Seven Petter M types |
Picture Links |
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| An 8 hp M type from 1922 (#60790) One of only
1250 made before production was ceased in favour of the 8hp S type in 1923 or 1924. I would love to hear from any previous owners |
Just arrived | |
| And for comparison a 1923 8hp M (#61044) that arrived here on
7/4/2002 One of the last 250 made and with a surprising number of differences from the very slightly earlier model above. The major differences are: - Ring oiled main bearings rather than Stauffer greasers - BTH magneto with built-in impulse (BTH M1 AF2) replaces the Thomson-Bennet AD1 with external impulse - Bolt top exhaust pot as opposed to the screw in top - A revised oil bottle which appears on no other model (AFAIK) and a style of separate dripper that makes a brief appearance on several sizes of both M and S during 1923. - Odd bosses on the base tank. (Purpose unknown - suggestions welcome). The incorrect drain tap has been replaced. - The absence of the speed control lever. Saw/file marks are visible. Was it sawn off in the works or did it break in use afterwards? Why the extra bosses and the duplication of the VB part number prefix between the M and S type? I don't know but I am reminded that a Petter designer went to Hamworthy in 1923 and produced a direct-injection spark-ignition engine. Here is a picture of an 8hp Hamworthy for comparison It runs well but as always the little end is slack and the starting side main is worn |
The whole engine (non-original priming cup) | |
| A 5hp Jellymould #44548 from late on in 1918 in very original
condition. Until recently this engines sawed logs for a domestic fire in Suffolk. It had performed this duty for some 40 years during which it was well maintained but the exhaust pot was exposed to the weather. Prior to that it is said to have driven a sawbench in the Greene King brewery to provide the staves for barrels. It does run but will need new little end bush and gudgeon pin and new mains. As can readily be seen the exhaust pot has corroded beyond redemption (Anyone got a spare to sell?). The big end is sound and there is plenty of compression. The Thomson Bennet magneto has some detail differences to others I have seen including having a cam that is not a complete ring. In addition to the usual Stauffer greasers on the front of the main housings it has smaller Staffers on the rear. These are labelled "System Stauffer 2". The pulley has been expertly enlarged by the addition of a beautifully made two part wooden pulley turned from Elm. Sadly the original skids and tank box are utterly rotted. The oiling system on this model is by the right hand carb chamber via a dripper into the air intake . The fuel is pumped from the base tank by a Petter patent piston pump the operation of which is rendered marginal by the loss of crankcase compression through the badly worn main bearings. The thick coating of sawdust and oil has generally preserved the original paint and the base has vestiges of the "Five horse" transfer. The head which gives this model its common name has a vertical crack on each side of the water jacket. These have been brazed in the past but have resplit. |
Running after a fashion
Carb detail. The brass label says Fuel and Lubrication Magneto (Thomson Bennet) later absorbed into BTH Governer showing sleeve added to take up wear. A production feature post 1931
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| A most interesting tank cooled 2
1/2 hp Petter Junior (VA) Serial 52636 with uncommon oiling system. It has
lain largely unrestored but in safe hands since 1977. It is complete with original skids
and tank which is very large for a 2 1/2hp. The serial is on the flywheels and keys. The mains have no provision for greasers and the main journals are both scrolled and both webs drilled for the big end oil feed. One main housing has a cast in boss for the oiler pressure-feed. It has the Victory style oil level plug but this has been filed off flush. The reed valve plate has the hole for the earlier type of oiling. The engine has the twin feed cast oiler operated by crankcase compression and adjusted by two horizontal knurled brass knobs. These discharge via copper pipes into holes in each main bearing housing and are then scrolled into the big end. Since there is no way to drain the crankcase all the oil must end up going out of the exhaust so this must smoke a lot...and it does!!! Anyone know what drip rate to set? David Edgington's excellent SEM articles on M types mentions that this feature appeared briefly on the Little Pet (Fart) series 1 and on some 3hp models. The article says about late 21 or early 22 and Mike Sage's dating guide gives very early 1922 for this engine. The magneto is a BTH M1-R serial 869115. It also has the remains of the five horses transfer and a speeder. The oiler has the outline of a transfer which says "Keep well filled". The tank also originally bore a stencil saying "Petter Junior Oil engine" which the previous owner traced out and which can therefore be reproduced. As loaded in the car in the dark and wet the engine clanked horribly and it sounded like the big end had gone. In fact although the gudgeon pin will need replacing its not too bad and the big end is fine. The noise was piston slap due to all rings being siezed. Strip, clean, unstick rings, a few new gaskets and a retime (nearly 180 out ) and it runs a treat. As it is such clean external condition I favour new rings and gudgeon pin and repaint the head only. In the last three pics the engine is running although the flash hides the fact. |
Roughly
reassembled on skids (the wrong way round) Oiler top, crankcase level plug, and reed valve housing |
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All together | |
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Front view, | |
| A 5hp tank cooled
serial 48007 which dates it to very early in 1922. It has the plain
whitemetal main bearings with Stauffer greasers. It also has all the Victory features
except the later Paraffin head. Restoration is stalled because it had a standard size
piston in a +1/16" bore very artfully contrived with piston rings that took up the
space!! Update from David Edgington 15/11/2000: Sold as a No.2 Petter-Light to E.L.Short & Co. on 1/6/1921 |
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| Here is the engine as it arrived home after being slightly dismantled so it would fit in the back of the car! | pic1 | |
| The flywheels which carry the correct serial | pic 2 | |
| A view of the big end. The level plug is directly below. Later models have a drain tap. The fuel cap has threads but the hole in the base tank does not , and looks like it never had. Probably because its been drilled out after the base tank was skilfully welded back together from 5 pieces | pic3 | |
| A view of the Victory style arch crankcase base and sheet steel "bed cover". | pic 4 | |
| A pile of parts in which the unusual diaphragm features :-) | pic 5 | |
| A front view of the Thomson Bennet type AC1 magneto (#20572) looks bad but cleaned up and works. The cap is missing. What should it look like and what is the purpose of the little cooper loop at the front? I now know that the copper loop is a fixing to stop the cover dropping off (hah!) | pic 6 | |
| Side view of the magneto | pic 7 | |
| The cylinder head showing the cast in "Paraffin" legend | pic 8 | |
| Two views of the big end journal. Now metal sprayed to original size and reground | pic 9 & 10 | |
I assume this is how a main flange is supposed to look? |
pic 11 | |
| But this one seems to have been worn badly by the excessive end float. I propose to machine this, and the crank web flat and make a phosphor bronze thrust ring. Now done. | pic 12 |