Fixing cylinder head oil leak

[Nobbie]

I've recently been running the Mk IV Spitfire more regularly and the constant leak from the rear of the block is getting annoying so I'm going to take the head off and sort it before my drive is ruined. It's a 1500 engine from an old dolomite, but basically the same as the 1500 spitfire. I believe this is a common problem, but my forum search skills seem to be lacking.

Could anyone advise me on what I need to do to sort this out once and for all. I have the external rocker shaft feed fitted if this makes a difference to blocking up any oil ways. From memory it seems to be a decent gasket? Some Hylomar and possibly new head bolts?

[WIMPUS]

First things first ... use a Payen gasket 🙂

[thescrapman]

it is a standard problem, and usually ignored (well certainly in my case) until the head needs to come off for another reason.

You can improve matters by using a smear of sealant round the oilway hole in the headgasket, and possibly a smear along the rear edge of the gasket.

Don't put sealant anyhere else.

Thinking about it, if it is leaking between the head and the block then the internal oilway was clearly not plugged, as needs to be done if using an external feed.

Take it off, make sure you are still getting oil up to the rockers and see if the leak reduces.

Other thought is that the oil is coming from the rear of the rocker cover as the high feed will flood oil up top unless a restrictor is fitted (they rarely ever are)

Cheers

Colin

[junkuser]

Seeping from that area is so common, if I ever have the head of my Spit I intend to wad-punch the hole in the gasket to a hole large enough to put an "O" ring in there with adequate clearance to accommodate the O.D. of the ring when compressed but small enough to support the ring when under oil pressure.
I only have experience with the old copper sandwich gaskets and so, this idea is based on them.

Don't know if this is possible, but thought I'd post this in case anyone would like to comment.

Getting the enlarged hole in the gasket concentric with the average of the head and block drilling centres would take some judgement. Can't assume they actually line up perfectly as manufactured.

[JohnD]

Unless that block oilway has been sealed REMOVE THE EXTERNAL OIL FEED NOW!

It is Ye Spawne of Ye Deville, that robs the mains of flow and ruins those and big end bearings, to no point whatsoever.
If your rocker shaft has insufficient oil though wear then deal with that.

Look it up under that name (YSoYD) to find iother discussions.
JOhn

[Nobbie]

Thanks for the info re the oil feed, it was 20 years ago I did it, but haven't done much mileage in that time and can't remember why I did it at the time. I'll try removing it as a starter as this should reduce the pressure up there.

[2Triumphs]

and note the news gaskets i got for my mk2 are 2 layers  card and stainless so if you seal do it between the plys as well as each face i suggest as  mine still appears to leak possibly because i only sealed the outside faces but also becase there some weep from the pushrod tubes - does bother me much though as a fair bit comes throug the crank case breather on these cars and gets  swallowed by the air filters - at least it did until i vented mine to atmosphere - i dont like the idea of filters or the valves getting caked in burnt oil scuzz - better out than in

[esxefi]

I inserted a piece of thin wall tube down the oil way,lightly squeezed in the middle so it wouldn't drop all the way down into the block(make sure it goes tight if you try to push it down the hole)put an 'o' ring around the tube to sit in the gasket hole and carefully fitted head,haven't had a leak at the rear for 10+years now.

but you must check that the hole in the block and the head align almost perfectly,the head studs do allow a small amount of movement of the head.

[Nobbie]

I removed the rocker oil feed after reading the links on the subject, can't think why I fitted it really, maybe it was all the fashion 20 years ago. Head is still leaking, so I've ordered a Payen gasket set off James Paddock (only £15+£3 P+P) and will whip the head off when it gets a bit warmer and use a bit of blue Hylomar to hopefully seal it.

Where did you get the thin wall tube from to go down the oil way? Might take a look at this option once the head is off. Maybe look in my tin of bicycle bits for something suitable.

[Gt6s]

On my sixes I drill down a little into the head and the block and cut a small sleeve tube (Dowel) If memory right 5/16 then a small amount of Hylomar on both sides round it the head is then set on.

Laurence

[JohnD]

Bobbie,
No Hylomar on a Payen gasket.  The faces have layer of heat setting sealant on them.
If you must, a thin smear around the hole for the oilway. No more.

If a Payen doesn't seal then you must suspect that the block or head faces are not properly flat.
A light head skim by a machine  shop will correct that.

John

[Nobbie]

Spent yesterday doing this and the initial run seemed to be OK, but only time will tell. I think half the reason may have been a lack of torque to the bolt on that corner as the nut was not running freely on the thread. I found a little brass valve extender in my box of cycle bits and almost fitted this in the oil way as it was a perfect fit, but thought it may reduce oil flow a bit so scrapped the idea.

Water pump looked like it was leaking, so I removed it, but the bearing seems fine and I refitted it to see how it goes. At least I sorted out the seized studs on the pump housing while it was on the bench. Any recommendations for a good replacement pump if this one has had it?