[Russ]

Cox & Turner have been excellent and the corresponding rings and circlips for the Heplex piston turned up Friday morning so double quick time....happy days......in the interim yesterday although not a bike I bought this old Jallopy to keep my 1927 Sunbeam and my 1929 Norton company.......a 1933 MG J2.....as if I haven't got enough to do.....LOL

[Russ]

here we go my Machine shop man comes up trumps with a super quick turn around I only gave it to him Tuesday afternoon so here's my new NOS Heplex 3051 Piston that he rejuvenated for me.....infinitely better than that 'orrible crackered CoVmO split ring thingy.....got to lap the cylinder head and barrel together for a nice tight seal and put it all back together which should take an hour....yay




my freshly honed barrel as you can see my mans marked it so .0015" or 0.038mm slightly out of round that's less than 1/4 the thickness of a human hair.....so nothing to be concerned about there then

[Russ]

I hear you but I'm not going to break the crankcases at this point in time I did a cursory check when I initially had all the top end and timing chest apart with using leverage on the end of the crank it didn't move and all seemed pretty solid.....Ian Hatton (Verrals) showed me what a rivetted crank did when coming loose on a 1928 Model 9 it visibly moves also there was no irregular wear in the Barrel suggesting nothing out of balance but as you suggest and as I was always going to do is pull the bottom end apart but later in the year as my Winter project I'll make sure I've got all the replacement parts already bought and to hand (brearings, Shims hopefully it wont need a new crank pin though) as far as the oil feed goes I usually aim for 3 to 4 drops / minute at about 30mph but it's not easy riding at 30mph looking down and counting 20 seconds for a drip and looking where your going.....LOL......anyway I'm hoping my man will have the piston issue sorted for me by next week it'll only take an hour to get it back together and hopefully I'll be able to bring it to Brooklands on the 6th of April otherwise I'll have to bring this once I've sorted the rocker geometry out as it's a bit off pulling the pushrod easy enough 5 minute fix.....

[wessex_man]

Agree not good and needs attention. At this stage it may be worth parting the bottom half to inspect the crankcase bearings and mains. This has a riveted crank and they can come loose. Easier to do at this stage and you know for sure what you have.

Re the oil when in use around 3-5 drops per mile when viewing looking at the sight glass.

[Russ]

Haha.....had my man look at the barrel and piston......upshot......Barrel not too bad at least it's round although it needs a bit of light honing.....COVMO Piston.....Old and pretty much knackered you could see where it looks as though it had nipped up at some point and someone has had it apart and took a file or Emery cloth to it....LOL...and as for the ring gaps they were quite amusingly large....Hahaha....I'm not surprised it was blowing oil out of every orifice the ring gaps measured 0.1" (2.5mm) give or take (measured in the bore before you ask)....I'd normally expect ring gaps to be about 0.010" (0.254mm) or even a little less so about 100x larger than useful add to that the fairly ineffectual oil scrapper ring positioning of such an old Piston and you've got one big old oil pump......I have got a NOS Heplex 3501 Piston which needs Rings when it's sorted I'll only add 100ml of oil to the sump for initial start up and set the the pump to about 1/4 on.....below is the piston that was in it a CoVmO jobby it's a bit crackered

[Russ]

Hi WM.....I've come to that conclusion that it's over oiling I put about 150ml in the sump on initial start up which may have been too much combined with the fact that I set the pump to about 3/4 on I think I'll reset it to about a 1/4 on and see how it fairs but I have whipped the head and barrels off and popped the piston off to see what's going on but by eye it all looks fine to me but as I've got it apart I'm going to get my engine man to have a look and measure the bore and check for roundness and fit with the Covmo piston and rings......the only question I have is what should the clearance be piston to liner? I guess my engine man will know I suspect it will be a bit slack considering it's not a modern engine built to precise modern standards....LOL...I've already spoken to Martin at Cox & Turner he was very helpful indeed and thinks they can sort something for sure....I'll stick some photos up later

[wessex_man]

Hi Russ,
I have been following the thread on FB, some interesting comments. I suggest you think about the oiling before you look at the piston and rings. You know the 1927 model is a total loss system. The oil is pumped to the quill in the front of the engine via the Best lloyd regulator or direct via the hand pump. This lubricates the engine and main bearings. Thinking of where the oil can go. Firstly it gathers in the bottom of the crankcases. As there is no scavange pump it tends to collect here and needs to be periodically drained otherwise you suffer drag on the flywheels and difficulty in turning the enging over to start it. Excess Oil will find it's way through the breather in the timing case, the valve guides and past the piston rings. If you have an oil control ring fitted it scrapes some oil back into the crank case. Remembering some needs to get past. Ideally When you open the throttle you aim to get a puff of smoke from the exhaust.

If there is to much oil getting fed to the engine, and the engine keeps running, it will get spat out. As I indicated earlier favorites are the head, guides, breather and exhaust. On my bike the Best Lloyed pump is barely open, the valve guides get lubricated, get a puff of smoke on opening up the throttle. I have to drain the crankcases periodically. As an aside I use graphite grease on the rockers as there is wery little lubrication up top.

If you have to look at your piston and rings, Cox and Turner, as has been suggested come recommended. There is Lots of Wellworthy Knowledge there.

I hope helps Kind regards WM.

[Russ]

Hi All.....so first major shake down run yesterday and she's blowing oil out of the Cylinder head joint and out of the end of the exhaust.....so not great.....my thoughts are Piston and rings are letting by.....when I did the top end I checked the Barrel and it looked fine to me I poured some light oil in to see how long it took to drain past the piston it took about 6 minutes so I thought it was Ok(ish) but clearly it wasn't below is a photo of how it looked...on reflection thinking about it, it would take 3 or 4 full kick overs to get it to come to compression (not knowing if that's normal for such a vintage machine) so I'm in real need of an unobtainium Piston, rings, circlips and gudgeon pin in either +40 or +60.....I could use an original +30 but would need to get the Barrel re-sleeved.....but first;y I need a Piston etc. attached is a remade piston of an original Model 9 piston which I think Sean Kelly got made a while ago but doesn't have any left so if anyones got any thoughts or  ideas please chime in.....Kindest Regards.....Russ

looked ok to me



Piston I'm after (sadly unobtanium it would seem)