98cc's Cyclecar Build

[98cc]

On 13/02/2019 at 19:35, rot808 said:

I hope you’re keeping the templates to make more for a new race class for surprise Chelsea sugar factory hill climbs haha

Yeah will definitely have to do a couple of early morning runs....

 

Have been working on getting a front axle put together. I’m using Austin 7 front drums and stubs. These needed a bit of a rebuild 

 

Reamed out the kingpin bushes with an adjustable reamer 

 

Set up the stubs in the mill, indicated the king pin to get them square. The dividing head was very good for this job 

 

The worn bottom surface that needs remachining 

 And after 

 

Then needed to make a couple of new kingpins to fit. 4140 bar stock 

 

Finished 

[98cc]

Good progress on the front axle this weekend.

I'm doing a tubular GN style front axle the same as Bloody Mary had.

Axle end blanks. 4140

 

Outer profile milled and kingpin hole bored 

 

Ready to go in the axle tube 

 

 

The axle tube. 1 1/2''   4130 3/16 wall, should be strong enough.....

 

 

Axle end in. These will get brazed into the tube 

 

 

Complete axle 

 

And mock up, made a couple of temporary axle clamps to hang it off the springs. 

 

Bloody Marys front axle showing the Austin 7 front stubs and wheels

 

 

[98cc]

Nice cardboard box arrived from the UK.

 

JAP V twin engine kit set, some assembly required.....

 

 

Should keep me busy for a bit. 

[SOHC]

At my old work we made a pair of chrome molly barrels for a pair of those reproduction cases out of solid bar, and used Ducatti pistons 

[98cc]

Did you ever see the engine run SOHC? 

A bit of info on this engine. It’s a 1930 JAP JTOR long stroke racing model of 1000cc. They were used in racing 3 wheel Morgan’s and Brough Superior motorcycles.  These v twins are very rare these days and are worth a large amount of money. Lucky a place in the UK has reproduced some accurate castings for anyone mad enough to try make their own. I will be changing a few things with this one to try and get a bit more capacity and power out of it. 

Made a start on machining the drive side crankcase half.

Bearing boss faced off to become the first reference surface 

 

Flipped over, mating surface faced and holes drilled.

 

Now clamped down with spacer blocks to machine inner surface and bearing bore

 

Inner features finished

 

 

Next up timing side

[63Ragtop]

All right man, this thread just got real interesting real fast!! Not going to cast your own post one like ol' bert?

 

[SOHC]

Here is the engine, it was built at Mcintosh racing,  it runs well, its around 1100cc, it dropped a valve when the retainer snapped in half but it was ok, I made the exhausts and oils lines, engine plates, mudguards, and half the shit on this bike. it has Hemmings heads, I know a guy who has a KTOR engine on the floor in his shed, I can put you in contact with people but you probable already know them?     

[SOHC]

We were going to use Iron head sportster flywheels with custom knife and fork rods but ended up using what it came with as it was ok, it has side by side rods and the drive side main shaft is very very small  

[98cc]

On 14/04/2019 at 21:55, 63Ragtop said:

All right man, this thread just got real interesting real fast!! Not going to cast your own post one like ol' bert?

 

Cheers mate, na I think I will be doing some flicking through the Wiseco piston catalogue when it gets to that stage...

 

On 15/04/2019 at 11:55, SOHC said:

 

Here is the engine, it was built at Mcintosh racing,  it runs well, its around 1100cc, it dropped a valve when the retainer snapped in half but it was ok, I made the exhausts and oils lines, engine plates, mudguards, and half the shit on this bike. it has Hemmings heads, I know a guy who has a KTOR engine on the floor in his shed, I can put you in contact with people but you probable already know them?

 

We were going to use Iron head sportster flywheels with custom knife and fork rods but ended up using what it came with as it was ok, it has side by side rods and the drive side main shaft is very very small  

 

Wow awesome, would of been great working at Mcintosh. I think I saw that engine run a few years ago when I was visiting Ken.

Were the Hemmings heads original upgrade parts for sidevalve engines? I take it the guy with KTOR on the floor would never part with it?

I’ll be making my own flywheels with press fits throughout, will get a 1.5” dia drive mainshaft with the bearings in have. A bit better that the original..... 

Have got the timing side case machined to the same stage now. 

 

Facing the timing cover mating surface as first reference.

Flipped over and same stuff done as first half 

Internal features finished on both half’s.

 

And with a couple of bolts holding it together.  

Next job get the timing cover bolted on 

[SOHC]

I think the Hemmings heads and barrels were an update for SV engines, the original Hemmings barrels on this engine had been bored too much and the front one blew off just above the flange and did a bit of damage to the frame.

The guy with the KTOR motor has just had a frame made for it, Steve Raffels on the north shore made the frame, that guy who use to own Henderson hire built Morgans and aJAP engine from scratch, I gess you know him?

[flyingbrick]

Awesome!

Since you have a CNC there you could totally put an o-ring groove on one of those mating faces and use rubber cord rather than a regular gasket.. Would be hardly noticeable once assembled and would be an easy foolproof way of ensuring no leaks and easy assembly/disassembly. 

[SOHC]

21 hours ago, flyingbrick said:

Awesome!

Since you have a CNC there you could totally put an o-ring groove on one of those mating faces and use rubber cord rather than a regular gasket.. Would be hardly noticeable once assembled and would be an easy foolproof way of ensuring no leaks and easy assembly/disassembly. 

There must be a reason no motorcycle maker dose that

 

[flyingbrick]

Dunno, i just know car parts do and its awesome

[98cc]

One year later......

So shortly after my post I packed my bags (including a JAP crankcase)  and hopped on a plane to the Uk on the big OE. I’m working in the vintage car world over here and have had some pretty amazing experiences. After spending so many hours looking at pics of cyclecars and the like it’s pretty neat to be at the events where they are running and get a real feel for them. One of the coolest trips I have been on was in Mark Walkers GN Thunderbug. A 4.2 litre Vtwin in a light weight chain drive chassis is definitely a good formula....

 

Some pics from the last year...

 

 

Have many more to put up.

 

With so many good vintage car events over here i need to get a car built so have been working flat out on the engine after hours and have made a fair bit of progress 

Cases bolted together and set up on the rotary table with a mandrel through the drive side bearing boss. Using the boring head to fly cut the decks 

Drilling and boring the cyl stud and follower holes prior to tapping 3/4“ 20 tpi cycle thread, mmmm lovely.....

After all holes drilled and tapped and cyl base spigots bored 

 

Next up barrels

 

 

 

 

 

 

 

 

[rot808]

This all looks like so much fun, you will find it hard to return I bet, did you have any cars going into the Monaco pre war class?

[BlownCorona]

that chain driven blower is so sick. 

 

i can hear it from here. 

[98cc]

On 20/04/2020 at 00:04, rot808 said:

This all looks like so much fun, you will find it hard to return I bet, did you have any cars going into the Monaco pre war class?

Yep I imagine this will be the case. We did, 3 GP Bugatti’s and was going to do the Mille Miglia the weekend before. Was pretty guttered when that was all cancelled. 

On 20/04/2020 at 05:29, BlownCorona said:

that chain driven blower is so sick. 

 

i can hear it from here. 

You just about could of. Chain driven blower might have to be in this cars future. 

Cyl time.

The crowd I got the crankcases of had just done a run of cylinders and heads so I managed to get a set. It was far easier getting them sent a couple of hours down the road instead of to New Zealand that’s for sure. 

 

First issue to sort, the only boring bar big enough was a bit large for the toolpost. 

Couple bits machined up and welded together 

Should do the trick

[98cc]

First cuts on the casting. This was a serious brown undie moment  holding the rough casting on some very narrow jaws boring out a rough casting at the other end.

 

 

Bored out and head spigot machined. 3.5 inch bore

Flipped over and cyl base machined 

[98cc]

Over to the mill to drill through stud holes.

 

Dividing head to do stud clearance cutouts

Repeat x 2 

Will need a final hone when the time comes otherwise finished 

[Mudlark]

Hi 98, great work, can I ask if you are using bushes or bearings to support the cams in the crankcase wall?   I believe the earlier motors had bushes, and later ones bearings, not sure when they changed. Also be very interested to know the dimensions of the main bearing you are using in the timing side, I was wondering about a Harley sportster needle roller bearing, as they are fairly compact and take a one inch mainshaft.  Also, do you have a source for the cams themselves, or are you going to make them?  I’m in Wellington and have some crankcase castings like yours.