Resucitar la carrera - Rebuilding the 1968

[RHough]

Just got the good news / bad news from the machine shop.

Crank and Flywheel spin up near perfect balance! ...

until they bolt on the pressure plate ...

There is enough slop in the pressure plate / flywheel location system (flange on flywheel fit to OD of pressure plate) that the assembly "wants to jump out of the balancer" ... FML out 6oz.

So ... what to do?

I told them to center it and dowel the plate to the flywheel ... if I ever have to replace the pressure plate I'll have to pull dowels and take my chances or pull the flywheel have the new plate/flywheel rebalanced ...

Life in the fast lane ...

What would Bob Hoover do?

[FJCamper]

Hi Randy,

I've noticed the really misshaped oil pickups for some time now. It was important to me because my oil suction kit pickup would not fit over the out-of-shape tube on one engine.

A windage tray, windage pushrod tubes, and an oil suction kit got our 1.6 through the Carrera Panamericana. No dry sump, no deep sump. We went classic.

We've just bought a new aluminum 85.5mm bore Autolinea "race case" for our Historic Sportscar Racing Ghia, and it's oil pickup assembly is really bad. We're replacing it with a nice, factory spec part.

I want to be able to run the oil strainer so as to increase my screening area compared to the smallish oil suction kit pickup. Anything that restricts oil pickup in the CB dry sump pump causes the double whammy of the input oil supply happily flowing into the engine at a high rate while the output oil volume is choked off.

You get an oil-filled engine real fast. It's happened to us a few times, each time due to some different problem.

Make sure you have a removable oil plate on your case so you can drop it and easily remove an obstruction.

Oh -- your observations about the VW crank oil passages was interesting. I'd like to add to your intellectual examination that in the automotive world, the VW/Porsche 356 oiling system is in a class by itself, despite having all the same major components arranged in the same way as other systems.

You will recall Porsche used a roller bearing crank beginning in the 1300 Super. This was pure sex and bragging rights back in the day. Aircooled, roller crank, aluminum cylinders, street racers. Heady stuff.

But the roller cranks were fragile. The Hirths had the worst reputation. The SPG's were a little better. The factory worked with test bed roller crank vs plain bearing cranks (only the rods were on roller), spinning the cranks with electric motors to measure resistance of different configurations, oil weights, and pressures.

Finally, and in the Porsche/VW oiling philosophy of volume, not pressure, the factory developed a plain bearing system that had no more rotational friction than a roller bearing.

This part should interest you. The original 356 and 912 Porsches did not have grooved main bearing oil holes, even though grooving was known to them. VW introduced the directional oil grooves in 1968!

FJC

[sideshow]

J...until they bolt on the pressure plate ...

I was wondering that from when you first posted pictures of that bent crank. My first thought is was the engine damaged in shipping (dropped on the flywheel, hyster aggression, something of that nature).

[Piledriver]

hyster aggression

Ouch, being run through with a fork lift has gotta hurt.

[RHough]

Hi Randy,

...

Oh -- your observations about the VW crank oil passages was interesting. I'd like to add to your intellectual examination that in the automotive world, the VW/Porsche 356 oiling system is in a class by itself, despite having all the same major components arranged in the same way as other systems.

You will recall Porsche used a roller bearing crank beginning in the 1300 Super. This was pure sex and bragging rights back in the day. Aircooled, roller crank, aluminum cylinders, street racers. Heady stuff.

But the roller cranks were fragile. The Hirths had the worst reputation. The SPG's were a little better. The factory worked with test bed roller crank vs plain bearing cranks (only the rods were on roller), spinning the cranks with electric motors to measure resistance of different configurations, oil weights, and pressures.

Finally, and in the Porsche/VW oiling philosophy of volume, not pressure, the factory developed a plain bearing system that had no more rotational friction than a roller bearing.

This part should interest you. The original 356 and 912 Porsches did not have grooved main bearing oil holes, even though grooving was known to them. VW introduced the directional oil grooves in 1968!

FJC

Ah yes the roller crank ... what a cluster. Ball and roller bearings (including needles) like two extremes of lubrication. Very little oil at high RPM or an oil bath and low RPM.

They are great in two-stroke engine that use an oil mix in the fuel for lubrication. Ball bearing mains, roller rod big ends, and needle bearing small ends all work at high rpm in a very low oil environment. Roller element bearing don't handle radial shock loads very well so lugging the engine or detonation hammers the bearings in short order.

In a four stroke crank with roller bearings and a very low volume oil system would work like a two-stroke but if you feed it too much oil the bearings stop rolling and slide. IIRC at about 5000 crank RPM a roller bearing with a constant oil supply acts like a plain bearing and depends on the oil film while the rollers slide along.

When you consider the many parts and large hammers required to assemble and true a roller crank and compare to a forged crank with plain bearings it is no wonder that VW/Porsche went looking for a plain bearing solution.

[FJCamper]

Ref: The Unbalanced (and Their) Pressure Plates

We have an important LeMons race coming up mid-September, and building three engines for LeMons and HSR, so my engine prep hormones are raging. Your out of balance pressure plate description really bothers me.

I have seen -- and have on hand -- some pressure plates and flywheels with big, aggressive balance holes in them. But your "pin-it-to-spin-it" description is the worst I've ever heard of. What about another pressure plate?

When our local shop balances, they have to make absolutely sure the flywheel-to-crank interface is flat and square. They don't do many VW's or Porsches, and on our first experience with them, one of their machinists called me and told me they couldn't get the crank-flywheel I'd left with them balanced.

Talking to the guy, I quickly realized the crank was seated crooked in the flywheel. I told him to remove the gland nut, separate the crank and flywheel, and reassemble it straight. The machinist was embarrassed for himself but disgusted an automaker would use offset, force-fit dowels that get burred and don't just drop into place.

My point is, do you have the world's worst pressure plate or does the machine shop not have the equipment to balance the crank, flywheel, and pressure plate as an assembly?

FJC

[RHough]

Drilling holes in your car ... OMG

Dry sump oil systems require external oil lines. Like deciding to run your veins and arteries outside your skin ...

More time was spent thinking and planning the install than it took to do the work.

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Where to start?
We knew where the Accusump was going to live, so that was the first big hole ... The hole wanted to be through the bumper bracket. No way. We used a 90° full flow hose end on the tank valve and managed to go through the lower corner of the bumper bracket support and into the fender. The hole looks round from this angle, it is actually through the corner of the sheet metal. When the Accusump is mounted, the hose is centred in the hole. Sealing the hole will be a challenge but the -8 (1/2") hose from the oil galley using the old full flow fitting is a short straight run to the Accusump tank.

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Next up was the scavenge loop to the oil tank. We wanted to use a filter adapter that did not have 90° passages, wed also wanted to use big hose. -10 AN is 5/8" so you should have 5/8' pipe fittings ... most full flow filter adapters are on the pressure side and use 3/8" NPT fittings and -8 hoses. Our filter adapter uses 1/2" NPT to -10 AN nipples so the entire run from the scavenge pump to the tank is as big as practical to reduce the restriction. Key design points are; hoses as short as possible, a minimum of fittings, no 90° pipe fittings.

Did I say practical? Just shoot me.

The plan was to mount the filter with the fittings inline with the pump outlet to keep the hoses short and straight. Nope ... not going to work with -10 hose. With a horizontal filter and AN -10 hose the run to the filter inlet was only 6-8". The hose might as well have been solid pipe.

To make this work would require one of these solutions; A filter mount on the engine so that short hose does not have to flex with engine movement, moving the filter to allow flex in the lines, or using a -8 sized system and a vertical filter mount with 90° fittings.

I'm lazy. I also don't want to learn enough engineering to build a oil filter support bracket that won't flex and crack with the weight of the filter on one end and the vibration and movement of the engine on the other ... so I looked for the smoothest curve in the hoses.

This is where the filter ended up. The nice curve in the hoses shown the first image is the good result ... the bad result is that the filter may have to come out to get the CSP valve cover off ... at least there is plenty of flex in the hose to allow that ...

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Back to the tank routing was the next challenge. The location is on the right side of the car to give the shortest, most direct route from the oil tank to the pressure pump. Gear type pumps love a gravity feed, they are great pumpers and lousy suckers. The scavenge pump is close to the sump to take advantage of its limited sucking ability and the return hoses to the tank can be long because the scavenge pump is a full sized 26mm and will pump oil all the way to Germany. The pressure pump is 21mm and with a good prime from a gravity fee of clean oil it can deal with the slightly convoluted internal passages to feed the engine. At least that's the theory.

The obstacles are; the exhaust system, the heater air hose, the O2 sensor & harness, the muffler, and a pesky flange welded under the engine deck ... and that's the bottom. Above the deck Access to the filler / dipstick and the ability to R&R the Carb on the right side without moving the tank are primary concerns. Secondary concern is access to the drain plug.

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It all fits ... The bungs get welded on the tank next week so the final mounts can me fabricated and installed.
Maintenance is more of a hassle now. Drain plug access will require another hole and may just aim the drain at the exhaust. Easier and cleaner to just use a vacuum pump from the filler. Valve adjustment requires removing the muffler on the right side and the filter on the left side so the two 8mm bolts holding the filter mount are not too much more work.

All the holes are 1 3/4" so I only have to source one grommet OD to seal them.

If it works as planned I'm pretty happy

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[RHough]

Ref: The Unbalanced (and Their) Pressure Plates

We have an important LeMons race coming up mid-September, and building three engines for LeMons and HSR, so my engine prep hormones are raging. Your out of balance pressure plate description really bothers me.

I have seen -- and have on hand -- some pressure plates and flywheels with big, aggressive balance holes in them. But your "pin-it-to-spin-it" description is the worst I've ever heard of. What about another pressure plate?

When our local shop balances, they have to make absolutely sure the flywheel-to-crank interface is flat and square. They don't do many VW's or Porsches, and on our first experience with them, one of their machinists called me and told me they couldn't get the crank-flywheel I'd left with them balanced.

Talking to the guy, I quickly realized the crank was seated crooked in the flywheel. I told him to remove the gland nut, separate the crank and flywheel, and reassemble it straight. The machinist was embarrassed for himself but disgusted an automaker would use offset, force-fit dowels that get burred and don't just drop into place.

My point is, do you have the world's worst pressure plate or does the machine shop not have the equipment to balance the crank, flywheel, and pressure plate as an assembly?

FJC

The shop is excellent. They do Formula Vee cranks for some of the best drivers in the area. I suspect that once centered on the flywheel the pressure plate will be okay. If not I'll get 3-4 and tell the vendor that they are going to get all but 1 back after they get checked for balance.

I think the issue is the flywheel. The pressure plate lip is not right. I forgot that VW pressure plates need that flange to center. I'll bet the flywheel is aftermarket from china that was butchered to 10# before it came to me. The pressure plates just drop into the flange, no interference at all.

Looking at several threads here and on the Samba out of balance pressure plates are a know issue ... even on the brand that states theirs should *not" go to the balance shop ...

I'll hear more Monday

[RHough]

My title at Cheap Thrills Racing is "Crew Chief" ... only because someone had to be for a series we ran a couple of years ago ...

bmfk_CheapThrillslogoSML.jpg

If you remember the 60's you know how that fits two old guys running a Spec Miata ...

Today CTR got stoned

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WTF?

Well, as CTR's Crew Chief and the president of OA we did some cam prep ... 50 hours after it should have been done by the first builder.

We're pretty sure Engle Cams are cast iron and they get heat treated after the lobes are ground ... the toe of the lobe looks like this inside:

CAMHARD02.jpg

This is a cam lobe (in case you were wondering)... the edges are sharp enough to cut yourself on.

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So we spent some quality time with oil and stones to take the edge off. If I had a lathe I'd chuck it up after taping the bearing surfaces and actually put a bevel on it ... de-burred will have to be close enough, after all it has run for over 50 hours like this ... The cam thrust bearing looked like it had been scraped so I used the fine stone to make sure the thrust surfaces are clean and smooth. Now the cam is safe for bare hands and new bearings.

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I'm not taking credit for thinking of this ... Bob Hoover wrote about it: http://bobhooversblog.blogspot.ca/2007/ ... tacks.html

You didn't really think I came up with this myself did you?

Big Brother ... and ?
Lead singer was?

Stoned again ...

[Piledriver]

There's a better way...
I use a diamond hone for that, bought from a outdoor supply for $10.
Still good as new after many years, very useful SS coated with nickel/diamond matrix, sold under the "Smiths" brand.
This one looks identical:



Big Brother and the Holding Company.
Janis Joplin

[RHough]

Pull the nut/stud, pull and wiggle, it just has a light press fit.
That really does look horrible.

Right ... about the only thing right about the pickup is it has been expanded to make a tight fit in the case ...

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The OEM pickup looks more expensive, wonder why? Maybe because it fits?

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Nice!

The other part of the VW design oil pickup is the strainer and sump plate assembly. The strainer is pretty elegant, the bottom of the strainer is at the level of the case floor. The sump has great large holes for the oil drain, magnet on the drain plug is cheap and will trap ferrous material small enough to pass the edge of the strainer. There is no concern about the strainer getting plugged, it has a bypass system! Look close, there is a spring in there. I always though the spring was to hold the top of the strainer on the pickup tube. Not so. The pickup tube goes into a collar that is supported at the base of the strainer, the top of the screen is held against a flange on the collar. Should the screen get clogged, the pump suction will try to collapse the screen. The spring will allow the screen to slide down the collar and that opens the pickup tube to unscreened oil. Very cool for a cheap car.

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I think that is about as good as it gets on the scavenge side of the system ... any oil in the sump will get removed.

[RHough]

Valve covers ...

We had the engine in the car while we were laying out the oil lines. I had the nifty new CSP valve covers on the engine because bling

When I was checking clearance between the valve cover and the oil filter to see if I could get the cover off and back on with the filter in place I discovered a fit issue.

The engine does not sit squarely in the engine bay. The back of the engine is high and the right side is a bit lower than the left.

The valve covers hit the body.

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Both valve covers touch the bit of tin that is part of the engine deck behind the air seal. The right side of the bellhousing seal has an air gap to the front air seal.

If the engine has always been not quite square I never noticed with the stock valve covers. The rear corners of the CSP covers hit the tin but have plenty of room at the front corner.

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If we loosen the front trans mount and jack the nose of the transaxle up until the shifter hits the body the engine the engine sits almost level. After we dropped the engine back out we looked at the bellhousing and the mounts. The left bellhousing mount looks compressed compared to the right.

If the wishbone is or trans mount is bent it would cause what we are seeing.

Which is more likely? The frame/wishbones bent or the trans mount bent? How do I fit it?

I'm concerned about trying a new trans mount if the wishbone is bent. If it springs out of whack I'm hooped trying to get it back together,

For now I can just use the stock valve covers while I over think the engine/body alignment problem. I can take some off the corners of the valve covers, trim and or bend the body around the seal for clearance to get the CSP covers to fit ... but I thing the engine should fit in the car correctly before I start filing, bending, or cutting ...

They should get the gloss paint removed and a coat of flat black anyway ...

[FJCamper]

Hi Randy,

If you can cut the body or hammer time, whatever, do it. You may have twisted frame horns or you might have a body setting crooked on the chassis. We do. You can crawl under our Ghia and see the fricking wrinkle in the body metal just forward of the left rear wheel well where the body bolts to the chassis!

Use a gunsmith acid wash and blackening agent to turn that nice CSP valve cover flat black.

On your oil pickup assembly. I take it you have the 19mm tube, not the older 14mm tube?

CIP sells good, straight German pickups. I have to buy one for replacement in the new Autolinea aluminum case we're using for our "Super 90" 85.5mm bore engine.

FJC

[Piledriver]

Make sure the mounts themselves are perfect, the HD factory ones are miles better than the urethane jobs...
The EMPI solid mount//trans strap setup fits like hell but it does work,once you can get it to fit.

Frame horns without a brace can easily get tweaked by reasonable power levels...
Remember, it was designed for ~60HP with a tailwind.

You should be able to tell what's bent with the engine out.

[RHough]

Hi Randy,

If you can cut the body or hammer time, whatever, do it. You may have twisted frame horns or you might have a body setting crooked on the chassis. We do. You can crawl under our Ghia and see the fricking wrinkle in the body metal just forward of the left rear wheel well where the body bolts to the chassis!

Use a gunsmith acid wash and blackening agent to turn that nice CSP valve cover flat black.

On your oil pickup assembly. I take it you have the 19mm tube, not the older 14mm tube?

CIP sells good, straight German pickups. I have to buy one for replacement in the new Autolinea aluminum case we're using for our "Super 90" 85.5mm bore engine.

FJC

They are more like 18mm not 19mm. The OEM (from CIP) is full diameter to the collector on the top of the bell. The one that came in the case is 15-16mm tube that was swaged larger to seal in the case.

When the engine goes in for real I'll try bending the flanges out to clear. I'm trying to avoid hard to reverse changes that kill any collector car value. VW put that flange there for a reason, probably to support the seal. I'll retain that function if possible.