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55 ES2 Banjo bolt holes

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55 ES2 Banjo bolt holes

Posted by George Phillips at June 22. 2017
Does anyone know the diameter of the small hoes in the rocker banjo bolt? Not the big hole down the middle (although that would be of interest). I'm investigating reduced oil flow. Cheers - George

Re: 55 ES2 Banjo bolt holes

Posted by George Phillips at June 22. 2017
I might be able to answer my own question. By a devious method of trying different wire gauges I reckon the holes are about 1.5mm diameter or 40thou or around 1/16". The wire (needle) that I have is 1.13mm diameter so by inserting it into the inlet hole the cross sectional area is reduced by 43.5%. In other words the flow of oil to the rockers is reduced by around a half. I'm not going to do anything yet until it's all re-assembled as it easily done afterwards but would be interested in views. There have been other threads on excess oil to the rockers so this may already have been covered elsewhere. George

Re: 55 ES2 Banjo bolt holes

Posted by George Phillips at June 22. 2017
Just before any one points it out to me, I've done a bit more calculation which shows that the flow rate would reduce to around 16 - maybe 20% of the unrestricted flow. It's a square law. George

Re: 55 ES2 Banjo bolt holes

Posted by Ian MacDougall at June 22. 2017

Just a thought, and I'm not in a position to confirm this right now, but my understanding is that the banjo at the tank return connection may be restricted to limit the feed to the rockers.

Ian McD

Re: 55 ES2 Banjo bolt holes

Posted by George Phillips at June 22. 2017
That's new to me Ian. I'll see if I can check it. Nevertheless I seem to have a lot of oil/pressure at the rocker box. G

Re: 55 ES2 Banjo bolt holes

Posted by richard_cornish at June 22. 2017

Hi George,

  I think your original calculation is correct, the drill size would be imperial 1/16th (1.57mm) and 1.13mm, with both being circles, is roughly half the area. The difference will be the viscosity drag of the crescent shape of the remaining hole. At a guess I would think the flow would only be about a third of the current set-up. It might be better to sleeve the holes with a fine tube and bore the new holes to the most suitable size or just block one hole completely!!

Regards,  Richard.

Re: 55 ES2 Banjo bolt holes

Posted by Dan Field at June 22. 2017

Hi George,

i think mine only has one hole, but I am a few 1000 miles from the garage to check at the moment! but mine is still over oiling. I think my problem is the fit of the banjo bolt in the banjo, it is so slack that the holes are redundant, the oil just runs around the sides. I've improved it by fitting tight fitting fibre washers but intend to work on it some more.

dan

Re: 55 ES2 Banjo bolt holes

Posted by Paul Knapp at June 23. 2017

Hi George, the 'KISS' approach must be used here. No need to sleeve, insert anything,  all these calculations are over my head!.. Simply solder one hole up. You don't need a flood of oil up there, a single 1/16" Dia. will allow enough oil, evident by the constant ooze I have around my top end. 

Re: 55 ES2 Banjo bolt holes

Posted by George Phillips at June 23. 2017
I like your thinking, Paul. Problem is I'm not sure that my soldering skills (or my soldering iron) are up to dealing with a big chunk of brass like the banjo bolt. For me, almost blocking one hole with a piece of wire is probably safest - and reversible if it fails to solve the issue. Glad your ooze is from your top end - as opposed to your bottom end! George

Re: 55 ES2 Banjo bolt holes

Posted by Paul Knapp at June 23. 2017

Hi George, not an iron job, but a propane torch does the job. De-grease the whole thing, put a drop of Baker Soldering fluid in hole and gently play the flame on it then apply resin cored solder in hole when hot. When correct temp is reached, the solder will flow to seal it up. Easy to drill out at a later date if need be.

Oh, and my bottom end also oozes,... unfortunately.  Frown

Re: 55 ES2 Banjo bolt holes

Posted by George Phillips at June 23. 2017
Just done a quick check, The bolt had one entry hole and one exit hole (for the rocker box). I thought the holes were drilled right through to give two of each. Not so. I've shied away from undoing the banjo connection on the oil tank, Ian. Too much faffing about. I'll see how the new banjo washers and pushrod washers do before digging further. Thanks for everyone's input. George
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