Squishy, dry-sumped 2276 build thread

[Crawdad]

After a decade of heavy lurking on this site, I have finally pulled the trigger on building a big motor. The cover photo on the original edition of Bill Fisher’s “How to Hot Rod Volkswagen Engines” has haunted me since the early 80’s. It was a picture of something built without compromise, and that’s what made it beautiful. As a teenager I was totally intimidated by the chapters on blueprinting and assembly, but now grasshopper is ready.

The motor will serve both for the street and for the hill climb events I hope to do.

After sending approximately one million dollars to the usual vendors, I’ve got the makings of a motor. Here are the essentials:

Aluminum case, 10 mm head studs
DPR 82 mm crank, type 4 center main, Chevy rod journals
Super Squishy 94s
AA cylinders
5.4 H-beam rods, 5/16 ARP bolts
Web 86A, 1.4 rockers
Los Panchitos heads (the new 044 casting) with 61cc CNC chambers
target CR 9.6:1
Scat Lube-a-lobe lifters
CB dry sump oil pump, ported and o-ringed
44 IDFs, initially
1 5/8 merged header

After waffling between NA and turbo, I have decided to build a NA motor with compression low enough that it can accommodate a turbo later. One major appeal of the squishies is that they will allow me to run plenty of static CR and still add a healthy dose of boost, to judge from the experience of Chip Berks and others (Chip, you’ve been an inspiration).

I’ve built aluminum, split-cased, air cooled motorcycle engines before, but this is my first full build of a VW motor. If it weren’t for this community I would never attempt it. So, thanks to everybody in advance.

[Crawdad]

Panchito casting voids.jpg

When I unpacked the heads from CB, I found these casting voids in one of the chambers. As you can see, one of them is only a couple of millimeters off the exhaust seat. I’m worried the sharp edge of the void could cause a hot spot. If I fill it with a TIG bead, doing so would surely distort the seat and I’d have to have to get both seats recut. I suppose a sharp-edged void is less worrisome than a sharp-edged protrusion? For what it is worth, I sent the picture to CB, and managed to get Pat Downs on the phone. He says the void is a total non-issue. Obviously Pat knows his stuff. Still, I wanted to throw this out to you veterans and get a second opinion.

[Crawdad]

Otherwise the heads look very nice. A straight edge across the valve stems shows them dead-even. That spring on the right is a light checking spring. I opted for the titanium retainers. Sorry for the huge photo.

[Crawdad]

With the crank on precision v-blocks, runout was barely detectable, perhaps .0003-.0004. This crank was welded up from a German core by Jose at DPR with a Type 4 center main and Chevy rod journals.

By the way, this flexible-arm, vice grip indicator holder is a lovely thing, so much faster to set up than a standard magnetic base. Once locked, it’s pretty solid.

[Clatter]

Nice!
Stoked to see a proper build thread!

Anyone with their own set of V-blocks will surely do a fine job..

WRT the casting voids,
Just think of how the carbon soot will eventually fill them in,
especially a void like that, right?

[Crawdad]

When I torqued the rods on the crank to check for oil and side clearance, the #2 rod gave me that queasy feeling you get from a fastener when it’s telling you something is amiss. The rod was binding on the crank too. I found this spot where the crank throw bulges into the rod. Obviously, removing the excess metal without damaging the rod journal will take some care.

[Crawdad]

I protected the rod journal with a hose clamp, with a strip of thin aluminum to prevent scratching the journal in the areas where the hose clamp has sharp threads. I didn’t run the aluminum all the way around because I needed to get the hose clamp as tight as possible up against the journal in the spot where I will be grinding.

Th picture with the magnifying glass shows I got lucky: the bulging bit of weld doesn’t extend all the way down to the fillet area, so I should be able to remove it with a square-edged file.

[Crawdad]

Rod oil and side clearance are now within spec, as measured by plastiguage and feeler gauges, respectively.

I requested the longer-than-stock dowel pins from DPR. Some are longer than others, or the holes are not drilled to equal depths. (I don't want to remove them to check, for fear of damaging them.) The offset pin is shortest. Is it supposed to be that way, maybe to ease flywheel installation? (I'm trying to come up with a charitable interpretation here.)

[Crawdad]

Clatter makes a good point that the voids in the chamber will likely get filled in by carbon, eventually.
I wonder if a little squirt of ceramic coating could be used to do the same? I don't think I'll risk it – adhesion to the sharp edges of the void would be dubious, and I certainly wouldn't want bits of hard ceramic coming loose and getting lodged in the ring lands, for example. At this point I'm inclined to trust Pat Downs and move on.

[Crawdad]

At aircooled.net, John gives a caution about the fit of the big Woodruff key (the one that holds the timing gear) in the crank: if it’s too tight, it will make the crank bulge on either side of the keyway, and if it’s really tight it could even cause the cam gear to distort into an elliptical shape. I used a small-bore gauge to measure the keyway on the crank at .317, and my new genuine Audi/VW key measures .315, so if anything the key is on the loose side.

I also measured the ID of the timing gear at 1.6525, leaving about half a thou clearance to the crank. I thought it was supposed to be an interference fit? Not this one. I submerged it in vegetable oil and heated it on the stove and it slipped right on. Should I worry about the combined effect of a lightly loose gear and a slightly loose key? It’s straight cut, steel, from CB.

Is this too much detail?

[Crawdad]

All eight lifter bores on my Auto Linea case had big burrs at their outer ends. In the second photo you can see that before duburring (top lifter), the lifter would bottom on the burr. After deburring (bottom lifter), they bottom on the underside of the head.

I used a chainsaw file to carefully deburr the edges of the bores while avoiding the bores themselves, and the push rod tube seal areas.

[Crawdad]

Rather than bore the center main saddle to accept a type 4 main bearing, I used an “adapter bearing” that is thinner. It is steel backed, internally grooved, and said to be a BMW part. I got it through Jose at DPR. For anyone looking to find one, it has these markings: AU M7016U AM.

The bearing shells have tangs on them, just like cam bearings. So the case needs to be cut to accept the tangs. (You can see where I marked with a Sharpie.) The bearing is too thin to accept a dowel pin, so the tangs (and bearing crush) are all there is to prevent it from spinning in the case. I used a Dremel to cut reliefs in the case for the tangs. My first go at it looked fine on visual inspection, but when I torqued the case halves together with the bearing shells in place, I could feel an edge where the two shells meet. One shell wasn’t seating completely into its saddle, and the notch needed a bit more notching.

[Crawdad]

I ordered my case from a prestige engine builder, because I liked the idea of the case getting a little attention from a pro. The deal was that he would match the oil holes in the saddles to the main bearings (as well as cut the tang reliefs), so I had the adapter bearing delivered to his shop for that purpose. Ten weeks after charging me the full total for my parts, I got the case. The tangs weren't cut. Below you can see where he ground away at the center main saddle. The sharpie represents the oil hole in the adapter bearing. The two aren't even close. What happened?! The moral of the story, I guess, is that you cannot pay somebody else to care about your motor. Not really. My punishment for thinking otherwise is that some of the support (and heat transfer area) behind the center main has been hogged out for no reason. Onward. I'll ease the hole over toward the sharpie marks with a burr.

[Crawdad]

I managed to finagle use of a granite surface plate (lent by the good folks at Classified Moto) for taking some case measurements, and bought a couple extra sets of precision 1-2-3 blocks for the purpose. They’re not expensive (about $15 per pair).

I had previously measured the distances from the case parting line to the bottoms of the main saddles, using a dowel at the bottom of the saddles for my depth mic to bottom on. Here I am measuring from the cylinder seating surfaces to the case parting line (plus and minus various blocks).

After measuring all around, then doing a bit of arithmetic, I determined that the axis of the crank is offset toward the 3/4 side by about .005.

[Crawdad]

Measuring the cylinders from the head seating surface to the case seating surface was also a two-step process: from the head seating surface to the bottom of the spigot, minus…
From the bottom of the spigot to the case seating surface.

In an attempt to equalize deck heights, I will put the shorter cylinders on the 3/4 side, and make up any difference from one bank of cylinders to the other with shims. (The rods measure equal in length.)