Over oiling Valve gear?

[LiamP]

This is my first ever post, and I am looking for a bit of advice!! 

Got a US spec car with an oil leak which I believe is coming from the rear of the head gasket, the car is fitted with the external oil feed, (not wishing to open that debate I have read the differing opinions on this mod on this site) and I was wondering if this mod could cause over pressurisation and failure of the head gasket?.

I also suspect that the valve gear is being overfed with oil, but am unsure of what the correct amount looks like hence the video's for a more experienced eye to look at!!!  Looks like a lot of oil apart from the No1 cylinder first valve' any advise is appreciated. 

Thanks Liam.

 

Edited May 14, 2020 by LiamP

[Mike C]

Make sure it's not the valve cover,  if so check the PCV system, or whatever US cars use to vent the crankcase & valve cover.

Edited May 14, 2020 by Mike C
Clarification

[RogerH]

Hi Liam,

welcome to the forum.

Where about's are you?

over pressurisation in the oil system is unlikely as there is a relief valve in the oil filter housing.

You should have an oil pressure gauge on the dash that should be about 60 - 70psi.

External feed could allow too much oil to the rockers; but this would possibly reduce the system pressure.

You could re-torque the head.

Check that the oil leak is not coming from the rocker cover.

 

Roger

[Andy Moltu]

I wouldn't have though the external feed would explain leaking of oil from the head. (Unless you restrict it the external rocker feed can pump a huge amount of oil to the rockers and lead to leaks from the rocker box and out of the breather)

Leakage is common on the L side of the head as this is relatively lightly compressed by the head bolts as the bolts are inboard. I was advised that when building the engine to lightly sand away the lacquer in this area and put on a thin smear of gasket sealant - being careful only to do the area outside of the pushrods.

[LiamP]

11 hours ago, Mike C said:

Make sure it's not the valve cover,  if so check the PCV system, or whatever US cars use to vent the crankcase & valve cover.

Hi Mike,

                I am pretty certain its not the valve cover, new gasket fitted and viewed the back end with an inspection mirror, when it is not under load no leak! it only happens when being driven a bit briskly!!! The other thing of note is that the engine is only vented via the rocker cover, to a Y piece and then onto the inlet side of the SU's so no PCV system fitted!!

Liam.

[LiamP]

Hi Roger,

                Thanks for the welcome and the reply, I am in North Yorkshire, I have attached a couple of Utube links to the original post as the videos didn't seem to work on the site. Oil pressure is 60/70 psi when under load so looks pretty normal, I don't think it'd flooding the valve gear just looks a bit excessive (but not sure) no blue smoke of any note, and of course the leak may not be related to the oil feed, I did wonder if anybody blocks the original feed when reworking the head or is it normal practice to leave both feeding the V/G.

I am pretty certain the leak is out of the head, but only when driven briskly, I'll try taking the rocker gear off and checking the cylinder head torque this weekend, but if they are ok, it looks like I might just continue and replace the head gasket. I just haven't seen a head gasket fail with a external oil leak and wondered if it was more common on the 6.

Mike has pointed out engine venting but I can only see a vent on the rocker cover,  no valves, catch bottles or flame traps, could this have an impact?

Liam.

[John L]

I'm sure there should be a restrictor in the bolt that fits into the cylinder head to limit the amount of oil going in there, but I don't remember the size of the hole, I'm sure somebody else will be able to tell, worth just to take it out and see what size hole is that bolt.

John

[LiamP]

Thanks John, I have had this bolt out the hole is about 1mm, but to be sure I have ordered a new one and a blanking bolt from Moss Bro's, might fit the blank and see how much oil I get with the standard set up.

Liam.

[Mike C]

Make sure you identify exactly where the leak is from. If necessary clean the area down and puff talcum or foot powder around it with a puffer.

If it's only happening when you really load the engine it could be loose headbolts. Try torquing them up  as Roger suggests. If that doesn't stop the leak you will probably have to replace the gasket and maybe skim the head.

If it's only a minor leak consider living with it until you do your winter TR 6 jobs.

 

Edited May 15, 2020 by Mike C

[John McCormack]

TR6s have a common oil leak from the head gasket on the left hand side of the engine. My car has an oily engine on the left side above the PI gear towards the rear of the engine. It is a known issue and I ignore it. It isn't significant in the big scheme of things.

You don't want to go into the external oil feed but I can't resist saying that a sound engine that isn't racing doesn't need such a mod. It does take oil from the lower end of the  engine which needs it far more than rocker gear. 

[john.r.davies]

Liam,

Keeping my mouth tightly shut on the Spawne of Ye Deville that is the external oil feed, your second video is interesting.     I can see a continuous stream of oil falling out of several of the rockers, but not No.1, as you say.  Nos. 3 and 9 are especially gushing.     This is an excessive amount of oil to be supplied to the rockers, but recall that it only goes in at the back end.   When the flow along the hollow shaft encounters such demand (aka leaks) from the rockers it first encounters, there can be no surprise that the one on the end goes dry.

But when such a torrent of oil is pouring out of the rockers, it's difficult to imagine that the pressure at the gasket is  so great as to force oil out between the head and the block.     Moreover serious external oil supply fitters obstruct the oilway so carefully designed and installed by Triumph, so that flow doesn't occur backwards, towards the rear camshaft bearing, past the head gasket.    So the only pressure there would be the pulse provided by the flat on that journal.   Not enough I feel to force the head off the block.

However, I fear that whoever did fit your external oil supply wasn't a serious fitter.    They also fit a restrictor to the supply, a narrow orifice or tube, to prevent what we have seen under your rocker cover, a torrent of oil that should be going elsewhere.     The usual sight is a drip - drip from the rockers, quite sufficient for road use.

So we have an unrestricted, excessive external supply, possibly losing some flow backwards to the cam bearing, that is going out of the rocker shaft unevenly.    I fear that you have worn rockers and/or rocker shaft to cause this, a condition that your DPO may, unwisely,  have fitted the external supply to overcome.    

All this  makes excessive pressure as a cause for your head gasket oil leak most unlikely, but may prompt you to inspect the external pipe - does it contain a restrictor? - and your rocker gear - are the shaft or rockers worn?   And the head - is the oilway blocked?   

Good luck!

John

PS a restrictor normally has an ID of less than 1mm, the actual flow requirement of the rockers being so low.

Edited May 16, 2020 by john.r.davies

[LiamP]

Thanks Mike like the idea of powder to try and spot it, after a run it leaves about a 3 ins diameter mark on the drive. So not really liveable with and just as the going for a run is about to start in the UK, after Rogers comments been monitoring the oil pressure a lot more closely and when hot (temp gauge mid point) the oil pressure is down at 55psi @ 3,000rpm, so looks a bit low, running on Millers classic 20/60 with a spin on filter, just hoping I can get the summer out of it without doing any drastic damage!!

Liam. 

[LiamP]

John, Thanks so much for looking at the vid's and confirming my thoughts that it is an excessive amount of oil to feed to the valve gear, the flow is restricted by the 'banjo' bolt that is fitted to the head (1mm hole) even for a hole of this size the amount of oil looked a bit much. I think my plan is to blank off the external oil feed and see what it looks like running on the original feed (if it's not blanked), then, I think remove the rockers and check the shaft, and if at that time the head bolts are tight I'll just have to bite the bullet and get on with changing the head gasket. Overall the oil pressure is a bit low at 55psi @ 3,000rpm when hot, not sure if removing the external feed will improve it by much!

Liam

[LiamP]

5 hours ago, John McCormack said:

TR6s have a common oil leak from the head gasket on the left hand side of the engine. My car has an oily engine on the left side above the PI gear towards the rear of the engine. It is a known issue and I ignore it. It isn't significant in the big scheme of things.

You don't want to go into the external oil feed but I can't resist saying that a sound engine that isn't racing doesn't need such a mod. It does take oil from the lower end of the  engine which needs it far more than rocker gear. 

Thanks John, starting to think this mod is not needed for a road car, I am going to run it without the mod and video how much oil I get so we can compare the two sytems.

[Tom Fremont]

My experience with the auxiliary oil feed has been excellent. TRF supplied back in the 1900s  it has done 95,000 miles on the head and 130K miles on the bottom end with the same rocker shaft assembly, rebuilt by who are now Rocker Arms Unlimited with bronze bushes and hard chrome plated shaft. The tappet clearances need little or no adjustment when checked 10K miles or so, if I remember to do so. 

Oil pressure is 65 psi@ 2000 rpm or higher, never below, benefitting from a thermostatically controlled 16-row oil cooler and Brad Penn 20W-50 oil. 

The engine shows no sign of fatigue whatsoever, though the timing chain has probably stretched 6 degrees ( crankshaft ) at this point so is ~ 3 degrees retarded w/r/t its valve timing. It does get driven fast, fit out with P.I. cam and triple Webers ever since its last rebuild in '96.

I reckon a rebuilt rocker shaft assembly as described above will obviate use of these. OEM the rockers were not bushed and the shafts not very hard. Life was perhaps 60-80K miles. I can't even speculate how much difference extra oiling would make on originals.

My concourse car does without, putting on 500-600 miles per year. It has the good rocker shaft assembly too.

 

Tom

[john.r.davies]

2 hours ago, LiamP said:

John, Thanks so much for looking at the vid's and confirming my thoughts that it is an excessive amount of oil to feed to the valve gear, the flow is restricted by the 'banjo' bolt that is fitted to the head (1mm hole) even for a hole of this size the amount of oil looked a bit much. I think my plan is to blank off the external oil feed and see what it looks like running on the original feed (if it's not blanked), then, I think remove the rockers and check the shaft, and if at that time the head bolts are tight I'll just have to bite the bullet and get on with changing the head gasket. Overall the oil pressure is a bit low at 55psi @ 3,000rpm when hot, not sure if removing the external feed will improve it by much!

Liam

Ah!  There is a restrictor!

But one that flows that much oil, through a 1mm orifice, at 55psi seems extraordinary!

JOhn

[LiamP]

6 hours ago, Tom Fremont said:

My experience with the auxiliary oil feed has been excellent. TRF supplied back in the 1900s  it has done 95,000 miles on the head and 130K miles on the bottom end with the same rocker shaft assembly, rebuilt by who are now Rocker Arms Unlimited with bronze bushes and hard chrome plated shaft. The tappet clearances need little or no adjustment when checked 10K miles or so, if I remember to do so. 

Oil pressure is 65 psi@ 2000 rpm or higher, never below, benefitting from a thermostatically controlled 16-row oil cooler and Brad Penn 20W-50 oil. 

The engine shows no sign of fatigue whatsoever, though the timing chain has probably stretched 6 degrees ( crankshaft ) at this point so is ~ 3 degrees retarded w/r/t its valve timing. It does get driven fast, fit out with P.I. cam and triple Webers ever since its last rebuild in '96.

I reckon a rebuilt rocker shaft assembly as described above will obviate use of these. OEM the rockers were not bushed and the shafts not very hard. Life was perhaps 60-80K miles. I can't even speculate how much difference extra oiling would make on originals.

My concourse car does without, putting on 500-600 miles per year. It has the good rocker shaft assembly too.

 

Tom

Thanks Tom, I think your probably right I might be looking at a new rocker assembly to resolve the problem, however I was surprised to see the amount of oil going to the valve gear via the external supply did you view the video's? must be badly worn to allow that much oil to flow.

[john.r.davies]

11 hours ago, LiamP said:

Thanks Tom, I think your probably right I might be looking at a new rocker assembly to resolve the problem, however I was surprised to see the amount of oil going to the valve gear via the external supply did you view the video's? must be badly worn to allow that much oil to flow.

Wot I sed.

[LiamP]

20 hours ago, john.r.davies said:

Ah!  There is a restrictor!

But one that flows that much oil, through a 1mm orifice, at 55psi seems extraordinary!

JOhn

Yes surprised me, the vid's are @1200rpm so below 55psi suspect, as Tom suggests, valve gear is shot!! 

[Tom Fremont]

Another question I have is how much ( if any ) longevity of the valve guides is affected by extra oil up top. I'm very happy with 95K miles and counting on mine but don't know if any credit is due the auxiliary feed line. No valve guide seals are present and guides are bronze.

 

Tom

[LiamP]

1 hour ago, Tom Fremont said:

Another question I have is how much ( if any ) longevity of the valve guides is affected by extra oil up top. I'm very happy with 95K miles and counting on mine but don't know if any credit is due the auxiliary feed line. No valve guide seals are present and guides are bronze.

 

Tom

Guess we will never know Tom, suspect that maybe the external oil feeder kit on my 6 was fitted to mask a problem that was already there. 95K  on yours is fantastic and still going strong so can't be much wrong with the principal, quality of the valve gear fitted will also have an impact so I suppose for me the lesson is you get what you pay for!!!

Thanks Liam.