Joined: Aug 2017 Posts: 3,372 Threads: 105
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Location: Darkest Bedfordshire
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.
Joined: May 2018 Posts: 2,091 Threads: 109
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Location: Llandrindod Wells
Car type: 29 Special, 30 RK, 28 C Cab
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
Joined: Jan 2019 Posts: 1,563 Threads: 20
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Location: Bala North Wales
Car type: 1933 RP Standard Saloon
03-04-2023, 10:50 AM
(This post was last modified: 03-04-2023, 10:51 AM by 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.
Joined: Aug 2022 Posts: 149 Threads: 27
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Location: Cheshire
Car type: Austin 7 RN - 1932
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.
Joined: Aug 2017 Posts: 3,372 Threads: 105
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Location: Darkest Bedfordshire
Are you sure it's not getting past the front oil jet access screw?
Joined: Aug 2017 Posts: 3,372 Threads: 105
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Location: Darkest Bedfordshire
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.
Joined: Mar 2019 Posts: 37 Threads: 8
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Location: QLD Australia
Car type: Austin 7 1936 tourer
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.