Tarpen generator

[mattblack 76]

This is the new project I mentioned in another thread. It's a Type 40, 110V DC, 400W. It appears to be complete but obviously hasn't run for a while. The first job will be be a session with the degreaser and pressure washer. Can anyone give an approximate year to it?

 

[Stormin 4,458]

 Paul Mackellow will no doubt help. He's a Tarpen collector.

[mattblack 76]

Forgot to mention, When I knew I was getting it I had a hunt round my Mum's garage for my late father's Tarpen hedgetrimmer, but it must have been the one and only thing he ever threw away...

[Rayp 46]

I no longer have the hedgetrimmer, but I do have the leaflet for it and am attaching a copy.

[Stormin 4,458]

 I like the cutting farm and road side hedges bit. Think I'd prefer a tractor and flail.

[Anglo Traction 1,016]

Good project there. Did a quick search for it and throws up several restoration builds of the same unit on 'U' bend toob

[pmackellow 2,738]

That unit would be late 1930's,

 

I have a couple of them and one was new in 1938 to Scotney Castle in Kent.

 

[mattblack 76]

1 hour ago, pmackellow said:

That unit would be late 1930's,

 

I have a couple of them and one was new in 1938 to Scotney Castle in Kent.

 

Wow, I thought it would be 60's at the oldest.

 

Am I right in thinking it's a JAP engine made just for this application?

[pmackellow 2,738]

17 hours ago, mattblack said:

Wow, I thought it would be 60's at the oldest.

 

Am I right in thinking it's a JAP engine made just for this application?

 

No, its Tarpens own two stroke engine

 

[mattblack 76]

Gave this a clean today, how does so much oil end up on the outside of a 2 - stroke machine 

I'm erring towards getting it running and generating (with luck) and doing an 'oily rag' resto rather than repainting it.

 

[mattblack 76]

Split into it big 'lumps' today.

Looks like I need to make a puller that picks up on the starter pulley holes to remove the flywheel (at least it's keyed so no faffing around with the timing, unlike a certain other engine make...)

 

[mattblack 76]

Not very pretty, but it worked.

 

I will clean and set the points and check for a spark and take it from there.

[mattblack 76]

Well, with the points cleaned and set I pulled it over with the rope and got a good spark 

So I delved in deeper...

 

Piston has some damage to the edge of the crown, and there is a lot of play in the little end (between the piston and gudgeon pin)

No major scoring on the bore

The head gasket was this homemade paper affair and not doing much, I would imagine that I will have to get one made unless I can lay my hands on some copper sheet and do it myself?

 

Is it worth (or even a good idea) to hone the bore if I re-use the same piston rings?

[Wristpin 400]

Rather than honing the bore which implies stones and the removal of metal , I’d clean it up with a flap  wheel.  The Cords piston ring people used to sell various sizes of what appeared to be standard 80 and 120 grit flap wheels on extended spindles to reach down the bore and I’ve subsequently used standard diy wheels with an extension shaft that I think came with some wood boring bits. 

Clean the bore as best you can and offer up the rings to it and see what gaps you have. If you need new rings you may find that Tarpen economised by using the same sizes as another mass produced engine manufacturer but if push comes to shove there are a couple of firms that will make rings to order - but at a price!

As you are probably aware, with a two stroke you not only need compression in the accepted sense but also sufficient sealing to transfer the mixture from the crank case via the transfer ports. That takes us to crankcase sealing  including , if applicable, the joint between two halves, the main bearing seals and the joint between the case and cylinder barrel. Two strokes are equally sensitive to crankcase integrity as they are to cylinder compression.

[mattblack 76]

That's a good idea about the flap wheel, I have a flexible drive so may be able to do it with a standard wheel.

 

I did wonder if the rings would be an off the shelf part.

 

The crankcase bushes seem good, with no movement that I can feel. My biggest concern is the movement between the gudgeon pin and piston.

 

At the end of the day I will be happy to get it running again, It's not like it's going to be a 'working' engine running on load for hours.

[Wristpin 400]

The wear between the piston and pin will certainly be noisy but shouldn’t prevent it running. My pet hobby horse for vintage two strokes is old oil for old engines. That is don’t make up the mixture with s modern synthetic oil , use a vintage two stroke such as those marketed by Millers or Morris Lubricants which are basically a non detergent SAE 30 or 40 and have plenty of body to help with main bearing sealing etc.. I’m guessing that the mixing ratio for your engine will be 16:1.

[mattblack 76]

11 hours ago, Wristpin said:

The wear between the piston and pin will certainly be noisy but shouldn’t prevent it running. My pet hobby horse for vintage two strokes is old oil for old engines. That is don’t make up the mixture with s modern synthetic oil , use a vintage two stroke such as those marketed by Millers or Morris Lubricants which are basically a non detergent SAE 30 or 40 and have plenty of body to help with main bearing sealing etc.. I’m guessing that the mixing ratio for your engine will be 16:1.

 

You've just answered my next question...!

[mattblack 76]

Had to remove the contact breaker cam to get the crank out but there wasn't much room between the cam and the crankcase, luckily I had an old puller that I could 'modify' to get it started.

 

The remains of the gaskets were well gummed on, but I remembered a trick from when I first started in the motor trade.

 

 

...Followed by a sheet of 150 grit wet and dry laid flat on the bench with plenty of lubrication.

 

[mattblack 76]

Bore was cleaned up with a flap wheel as suggested, followed by a sanding pad with plenty of maintenance spray.

When I cleaned up the head the lack of head gasket was revealed... there isn't one, this seal sits in the recess in the head. But I only found out after I had damaged it with the wire wheel. 

Not sure what's going on with spark plug, this is the one that was fitted (which looks like one for a Ford Pinto engine) but the hole isn't fully threaded anyway. 

 

Piston cleaned up.

 

[mattblack 76]

Still plodding away on this...

 

The engine is back together with home made gaskets and (cover your ears) a smear of gasket goo.

 

I enquired about a head sealing ring, Cox and Turner had a slightly smaller on in stock but I decided to have a bash at making one. I got some 1.5mm thick copper, cut the centre out with a 50mm cutter in the bench drill and then cut the outside out with snips. After a session with the bench grinder it didn't look too bad.

 

 

I temporarily refitted the engine on the frame to make tightening the head bolts easier.

Carb stripped and given a good soak in brake cleaner.

 

The air filter/choke has had a bash, it was jammed open and is missing the lever. I'm going to try to split it and repair it.

Edited April 16, 2019 by mattblack

[Stormin 4,458]

Nice job with the sealing ring.

[mattblack 76]

20 hours ago, Stormin said:

Nice job with the sealing ring.

 

Thanks, I hope the copper is soft enough to form a seal, but it won't be the end of the world if I have to find an alternative.

[Stormin 4,458]

Look up annealing copper on google. Might be worth doing.

[mattblack 76]

Progress has been slow on this of late as I am trying to sort out my Cortina so it is back on the road for summer.

 

I had a go at annealing the sealing ring, not sure if I got it hot enough with my little blowtorch but fingers crossed.

 

I split the air filter/choke by grinding away the folded-over edge and drilling out the centre rivet, then straightened it out as best I could. I then welded a new lever on the inner piece. welding it back together was a pain, it kept catching the inner so I had to grind the weld off and start again. It ended up looking a bit dog-eared so I wrapped some metal pipe insulation tape around it.

 

I did manage to have a couple of hours on it this afternoon, it now looks like this. next job is to clean out the fuel tank and then it will be a case of seeing if it will actually run.

 

 

I now seem to be sharing my limited workshop space with one of my O/Hs projects...

 

[mattblack 76]

The bottom of the tank was coated with this 'orrible sludge, the outlet and tap were completely blocked. I had to sacrifice the gauze filter on the tap.