Newbie Questions

Malc, Nice engine, and a reasonable price for one that is almost complete and on a trolley. You will need lots of petrol for it - unleaded will be fine unless you intend running for long periods under full load when some upper cylinder lubricant (eg Redex) and a lead additive might be advisable - they have a reputation as being excessively thirsty engines, likely as not due to the long inlet tract. Get yourself a copy of the Stationary Engine Magazine, their is a helpline contact for Petters. Their may be a manual available at

Best of luck!

Cheers Dan

It may be worth asking on the Internal Fire Museum forum. There's a contributor there who's particularly knowledgable in all things Petter.

Internal Fire also have many manuals on their site. You have to be a friend of the museum to access them but that's well worthwhile. So is a visit for that matter.

Your engine will be fine on unleaded petrol, Lead was generally added to petrol post WW11 so your's is designed to run without it. Even if it wasn't, you're unlikely to run it enough to cause any problems.

Good find BTW

John

Malc,

Its a Petter PU2/8 or as your badge says a Universal. I owned a military version for years in a two man carry frame with tool box included. As Dan points out it runs at approx 3000 rpm and can be thirsty, if you know anybody with Stationary engine magazines you want April 1984 as it has an article on them in it or I could copy my copy. Try The Petter Universal Engine Register, 42 Richmond Road, Rugby, Warwickshire. CV21 3AB a Mr IC Purvis.

Martin P

Thanks everybody, I'll start looking at some of those sources. According to the plate on mine it should run at either 800 or 1800 rpm.

This is the PU2, the PU8 is a much bigger beast altogether. The 2 isn't so bad on fuel but you'll certainly get more bangs per tankfull if you lag the inlet pipes!

Good price, they usually fetch £100 more than that!

regards,

Kim Siddorn

Teach a child to be polite and courteous and you create an adult that can't merge a car into faster traffic.

Ok but why? Condensing fuel air mixture?

That's comforting, at least I haven't been ripped off.

an interesting engine. the photos of it remind me of a quite similar engine that was used in the Crosley model CB-42 auto. it was, ISTR 32 cubic inches displacement. the crosley car company certainly didn't have the resources at that time to design it's own engine. i'm wondering if the crosley l-head engines could have been these as a basis. the later onan model CCK looks somewhat similar but not as close as the petter. a friend had a CB-42 car and i had an old harley motorcycle engine of

"malc" wrote (snip):-

Probably. Those long, cold inlet pipes encourage fuel to drop out of suspension at the low gas speeds pertaining in light running. The liquid fuel will not burn properly and the specific fuel consumption goes sky high. The Norman T600 is another engine of the same layout noted for its thirst under rally conditions. Curiously the smaller T300 does not suffer the same problem, perhaps because its inlet pipes are cast into the cylinder walls and thus pick up a bit more heat. Rather than lagging the inlet pipes, perhaps one could try and duct a bit of hot exhaust around them - clearly this would reduce volumetric efficiency and thus maximum power output, but might help with light load fuel consumption.

Nick H

Many flat twins suffer from chilly pipes! The Coventry Victors have exposed inlet pipes and only when under load are they warm enough to pass the fuel mixture intact. However, the larger ones are pigs to start - as indeed is the PU8, the fuel falling out of the mixture as the gentle rain from Heaven ;o)) I've poured a kettle full of boiling water over the induction systems before now with gratifying results.

The Norman T300 is - as Nick said - free of this curse, the induction being buried in the crankcase & barrels. The huge fan (the spokes of the BIG aluminium flywheel) passes so much air over the whole engine that it never gets past warm when run off load.

To preserve originality, temporary lagging with a strip of old towelling would be good, especially as it will retain the heat from the kettle for a few minutes which might well be all you need.

Of course, the slower you can get it to run, the fewer times it goes bang & the less fuel it uses. I have a PU2 with one cylinder replaced with an air compressor cylinder. I exhibited it at a Lister-Tyndale rally some years ago & spent an interesting day in the sunshine leaning off the mixture, experimenting with different plugs, slow running needle & choke settings. In the end, I had it running reliably with an NGK extended nose plug with a somewhat smaller gap than recommended on both plug and points. The plug nose was grey and the engine would run quite slowly - I'd judge around 400 - 500 RPM. Subsequent running showed that it could not be run this slowly on cold winter days as the induction pipe would frost with condensation on the outside and - one assumed - with fuel on the inside.

One last thing, I've noticed that the plug still gets wet whilst condensation of fuel is taking place. I assume that this is either water condensing from the induction air or the heavier - and less volatile fractions - of the fuel.

What does the panel think??

regards,

Kim Siddorn

It's not only flat twins that are affected by inlet freezing. V twin Morgan 3 wheelers are also suseptible as was my Mini after I'd split the inlet and exhaust manifolds. Does lagging the inlet pipes help? As the fuel evaporates it absorbs heat. This lowers it's temperature and that of anything it's in contact with. Surely insulating the inlet manifold will reduce any possibility of heat pickup.

John

"John" wrote (snip):-

That would certainly be my working hypothesis, though I do take the point that Kim's 'steaming nappies' may be a temporary palliative to aid starting. BTW. If I remember my Vizard correctly, separating the inlet and exhaust manifolds on a BMC A series is worth something like a 10% increase in peak torque.

Nick H.

You do indeed remeber correctly. However, that's on the dyno and in the real winter world of Derbyshire rallying, the carb ices up to the point where the throttle and dashpot stops moving. The effect is particularly pronounced after going through water and creating large amounts of steam which condenses and then freeze on the carb. That reduces the power somewhat. A water heated inlet manifold solved that problem. Strangely, twin carbs didn't seem to suffer as much.

John

John

(snip) J> Strangely, twin carbs didn't seem to suffer as much.

J> John

Getting dangerously OT here, but the twin SU manifold for the BMC A (or B for that matter) series is so short that heat soak from the head is probably enough to take the chill of the carbs.

nickh=== Posted with Qusnetsoft NewsReader 2.2.0.8

I'd not intended that the lagging should be permanent & John is quite right of course. Once the thing is running, the cooling air becomes warm & keeps the exposed pipe from getting chilly.

I'm surprised the inlet manifold on a JAP freezes - It is pretty short & lodged between two hot cylinder heads - just goes to show the power of condensation.

In an effort to get my old CF van to do more than 15 to the gallon, I once made up a SHORT manifold adaptor in steel & fitted an SU carb. It promptly froze solid on tickover. Various attempts to ameliorate the problem by ducting warm air to it were not a complete cure & it had the most enormous flat spot at higher revs. I put up with it for a few weeks & put the old Zenith back on. It didn't make a lot of difference to the MPG either ............

regards,

Kim Siddorn