UpFixing the CB Performance Dry Sump Oil Pump Kit

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UpFixing the CB Performance Dry Sump Oil Pump Kit

Post by FJCamper » Wed Aug 24, 2016 12:28 pm

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Above: Two things to fix, the crank pulley and the oil pump cover plate

UpFixing the CB Performance Dry Sump Oil Pump Kit

The CB Performance Dry Sump Oil Pump kit is simple and easy to install, but our experience with them over the years in several engines has revealed two issues that need fixing, one critical, one more of a refinement.

We had recurring problems from the beginning with the press-in oil seal spinning with the crank pulley and leaking oil. Press-in seals are more commonly know as sand seals, and not most engine builder's favorite type of part. "Real" sand seals are machined into the engine case.

On the subject of sand seals, an interesting bit of trivia is the VW engine actually intakes air around the stock crank pulley hub. It has no oil seal. While most VW guys know about the factory design of threads on the pulley hub to "screw" oil back inside the engine that escapes the oil slinger, they are not aware why VW designed the case without a crank pulley oil seal. The air intake around the stock pulley hub normalizes crankcase pressure and helps the venting of vapor and pressure up and out the alternator stand vent tube.

Dune buggy builders soon discovered that the case ingested sand around the pulley hub and the machined-in sand seal was invented. The Porsche 356, once the factory adopted the 3-piece case, has an oil seal behind the crank pulley. To compensate for lack of ventilation breathing, a series of valve cover vent designs were tried. The winner was a vent tube directly in the top of the head (not the valve cover) with a hose feeding to the carb's air filter housing.

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Above: Fixing the crank Pulley

Once during a 14-Hour LeMons enduro, we had seal after seal seize to the pulley hub, spinning the seals, and causing big oil leaks. In desperation, we jammed the pulley down on the nose of a drill motor and with a flat file turned down the hub just enough to clear the seal.

But on two other occasions, with newer but unmodified parts, with the seals firmly JB-Welded in place, we had the seal absolutely weld itself to the hub, ruining the seal and holding on so tight the engine would either not spin over or hold the crank so tightly it felt as if the engine was locked up. And we have a high-torque geared starter.

That is serious friction. And a testimonial to JB Weld!

The permanane fix was to machine 0.007" off all our new pulley hubs. With that clearance, the oil seal still seals and the engine turns easily. Problem solved.

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Above: Replacing the pump cover plate

Aluminum is not a good material for oil pump cover plates. The steel pump gears eat into the softer aluminum, and at some point, the headspace becomes wide enough for oil pressure to bleed around the gears, and you slowly loose oil pressure.

VW and Porsche always used steel pump covers to reduce wear, and even then it was a good idea to flat face the steel pump covers from time to time.

EMPI sells a simple unpainted steel pump cover (part number 9148-7) just 6mm slim, that if used with low-profile valve adjuster nuts on the top two studs, fits under the installed pulley like it was made for it.

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Re: UpFixing the CB Performance Dry Sump Oil Pump Kit

Post by sideshow » Wed Aug 24, 2016 6:58 pm

You know that valve adjusters are M81x1 and oil pump studs are M8x1.25?
Safety wire is better, and maybe bolts compared to cross thread.
Yeah some may call it overkill, but you can't have too much overkill.

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Re: UpFixing the CB Performance Dry Sump Oil Pump Kit

Post by FJCamper » Wed Aug 24, 2016 7:26 pm

Hi Sideshow,

Even before I sent this on today, Jamie, the guy working on this engine, had already converted to bolts.

The stud photos were taken yesterday.

The advantage to bolts is we can now remove the oil cover plate without removing the pulley, should the need arise.

And yes, there is a big difference in valve adjusting stud nuts and regular 8x1.25 "13mm" nuts. We actually have a small supply of 8x1.25 low profile jam nuts. What I failed to do when describing them was qualify "valve adjusting height" nuts.

You must be reading these posts sober. Here's one source:

http://www.ebay.com/itm/like/2009737943 ... noapp=true

I had to have these for some project long ago, and happened to get the carbon steel versions.

FJC

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Re: UpFixing the CB Performance Dry Sump Oil Pump Kit

Post by Piledriver » Wed Aug 24, 2016 11:56 pm

I actually thought about countersinking those for flathead *bolts, torx or such. Pretty common.
Also can be had a low profile panhead.

Didn't gain anything on a T4, but having the fastener flush could be useful on a T1.
Might allow a full size pulley with a little shimming effort.

(I suppose since it would thread into the block it's technically now a "screw" but they are still available in 8.8 or better grades)
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Re: UpFixing the CB Performance Dry Sump Oil Pump Kit

Post by farmer » Thu Aug 25, 2016 12:12 pm

I agree on the steel pump covers. Just steer clear of the cast iron versions, Berg or Empi. They crack.

T

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Re: UpFixing the CB Performance Dry Sump Oil Pump Kit

Post by Piledriver » Thu Aug 25, 2016 1:36 pm

Wasn't someone trying a hard anodized aluminum cover awhile back?
The surface of that is much harder than steel.
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Re: UpFixing the CB Performance Dry Sump Oil Pump Kit

Post by Jerry c 68vw » Wed Feb 14, 2018 5:27 pm

My problem is that it didnt leak at all prior to the rebuild. Now it pours out of the pulley.
It does appear to have a dent on the case where the pulley hub spins that I was not aware of before. I'm assuming thats my problem, along with...how do i fix that?

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Re: UpFixing the CB Performance Dry Sump Oil Pump Kit

Post by Ol'fogasaurus » Wed Feb 14, 2018 7:30 pm

When I saw the words "countersink" (CSK) it put a red flag up. I did do some design work with CSK fasteners and had to do a lot of research in using them. Here are somethings to think about when considering them for use:

There are 4 standard CSKs: 82°, 90°, 100° and 120°. The 82° is going to have the smallest dia. head and it seems to be the most common used one while the 120° is going to have the largest dia. head by far. The 82° CSK is going to go the deepest head penetration (for flushness) into the object and, again, the 120° is going to have the shallowest penetration for flushness so this needs to be considered when going into the thickness/strength of a part.

Strength wise a lot of it has to do with the bolt's material, design qualitied and of course heat treat after forming.

I did a search to give some additional information but there seems to be "hangers" on a lot of the sites so I didn't grab a URL. I did seen some styles of CSK bolts I had never heard of before including a CSK carriage bolt... go figure!

One of my after market parts was designed to use the 120° style (the casting was fairly thin so it required the large head to spread the loading around) and I had a lot of trouble finding one w/o buying a while box of them. Some of the car business guys I talked to, including fastener people, had never seen or even heard of that degree of CSK design head before (many years ago now).

Lee

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