Tappet Lubrication from cold

[SimonBrown]

Good Evening
Still struggling with a top end rattle from cold on my S2 4.2, which I am pretty sure is lack of camshaft/tappet lubrication until run for a couple of minutes.
Having satisfied myself there is sufficient supply to the camshafts, the rattle is improved if the tappets are lubricated manually before starting.
The engine number is 8682, meaning it should have 2 hole cams with 4/6 thou clearance.
It is fitted with later 4 hole cams, post engine number 14075, so has oil holes deleted.
In order to improve lubrication, can anyone see any issue with drilling oil holes in the back of the lobes?
This would save the cost of buying an unknown pair of camshafts
Any thoughts much appreciated
Thank you
Simon

[Gfhug]

Simon, are the four hole cams the later ones with the 12-14 thou clearance? If this is what you have then they do sound much more tappety on start up compared with the earlier cams.
Sorry, can’t comment on your point of drilling oil holes, leave that for the knowledgeable.

Geoff

[mgcjag]

Hi Simon...just thinking out loud here....the valley in the head under the cams hold a lot of oil and almost bath the tappets....is your head somehow not holding the oil in the noisy tappet area overnight....or why is it slow to fill?....Steve

[chrisfell]

The cam oil feed pipes can become blocked or restricted. I'll rephrase that. The cam oil feed pipe on my car did become blocked. It was blocked, to be more precise, the inlet feed pipe became blocked by swarf created when an undersize big end split pin rattled loose and the bits were sucked through and chewed up by the oil pump, blasted through the paper oil filter and lodged in the banjo bolt of the inlet feed pipe.

Result, noisy cam quickly followed by heat damage to the cam and followers. Three followers needed replacement as well as the cam. No other damage has subsequently been found.

[mgcjag]

Hi Simon....from our chats I think you have cleaned out your cams already?....I'm thinking on this pre oiling that solved the problem...but as mentioned in my previous post oil should be well pooled up in the valleys.....so is the offending one draining overnight...has a previous owner fitted a hold down kit and oil seeping down through it...is the valley damaged somehow so not letting it fill enough...have the valley drain holes been enlarged and therefore the pool level reduced?....when you remove the cam cover is there the same level of oil in all 3 sections....As you have no cam lobe holes you could remove a cam cover...empty the valleys of oil..start up the car...and see how the vallys are filling...or pull the spark plugs disconnect coil and just turn it on the starter...oil pressire will come up and you can see how its filling.....Steve

[SimonBrown]

Thank you and to answer questions,
The cams fitted are later 12/14 thou clearance, probably from a later XJ6, with no lobe holes.
It does not have a tappet hold down kit and there are no witness marks where lobes could have been touching loose tappets.
The cam oilways have been cleaned out.
After standing, all 6 valleys have an equal amount of oil residue, almost over spilling when the covers are removed.
This covers the bottom of the guide and a small amount of the tappet until started.
After a cold start it takes about 15 secs for oil to seep from the cam bearings, at the front, witnessed through the oil filler cap. Oil pressure is evident from the feed gallery immediately on start up.
The oil feed pipes have been changed from braided to original using new thin washers.
After deleting the lobe holes at engine 14075 (Aug 1970), Jaguar then changed (at a later stage) oil feed from the rear main gallery to a direct feed from the oil filter housing.
I am wondering if this was because they had an issue with slow camshaft feed?
Appreciate your comments
Simon

[mgcjag]

Hi Simon...my understanding is that the cams changed to no holes and an uprated higher rate oil pump and as you say a different oil feed path....if your prepared to take a chance then drill the lobes i cant see a problem as you just converting back to a previous design....or get earlier cams...Steve

[SimonBrown]

Thanks Steve,
Yes, lobe holes were deleted Aug 70.
I am unable to establish when, but sometime after, the filter housing feed was introduced. I was unaware of the uprated pump.

I am more inclined to drill my existing cams, as in other respects they work fine, then I can buy a second hand pair of cams if all goes wrong
Appreciate your help
Simon

[mgcjag]

Hi Simon....these change over dates I'm not sure of..I have a 1987 xj6 S2 parts catalogue..it shows cams with lobes drilled....I thought the non drilled were later S2/3xj6 with the higher rated pump and higher rated oil guage.....where did you find tne 1970 date.. maybee Jaguar changed back and forth ?Steve

[mgcjag]

Simon..did you ever look at your cam part number to see what they actually came off

[SimonBrown]

Hi Steve, Yes, from memory C55556 and C55555, which is XJ6
Aug 70 oil hole delete came from Factory original Jaguar E Type, 9 months after change to 4 hole cams, 12/14
Thou clearance.
I wonder why, sometime later they changed the oil supply from rear main to oil filter housing?

[SimonBrown]

Apologies, C35555 and C35556

[mgcjag]

Hi Simon..so they are E type cams...not xj6?

[SimonBrown]

With no oil holes?

[mgcjag]

Have a look here...read post 10.....3 sets of cams used on S2 E types....Steve viewtopic.php?f=3&t=11681&hilit=Parabolic+cam

[SimonBrown]

Thanks Steve,
I had assumed that “END” related to End of XJ6 Series 3 production, but I am probably incorrect in my assumption.
I have also read the Georgia Jag article which states the lobe oil holes were deleted when 4 hole cams were introduced, but in the Clausager book it says lobe oil holes were not deleted until Aug 70?
C35555 and C35556 are listed on the SNGB website as XJ6 Series 1 camshafts, and late E Type Series 2 camshafts are C41680, which is apparently incorrect.
Either way, my car does not have lobe oil holes, and with so much confusion over camshafts, I think it is probably worth drilling holes in the lobes and see what happens.

[mgcjag]

Here is the service bulletin note the gap of 12 and 14 are incorrect and was detailed in the next Bulletin as 12 to 14 .....Steve

[SimonBrown]

Thanks Steve,
Amazing information as usual!
So, my cams could have come from either a late E Type or early XJ6.
All I need to find out now is when the change to a direct cam oil feed took place. As far as I know this was not during E Type production, but was it done to improve oil supply to camshafts, without going back to holes in cam lobes?
Simon

[Rich70]

Simon,

Before you drill your camshafts just keep in mind that if you increase the flow rate out of the camshaft you will reduce the oil pressure in them which could increase bearing wear.

What grade of oil are you using?

If you’re looking at replacing the cams, change the tappets and cam bearings too whilst it’s apart too.

R

[SimonBrown]

Richard,
I use 20/50 oil.
The oil pressure on my engine is too high in my opinion at 60psi 2000 rpm hot, so I slight reduction might be a benefit?
Simon