Sunday, April 10, 2016

Building a power plant for the Nautilus, Part 2

As mentioned, I'm building two VW engines right now.  I figured that if I'm in 'engine building mode', I might as well stay with the program.  Besides...there are now some serious space considerations and building and installing engines fits with my goals.

I thought I had a well developed plan for the 1500S years ago.  I found a decent, potentially numbers matching engine case from a completely parted out Type 34 in reasonably good shape.  I had it sent off to RIMCO for double thrust cam bearing cut, line bore, cylinder decking, lifter bore dressing, case savers, oil galley plugs removed and threaded, and to have the top breather port cut to the 'D' shape.  This last bit was to address potential blow-by issues in the Type 3 1500S engine as noted in a factory bulletin from early '64.  I'll have to address this opening a bit because it really isn't the correct shape and needs a little cleanup to allow the metal breather plate to be installed flat and in the correct orientation.  My new drill press will get a workout, I think.  Otherwise, the case just needs a really good cleaning...or, so I thought.

I've never really been happy with the 69mm crank I have.  It's a DPR crank and should be a good fit in the engine case, but I noticed some welding at the gussets that should have been better dressed during its production.  Maybe no big thing, but I'm not happy with it.  The rods I have are reworked stockers and are ok, but nothing special in the balancing.  The flywheel is stock weight, but 8 dowelled/6 Volt/200mm with an O-ring--so that's kind of different.  Nothing really unique in this engine configuration and it really just represents an overall upgrade of the stock configuration.  On the other hand, it could be argued that it comes with a downgrade because the counterweighted crank is heavier than stock.  To offset this, a couple of years ago I decided to have a lightened 13lb flywheel constructed, 8 dowelled/6 Volt/200mm with an O-ring.  I have a tachometer for the Type 34 to monitor RPMs and I figure it might liven things up for the typical driving I plan to do in the car.  If I dislike it and the car bogs like heck on the hills, I'll have the stock weight unit to go back to.  I plan on having both flywheels balanced for this engine so I can do that without throwing things out of balance.

A few months ago I was inspired by Aaron Britcher and his 74mm SPG based engine to purchase from DPR a 74mm plain bearing crank for my engine build.  At the same time, I also purchased a set of 'AA' brand Porsche length (5.325") stroker connecting rods, which should help maintain the external size of the engine given the 'A' pistons I will be using.  A set of ARP 2000 rod bolts was included with the rods, which was unexpected and very nice to find.  The pistons I plan on using are the Kolbenschmidt 83mm dome top 'S' style, so this should essentially give me a Porsche 356/912 internal engine dimension and result in an approximate 1602cc displacement.  This configuration worked for Porsche and their relatively heavy cars, so it should work for me and the Type 34.  With an Engle W100 cam, gear and lifters, I should be all set, but I also plan to try 1.25 to 1 rockers.  None of this is earth shattering, but it should give a little extra grunt to move a heavier Type 3 vehicle.

The heads are square boss single ports with heavy duty springs.  I want to say that these are those that would be found on the '66 Type 3 engine.  I had some polishing done, but their ability to breath might be the weak link in this engine.  I might want to have some more work done to them by folks who know best.  It also depends on what needs to be done to help the carburetors breathe a little more.  I plan to run stock carbs, re-jetted for altitude, with larger venturis.

I'm doing a lot of measuring and gut checking right now.  I might need to do some grinding on the case to fit the larger crank.  Once everything is clearanced, I'll send parts out for balancing--but I think I need to find another shop for that work.

Quality time with Winston, Part 2

It's taking me forever to get anything done with anything VW related.  I have decided the best use of my time is to focus on projects that result in a significant reduction in the use of storage and garage space.  VW engines are fairly compact packages when built out, but not when strewn about in pieces.  And I think we can all agree that the best storage place for a Karmann Ghia engine is when it's correctly built and installed within its respective car.  So, I'm getting on with it then. Two engines to build.

I next decided to 'warm-up' my engine building skills with Winston's 40 Horse.  When last we checked in on Winston and his 'freshly rebuilt--though seriously ailing' power plant, it had a significant oil leak.  It was misfiring, had an exhaust leak or two, and was just generally unhappy with its lot.  In the three years since then, I've collected a bunch of parts and should have some good options for this rebuild.  As mentioned, I found enough wrong during the main seal replacement with the flywheel and its shims that I decided a complete teardown would be a good idea.  Again, that big puddle of oil developing under the car after each run really drove my decision.  I also felt a little excessive heat, saw a fluttering oil light and some disturbing ping'ing during hard acceleration, even with modest distributor advance.  Made me wonder if the installation of the Mahle 40 Horse Big Bore kit and previous head flycutting resulted in an excessive compression ratio.  Lots of concerns and time to lift the veil of mystery and get my hands dirty to resolve it all.

I chose to use the original heads, case, 180mm flywheel and hardware.  The heads are square boss '65 heads and they cleaned up real nice.  The flywheel was already done.  The case was sent to three different places to check for cracks--with none found.  It was then sent on to RIMCO to again check for cracks, then machine for double thrust cam bearings.  It also got ANOTHER line bore!  Because after 375 miles it needed one!?!?  And that line bore also went along with a custom thrust cut to #1 main bearing.  The lifter bores were surfaced/clearance.  The case already had the inserts for the head studs and cylinder deck seemed ok.  I had RIMCO send along a set of Silverline (#2 steel backed) main bearings and found that they are really, really nice bearings.  Dare I say nicer than the Mahle/Kolbenschmidt bearings I've seen of late?  I was worried about Silverline--but no longer.  Cam bearings are Mahle double thrust, because they were locally sourced at NuVintage.  I chose a set of Bugpack lightweight lifters and a Norris 329S cam, with a Webcam bolt on gear I had laying around.  The pump is a nice old Schadek 21mm.  I found a set of 6mm sealing nuts and a real nice stock cover for it, then blueprinted the pump.  No clearance of the pump body was required, otherwise.  I did have to work over the cam bearings to give the cam a little endplay in the case, but the lifter to lobe clearance was plentiful.  The crank was NOS 64mm.  The rods were the original to the engine, balanced end to end and for total weight.  New pressure place was sourced, because that's what you do.

I then decided to have the engine parts dynamically balanced, but I made a mistake by not using Denver Balancing for the work.  The shop I used instead found a bent crank pulley, so I had to source one and this turned into a year long inexplicable ordeal to find the correct part and have it powder coated.  The second round of dynamic balancing went well--until I checked the shop's work.  Let's just say that I might as well have not bothered with balancing because their idea of balancing is not mine. and had to fix some of it.  I've got to check and see if Denver Balancing is still in business and use them instead.

Anyway...all seemed in readiness...until I requested a re-hone of the cylinders.  The shop delivery person accidentally dropped them onto the shop parking lot and made quite a mess of them.  I don't know the whole story, but a scramble ensued to find me another set.  These pistons and cylinders were the old style Mahle 83mm 40HP big bore with ~350 miles on them, so they were essentially like new.  I paid good money for them.  However, what I got back was...well...I don't know their provenance, really.  They aren't well balanced.  I don't like what was done to the piston pins to clean them up because they are really sloppy in the rod bush.  It's not the stuff I sent them and I kind of feel cheated, really.  And, they are not easily replaced with as new parts.

The 'cylinder kit incident' happened easily two years ago, but it sort of left me a bit disinterested in the project--that is, until I purchased an  'AA Pistons' 40Horse Big Bore 83mm kit shortly thereafter.  Yes, they are Chinese parts and I was afraid of them.  It served to stall the project, further while I half heartedly looked for NOS Mahles.  Only recently did I actually pull one of these AA pistons out of its liner and take my first look at things.  Let me say that I was really impressed and unimpressed, all at the same time.  The cylinders are great.  I ran calipers, tested ring gaps (Deves), and used an internal bore gauge to measure everything, and was quite happy with the cylinder.  The piston rings seem like they might be Grants--or, clones.  Completely usable, but I'm going with Deves.  The piston pin retainers are decent circlips and completely usable.  Now, what I did not like at all was the casting and machining of the pistons themselves between the crown and the first ring land.  Two pistons were scratched and pitted, where it seemed they didn't get the machining correctly done to remove all of the casting recesses in the raw piston.  I'd classify these as 'Seconds' and not necessarily something I'd want in my freshly rebuild engine.  Having discovered this well outside of my warranty period, I ordered another set of pistons from 'AA Pistons' for $100.00, shipped.  We'll see how these look, and then go from there.

While I'm waiting for the pistons, I've decided to get the deck height sorted using the pistons I have.  I'm assuming that AA Pistons hasn't made any broad and sweeping changes to their piston design in the past three years...and probably is a rash assumption on my part in any case...but what I found is that the AA Pistons do not like my '65 Type 1 case.  The case at the case webbing at the #3 spigot interferes significantly with the piston side skirt at the flywheel side and I believe I will have to crack apart the case to do some grinding.  The Mahle pistons don't have any problems, here, and when comparing the two pistons I can see why.  The Mahle's have a shallower side skirt by quite a margin.  So...there's that.  I also compared the deckheight measurements for both the Mahles and the AAs and now have an idea of the cylinder base shims I need for piston to head clearance for each, but need to 'cc' the heads to adjust that to reduce the compression ratio to sane levels.  In the AAs favor, I was given a more consistent deck height measurement across all cylinders.

This is getting fun!

UPDATE:  The pistons arrived today and they are excellent.  No casting marks, scuffs or other abnormalities.  Unfortunately, the piston design remains the same and there's still the interference with the case at #3--and possibly with at least one other cylinder spigot.  Deck height remains unchanged with these new pistons, so that's good, but weights are all over the place.  Piston pin weights are nearly 20 grams more than the Mahle pins.

Now...do I use the old Mahles, or crack the case and clearance it, then go with the new AAs?  Hmmm....