Petter A1 rebuild

Hi All

I have got a Petter A1, mostly complete but just trying to figure out what I need to get it running. It seems to have some compression but there is a hiss from what i think is the oil breather which I would assume is bad? I'd assume something like piston rings would need doing? Unless this is normal?

Other than that its pretty complete, the magneto works and the opening and closing of he valves all works. The only missing things are the starting handle and the bolt that holds the carburetor on. I have never rebuilt an engine but would like to learn so if it needs stripping, I'm happy to get my teeth into it but I don't want to strip things apart that are fine!

Any thoughts/advice much appreciated

Thanks,
Luke

Hi Luke & welcome aboard. The hissing from the breather sounds quite normal. These engines never did have a lot of compression, & usually you find it comes back after a good run.

If you do want to strip & rebuild an engine then this would be a great one to start with. We'll help out as much as we can, but it might be nice to see if she'll run before you take it apart. I don't always do this as if there are any major problems it can be best to find them before they cause any damage, so sometimes it's best to take it apart first. It all really depends if someone else has had a go before you.

Hope this helps a bit, good luck with it.

Oh yes, where abouts are you in the country (or the world?) We might have a member close to you, just in case you encounter any problems. Also, it's nice to pop along to a show & meet up, if there's any members in your area.

I'm in south wales (near Newport). Everything seems to be there but the HT cable is very frayed and the carburetor is not attached so I've not tried to start it. I've managed to straighten the bolt that holds the carb on but I've no nut to go on the end. Since its imperial size I don't have anything in my nuts and bolts collection that will fit. Anyone know what size this is or which bit to measure to figure it out? (I'm used to Metric so struggling a bit with imperial).

When I have replaced the HT cable and got the carb bolted on I shall try and start it. I did spray a bit of petrol into the inlet manifold, kicked it over and got a satisfying thud noise and some smoke so I'm hopeful it will run without too much work. My biggest concern is that the fuel tank is full of some black gunge that I hope was once petrol. Its like old paint (smells like old paint as well) so I'm hoping its VERY gone off petrol and not that someone has tried to run it on something stupid.

Anyway, thanks for your advice, I'm looking forward to the challenge!

The nut is 5/16th so that's that sorted. I've got a pack of them ordered so once the carb is on I'll see if it runs, watch this space!

bgoth wrote:The nut is 5/16th so that's that sorted. I've got a pack of them ordered so once the carb is on I'll see if it runs, watch this space!

Could be 5/16 Whitworth or 5/16 BSF, Later engines may well have moved to the American threads. But that's unlikely on this one.

I expect it's BSF. But don't worry if you've ordered the wrong type, you'll need some if you're going to pursue the hobby & this engine will probably have both types on it.

I bought a variety pack of BSF nuts, which had the 3 most popular sizes (1/4, 5/16 & 3/8 ), which have come in very handy. Also, if you go to any shows or autojumbles, look out for old tins & boxes of nuts & bolts. Whitworth is the coarser thread, BSF (British Standard Fine) is the finer. Even finer than that is BSC or BSCY (British Standard Cycle thread, otherwise known as Cycle Thread, & yes it does occasionally find it's way onto engines, especially JAP engines).

Whitworth is interchangeable with the American SAE, known to us as UNC (Unified National Coarse) up to about 1/2 inch. They share the same TPI (Threads Per Inch) up to that size (1/2"), but the thread angle is slightly different (but it still works). UNF is the American finer thread & is not interchangeable with any of the British threads.

Small stuff (like magnetos & electrical nuts & bolts) are BA thread.

Confused??? You will be.

So, what's your background? You say you have nuts & bolts, so do you mess around with mechanical stuff?

Also, what's your plans with this engine? Do you intend to show it at steam rallies & get yourself a collection together? Or will it just be a home-based hobby? Something to tinker with in the garage.

Ok, I'm confused now :-) I bought Whitworth because I saw that some other Petter engines used Whitworth but its no loss if I have to buy more, you can't have too many nuts :-)

My background is computers, I'm a software development manager by day but I tinker with stuff, make things out of junk mainly, these are some of my creations to date; (I can't post a link but go to www dot flickr dot com/photos/steampunkjunk/) most of it is work in progress but since I make stuff out of junk I have boxes of nuts and bolts and other less obvious things.

I have no idea what I'm going to do with it to be honest, I want to see it run and I love playing with mechanical things and would be good to get my daughter to understand mechanics a bit as she shows intermittent interest in such things. Other than that, I dunno really, I'm sure I'll think of something to do with it!

Sounds great! Just something to tinker with, so it could go in any of a large number of directions.

Most engines use a combination of Whitworth & BSF. They tend to use the coarser threads when going into softer metals, like aluminium castings, then the finer ones for steel & for nuts. So a typical stud, going into an aluminium casting, would have whitworth on the end going into the ali, & BSF where the nut goes on the end.

But many manufacturers just stuck to one thread type. I'm pretty sure the Ruston Hornsby I just restored was all whitworth threads, even on the smaller stuff, & there was no aluminium on that engine at all.

The trouble is all the spanners & sockets are generally known as Whitworth tools, so many people just assume it's all whitworth threads, but "whitworth" spanners will fit BSF nuts & bolts as well (that was designed to make life easier, & I suppose it did, back in the day)

Anyway, it may be worth your while looking through the restoration threads on the forum, as there are a couple of Petter A1 threads I can think of, & there are undoubtedly more. Maybe try doing a search (I hate saying that to new members, or to anyone, I will find a thread for you & post a link, to get you started).

The Petter A series engines were all very similar, I think there's the Petter A & the Petter A1, possibly the A11. There was a twin cylinder one as well, which I think was the A2 (I've wanted one of those for a while & very nearly bought one a while back, but had too many projects & too little money, so another forum member got it instead, dunno what happened though, he's not been on for some time).

Best of luck, & I can't wait to see some pics.

Oh yes: It might be worth your while going to a few steam rallies in your area. I will have a look at my list & see if I can find you some. There's bound to be a Petter like yours there, there are quite a few of them about, they were a very successful engine in their day.

Here's the link to make it easy to have a look.

http://www.flickr.com/photos/steampunkjunk/

You sure make some ermm strange items.

Stu.

Yes my creations really aren't all that normal :-) They're a bit eclectic so a Petter A1 will fit in just fine :-)

The inevitable has happened, I'm stuck. I cannot start the engine or work out why.

I have taken the head off and after cleaning the valves I now have a decent amount of compression. There is a small amount of blowback through the inlet valve but significantly less.

I have a spark (not sure what a weak spark looks like but I definitely have a spark). I have swapped the broken HT lead for some mains lead (which is the best I had to hand), I assume this will handle the high voltage sufficient to make it work, I'll swap it for proper HT lead later.

I think the timing is ok, it goes off just before the piston reaches the top.

There is petrol in the carb, the float works and pumping air through the carb seems to draw petrol out of the jet (though I expected a bit more of a mist like spray than the big globs of petrol that I get).

I have a tiny leak in the head gasket near the exhaust manifold and the stud that holds the manifold one is a bit bent so its not an amazing fit onto the engine block.

I have sprayed flammable stuff into the inlet valve while turning over and occasionally get combustion but never enough for the engine to seem to be even slightly likely to start. I have downloaded the manual for it and followed several online guides about starting the engine but nothing stands out to me as being an obvious issue. I clearly need some new gaskets and a new stud for the manifold but none of this seems to be sufficient to stop it at least trying to start. I'd suspect the carb but I'm told it should splutter if I spray petrol into the inlet and while it has occasionally ignited its far from consistent.

Any ideas?

Thanks!

Spark! Probably the condenser is knackered. Look up Nutts guide on how to rebuild it, by far the cheapest method. If no improvement then likely to be coil. You can check the coil with a meter. One end to the earth wire and other to the HT pickup on the coil. You need a reading above 3000 ohms for it to work ideally around 5000 ohms. The other thing to check for is any leaks to earth. How clean is the mag? if its covered in grease and dirt then it needs a good clean.

bgoth wrote:The inevitable has happened, I'm stuck. I cannot start the engine or work out why.

I have taken the head off and after cleaning the valves I now have a decent amount of compression. There is a small amount of blowback through the inlet valve but significantly less.

I have a spark (not sure what a weak spark looks like but I definitely have a spark). I have swapped the broken HT lead for some mains lead (which is the best I had to hand), I assume this will handle the high voltage sufficient to make it work, I'll swap it for proper HT lead later.

I think the timing is ok, it goes off just before the piston reaches the top.

There is petrol in the carb, the float works and pumping air through the carb seems to draw petrol out of the jet (though I expected a bit more of a mist like spray than the big globs of petrol that I get).

I have a tiny leak in the head gasket near the exhaust manifold and the stud that holds the manifold one is a bit bent so its not an amazing fit onto the engine block.

I have sprayed flammable stuff into the inlet valve while turning over and occasionally get combustion but never enough for the engine to seem to be even slightly likely to start. I have downloaded the manual for it and followed several online guides about starting the engine but nothing stands out to me as being an obvious issue. I clearly need some new gaskets and a new stud for the manifold but none of this seems to be sufficient to stop it at least trying to start. I'd suspect the carb but I'm told it should splutter if I spray petrol into the inlet and while it has occasionally ignited its far from consistent.

Any ideas?

Thanks!

Where in the country are you? Someone may be able to meet up and help.
Oh and Nuts, A1's have plenty of compression when they are right, you can start mine at Wiston
also, it should go "clang" dead on tdc

It does have a spark when the plug is out but I guess not good enough?
I checked the plug gap (don't have a feeler gauge so it was a bit approximate) but it seemed ok.

Come to think of it I've had less success since I've cleaned up the valves and improved the compression and I've read a few articles that say the spark is harder to generate in compressed air (more resistance as there's more air between the electrodes, makes sense really).

The magneto is absolutely filthy and maybe that mains cable isn't exactly helping either. Hmm. I've had a beer now so I'll look tomorrow, alcohol, petrol and a spark don't mix!

Just a thought, should the mains cable be beefy enough for the job (as a temporary fix) or do I need to go get some HT cable before I go much further? I'd imagine the resistance is pretty low on it. The insulation might not be up to the high voltage but frankly its better than the HT cable that came off it!

I'm in South Wales, just East of Newport, is this where I discover you live half a mile away :-)

bgoth wrote:It does have a spark when the plug is out but I guess not good enough?
I checked the plug gap (don't have a feeler gauge so it was a bit approximate) but it seemed ok.

Come to think of it I've had less success since I've cleaned up the valves and improved the compression and I've read a few articles that say the spark is harder to generate in compressed air (more resistance as there's more air between the electrodes, makes sense really).

The magneto is absolutely filthy and maybe that mains cable isn't exactly helping either. Hmm. I've had a beer now so I'll look tomorrow, alcohol, petrol and a spark don't mix!

Just a thought, should the mains cable be beefy enough for the job (as a temporary fix) or do I need to go get some HT cable before I go much further? I'd imagine the resistance is pretty low on it. The insulation might not be up to the high voltage but frankly its better than the HT cable that came off it!

I'm in South Wales, just East of Newport, is this where I discover you live half a mile away :-)

Unfortunately not lol, I'm in Southampton.
Mains lead will be fine as a conductor, the main difference is HT lead has a much higher rated insulation, poor spark may not be down to the mag, is it a new plug? if not and you've cleaned the old one, how well have you cleaned it? when you turn her over, does it make a nice CLANG noise at TDC whilst giving a spark? If not, you will need to look at the impulse coupling. Then move on, are the points clean? Then condenser, followed lastly by coil. Is the timing right? Does the impulse clang dead on tdc? Sounds also like a new head gasket is required, good luck, keep fighting
Andy

oh and HT cable is best being copper core

The way to look at it, if it was running before and not now what's changed? You've not moved the mag timing so that should be ok. As you say the plug has to do a lot more under compression so maybe re-new the plug and HT lead, don't use a baker-lite cap with a suppressor fitted, try to use just the brass ring type of connector to attach it to the plug. Clean and gap the points look at the points to see if it's been arcing across the tips. Check them first and see how you get on.

Stu.

stationary stu wrote:The way to look at it, if it was running before and not now what's changed? You've not moved the mag timing so that should be ok. As you say the plug has to do a lot more under compression so maybe re-new the plug and HT lead, don't use a baker-lite cap with a suppressor fitted, try to use just the brass ring type of connector to attach it to the plug. Clean and gap the points look at the points to see if it's been arcing across the tips. Check them first and see how you get on.

Stu.

it was in a hedge for an un-known amount of time before stu

The history is a bit limited, "someone chucked it in a hedge, I rescued it". Thats the lot!

Timing looks good, the spark goes off at TDC. The sparkplug is well recessed into the hole though, looking at a diagram on a different type of engine the plug is protruding into the chamber whereas on mine the spark is maybe 5mm back into the hole, I wonder if someone has changed the plug and put the wrong one in at some point. I would expect it to be more "in" the fuel air mix?

I have been turning it over today and got some satisfying pop noises so it feels like its not far from running.

Silly question time....

How fast are you cranking it over?

Petter A1 engines have an impulse on the magneto, turn it too fast and it trips out and you will have a bugger of a job to start it. It should "clonk" when you turn it over.

Silly questions are good, I'd rather it started even if the problem turns out to be me :-)

I watched a video on youtube of someone starting one. I don't have a starting handle (I've seen starting handles go on ebay for nearly as much as a whole engine) but my efforts with a bit of rope around the drive wheel seem to produce a comparable speed. I got a distinct clonk noise from the magneto at TDC, both at the end of compression and exhaust, looking at the gearing I guess that's normal?

The clonk sounds the same when I turn it over really slowly as it does when I'm trying to start it. How would I know if I tripped it out, does it sound different?

I've bought some grinding paste as the valves aren't sealing right and I'll get a new spark plug and a HT lead as those are the main suspects right now. It does feel frustratingly close to running, if I could just get it to run before I went any further I'd know which bits to focus the repair work on.

Also anyone know how to get old petrol out of the tank, its formed a thick glue like jelly at the bottom of the tank?

Right, the "clonk" is right, it should be at TDC on both power and exhaust stroke, when the engine gets up to speed (185rpm I think) the pawl stays in and the clonk stops.

As for old petrol, add new petrol to it, it will de-solve it and you can flush it out that way.

Make sure your valves are well seated, grind them in well, no air leakage on the manifold gasket as this will weaken the mix. and check everything.

OK, lap those valves in, replace head gasket and the HT lead and pop a new plug in
Plugs you could use:
NGK B4ES (best plug to find and works well, if your stuck Halfords sell them but far cheaper if you have a trade card)
Lodge BL14 (like rocking horse pooh but the original spec plug)
Champion N7 or N21

Do you have the engine number? If I get bored I may look at the Petter archives for you

Thanks for your advice, I'll get a new plug, make the temp repairs more permanent, sort out the gaskets and have another go. Need to get myself a starting handle as well, I'm making hard work for myself starting it with a bit of rope!

Engine number is 153958? Last digit is hard to read, I'm guessing a 3 or an 8

Thanks

bgoth wrote:Thanks for your advice, I'll get a new plug, make the temp repairs more permanent, sort out the gaskets and have another go. Need to get myself a starting handle as well, I'm making hard work for myself starting it with a bit of rope!

Engine number is 153958? Last digit is hard to read, I'm guessing a 3 or an 8

Thanks

Ok, I got bored

Engine No 1539583
Customer:
William Bunce & Son
Engineers
Ashbury (Berks)
Swindon (Wilts)
order placed 19/06/1959
2HP at 1000rpm

Engine No 1539588
Customer:
Bomford Bros. Ltd
Pitchell
nr Evesham
order placed 28/04/1959
2HP at 1000rpm

how does that play out?