Oil leaks

[Old Dave]

Well my RN drips oil. Not an earth shattering thing to admit.

When I bought the car a few year ago I removed the sump and replaced the gauze. I replaced most of the fixing bolts and washers, applying a new gasket with the blue stuff seal.

       

You can see that 2 of the bolts (one each side) have had a problem in the past. I was loathe to fiddle much as I was new to A7’s. I think something like an 6/8mm bolt has been tapped in and a nut used to apply pressure to the sump plate.

On the assumption that the original bolts were meant to be tightened as much as a spanner would allow I hoped that was good enough. No torque settings of course.

Do you have any advice as to how I should proceed with the “funny” bolts or just leave alone?

I tighten the others now and then. Are there any suggested torque settings?

[Chris KC]

Dear Old Dave,

The first thing I would say to anyone who thinks their sump joint is leaking, is "are you quite sure it's the sump joint?" - as pretty much anything above that (e.g. the block/ crankcase joint, or the valve chest) will dribble down to the sump and unless you catch it in the act it's not easy to determine with confidence which is the culprit.

If you're hell-bent on fixing it (certainly advisable if you're in the gallon-a-week bracket) yes, personally I'd do something about those screws, although they do appear to be doing their job. You could tap oversize or personally I'd make an oversize threaded plug and start again with a fresh drilling and thread. Others prefer helicoils, no argument here unless the holes break through into the sump, in which case you'll need some sealant on the helicoil. (If already tapped metric this door may be closed to you). Either way you CAN do it under the car but you'd be much better off noting the job down for next time the engine comes out.

About tightness, personally I'd say "tight with a spanner" is TOO TIGHT. I use slotted round-head screws in mine and nip them up with a screwdriver, never had one drop out. If you are using a standard A7 "tin" sump heaving up on these screws will only distort the flange, which is what causes the leaks. It probably also accounts for the vast number of stripped sump screw threads one encounters on old cases.

[Howard Wright]

Hi Dave

I’m with Chris on this one. Leave well alone until you really need to do something. However you are going to need to have the sump and gauze strainer off sometime so I would wait until you do this.

A couple of tips for when you do. 

1. Use a silicon gasket, applied dry. Recommended by many on this forum.

2. I put strips of steel plate (1/16” thick) in the well of the sump flange, shaped to fit in the well and around the corners and drilled to accept the sump set screws. This gives more support to the rather flexible sump flange.

Hope this helps

Cheers

Howard

[David Stepney]

Dave, I would echo what both Chris and Howard have said. When I had my engine to bits, now some two and a half years ago, I found that some butcher had been at my sump bolts and two of them had been drilled and tapped to take a couple pf 5/16 BSF bolts, whilst several others had been strained so that they 'slipped' when tightening. I helicoiled all the damaged ones, including the ones that had been drilled out. Cherished suppliers can supply oversized sump bolts.The job is much easier to do with the crankcase upside down on the bench. At well past my 70th birthday, I wouldn't fancy doing it on my back!

Personally, I have used a standard thick paper gasket from one of the cherished suppliers, well greased both sides, bolts in good condition with their attendant oval washers done up to a good nip - nothing more. Yes, my engine does leak a bit of oil (mostly from one corner of the block to crankcase gasket); getting an Austin Seven engine to be oil tight is a bit of an impossibility, but unless the oil leak(s) is (are) of Torrey Canyon proportions, I would leave well alone. My own car does about 250 miles per pint, which I can live with.

Hope this helps.

[Old Dave]

Thank All for the info and advice. I will have a careful appraisal of where the oil is coming from. It is now beyond bearable, not so much in money terms as pools on the ground (or in the drip tray).

Was out on the Spring Run today and the effect at ground was profound, even when spending less than 5minutes topping up the petrol tank.

I did replace the valve chest gasket with a silicone one a few months ago. Maybe oil near the rear of the panel is from the breather holes and blown back?

I think I may do both the valve chest and sump with a silicone gasket. I believe the surfaces must be clean and dry to get a good seal.

Thanks again for your help. Any major surgery of the threaded holes in the crankcase will have to wait for an engine out adventure.

[Old Dave]

Oh Dear!!!!!

Things look somewhat worse than I thought. I reckon the oil is leaking from the block/crankcase joint - see photo

   

Is this definitely an engine out job? I am thinking of time as much as cost really. And once out you always replace stuff you might have used for another year or two or more. I have never worked on an A7 engine and the last time I stripped any engine was when Noah was a boy and I could'nt afford to pay anyone else to do it.   I have most of the tools 

Any advice on the best way forward appreciated.

[Chris KC]

Are you sure it's not getting past the front oil jet access screw?

[Old Dave]

Hi Chris,

Well that thought had occurred to me - given the proximity of the oil stream in the photo. Oil seems to be spreading fairly widely - see these pics taken at the same time as the first one.

   

   

It has lost a lot of oil - don't ask.

I am thinking of filling the sump in the morning and running her on tickover to see if I can see more of what is happening.

[Chris KC]

That's a good plan Dave. I'd squirt the case down with some brake cleaner or similar so it's clean and dry to start with then it'll be easier to see what's coming from where.

[Peter Arnold]

I sympathise with Old Dave having had problems that way myself when I first got my 36 tourer and was in the process of overhauling the engine I cut a full reinforcing flange for the sump from 1/16 plate and used a similar thickness rubberised cork gasket and have had no problems.
The main oil leaks on my engine were from the tappet cover and the crankcase/block seal. I fixed the tappet cover by putting a very thick bead of silicone sealant in the groove, having first cleaned up the crappy old gasket, then a further bead of sealant over the top of the old gasket. I then covered a very flat, smooth piece of timber, with cling wrap and pressed the cover down with a piece of steel and let it set. After removing the cling wrap and cleaning up the daggy bits around the edge with a sharp blade, I was left with a lovely flat surface which no longer leaks.
The crankcase join was attacked as per a forum members suggestion (I can’t remember the name) by cleaning around the joint thoroughly with solvents and then applying a bead of the blue stuff around the join. That was 1,500 miles ago and I have not had a leak there since.
I hope this might help someone.