Suffolk engine dating

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suffolkalan
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Suffolk engine dating

My first post!

About 20 years ago I was visiting our local tip and spotted an abandoned mower with the same type of engine as my Dad's old Atco, it was a Suffolk (75cc) I had fond memories of this mower with which I would now front and rear lawns - leaving my Dad to clean the mower! which he did and it always looked spotless and well oiled to prevent any corrosion!

Anyway, I whipped the engine off the mower, rebuilt it and used it to drive an alternator via a V belt, it was an early engine with a lovely round silencer.

I have just got hold of another engine which I believe is of an earlier build. Instead of the dipstick being positioned halfway up the crankcase and fairly long this has a short dipstick (actually a calibrated split pin!) positioned in a fitting in the alloy sump section.

It has no spark which is being investigated and the whole engine will be dismantled for cleaning, painting and rebuilding with new seals etc.

Mechanically it seems in pretty good order with compression and no detected shake on the crank.

 

Been reading up on these engines and there seems to be a lot of them manufactured, I believe this one could date from the late fifties with an engine number of 264382, do any of you knowledgeable guys know if that's about right?

Alan

 

wristpin
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As far as I can find out, the

As far as I can find out, the split pin dip stick was used on some models until 1962.  Your engine has the id plate in place and along the top edge it will give the engine type, eg 75 G 14 5A ,B,C &6A etc  which may help to date it more precisely.  The really early engines, pre 1960 usually have cowlings that don't cover the cylinder head  but do have a semi circular baffle around the front of the cylinder fins. In the absence of those two identifying features I would be inclined to date your engine as early   60s rather than late 50s .  

suffolkalan
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Thanks wristpin, the ID plate

Thanks wristpin, the ID plate on the engine says it is 75G14 model 5A.

I have dismantled it for evaluation and it appears in very good order and certainly worthy of saving. A quick resistance measurement of the coil indicate the HT side is open circuit though, hence no spark!

Didn't take a photo but it is a crude looking unit and appears to be wrapped/sealed in paper and brown wax, is this type of coil still available would you know?

I have another engine which is of later years the ID plate on that one says it is a model 28A. This has a plastic encapsulated coil although the flywheel is different the basic engine components look identical.

Is it possible to relate the model numbers to a manufacturing date?

wristpin
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Despite their rather crude

Despite their rather crude construction those fabric wrapped coils seem to last quite well  They are still available from the likes of Villiers Parts - at a price.

Dating. I have a parts sheet for a 5a relating it to 1962 production so presumably a 5 is a bit earlier but as I said in my earlier post the enclosed design of the blower housing suggests post 1960. Your 28 with the self adhesive ID plate is far later.

Hopefully someone else has some more precise information.

 

 

suffolkalan
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Thanks again for the info I

Thanks again for the info I have found examples of the early type you refer to with the open head cowling - quite unusual!

I shall continue with the refurbishment of the engine until I get to the coil!

One more observation is when I removed the crankcase cover/bearing both my early engine 5A and my 28A had two gaskets fitted? Neither leaked but does result in more crankshaft end float?

 

Alan

wristpin
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I can’t remember ever seeing

I can’t remember ever seeing a figure for the end float. Perhaps it was just a matter of ensuring that there was a bit and fitting those gaskets accordingly. It’s years since I’ve had a reason to strip an SIF engine down that far!

suffolkalan
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Just as a point of interest I

Just as a point of interest I know some forum members have raised the point of fuel additives to prevent valve seat recession that once was performed by leaded petrol.

I noted upon cleaning up engine components that the exhaust valve of the Suffolk does in fact have an inserted valve seat which was also on my other engine of later date.

 

Alan

wristpin
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Re valve inserts. Are you

Re valve inserts. Are you sure? I have never seen an iron block SIF engine with inserts, hardened or otherwise - and I’ve owned and worked on a good few. 

My own view is that when used in the lawnmower application they don’t run hot or long enough for seat erosion to be an issue.  If you feel that an additive would help, a drop of Redex is probably ad good as anything.  Most  seat damage is caused by the engines left standing in damp conditions with the valves open and the seats and valve faces getting rusted.

Storing the engines with the valves and contact breaker points shut avoids two of the major causes of starting woes ; stale fuel being the other.

 

 

 

 

 

 

 

suffolkalan
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Definitely sure!

Definitely sure!

I have a 1952 Morris Minor side valve in which I use Castrol Valvemaster as this has been proving that this prevents, or at least slows down the risk of valve seat recession - seems to be doing its job.

As you say these engines are low stressed so like you I was surprised at finding them.

 

wristpin
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I was just about to post an

I was just about to post an edit to my post as I've found a couple of SIF parts books referring to an insert. The strange thing is that having overhauled many engines and sometimes re-cut the the seats, I've never noticed anything to indicate the presence of an insert. Assuming that "insert" refers to a harden steel insert, there should be absolutely no reason for concern about the use of unleaded fuel - at least as far as the exhaust valve seat goes. . 

I've got a couple of spare Suffolk blocks and will be having a closer look!

  

suffolkalan
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Still plodding on with

Still plodding on with component clean up and was considering the replacement coil I will probably need.

Is it known if the later plastic moulded coil is able to replace the earlier waxed/paper version?

I can find the later one but the earlier design is appearing a bit elusive!

 

Alan

wristpin
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The possible incompatibility

The possible incompatibility may be a difference in size of the part of the laminated stator that forms the core of the coil. I should have examples of both stators - somewhere! 

As well as different stator designs earlier engines had bigger , heavier flywheels and I vaguely remember different crankshaft bearing and crankshaft taper sizes.

If it comes to a mixing and matching operation , what will help will be an image of the exterior of the flywheel and a measurement of the internal diameter.

Incidentally do both your engines have the same design and size of flywheel and stator?

EDIT

Just had a bit of a delve into the parts bins and it would seem that the laminates on your engine will be 15mm square where as the more recent plastic coverd coils fit a 9mm square laminate.

Looking at the Villiers Parts web site it appears that George can still supply the old fabric covered coils, S0447,  - £57 !! 

 

suffolkalan
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Thanks for the reply. Your

Thanks for the reply. Your right the laminations are very different in size and obviously not interchangeable. It would mean changing the complete assembly and flywheel, and then if the taper is different! Not wishing to go that route.

By chance I found a place locally which is like a lawnmower breakers yard, fantastic. Guy who obviously knows his stuff knows he has one/some and is going to have a look for me.

Fingers crossed!

£50+ is pushing it a bit.

 

Alan

wristpin
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By chance I found a place

By chance I found a place locally which is like a lawnmower breakers yard, fantastic. Guy who obviously knows his stuff knows he has one/some and is going to have a look for me.

You are fortunate - such places are fast disappearing. Six or seven years ago Suffolks from the 50s and 60s were fairly plentiful on that auction site . Now searching on Vintage.......   brings up stuff that I was selling new 30 years ago!

suffolkalan
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Not heard about a replacement

Not heard about a replacement coil yet so I have been cleaning/refurbishing the ancillary components.

I found the 'jet'? was stuck in the body of the carburettor, penetrating oil and heat finally freed it to reveal the end to be solid with a white powdery compound. Used a piece of wire from a wire brush to clear the small hole in the end of the jet and various sized drills to clear it's it's bore and carb body orifice.

Interestingly I found the butterfly spindle to be very unworn. My original engines spindle was in a very bad way so much so that I made a new one.

Bit disappointed at the short manifold that the carb mounts on as it has been overtightened onto the engine causing it to go quite banana shaped! Have squeezed it back into shape a bit but not wishing to crack the alloy I shall have to machine it flat to ensure some hope of a seal.

Quite enjoying the rebuild though.

Photo of a previous model 26A engine with improvised intake filter.

 

 

Alan

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Not unusual to find bowed

Not unusual to find bowed carb and manifold flanges. Not having machining facilities in house, I find that a surface plate and a sheet of abrasive cloth with lots of lubricant does the job . Start with 80 grit and finish with 600.

I have also found throttle spindle wear to be rather random. Not sure whether it’s a result of very dusty operating conditions or an over active governor. Back in the day a couple of aftermarket supplies sold replacement spindles with a threaded end and nut which overcame the two issues of a worn spindle and a loose arm in one hit.

suffolkalan
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Well I didn't hear anything

Well I didn't hear anything from my breakers yard guy, called in and it seems he hasn't got one after all.

Found another 'mower place' locally who also didn't have one but they had the later Wipac assembly, for £20, I bought one with a view to 'experimenting'

I have removed my defective coil from its laminations, removed the lamination pack from its frame and removed the rivets that hold them all together!

My plan is to reassemble enough laminations so they will make up the required thickness. Obviously they will then be too wide so I was going to machine the pack sufficiently to enable the coil to fit.

Might even work, I'll post the results! (good or bad)

 

Alan