ES2 Engine problems

Hi Dan....yes it does seem a mystery.....but the top -end noise might be the rockers spindles are loose in the rocker cover and when it warms up there is clearance enough to let them move up and down.....Also check that the rockers are not touching the inside of the rocker cover, perhaps the rockers are incorrect but only slight grinding needed if this is so to achieve clearance.

I always use a long screwdriver as a stethoscope to narrow down engine noises and to make it more effective either block the opposite ear with a finger or wear a tight fitting ear plug. This way only sounds from the stethoscope enter the ear making it much more effective.

As for the oil, well you've covered all the head possibilities, unless the oil is travelling across the head joint directly into the bore, in effect head gasket leak. OR the new piston has not yet bedded in....also use at least 40 weight oil.

Les

Hi Dan, I had a similar smoking problem with my 1935 ES2. I had the head rebuilt,again by Mike P. I also sent him the Barrel,Piston and Rings. He found that the ring gap wasn't only just to big but instead of the rings being gapped at an angle they had been filed straight.The piston,strangely was found to be slightly tight in the bore,even though it wasn't a new piston.Anyhow,he replaced the rings,honed the barrel so the piston wouldn't be tight and the rings would bed in properly.I should point out the piston was only a tiny bit tight. I also made sure the bearing in the crankcase breather was free as per Mikes surgestion.Having put it all back together,it runs perfectly.I have done 400 miles of running in ie not labouring the engine,reving hard,and not holding it at a constant speed etc and not the slightest hint of smoke.Before it was literally like a bonfire coming out the exhaust,you couldn't use it on the road it was that bad.Good luck hope this might help.Regards.Nick.

Dan.Sorry forgot to add that Mike also lapped the head to the barrel for me too as mine also has no head gasket.

Hi Dan

Your oil problem sounds very similar to mine a while back. The responses on this thread where very helpful and all seems ok now. I have done about 150miles with the rubber o-rings on the stems and the correct size washers on the union bolt, as per the drawing Barry posted. It's using virtually no oil, there are no leaks and it doesn't seem to be smoking at all. It's definitely worth checking those sealing washers!

Good luck

Andy

Hi Dan I also had the same excessive oil burning problem after a total engine overhaul. When I removing the rocker box, I noticed it was dripping with oil and even though I had reamed the valve guides on the minimum clearance side, when removing the valves, a very obvious bead of oil had collected around the underside.I discovered the excessive oil was flooding down the inlet guideand burning off on the piston crown and blowing out the exhaust. I removed the banjo bolt feeding the rockers and soldered up one of the two inlet holes under the banjo effectively halving the oil flow. Instant improvement, no more smoke nor oily exhaust pipe. I also machined up a larger bore breather behind the primary inner cover, though I don't know how much effect this had as the original had performed apparently OK previously.

Paul

Hi Dan,

Your engine seems to have the symptoms of excessive piston to bore clearance. Can you remember the measurement when you built the engine? It should be 0.005"/0.006" ( 0.12/0.15 mm ) measured at the bottom front or back of the piston. If the gap is more than 0.015" ( 0.4 mm ) this will be excessive and cause piston slap which may well be the noise your engine is making. Compression will be good because the excessive oil will make a hydraulic seal when you kick it over. If this is the case you will also have excessive crank-case pressure which can force oil up the push-rod tubes into the rocker box. The diameter of the two oil feed holes in the rocker box banjo bolt should only be about 2 mm to limit the oil supply. Regards, Richard.

Hello. like i said before without the head on with the piston back in the bore clamp the barrel down. collect the oil from rocker feed into something. clean all the oil out of the bore and off the piston then kick the engine over about 30 times and observe if any oil is being left at the top of the bore. noise wise on mine before it was re lined the back pressure would force the valve lifter to clack being pushed in and out against the alloy on the rocker box i thought it was piston clacking at the time. Barry.

just found a photo of mine

Block off the oil feed to the head,if after a few miles the smoke stops you know its NOT the piston.

Its a simple and quick test to block the head feed, assumptions are worth nothing if wrong, even the best expert can make the odd mistake.

Hello.as i found out at the end of the day the bore had been honed to the next piston size not a good thing as i was told it was probably done with a cheap three leg honer because of how the bore had a mirror like Finnish. in turn this effected the next size piston fitment it would have been out of spec so i decided to have it relined by SRM. Barry.

Well, having had EXACTLY the same problem after completely refurbishing my ES2 engine several years ago. After swapping pistons, rings, making a much larger case breather valve, checking how much oil residue was in sump etc etc, I did notice upon one quick strip down after a run, that the inlet valve, when I popped it out and stood on the bench, that a very obvious circle (read puddle), of oil was gathering around the seating face, from the tulip(the port was dry).It was coming down the stem, I also noticed that the rocker box was very wet, evident when I sat it on the bench, and then lifted after a while to see how much oil had drained down.

I then soldered up one of the cross drilled holes in the feed banjo bolt for the rockers...............Instant success, no more smoky exhaust. Give it a go Dan, you have tried just about everything else.

Paul

My 99 was getting too much oil on the plugs, but not enough to the rockers which were dry. the overoiling to the plugs solved itself after a number of spirited rides finally bedded the rings in after many years light use . Now its a pain to kick over ,the compression is not helping the sciatica. I fitted a jubilee sized banjo on the return to get more oil to the rockers,this brought back the overoiled plugs plus a puzzling tendancy for the tank to fill with mayonaze and the distributor to fill with oil. My thinking was that the oil was now circulating the engine and not bothering much with the oil tank!I am gradually reducing the tank restriction in steps till I get the head flow correct. The plugs are now ok ,the dissy seems happy,and the bike is performing like never before,except the clutch is now protesting about the power its handling. This is what classic ownership is all about. Involving ,it is.

Here is a the inlet valve I removed when the engine cooled down after a hour or so. I pulled it straight out of the guideand placed on bench in the position in photo after a smoky run.The oil was very evidentabove the seat after I returned to the shed later in the day for more head scratching. The valvehad beennew and I had previously reamedthe guide a tad on the tight side upon the initial full restoration.

Another thing that hasn't been mentioned is the oilway between the head and barrel. Like other people I've had my 1955 ES2 improved by Mike P, in this work the oil way that drains the rocker box to the sump had a small oil seal (O ring) fitted into the head. After putting the engine into my frame and test riding it I had an unusual noise, which I wondered if it was the dynamo bearings - but no.

After some investigation I found that this little O ring between the head and the barrel was badly deformed, thus allowing crankcase pressure to push oil out between the head and the barrel i.e. an external oil leak! This was happening because the drain hole on the head was not in line with the hole in the barrel, so the little O ring was not sealing oil way and was partly blocking the drainage route.

Now this may not be the solution to the excess oil getting into the combustion chamber, but it's worth checking to see if this is causing the noise where hydraulic pressure is being released at the head / barrel joint.

I'm planning to remove the head an barrel over Christmas to see how to resolve the O ring problem, so may have more to report after this.

Philip

just wondering if the piston oil ring only fits one way and its upside down. Barry.

Previously Dan Field wrote:

I'm looking for some inspiration/guidance!

I have two problems with my engine 55 ES2, one is oil getting into the combustion chamber and the other is a noise a bit reminiscent of a high mileage Ford pinto engine!

The bottom end was allegedly rebuilt before the bike was put away in the 90s, it has since had a rebore and was fitted with modded 16h piston. It has smoked excessively, esp when cold, since I bought it and got it going - compression is good and it runs without a head gasket, on removing the head there was oil on the top of the piston, about half a teaspoon. There was also oil in the ports. The head has since away to mike P, and has new valves guides, valve seats and springs etc. There is no longer any oil in the intake port but there still is on the piston. I was unsure about the piston so have just fitted a new Gandini piston, all in spec, and I was hopeful that this would solve the problem but alas no, it smokes as much as ever! Primary and mag chains are adjusted properly.

I thought the oil might be because of wet sumping, but I tried draining the sump before starting and that made no difference either.

Which brings me on to the noise, this seems to be at the top end but it's difficult to say. When I removed the 16h piston to my concern I could see that it had been just hitting the head because the chamfer on the piston crown was too small. There is no evidence of the new piston hitting but the noise is still there. I've checked the push rods, they are ok. And nothing is lose. My disadvantage is that I don't know how noisy these engines are normally, mine is certainly lovely and quiet when cold, it takes about a minute for the noise to appear.

i can only think big end/Rod damage as a result of the piston touching the head but it seems to be higher than that. Do the cam bushes or followers suffer wear on these engines?

any thoughts?

If there is no head gasket, the oil could be coming from the oil feed that comes up through the back of the barrel to the rocker box. Well there is one on my Model 18.

Paul Gerrard

If there is no head gasket, the oil could be coming from the oil feed that comes up the back of the barrel to the rocker box. Well there is one on my Model 18.

Paul Gerrard

Hi Dan. Don't know if you have managed to sort the oil leaking into the cylinder problem.? I also have a 1955 es2 520cc short stroke motor which Mike P tuned about 12 years ago which I have done track days on and have been to the Isle Of Man 7 times ( oh and not hanging about.) However. I have also experienced oil coming from between the cylinder head and barrel externally so I removed the head and found that the two small rubber rings had become hard and brittle allowing oil to be forced out so I replaced them following lapping the head in ( no head gasket.) which solved the problem.

While I had the head an barrel off I drilled and tapped the crankcasesand fitted a 1/4" breather in the same position as a Norton International which also seems to have helped this high revving engine.

Brian Gore.

Quote:

Any suggestions welcome! dan

You are running it on 2 stroke petrol mix?.....

Les

Hi Dan

I am sure the problems I had with oil getting into the head and a smoking exhaust where caused by too much oil in the rocker box. The banjo bolt is quite a loose fit in the banjo but the washers on either side need to be tight on the bolt. I had oil running up the outside of the banjo bolt so the holes in it where doing nothing at all to regulate the flow. Fitted different washers and saw a huge improvement. I've attached a picture that was sent to me on another thread that made this clearer.

I also did some work on the breathing of the engine. I now have a 12mm pipe running to a read valve breather and going into a dump tank tucked up in front of the gearbox and out of sight once the primary chain case goes on. This also helps with the oil tightness of the engine, I presume by reducing the crankcase pressure. I also no longer have that annoying drip under the breather. Touch wood my engine is now oil tight apart from the odd drop from the timing chest breather. But next time I have the bike up on the bench I have an oil seal to fit behind the sprocket on the inlet cam so should hopefully solve that as well.

Now if only I could get the gearbox oil tight!

Attached are some pictures. Good luck

Andy

And as I still don't seem to be able to load more than one picture at a time, here we go...

Excuse the rough soldering and paintwork, it was very much a case of lets just fit it and see if it works at this point, it does so next time its off I might tidy it up a bit.

The finished item in place and connected up. The 12mm pipe is too big to get a normal fitting that close to the case, so I made a special fitting that uses a jubilee clip to pull the thin walled union that's had slots cut down the sides in to clamp the 12mm tube. So far so good.

And finally with the primary chain case in place its virtually out of sight. Just a glimpse of the rubber pipe.

Now what can I play with next?...

Andy

Fingers crossed for Dan's problem, but Andy,if you fit an oil seal behind the inlet cam sprocket, you will be running the maggy chain dry! I fitted a small round plastic catch bottle zip tied to the frame rail and out of sight in front of the gear box to catch the occasional drop of oil.

Previously Dan Field wrote:

Thanks guys, I was using lose fitting fibre washers on the banjo, having them fit tight to the bolt will help because as you say at the moment the holes are superfluous! Not sure if there's room for an o ring but will have a look, otherwise I'll make a couple of tight fitting washers.

Andy thats a sophisticated catch tank! Mine is a trials bike so I'll run the breather up under the seat and fit it with a small k and n type filter.

HI Dan,

The piston Oil ring for the GPM piston is designed to go one way only. The rings are normally fitted when they arrive but I have on a few occasions found them up side down. I have attached a picture of the rings correctly fitted...NOTE the taper to the top. Cheers

Steve

G'day Dan. We spoke at the Bristol show when you were hopeful that the problem had been solved. Any recent news? Cheers....Chris

George. A quick share of your hijack of Dan's thread.

I used felt for making oil seals available in sheet form in different thicknesses from www.vintagecarparts.co.UK. nice and compressible.

In theory you shouldn't need a seal but as they say, every little helps.

Dan, if you have starved the oil from the top end, it has to be coming up past the rings. Assuming that you can't have two duff pistons, this limits it to clearances, surface finish of rebore, alignment (bent rod, bore not parallel with vertical axis of engine) excessive oil in crankcase which is unlikely as you have drained the sump or a breather problem. With the engine running can you feel the breather working?

Colin

I don't suppose it's just a bit of oil that runs down after the engine has stopped is it? Perhaps you could do a check of actual oil consumption. It could also be the need to run the piston in. Just my two pen'orth.

It took my big bore (530cc) ES2 near 2,000 miles before it settled down and oil stopped coming out of the relief at the bottom of the timing chain housing. Not to mention the smoking. Running rich didn't help with the running in either, making the oil dirty very quickly. It's not bad now, slightly rich so I always carry a spare Champion N5c just in case. I'm trying to find the N8, Martyn Bratby gave me years ago. That helped quite a bit to keep it clean up top.

Now, on the other hand my rebuilt poor man's Manx ES2 motor with a re-sleeve and standard bore AP piston had no such issues but then, carburration was by the book. Incidentally, with the standard bore I run very tall gearing and it pulls fine. 23 T engine and 20T G/box. This keeps the revs down to compensate for the heavier piston.

Hi Dan

What did you do for the breather?

I did about 400miles in France on mine at the weekend and there was no smoking and the engine is pretty well oil right. Slight mist from the pushrod tubes and still got the drop under the timing chest breather but that's it.

Andy