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Triumph TR6 - Rocker oil feed kit
|Victoria sells a Rocker oil feed kit that is supposed to increase the oil to the Rocker shaft. Anyone use this? A mechanic recommended it.|
|Hey, Dan. The opinions vary, but I've used one for at least 5-6 years with good results. It's helped keep the roller rockers lubed, and the volumetric loss to the bearings is quite small. I recommend it.|
This modification is HIGHLY RECOMMENDED by everyone I know that has dealt with six cylinder TR engines over many decades. ( Unfortunately I can't comment on the VB kit)
The rockers operate on a 'total loss' lubrication system, fed by pressurised oil coming up the rear pedestal, travelling along the shaft to the front. The last rocker to be lubricated is No 1. This is where the first sign of wear will show, most often on the shaft itself. ('Total loss' means that when the oil enters the gallery, it lubricates a moving part, then the excess flows onto the next lubrication point and so on.)
In old engines and depending on maintenance / quality of oil etc, there will be a gradual build up of deposits restricting the galleries slightly - (athersclerosis of the engine so to speak!). Narrowing of the galleries (as we all know) will lead to restrictions in oil flow. The last point of the cycle before the oil drops back down to the sump, is No 1 rocker!!
To make matters worse, the engine has a natural tilt to the rear, making this the driest point when drained (if the car has been sitting for a while).
The take off point for the external oil feed is preferred to be at the last camshaft journal. There is a plug (or bolt) where the gallery was drilled at the time of manufacture of the block.
There are kits around which use an adapter to fit onto the oil pressure gauge take off point. These are not recommended as this point is the second last camshaft journal, which is earlier in the path of the oil in the 'total'loss' system. If you rob this point of too much pressure, you can comprimise the supply to the last cam journal with obvious consequences.
There are a couple of things to consider.
Firstly, the overall condition of your engine. If your engine is recently rebuilt, or in very good condition, the ext. feed is worthwhile.
If you are considering this mod because there is an existing problem with the rocker shaft/rockers, be a bit more careful. Installing this could have a detrimental effect on the rest of the oil pressure, leading to sooner a than expected rebuild!
Secondly,assuming that you go ahead, there is an increase in oil present under the rocker cover which:
a) increases the potential for gasket leaks at this point and
b) can lead to seepage of oil down the valve stems/guides and into the combustion chamber when the engine is turned off.
If your valve guides need replacing, you may want to get stem seals fitted as well.
This will prevent the small puff of blue smoke on start up which many people find disconcerting/annoying for a daily driver.
When my engine was built, it was the first essential modification on the list.
Hope this helps
PS If someone knows where I can get (inexpensive) 5/16 UNF banjo BOLTS, I can make up the kits at a fraction of the cost of the aftermarket ones!!! - the cost of the bolts here is crazy!!!
|Ditto. I see little difference in pressure with/without the feed. I've heard from others it can rob oil from the bottom end. With no/little pressure loss, I fail to see this to be the case. I've had no problems with it.|
|I just did a total rebuild, and the only area in the engine that had real sigificant wear was the rockers. I had to replace all 12 rockers, shaft, and 12 lifters. So I'm using the external feed.|
|Thanks for the info on the take-off points Roger. I've had the external feed on for 11K miles and you've got me wondering whether to route the take-off to the rear cam journal instead of the oil pressure port. Who else is using the rear cam take-off?|
I'm hooked into the oil pressure gauge take-off. Wondering if I'm headed for trouble. Pressure is still 45+ at cruise and 15+ at idle. Does anyone else find this setup to be an issue?
Thanks, Don in Jersey
Snow predicted this weekend, so I really don't mind the 6 is in pieces at the moment.
I didn't mean to cause undue concern over this, just giving Dan a bit to chew on!
My experience with TR's is quite recent (8yrs rebuild, 4 years running) but there is one guru here whom I know very well, and who only works on Triumphs. He has done so from when they were in production.
Opinions are varied as to whether the take-off from the oil pressure gauge is a critical issue. The bottom line is that there are so many variables determining oil flow and pressure, that any failures that are seen cannot be generally attributable to a single cause (unless it is obvious eg low oil).
The preferred take off point at the rear of the block is simply more sound from a theoretical point of view. It makes good engineering sense to give as much oil to the more critical parts and assist the less critical ones with additional flow.
After the excess oil has passed the last cam journal, it heads up to the top rear of the engine and into the overhead gear. Unfortunately, the design is such that this is not a direct route and there are a couple of turns before it gets to the pedestal. Any restrictions in this gallery limit flow to the rocker shaft - but how the hell do you tell!! The external feed essentially bypasses this gallery and guarantees that the maximum available oil at this point is delivered to the top of the engine.
I don't believe that the engine design is so sophisticated that by allowing more flow at the back end, there will be a reduction in pressure causing a by-passing of the critical earlier take off points - I understand that they take what they can and the excess oil moves on. There is a bucketload of oil moving around in there - seems like all it wants to do is try to get out!!
Rick - as you already have the take-off at the pressure gauge, I think it would be OK if your general oil pressure was good. It would only becomes an issue when the pressure is marginal. If you are doing a rebuild or have good access to the rear port, it may be worthwhile swapping.
Don - I don't know the condition of your engine, but your oil pressures would be considered a little low (if you were in a warm climate) 20 at idle and 50 at 2000rpm would be better minimums. - first thing to check would be the seating of the oil pressure relief valve - see if it is worn on one side - also check the spring pressure. Put packing in behind the spring and re-instal to see if it makes a difference. Next thing would be sump off and check main bearings and pump clearances. I hope your garage is heated!!
|Excellent Post Roger.|
RickO re: your previous post regarding lift on the back valves and my inquiry as to the use of the external oiler. David's follow up on his tear down saying rear lobe looks hammered.
Rogers point I quote:
"There are kits around which use an adapter to fit onto the oil pressure gauge take off point. These are not recommended as this point is the second last camshaft journal, which is earlier in the path of the oil in the 'total'loss' system. If you rob this point of too much pressure, you can comprimise the supply to the last cam journal with obvious consequences."
I have alway's had a theory if the back journal is somewhat starved it will tend to vibrate? Creating a mild hammer effect. My personal opinion is ALL of the top oiler designs Rob Peter to pay Paul. Fortunately Pauls easy to get at. Pauls a pain? Lesser of two evils.
I didn't check back but didn't you have a strange vibration from the engine you could feel in the pedal? Wonder if David or others have noticed anything?
I have never used the Top oiler systems so I don't have any hard facts but I keep seeing the same clues.
|Thanks for the compliment Bill - from the months that I have been checking in, I have come to respect and value your opinions greatly. I must say though, that I am not an engineer or a mechanical professional and just about all I can share has been learned from the mistakes of others!! (says me with a gearbox o/haul and new clutch going in this weekend!)|
|Bill, I never had any unusual 'vibration' symptoms. The engine actually ran very well and quite smoothly even though the #12 rocker was badly worn/flattened and lift at the valve was only 65% that of all the other valves. I was astonished at the amount of blow-by in the engine , the oil control rings seemed almost glued to the piston walls - however,there was no engine smoking before the teardown. This motor has never had a separate oil line to the head installed --however, I am going to install one now (reversing a decision I made a few weeks ago) as it seems now that the increase in oil flow to the rockershaft,lifters and to the cam is more important than a 'potential'(and clearly debatable) loss of oiling to the mains.|
I've a question for you all : I'm installing new all bronze thrust washers in the upper rearmost position as well as machining the rear main bearing cap to accept an identical thrust washer/bearing. It seems like a good idea to 'pin' the upper washer by drilling the block to accept a hollow dowel pin that goes to the oil gallery that feeds the rear main bearing so that the thrust bearings will be constantly lubricated. (I will use at least one, probably two other pins in a softer metal than the bearing bronze in both upper and lower thrust washers). Have any of you actually done this modification ? Your results/observations ?
Obviously, if I "pin' the upper thrust washer/bearing the only way to replace that washer/bearing would be to remove the crankshaft. The machinist that I am working with on this project sees the 'pinning' and the machining of the cap as a way of "solving the TR thrust washer problem" and that it shouldn't need to be even considered until the next major overhaul - 50,000 - 75,000 miles. I agree with him in principle but am still a bit leary of solutions that force major surgery in the event of a recurring problem. Opinions based on experience would be appreciated.
Interesting/Depressing Note : Six years ago the previous owner bought the car and immediately started reading religously the 6-pack and vtr sites/lists. He was alarmed when he read of the TR6 thrust washer "problem" and quickly took the car into a local shop to check/adjust --He was quite happy with the way the car drove and so was I --(I bought it !) until I took the crank out and found that that "shop" had put the thrust washers in backwards. The interesting part of this comment is that when I decided to buy a new crankshaft I found out that Rimmer Bros has extended it's free shipping special to the States till Dec 31 and a brand new , Stanpart 'old stock' crank cost $195 delivered to my door in Seattle. I ordered it on the Rimmer website at midnight on Sunday night (8am Monday morning in London) and received it on the next Friday morning at 9am !!
**I am truly an English car 'nut' when I think fondly about what a "deal" I got on my new crankshaft for an engine with 65000 mies on it . So it goes...
|Looking at the block it would appear that there is essentially no advantage to tying in the external oil line at the back port vs. the oil pressure port. Both appear to be drillings through the main galley to the cam journals, so either will have essentially main galley pressure. That's my read, anyway.|
Also, the operating oil pressure on my car dropped from 55 to 50 psi when the eternal line was installed. That translates to a 9% decrease in oil flow to the bearings if laminar flow is assummed, but only a 5% decrease if turbulent. It's probably in between - call it 7%, which is probably conservative. The small i.d. of the external line banjo bolt is the flow limiter, and that's probably turbulent.
The best thing is that when the engine was rebuilt in 2002 all the bearing wear was "normal". The machinest, whose real work is with race cars, found no problem areas.
|In response to Roger's question about the state of my engine, it's got quite a few miles on it (60K plus, but odometer is not currently working). I replaced the pressure relief valve plunger and spring after finding wear. The spring was also out of normal specs. The pressure numbers I quoted were prior to replacement. I've yet to get the engine warmed with the new plunger and spring. I would suspect to see some improvement.|
With 4 1/2" of ground clearance, I've got to drive the car onto two stacked 2x10s in order to get the flor jack under it. If I need to get into the bottom end, it'll be a weekend job in the spring. I don't see this to be the case at this point in time.
(old TR in garage, shiny new car out in the elements, wife laughing as I scrape ice every morning)
|A bit to chew on indeed! Thanks guys. My engine is original with about 73k miles. |
My idea was to add the feed kit, adjust the valves and replace gaskets. I had a mechanic listen to it because I heard a new noise when I let off the accelerator. He suggested the feed kit.
No one commented on the Victoria kit, so where did you get yours?
Nope no engineer either. Just observant. Why do some engines have certain problems.
No debate here just want idea's and info. I have seen the rear lobe problem on 2 other cars. Both had the top oiler. Mains OK. I start thinking the rear cam journal is not getting oil with enough pressure to offset lift vibration. Overall oil pressure means nothing. Oil pressure and volume in a critical area is all that counts.
With the extra oil volume at the top end is that stopping proper crankcase breathing? What do you think caused it?
|Dan--I got my feed kit directly from Moss. I believe all the kits are made by the same manufacturer.|
I didn't write down where I got it from - one of the big 3, though. Installed 2/23/96.
|Can't answer the connection between bad lobes and the oil line. Vibration? Certainly possible. The lobes are oiled mainly by splash (unless up have those neat lifters with the holes drilled in them). But things wear out.|
I do recommend using the best oil you can, though. I ran Mobil 1 for years with good results, but switched to Redline after the rebuild. Nothing at all against Mobil 1, I just think Redline is a little better.
|Bill , I really haven't an informed opinion |
on what causes the #12 journal (and lifter) to wear out. There seem to be so many possibilities -- But, a long time ago, I bought one of those garden hoses with a lot of little holes in it to water my wifes roses and I noticed that the holes closest to the water spigot seemed to have less water flowing from them than the holes at the end of the hose. (?) The rear cam journal is right there at the oils source --right at the spigot, so to speak... I definitely follow and agree with your point about pressure and flow being the key. And vibration could be a part too, the "harmonics" of this long stroke crankshaft engine are definitely powerful--
|The garden hose thing relates a classic engineering problem. I don't think it applies to the oil gallery, though (I guess gallery is right, galley wrong?)|
In simplistic terms, and there's no slight intended, fluid flow pressure and velocity are somewhat interchangable. Fluid moving at high velocity is at a lower pressure than the same fluid moving at lower velocity. In the garden hose, the water going down from the spigot is moving fast to fill the end of the hose. It's at high velocity, so the pressure is lower - it squirts less out the holes. At the end of the hose the water slows down and the pressure rises. The water thus squirts out farther. An engineer would either sell you an expensive 3" diameter garden waterer, or an even more expensive waterer with big holes at the spigot end working to smaller holes at the very end. In any case, the main oil gallery should be drilled large enough so that sort of thing should'nt happen - a 3" hose, if you will.
I get a bit lost when the terminology gets technical, but please bear with me!
Not being into fluid dynamics, my flow/pressure experience is also from a lot of garden watering!!! "the longer the pipe is, the bigger it need to be" (to deliver a nominated volume due to friction loss). There is a direct relationship of the diameter of the bore etc etc.
The way I see it is that there is a fixed amount of oil in the system starting from a single point (the pump).
If you take off (say) double the designed volume at the first point of exit, the pressure and volume (or rate of flow) MUST be reduced to the next point - the question for the TR6 is - is the reduction significant enough to be of concern?
The only way to tell is to look at the end of the "pipe" to see how much is coming out.
If you run at say 2000 rpm and check the end of the rocker shaft at No1 rocker, you should see oil 'oozing' from under and around the bearing area. If the oil is 'pouring out', you have more than you need there and a flow restrictor would be a good idea. They don't need a lot of lubrication - leave as much oil at the bottom end as possible.
Just to mention also, for anyone considering valve stem seals, you really only need them on the inlet valves, as they are on the induction stroke, and tend to suck oil in from above, patricularly if you have a lot there.
PS - g/box inspection - we found that the increasing whine was due to the case hardening on the first gear worn through. - still can't really complain after 20 years of use.
|Hey Roger. You're exactly right. I've not dissected a block or inspected the galleries. If properly designed, though, the main oil gallery should be big enough in diameter so that the pressure drop along it is low pretty low. That way the oil pressure's about the same at all the take-offs, the pressure drop's about the same through all those drillings, and there's no "built-in" distribution problem like with the garden waterer. When you tap off 5% of that oil to the top head, the pressure in the main gallery will drop off, but the distribution to the secondary drillings should be essentially unchanged. |
|As a matter of interest there was quite a long thread recently in the TR Register forum about this subject and on the whole the posters came out very strongly against using an external feed particularly from people who had experience of performance engines. As a result of this I removed mine!!|
|Algie--You can't keep us in suspense like that: what happened to these engines with the feed line installed?|
|Rick--the main problem seems to have been excessive wear of the bottom end bearings due to worn rockers getting much more oil than they normally do, the general opinion seemed to be don't fit this mod at all but if you must do make sure the rockers are tight and fit a restricter in the line.|
One poster suggested that some early high power racing engines had been fitted with separate oil feeds to the main bearings and the rockers but as the feeds to the main bearings was not an easy DIY job the parts suppliers continued to supply the rocker conversion and a fashion was started.
PS Algie is my surname
|My apologies Ron. Thanks for the info.|
|Ted at TSI strongly recomended to me not to run the line.Reason I don't remember,but the recomendation stayed with me.|
|Just a brief comment from a former TR6 owner.|
I have been told that running this oil line tends to reduce the amount of oil available to the rear camshaft bearing, not cam lobes.
The cause of wear to the lobes may be from the famous "drainback" problem where the filter housing needs to be filled by the oil pump before the engine gets oil, (unless you have a spinoff adaptor).
Lobe wear could also be caused by worn valve springs having insufficient tension, thus causing bounce of the follower on the lobe.
My TR6 ran at 65psi at about 3000rpm, I think thats about right.
Simon, (now a TR4 owner, no oil pressure or thrust bearing problems)
|I asked Richard Good (Goodparts USA) if he recommended the external feed in conjunction with his roller rockers (Note: his rockers ride on needle bearings, not bushings). Here's his response:|
"Yes with an if. It seems the amount of oil fed through the stock channel can
vary. I usually end up using the external line with a restriction to get what I
feel is the right amount of oil. I restrict it with a roll pin (I think I use
5/32" x 3/4") pushed into the end of the hose fitting at the lower end of the
hose. I leave the end of the roll pin stick out in case I want to remove it.
There is room in the fitting for the protruding end of the roll pin.
72 TR6 w/external feed
|Hi Simon and all.|
Just so were all using the same terms.
From my previous post
"I have alway's had a theory if the back journal is somewhat starved it will tend to vibrate? Creating a mild hammer effect."
The rear journal of the crankshaft rides in the rear journal bearing. The Lobe is a another area that provides valve lift. Splash mist whatever lubed.
My definition of a journal bearing simply put is 2 machined metal surfaces like or unlike designed to run within a given tolerance with a supply of oil under pressure at high speed or grease at low. Thats a short form from my Industrial mechanical bearings manual.
The oil at pressure is the bearing surface.
In a perfect situation the 2 metal surfaces should not touch. I don't know what the tolerance is never measured myself. But even with assembly lube slathered I know it slips in easy? Now add rotating lobes lifting other devices etc. lower the oil pressure and you have a candidate for vibration? "Mild hammer effect"
|Just to cofuse the issue (I took off my external feed after previous controversy) seems to me that IF oil has been changed regularly IE no sludge build up to cause constriction, AND (bushed) rockers are tight, there is no advantage at all from an external feed. If rockers are worn, OR have needle roller bearings, there is little or no resistance (in the case of the rollers, the oil squirts out the gaps between them) so it IS likely to starve somewhere else and if you add a restrictor, what is the point. My engineering days said NEVER use needle bearings on reciprocating parts - small load bearing surface running in the same spot all the time, witness what happens to universal joint journals over time. Also, at 102K,(point of rebuild due to being left sitting with water in the crankcase after a head gasket failure demoralised PO ) almost no wear on valve gear! So go figure ?|
Peter 74 TR6
This thread was discussed between 03/12/2003 and 14/12/2003
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