Additional Oil Feed for Rocker Shaft

[OldBob]

The PO fitted the additional oil feed pipe after the rocker shaft wore badly / prematurely on the rebuilt engine. I'm looking for a simple method to regulate the oil flow that the pipe supplies so some of the additional lubriction can be retained.

Has anyone found a good/ simple method to add a restriction of some kind into the pipe or banjo union ?

Many thanks

Bob

[Motorsport Mickey]

Do what the racers do.

On my 4 cyl race engines (without additional rocker feed from the camshaft) I fit a small restrictor bush into the hole of the rocker shaft pillar at the pillar to head point. using a 3 mm hole for the oil feed, it's plenty' Which is why I won't fit an auxiliary rocker shaft feed, robbing oil and pressure from parts of the engine that needs it.

Mick Richards.

[BlueTR3A-5EKT]

Original Triumph TR5/6 rocker shafts were just hollow tubes as supplied from the factory.   You had to fit a sealing plug at each end of the shaft to make the oil stay in the shaft and deliver only to the rockers.   This is forms a sealed oil pressure gallery that the rockers run on.    Without the plugs oil just spills from each end of the shaft and does not flow into the rockers.

Repro shafts tend to have plugs already fitted …..BUT CHECK WHEN FITTING or replacing.

 

TR2-4  rocker shafts are hollow tubes also but originally have caps at each end that retain the end rockers are are sealed with a solid cross pin.

[Andy Moltu]

Fill the end of the banjo bolt with a blob of braze and drill out to 1.5ml

[Tom Fremont]

I've done over 140,000 miles with the unmodified auxiliary feed line. The rocker shaft doesn't wear at all and the oil pressure is still 65 psi @ 2000 rpm fully hot ( oil cooler with 'stat is fitted ). I just fitted another one to my trick engine with the wholehearted approval of my engine guru ( whose like in the US can be counted on the fingers ). I got the feed line kits from TRF, and don't know their source.

The only problem I've had is sealing the banjo fitting to the head. According to my engine builder an extra copper washer is needed to keep the bolt from bottoming in the head instead of on the washer(s).

IMO if the rocker arms are bronze bushed and the shaft hard chrome plated no wear will occur on the assembly. The one on my trick engine had 7000 miles on it when it was taken down yet the builder said it was " fine " and he's a perfectionist who reworked an assembly for another of my engines himself rather than sending it out ( as I had done with the one he approved with 7000 miles ).  But he likes having the extra oil to lubricate and cool the valve train anyway and fits them to any TRIUMPH engine he takes on now, e.g. Spitfires.

IMO with such kit, properly prepped rocker assembly as above and hardened timing sprockets these engines can easily go 200,000 miles between rebuilds and possibly longer ( just don't have firsthand exp. ). That's with no less than 150 BHP on DCOEs or whatever can keep the A/F mixture where it belongs across the range.

Edited April 29 by Tom Fremont

[OldBob]

Thanks for the thoughts everyone - especially Andy with the brazing solution.

I'd heard 2 negative issues which seem to come up commonly when discussing the additional feed pipe :

                                                              1)  It can adversely affect oil flow to the bottom end - maybe causing an issue on some engines?

                                                              2) The increased flow from the full bore unregulated pipe & union can increase oil consumption by flooding the valve stems.

The above is clearly debatable by some of your previous comments gents - only fact I can go by is my rocker assembly needed replacing by 7k miles. That said, its a lot cheaper / easier to replace the rocker shaft than to rebuild a botton end.

SO my simple solution was to keep half the benefit by reducing the flow, but to not overdo things - unfortunately I don't have any brazing kit so still looking for a simple fitting to buy/add OR a supplier of a union with smaller hole than 3mm. 

Thanks

Bob

[stuart]

19 hours ago, OldBob said:

Thanks for the thoughts everyone - especially Andy with the brazing solution.

I'd heard 2 negative issues which seem to come up commonly when discussing the additional feed pipe :

                                                              1)  It can adversely affect oil flow to the bottom end - maybe causing an issue on some engines?

                                                              2) The increased flow from the full bore unregulated pipe & union can increase oil consumption by flooding the valve stems.

The above is clearly debatable by some of your previous comments gents - only fact I can go by is my rocker assembly needed replacing by 7k miles. That said, its a lot cheaper / easier to replace the rocker shaft than to rebuild a botton end.

SO my simple solution was to keep half the benefit by reducing the flow, but to not overdo things - unfortunately I don't have any brazing kit so still looking for a simple fitting to buy/add OR a supplier of a union with smaller hole than 3mm. 

Thanks

Bob

Bob Ive had a message from Moss technical department saying "We sell a restricted banjo bolt part number of the bolt which is TT1226D, with a centre bore of 2mm and a single side bore of 3.2mm which will do the trick, copper washers to suit are TT1226B"

So there is your answer.

Stuart.

Edited April 30 by stuart

[OldBob]

10 hours ago, stuart said:

Bob Ive had a message from Moss technical department saying "We sell a restricted banjo bolt part number of the bolt which is TT1226D, with a centre bore of 2mm and a single side bore of 3.2mm which will do the trick, copper washers to suit are TT1226B"

So there is your answer.

Stuart.

Hi Stuart,

yes, that is indeed the solution I was looking for. I tried to insert a restrictor screw today but could only get a 1.5mm hole in the screw due to the threads being so close. That gives a 75% reduction in diameter which I think would be too much - so I'll be ordering the 2.0 hole version.

Many thanks for your input.

Bob

ps - my creation attached.

 

[stuart]

12 hours ago, OldBob said:

Hi Stuart,

yes, that is indeed the solution I was looking for. I tried to insert a restrictor screw today but could only get a 1.5mm hole in the screw due to the threads being so close. That gives a 75% reduction in diameter which I think would be too much - so I'll be ordering the 2.0 hole version.

Many thanks for your input.

Bob

ps - my creation attached.

 

The racers who used them years ago just brazed up the hole and then re-drilled to their chosen size. Bush engineering!

Stuart.

[roy53]

BUT  do you need it ?

Roy

[stuart]

18 minutes ago, roy53 said:

BUT  do you need it ?

Roy

Not on a standard properly built engine no.

Stuart.

[roy53]

11 minutes ago, stuart said:

Not on a standard properly built engine no.

Stuart.

I don't think that you will see it on full race 6cyl either .

[john.r.davies]

There is a way to determine if it is safe to add the external oil supply. You need a oil pressure gauge to be fitted

Warm up the engine, properly.  This can take twenty minutes to half an hour of road running before the oil is fully heated.    If you don't have an oil temp gauge, then run until the oil pressure AT IDLE is at its lowest.

Fit the external supply.   This need not take long to do, and the oil will not cool down that quickly.

Run the engine again, observe the oil pressure at idle.    If it has fallen from before, then the external oil supply will KILL YOUR CRANKSHAFT!   Because the external pipe is diverting oil along a path of lesser resistance, to the rocker shaft.

The rocker shaft does NOT need a large oil supply.    If with the cover off, and the engine warmed up as above, you see two or three drips a minute  from each that is quite enough.

If you feel that you must, then add smaller and smaller orifices/restrictors to the line until there is no pressure drop.   

John

PS in my ignorance, when I first started racing, I did add the external line - and blew/blued my crankshaft.

Edited May 1 by john.r.davies