dipped and etched 1500 'S'

dipped and etched 1500 'S'

Monday, September 2, 2013

1602 cc out to the heads 01/09/2013

 
Of course the pulley is only there while I assemble the engine. NOS fans will end up being used.


New AS-41 case used due to cracked original 1500 'S' case.

 
Yes, genuine 40hp Okrasa heads on the engine instead of on my shelving. About time too!


Correct for my model 1500 'S', a 311 905 205D Bosch distributor.


An old Gene Berg pressure relief valve cover I have had for about 20 years. Correct oil pump nuts used of course!


40hp push rod tubes, nickel plated. No room for a thermostat on this engine due to the Okrasa design. Will be on the hunt for a very early 6V magnesium housing without the thermostat rod...


Not original case but hey, not many options now in 2013. Not losing sleep over this though.


Swanky flywheel was a complete and utter bastard. It's on now but wow what a job.


Cylinders were lightly coated in VHT cylinder paint to keep it looking reasonable for a while.


Fuel pump block off is installed just to keep the fuel pump base and gasket compressed while I mess about with sundry other issues. Not a permanent fixture.

 
Gene Berg rocker shafts with NOS 1.1:1 VW rocker arms. Simple and reliable.


What a load of work!

Compared to any other engine I have worked on, including Porsche 911 6 cylinder's, this has to be the biggest pain in the arse engine I have ever dreamt up.

So why the head aches?

Start with an NOS 74 mm SPG roller bearing crank, but consider it has 20 mm pins due to being for a 40hp 1200 cc. Not a big drama surely???

Of course I would have liked to have re-used the original crank case for the 1500 'S' but upon inspection, it was very badly cracked behind the #1 cylinder. Bearing in mind I have repaired this case previously with welding about 15 years ago, I exercised some wisdom (!) and parked the old case. A new AS-41 was purchased and is probably one of the better decisions I have made on this engine. I bought 2 of these crank cases when I built the 2028 cc for the black car so it was just collecting dust anyway.

So the crank is in (with rods obviously) and then the cam dropped in situ.

An Engle 100 with Engle lifters will do the job nicely.

Oil pump is an off the shelf Schadek 21 mm, plugged for full flow and using an old (but 100 miles old so not very old) Gene Berg full flow relief valve pump cover.

Flywheel should be easy as I had an NOS Crown aluminium 200 mm unit from back in the day.

Of course, it did fit but there was a problem. First off, the ring gear was 12V. No biggie as I have numerous ring gears and sure enough an NOS 6V one was found stashed away that I purchased from Gene Berg back when he was still with us (I bought 2 x 6V ring gears from him with the other now fitted to my NOS 1500 'S' engine I have been assembling for the last 20 years but that is another story). Off with the old and on with the new - easy enough.

So while all this is going on, I find a crack in the center of the flywheel where one of the original rivets has cracked the very very very hard center. Hmmm. Obviously this is bad.

I found a perfect 'O' ring flywheel under the bench and proceeded to machine the center out of, handed the center of it to my machinist who then finish machined it to be an exact copy of the original but this time, it's softer than the Crown center being a VW flywheel center which as we all know is not as hard as the gates of hell. We then found some rivets, installed them with an oxy and hammers (!) and finally drilled the center to suit the SPG 8 dowel pattern.

Of course I then had it balanced.

What a load of work for a bloody flywheel.

Anyway, it's a perfect fit and now installed with a Gene Berg chromo flywheel gland nut.

Another win, but not a quick one for sure.

Heads were the next item. These are genuine Okrasa 40hp units that have been machined out to suit the 83 / 85.5 cylinder OD. Nothing too difficult about that. Guides and seats were measured and found to be like new, so after a bit of a search, some NOS valves were located (with the intakes being a non standard VW diameter except for some obscure heads released somewhere at some time) and I thus then assembled the heads with a set of Gene Berg dual springs, chromo retainers and collets.

Another head ache down.

Well kind of as the rocker covers for those of you with a view to detail will see are 'bastard' style. I tracked down a near perfect set of these out of the USA and they are indeed a perfect fit so will be sent off to be baked enamel painted soon (gloss black).

Pistons and cylinders were the next candidate for my grinders and tools of destruction. I was lucky enough to have a set of NOS KS 83 mm 40hp big bore pistons put away so these were utilised (yes, these are quite hard to find!). Of course I machined them on the underside to allow for the clearance required due to the wider width small end of the rods. Not a big drama but afterwards had to balance them again...

The cylinders were the next problem. Because this crank is essentially a stroker 40hp, the cylinders were too long by 4.5 mm when calculated out against the combustion chamber volume I already had and the desired CR of 8.5:1. So with that, I machined up a mandrel to support my NOS Mahle 83 mm 1500 cylinders which took a bit of time in itself and then cut all the cylinder bases the 4.5 mm on a lathe at school. Perfect!

But of course I am not quite finished there am I?

No, of course not.

The cylinder bases needed to be clearanced to allow for the opposing connecting rods hitting them at BDC. Some judicious use of the power file produced the right result and I finished them off with a hand file etc. Lovely stuff.

Next issue to deal with was what head studs to use? It transpired that I had to locate enough original German 8 mm studs of appropriate length (I forget exactly what length was required now) to make it work so I went on the rummage and found just enough in my head stud boxes. Still slightly too long, I then machined off 5 mm from every end of every head stud to get it just right. Again, not a big job, but more time required.

Push rod tubes were a fairly simple affair being stock brand new 40hp push rod tubes and I sent them off to a local chrome plater for a quick nickel plate. They never look great around the corrugations after plating (in my experience) but such is life. They look pretty good and if anyone wants to point out the minor rust that will occur there, fill your boots. It's better than stock rusty crusty which is what would have happened.

So the big day was before me! I had to fit the pistons to the cylinders from the top of the cylinder so as not to destroy the rings by going in through the bottom of the cylinder due to the scalloping of the bases now. Not difficult but a bit of work and not how I do it 99% of the time. With that done, I then wound the head studs into the case (yes they are lightly painted with VHT cylinder paint) and pushed  the heads down to the case. Of course a pair of NOS deflectors were installed after being bake enamelled black. Perfect fit of course (having tested all this out previously).

I also trial fitted the Gene Berg rocker shafts with NOS 1.1:1 VW rockers to correct the side to side shimming and it's all spot on now.

I think it has turned out quite well. It has taken a long time to get it out to the heads and I am now faced with some issues such as completing the intake manifolds for the heads (being Okrasa pattern). I also need to shorten my Gene Berg chromo push rods (probably the next job) and of course all of the tinware needs to be fit and shortened etc to make it all just 'so' and look right.

I do have an NOS abarth 1500 muffler for the engine but I suspect it ain't going to fit so I am probably going to engage Dave Orozco to fabricate a repro Abarth muffler for this engine based on my new exhaust flange to flange dimension but bearing in mind correct center of engine to tail pipe distance.

Some of my friends wonder why this engine has taken so long to build. I think it's fairly evident now why it consumed so much time if you go through it all. I didn't even go into the amount of time required to select the perfect cam gear, clearance the main bearings to suit the SPG crank oiling requirements or tightening up the distributor drive free play or finding correct 1964/65 case hardware or machining down 6 x hardened washers for the main bearing nuts (tighter fit). All this takes time and materials and more time.

This engine confirms I am a masochist.

It is the perfect remedy for an active brain though and I recommend it!

Be good people. Make well judged irrational decisions if you can. Then follow through with them.

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