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55 ES2 Banjo bolt holes

Submitted by george_phillips on Thursday, 22 June, 2017 - 01:00
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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

Submitted by george_phillips on Thursday, 22 June, 2017 - 01:01

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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

Submitted by george_phillips on Thursday, 22 June, 2017 - 01:02

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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

Submitted by ian_macdougall on Thursday, 22 June, 2017 - 01:03

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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

Submitted by george_phillips on Thursday, 22 June, 2017 - 01:04

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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

Submitted by richard_cornish on Thursday, 22 June, 2017 - 01:05

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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.

Submitted by dan_field on Thursday, 22 June, 2017 - 01:06

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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

Submitted by paul_knapp on Friday, 23 June, 2017 - 01:00

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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 single1/16" Dia. willallow enough oil, evident by the constant ooze I have aroundmy top end.

Submitted by george_phillips on Friday, 23 June, 2017 - 01:07

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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

Submitted by paul_knapp on Friday, 23 June, 2017 - 01:08

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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 onit 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

Submitted by george_phillips on Friday, 23 June, 2017 - 01:09

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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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