Wondering why I shouldn't pressure feed the rocker shafts on my T140 project bike. I understand Norton Commando's use press. fed rockers and I have followed a post on another site where a rather ingenious fellow runs his rocker oil through 2 coolers before it gets into the head, this arrangement is said to be more beneficial at engine cooling then the std. way of routing the engine oil through a cooler and back into the tank or into the crank. I know Triumphs need and get very little top end oil and it is tapped off the oil return but I'm more interested in the cooling benefits of more and cooler oil through a high performance tuned head. I would imagine valve guide oil seals would be required and perhaps opening up of the drain back holes in the tappet guide blocks. Taking the oil press. off the forward timing cover boss would be easy. The rocker feed oil line could have an adjustable or replaceable restictor to tailor the amount of oil getting to the rocker boxes if necessary or a differential amount to ex. vs. intake. So I'd like any opinions, from a cooling/longevity stand point, of why or why not pursue this...Mark
You would have to run oil seals or it would smoke like mad. I run the outlet of the oil pressure relief valve up to the rockers on my A65s but the plumbing is easy on those and a few mods allows it to be done.
Nick, oil seals and plumbing are no problem, it's an easy mod but is it worth the effort? The ex. rocker box area runs pretty hot, I plan to modify the ex. ports with a machined stainless steel insert with an air gap to keep as much of the ex. heat as possible out of the head and perhaps with a higher flow of cool oil the head will benefit from a longer life. I view the Triumphs head design as it's weakest point so feel that any effort to improve things up top can't hurt...Mark
This, or a very similar question, has been asked before, and answered at length by John Healy. He might answer again but in the meantime:-
Originally Posted By: MarksterTT
Taking the oil press. off the forward timing cover boss would be easy.
I assume you mean the "press." feed for the rockers from the timing cover? If so, you would then rob the crank bearings of oil they need to feed rockers that don't.
Originally Posted By: MarksterTT
I'm more interested in the cooling benefits of more and cooler oil through a high performance tuned head.
You can increase oil supply to the rockers by completing the modifications that Meriden failed to complete. John has detailed these modifications in earlier posts. This would achieve your aim more simply and without robbing the bottom end?
You could probably have the exhaust ports and the inserts ceramic coated. Increasing the lube flow by robbing the bottom end may not be a good idea without say running a morgo pump. The old 'suck it and see' statement coms to mind. My mod on the A65's is utilized with an iron bodied gear pump which I know pumps way more than is needed, when the relief is open it feeds the rocker gear via expanded oilways. The system required setting up with a gauge initially. The quantity of oil you would have to pump up to the top to increase the cooling on a triumph may be more than you can pipe anyway.
Stuart, I was sure this had been discussed but for me this site is very frustrating when it comes to 'searching' for anything. I just don't have the ability to find what I'm looking for so please forgive me for that. I have the Meriden mods covered from posts on this forum and 30 yrs. of the TIOC magazine, to me J.H. is a national treasure but what I was proposing goes beyond proper parts and assembly techniques and would hopefully improve head cooling & valve train longevity. Also from this forum, I've been led to believe that a Triumph end feed crank can almost survive on gravity feed alone, so with an uprated Morgo plunger pump I was hoping taking some press. feed off for the rockers would be o.k., do you think this is a false assumption? I could just do the ex. side and use return oil for the intake rockers per standard procedure. I'm sure the Morgo rotary pump would be up to the task but I have already seen one Triumph big end sieze up from a rotary pump that had lost it's prime so don't really want to go there.
Nick, I have planned on c.c. and port coatings so I'm with you there but you do make a good point about drain back being a potential issue, there is room to drill out the drain holes in the tappet guide blocks a bit.
TT, do you know why Triumph undid what I'm proposing back in the '40's? I realize that 1000's of Triumphs have run and raced on the stock set up but I've also seen some very worn and over heated valve train parts (esp. ex. side) but perhaps the meager amount of cooler oil I'm talking about wouldn't do much in regards to extra cooling. I'm trying to think of any and all means to keep my 825cc street tracker cool on our super slabs and this seemed to be one small step to consider, I've already gone to dual plugged head (Pazon), will do coatings, ex. spigot air gap, 9.5-1cr 'squish' low profile pistons, nicasil bores etc., even an air duct to dump cool air between rocker boxes.
So I wonder why Nortons (Commando's)run system press. to their rockers and why isn't it a problem for them? Do Commandos run valve guide seals on intake & exhaust guides? I'm pretty sure some of the smaller, earlier Nortons tapped rocker feed oil off the scavenge return like our Triumphs so they had experience with both methods.
Thank you for all the replies and I'd like to hear more so feel free to argue this idea, it still sounds good to me especially if oil drain back and robbing the crank of pressure are the only perceived issues...Mark
The most I've ever done to increase rocker oil flow is to reduce the size of the tank restrictor hole to about 1/3 the area. That will give you about 9 times as much pressure in the rocker feed line, and it seems to cause no problem.
You can jam a suitable sized wire into the tank restrictor hole to get the same effect, but just make sure it can move and fall out of position.
Thank you John, Stuart, Pete and TT for your input on 'searching' I'll give it a try and see what happens. Eventually I'll learn how to post pix also as it's real nice to be able to see and share.
Pete R., I agree, blocking the scavenge return hole to force more oil to the top end would normally be the easy way to increase flow but in my case my oil return outlet is internal to a custom C&J oil in frame and I still need to get a bore scope to look in there to make sure there is even a restriction built in...should be but you never know.
I'll go and search for Commando valve guide seals and see if indeed they have them on both intake and exhaust as I'm pretty sure they must to be able to run full system press. to the top end, in which case I would probably have to do the same...Mark
I think it's a waste of time to increase oil flow to the rockers. The rockers and shafts don't seem to wear out any faster than anything else. It's the valve guides that wear out way too fast. So, increasing the oil flow to the head will have no effect on valve guide wear since fuel supplies the only lubrication to the guides.
Valve guide wear has been reduced, I think significantly, by selecting top quality guides and valves. I had good luck with Ampco 45 guides and Kibblewhite black diamond valves.
But at the end of the day what I put in my bike will be what available at the price I want to pay. I can easily get 5 years of riding with ordinary parts but If I put the Kibblewhites and good guides I suspect the bike would certainly outlast me.
Bikes 1974 Commando 1985 Honda Nighthawk 650 1957 Thunderbird/T110 "Flying Tiger" Antique Fans: Loads of Emersons (Two six wingers) plus gyros and orbiters.
Thanks Kommando, seals on the 'inlets only' makes sense due to vacuum drawn on intake stroke so maybe with a nice close fit ex. valve stem to guide my excess oil delivery wouldn't be any more of a problem then on the Norton.
John, I've found the same with some aftermarket oil tanks but this frame was built to my drawings and I specified a similar return pipe scheme as found in the Triumph oil tanks but I'm not real comfortable assuming it was done...so I will have to investigate.
Thanks for picture JB, brought back an old memory with those clear oil lines, I had a similar rocker feed line to my Webco rocker box oil manifold (1970)and while on a long trip with nothing much else to do, I leaned over to see how much oil was flowing to the boxes, next thing I knew I ran off the road and through a road sign, my left hand, clutch lever and left exhaust pipe took off a 4x4 post which left me in the ditch with the ex. header smashed against the front of the primary case with the top end no longer attached to the cylinder head. Pop, pop, pop and not much horse power. By the way there seemed to be plenty of oil in that clear line...Mark
To me the witness marking on the pumps' pistons is very suggestive that it will scrub up OK. To properly evaluate it, lightly rub the pistons with 600 or finer wet&dry. Then buff them on an electric wire wheel. Next take the valves out of the body and wash all the parts in solvent and air blast clean. Apply engine oil to the pistons and bores and test the fit. It should be a nice sliding fit with negligible play. Then refit the valves, testing them by using the piston to pump oil through each valve. Oil should go through but not pull back. In addition with the pistons fully home when you gently pull each one, there should be a small amount of "spring back" from the vacuum. If it passes this, I call it good. HTH
To me, the interesting question is how did those wear marks appear on the plungers? Both feed & scavenge seem to have identical marks. I can't envisage how this could have happened and I'm curious to know. I must admit, if it was off a bike of mine, I'd consign it to the 'interesting things' shelf and buy a new one, not mess around trying to fix it.
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