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eschneider
Jedi Warrior
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Anyone have a picture of one installed? What exactly do these things do?
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external rocker oil feed line
- Thread starter eschneider
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Alan_Myers
Luke Skywalker
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Hi,
Sorry I don't have a picture of one. In fact, you'll never see one installed on my TR4.
These are pretty much intended for just what the name implies: An auxiliary line that delivers additional oil to the rocker assembly. That's done in hopes the additonal lubrication will reduce wear and help quiet the operation of the rockers.
Depending upon what car you have and who you talk to about it, this modification might be helpful... Or it might be harmful.
In general, the auxiliary line "robs" some oil from the main gallery and delivers it to the top of the engine. There are already internal oil feeds to deliver oil to the rocker shaft, so this is in addition to that.
In my personal opinion, I'd rather have as much oil as possible being delivered to the bottom of the engine (mains and conrod bearings) and camshaft bearings, am less concerned about putting lots of lube onto the rocker shaft itself.
For one thing, if it does wear, the rocker assembly is easily accessed and rebuilt while most of the engine remaining in the car.
To me, the bearing surfaces in the bottom are more important and failures or increased wear there usually will mean pulling the whole engine out for a major overhaul, at best. Worst case, poor lubrication in the bottom end might lead to catastrophic destruction of the entire engine, say if a conrod breaks.
Some people find the auxiliary rocker feed beneficial on the TR6's 2.5 liter 6-cyl. motor. The extra oil in the top end finds it's way back down to the crankcase via the pushrod tubes, and some will undoubtedly end up on the camshaft and perhaps even work it's way into the cam bearings.
Unique to the 2.5L engine, the camshaft runs directly in the block without any actual bearings, so some additional lube there might be a good thing. However, I think this is pretty unlikely to be provided by this auxiliary feed. (BTW, the 2.5L can have proper cam bearings put in during a rebuild, a good thing to do IMHO. I think Spitfire cam bearings are used for this and the installation is fairly straightforward, except that the block needs to be align-bored at a machine shop to fit them. Not too big a deal when the block is already in for other service work.)
In fact, on the 4-cylinder TR motors, I've heard it said any number of times that the auxiliary feed line mostly just increases oil burning (there are no valve guide seals on that motor) and can lead to more plug fouling, etc.
On the 2 liter GT6 motor, I'd be very reluctant to rob any oil from the main gallery because that engine already has enough problems with significant loss of pressure at the front main at revs much above 4500-5000 rpm. (One solution for this issue *is* an external oil feed: But one that bridges and augments the mains instead of feeding the rockers.)
I don't know if anyone is using them or how well they work on the smaller 4-cyl. in Spitfire, etc.
The one place that I think any of these cars might see some benefit from the auxiliary feed is at the cam lobes and cam followers. These lead a rough life and a bit of additional lubrication there can't hurt. Still, if they are the correct hardness, properly installed and carefully treated during initial break-in, cam and followers can last a long time without need for a bath of extra oil.
Overall, I'd think it better to just make sure the already existing, internal oil feeds are doing their job well, and let it go at that. But, that's just my opinon.
Sorry I don't have a picture of one. In fact, you'll never see one installed on my TR4.
These are pretty much intended for just what the name implies: An auxiliary line that delivers additional oil to the rocker assembly. That's done in hopes the additonal lubrication will reduce wear and help quiet the operation of the rockers.
Depending upon what car you have and who you talk to about it, this modification might be helpful... Or it might be harmful.
In general, the auxiliary line "robs" some oil from the main gallery and delivers it to the top of the engine. There are already internal oil feeds to deliver oil to the rocker shaft, so this is in addition to that.
In my personal opinion, I'd rather have as much oil as possible being delivered to the bottom of the engine (mains and conrod bearings) and camshaft bearings, am less concerned about putting lots of lube onto the rocker shaft itself.
For one thing, if it does wear, the rocker assembly is easily accessed and rebuilt while most of the engine remaining in the car.
To me, the bearing surfaces in the bottom are more important and failures or increased wear there usually will mean pulling the whole engine out for a major overhaul, at best. Worst case, poor lubrication in the bottom end might lead to catastrophic destruction of the entire engine, say if a conrod breaks.
Some people find the auxiliary rocker feed beneficial on the TR6's 2.5 liter 6-cyl. motor. The extra oil in the top end finds it's way back down to the crankcase via the pushrod tubes, and some will undoubtedly end up on the camshaft and perhaps even work it's way into the cam bearings.
Unique to the 2.5L engine, the camshaft runs directly in the block without any actual bearings, so some additional lube there might be a good thing. However, I think this is pretty unlikely to be provided by this auxiliary feed. (BTW, the 2.5L can have proper cam bearings put in during a rebuild, a good thing to do IMHO. I think Spitfire cam bearings are used for this and the installation is fairly straightforward, except that the block needs to be align-bored at a machine shop to fit them. Not too big a deal when the block is already in for other service work.)
In fact, on the 4-cylinder TR motors, I've heard it said any number of times that the auxiliary feed line mostly just increases oil burning (there are no valve guide seals on that motor) and can lead to more plug fouling, etc.
On the 2 liter GT6 motor, I'd be very reluctant to rob any oil from the main gallery because that engine already has enough problems with significant loss of pressure at the front main at revs much above 4500-5000 rpm. (One solution for this issue *is* an external oil feed: But one that bridges and augments the mains instead of feeding the rockers.)
I don't know if anyone is using them or how well they work on the smaller 4-cyl. in Spitfire, etc.
The one place that I think any of these cars might see some benefit from the auxiliary feed is at the cam lobes and cam followers. These lead a rough life and a bit of additional lubrication there can't hurt. Still, if they are the correct hardness, properly installed and carefully treated during initial break-in, cam and followers can last a long time without need for a bath of extra oil.
Overall, I'd think it better to just make sure the already existing, internal oil feeds are doing their job well, and let it go at that. But, that's just my opinon.
G
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I have an auxiliary oil feed line on my modified TR6 and don't seem to have a problem with low oil pressure. Now, I have a good oil pump (later model, higher pressure), a 16-row oil cooler and carry over 6 quarts of oil (because of the cooler). I tend to maintain about 75 lbs of oil pressure when hot.
I have personally seen some rather tired TR6 valve trains that suffered from extreme starvation of oil on the front section of the rockers, all gunked up. Of course, these were hard-run engines that probably never saw regular oil changes. I use a Fram 3600 oil filter.
I have personally seen some rather tired TR6 valve trains that suffered from extreme starvation of oil on the front section of the rockers, all gunked up. Of course, these were hard-run engines that probably never saw regular oil changes. I use a Fram 3600 oil filter.
RomanH
Jedi Knight
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Alan_Myers said:
Have to agree with Alan on this. The increased oil consumption is also an issue with the TR6. If your valve guides are worn you will have more oil pass by the valve since there are no valve stem seals on these motors either.
Removed the feed line on mine and the oil consumption went down noticeably.
G
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RomanH said:
I have the GoodParts Teflon valve stem seals on my valve train. Are we talking about the same thing here?
TR6oldtimer
Darth Vader
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Personally I have gone back and forth on the benefit of this modification.
It is my opinion that on a new engine, little will be gained (or lost) with this modification as everything is tight and oil pressure high. A new engine warm at speed should have oil pressure of 70psi or better and an idle pressure of around 40. At these pressures there is sufficient oil for all parts.
However, on an old engine I believe the addition of the external bypass could actually cause harm. Why? If the engine is running 15psi at idle, and 45-50 at speed, diverting oil to worn rockers will provide a reduced restriction route for oil to flow and lower pressure to the rest of the engine.
This is why I go back and forth. A new engine does not need it, an old one will probably do worse with it.
The designers had no problem with the original configuration so why toy with it.
As Bill alluded to, I believe regular oil and filter changes with quality products will do more to lengthen engine life then this bypass system.
It is my opinion that on a new engine, little will be gained (or lost) with this modification as everything is tight and oil pressure high. A new engine warm at speed should have oil pressure of 70psi or better and an idle pressure of around 40. At these pressures there is sufficient oil for all parts.
However, on an old engine I believe the addition of the external bypass could actually cause harm. Why? If the engine is running 15psi at idle, and 45-50 at speed, diverting oil to worn rockers will provide a reduced restriction route for oil to flow and lower pressure to the rest of the engine.
This is why I go back and forth. A new engine does not need it, an old one will probably do worse with it.
The designers had no problem with the original configuration so why toy with it.
As Bill alluded to, I believe regular oil and filter changes with quality products will do more to lengthen engine life then this bypass system.
swift6
Yoda
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So, on my TR6, I have had the external oil line on both my original high mileage engine and my new performance motor. Never noticed or saw signs of a oil pressure difference with or without the line. Did see a pressure difference when I installed the oil cooler on my high mileage engine but that's a different story.
The original design does have oil routed to the rockers. However, the passages are very small and can be easily plugged leading to oil starved valve trains. Frequent oil changes can help prevent this but these cars weren't always treated correctly by PO's so it can happen.
On a newly rebuilt engine, the hot tanking (cleaning) of the block and head prior to machining and cleaning the head and block prior to assembly should give you fresh and open oil passages. Which should be adequate for stock rockers.
However; I have been told that if you are using roller rockers (which I, and I believe Bill is as well, am using) then the additional oil to the valve train can be a good idea.
I do have a question about all of this though. What is the reason for that bolt in the back of the head. What purpose was it originally designed for? You don't put them in as part of the external feed line kit. Its there for a reason and I am just wondering what that might be.
The original design does have oil routed to the rockers. However, the passages are very small and can be easily plugged leading to oil starved valve trains. Frequent oil changes can help prevent this but these cars weren't always treated correctly by PO's so it can happen.
On a newly rebuilt engine, the hot tanking (cleaning) of the block and head prior to machining and cleaning the head and block prior to assembly should give you fresh and open oil passages. Which should be adequate for stock rockers.
However; I have been told that if you are using roller rockers (which I, and I believe Bill is as well, am using) then the additional oil to the valve train can be a good idea.
I do have a question about all of this though. What is the reason for that bolt in the back of the head. What purpose was it originally designed for? You don't put them in as part of the external feed line kit. Its there for a reason and I am just wondering what that might be.
A TR250 owner in our club added this kit to his rebuilt engine and now it smokes on start up and consumes oil daily.
We discussed adding seals to the valve stems but that would require you to remove the head to compress the springs and remove the keepers etc.
I have heard of connecting compressed air to the plug port to hold the valves closed so the valves do not fall onto the piston and or stuck in there. But thats too tricky.
Bottom line, I agree with the others, a properly rebuilt engine should not need this mod.
cheers
/bcforum/images/%%GRAEMLIN_URL%%/cheers.gif
We discussed adding seals to the valve stems but that would require you to remove the head to compress the springs and remove the keepers etc.
I have heard of connecting compressed air to the plug port to hold the valves closed so the valves do not fall onto the piston and or stuck in there. But thats too tricky.
Bottom line, I agree with the others, a properly rebuilt engine should not need this mod.
cheers
/bcforum/images/%%GRAEMLIN_URL%%/cheers.gif
swift6
Yoda
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Brosky said:
Thats along the lines that I was thinking. I also remember reading somewhere, can't verify the source or the accuracy, but that it was added by the works department (could have even been the Standard 'Works' department instead of Triumph) specifically for increasing the oil to the valve train on works engines. I do not recall where the works boys got the oil from, whether it was from the mail oil gallery or not I don't know.
Given the history of the basic design, that predates the TR5/250/6, GT6, 2000/2500 sedans, and the reluctance of Standard Triumph to change an overall design very much, it could be a left over from a very early thought process in performance lubrication thinking.
In this example, I don't buy the cross drilling holes explanation. There are plenty of heads from the era that don't have tapped access holes like these heads. If it were strictly for allowing a maching process, why tap threads into the hole and thread in a bolt? Why not use a form of plug that would take more effort to remove?
If you increase oil to the valve stem area, then increased oil consumption should be expected if you don't use valve stem seals.
Alan_Myers said:
Alan, neither my 2.0L GT6 or the 1500 Spit had cam bearings. I <u>did</u> install them in the 1500 I raced, but the 6 is still running in the block.
I also ran the external line on the Spit, but that was mainly for valve spring cooling, and I was running a modified GT6 oil pump.
Jeff