished and made better than it ever was when GM was having the covers made with it. The quality of the stampings of these covers is FAR, FAR, FAR better than any GM cover that I have ever seen. There are NO die marks, "wrinkles", "crinkles", or creases anywhere on them. You'll NEVER, EVER see a GM cover like that.

[Patrick Hulst (16386)]

Re: C2 427 valve cover drippers?

Aren't you thinking of roller rockers for the ZL-1? It seems sort of backwards to use a roller cam but use the old style rockers.

Just a thought.

Patrick

[Clem Zahrobsky (45134)]

patrick

roller rockers will not fit under the stock BBC covers because of the poly locks being too tall.

[Joe Lucia (12484)]

Re: patrick

Clem and Patrick----

Yes, that's EXACTLY the issue. If I was sure that they'd fit under stock valve covers, I'd already have purchased them and have them waiting to install. However, I keep getting conflicting information as to whether they'll actually fit under stock valve covers. Some say they won't fit under any circumstances; some say they will fit if there are no drippers in the covers; some say that they will fit if there are no drippers AND a slightly thicker valve cover gasket is used. So, to settle this whole issue I've been thinking of just buying a set and determining for myself if they'll fit. If they don't, I'm out $350. But, at least I'll know for sure.

By the way, I would NEVER, EVER use anything but stock style valve covers on my engine. NEVER, EVER, FOR ANY REASON. Also, I'd NEVER, EVER use the Comp Cams "Magnum" rockers (the die cast ones that use a stock type rocker ball and nut but have a "roller tip". 95% of the benefit in aftermarket rocker arms is in the roller bearing fulcrum, NOT the tip. To me, I think that the "Magnum" rockers are "hokey" (but, PLEASE, if anyone out there uses them DON'T be insulted; that's just my OPINION and NOT a statement of fact). I'll either be using Comp Cams Pro Magnum roller rockers (the most likley to fit if ANY roller rocker will fit), stock GM #3959182 (which I already have), or Crane Nitro-Carb stock-type rockers.

By the way, an update on the "ZL-1's" status: it would already be completed save for 2 issues that have been "hanging" for quite awhile:

1) The roller lifter anti-rotation plates did not fit properly in the block (they couldn't be installed over the lifters due to insufficient machining of reliefs in the lifter valley). I solved the problem by judicious and careful grinding of the anti-rotatation plates and very slight grinding (with a Dremel tool and micro-bit) of the corners of the core plug bosses in the lifter valley. However, I'm still waiting for GM's approval of the "fix" and confirmation that no other problem exists. I don't want to proceed with assembly until I get their ok. My fix seems to have worked perfectly, though;

2) The curent-production ZL-1 block (but NOT the original) uses special, bullet-nosed main bearing cap studs. These studs do not provide for the installation of the windage tray. GM sent me a set of the bullet-nosed studs which do provide for installation of the windage tray and those are what I installed. The problem is that these studs only work with a new design windage tray (the same one used on the "Ram Jet ZL-1" engine assembly and the new "ZZ-620/720" big blocks). That tray has not been released yet as a seperate part and is not in GMSPO inventory. I have a few folks "bird-*******" it and, supposedly, its release is imminent. I should have one of the first ones sold.

I have made adapters that would allow me to use the original style windage tray with the ZL-1 studs. However, I know that as soon as I do this, the new tray will become available the next day and then I'll want to disassemble the thing and install the new one. So, I'm "in waiting".

[Joe Lucia (12484)]

Addendum

By the way, I've discovered many "challenges" in the assembly of the "ZL-1" from the current-production short block. I hope that I've successfully surmounted ALL of the "surprises" that are in store for me and that additional ones aren't "lurking" out there, ready to "rear their ugly head". Assembly of this engine is NOT as simple as building up a normal cast iron big block or, even, an original, 1969-72-era ZL-1 block.

[Clem Zahrobsky (45134)]

roller rockers under stock covers

we machined aluminum spacers to use between the heads and the stock covers for the BBC we ran at daytona. i think someone now sells these. make sure you "break" all the sharp edges on the roller lifters that come in contact with the aluminum lifter bores unless they are sleeved because they will wear the aluminum lifter bores very quickly. i would sleeve the lifter bores on any aluminum block just to be safe.

[Joe Lucia (12484)]

Re: roller rockers under stock covers

clem-----

The current production ZL-1 block has the lifter bores sleeved as-delivered, so there's nothing else that needs to be done in that regard. That's one problem that I didn't have to deal with.

I've seen some of the spacers that you decribed. The problem is that they still make the stock covers look "too tall" and make the engine look "out-of-proportion". Certainly, that wouldn't be a problem at Daytona where functionality counts for everything and "appearance" is a minor matter. But, for me, keeping the engine's "stock proportions" is very important. I'll forgo roller rockers to do it, but I'd like to use them if I can get away with doing it by eliminating the drippers and using slightly thicker valve cover gaskets (I usually use Fel-Pro 5/16" thick Cork-Prene anyway, but I might use Earl's on this engine).

In the last few years I somewhere saw an ad for ultra low profile "poly-lock" type nuts to help solve the valve cover clearance issue with roller rockers. The nuts are, of course, the whole problem; the rockers would otherwise clear just fine. I just can't recall where I saw it. I really think that these lock nuts could be manufactured with a lower profile than they typically have.

Also, I don't understand why a Nylock-style lock nut couldn't be used with these roller rockers if a really thin-walled socket could be found. Functionally, I would think that the Nylock-type nut should work as well for the roller rockers as for stamped steel. The main problem is getting the nut and/or socket into the cavity on the roller rocker.

The "Stover-type" lock nuts have a larger across-the-flats dimension than the Nylock or "distorted thread" type lock nuts for any given size. That's why I suggest the Nylock (or, "distorted thread") style lock nuts. I don't think that the Stover-type lock nuts would even fit into the cavity on the rockers.

[Craig Schultz (29385)]

Re: C2 427 valve cover drippers?

Thx Joe - the specific covers I bought were listed as Corvette specific for 66 with the large squash for PB booster, and the bracket for the wire loom was different than for 67. However, I can't attest to the exact bracket configurations as far as accuracy. Maybe I will take a few pictures and compare with some of the cars being judged this year in Bloomington...and you are right, the stamping quality appears excellent. When you speak to someone on the phone at these places, it is always hard to tell if you are getting a line or the truth, but they certainly will be a nice set of covers for the car....thx, Craig

[Craig Schultz (29385)]

Re: patrick

Clem and Joe - I used comp cams pro magnum roller rockers on my LS6 crate engine with a set of aluminum winters d port heads circa 1995. I used the poly locks and a set of 68-70 vintage chrome GM covers with drippers (although the drippers are probably not necessary, and maybe I should change covers). I used the GM neoprene metal core reusable gaskets with the spreader bars from GM. As I sent photos to Joe a while back, this did clear after I machined the poly lock length down on certain rocker studs, and I don't remember which offhand. As I recall, it was the ones on the drivers side rear, in the cyl 7 area due to the "squash" for the PB booster. I was careful to allow clearance for the full valve lift as you can get the hex of the poly lock too close to the rocker arm slot if you don't pay attention, but it did work with the stock 4362 cam with .520 lift. I am not so sure this would work with Joe's roller cam which would probably have much higher lift than the .520 (.496 taking tappet clearance into account). This was a very "tight" fit to make this work....Craig

[Clem Zahrobsky (45134)]

Re: roller rockers under stock covers

joe if you are using a hydraulic roller setup where you do not have to adjust the valves you could use a fixed length stand off and a allen bolt like the GEN III engines. you could contact "harland sharp" in strongsville ohio as they do custom roller rockers setups. 440-238-3260

[Patrick Hulst (16386)]

Re: Patrick

OK, I thought we had discussed using them, and now I recall your issue of height.

I, too, recall someone advertising the shorter locks as you describe. I had considered using roller rockers in my 71 350 when I rebuilt it, but had the same concern regarding clearance issues. At that time the Internet was in its infancy (1995) and I couldn't hop on a Discussion Board and see if it had been done. So, instead I used Hokey CompCams Magnum roller tip rockers as below.

If nothing else, I hope the roller tips keep the valve aligned a little straighter when going up and down and save some wear on the valve guides but more importantly the valve seats. They were free, and couldn't be any worse than stock rocker arms.

Patrick