Found My Block Oil Leak - What A Mess - How To Fix?

[revilla]

Since September 2013 I have been trying to trace a mysterious oil leak on my K-Series VVC. Oil was appearing on the block below the starter motor and around the top surface of the big lug that acts as the bell housing mount. It actually appeared at the time to be coming from the corner of the joint between the block and the crank bearing ladder.

 

I've already run a couple of threads about which I will now close, as I have found the cause:

 

Original Thread

Later Thread With Details

 

The engine in my car appears to be a converted MG TF or ZR engine, not a Caterham supplied unit. This is supported by lack of Caterham branding and NS (Not Supplied) in the appropriate place in the VIN code.

 

When converting a K Series for use in a Caterham, you have to grind away a couple of ribs from the side of the block to allow for the repositioned starter motor. You have to be careful not to take away too much metal to avoid hitting an oilway (actually the oil return channel where one of the head bolts runs). It appears that the original builder of my car either went too deep and nicked the oilway or hit some porosity in the casting. I don't know which yet, as they then effected a "repair" with what appears to be some form of metalised epoxy resin. This has started to separate from the underlying metal over the years, allowing a small oil leak. The oil is then running down the edge of the cutout behind the starter motor and wetting the block below it.

 

Photograph Here

 

What a mess! Not feeling very impressed at the moment.

 

I'm currently in the process of carefully scraping the expoxy away to see how bad it is. I'm either going to find a big hole, a little hole or a patch of porous aluminium. I'll update this thread when I've got a clearer idea of how bad it is.

 

In the meantime, suggestions please on possible remedies?

 

If I were building or converting the engine myself I think I would probably have scrapped the block and got a replacement or had it welded, but given that the engine runs very nicely and that the repair that was done before seems to have lasted 10 years, I think I'll have a good go at repairing it in situ, even if a repair won't last forever.

 

I'm thinking at the moment in terms of patching any obvious holes I find when I get down to bare metal, possibly with something similar to that used before but only in the areas needed, followed by a deep clean of the area with acetone/solvents and a neat high temperature RTV patch.

 

Thoughts please ...

[Jonathan Kay]

Talk to Ed?

 

Jonathan

[Guest]

I've used this with some success in the past.

http://www.belzona.co.uk/en/products/1000/1111.aspx

Your problem will be getting the repair area clean to ensure good adhesion.

Acetone & a high pressure air line might be ok.

Best of luck

Ian

 

Edited by - IanL on 10 Jul 2014 21:06:29

[Mankee]

Flipping heck, so I was actually right in your second thread! What a pain in the backside though. I do remember a thread in the archives of someone also going too far with the grinding when converting a "normal" K-series for RWD use. They got it welded up without dismantling the bottom end from what I remember. Maybe you could do the same with the engine in situ?

 

I'll try and find the thread, if JK doesn't beat me to it.

[Ed White]

I'm just talking to our insurers to make sure they are happy with us doing stuff like this. Plan if they are is to do stuff by word of mouth. Limit of liability I'm thinking of being the value of the job only. I've seen this form of liability release before. About the first thing we tackled was a cracked wheel on my scirocco. £400 plus for a wheel so we had a go. Ground into the crack, and beyond it. Welded it bringing the weld above the surface, as apparently the impurities sit on the surface. Ground back, and off to kiwi fit for tyre back on. All the lads there asked who had done it, and could we do there's, so that suggested it was ok. Did around 50k miles on it and after a while didn't give it a second thought.

 

There are however good epoxy type materials that you could use, but you need a spotless surface to apply them to.

 

Let me know if I can help.

 

Cheers, ed

[Mavic82]

Had really good success with evostick metal epoxy putty.

 

Can be drilled and tapped, sticks really hard and seems impervious to oil and reasonable heat. But it needs to be super clean.

[revilla]

@JK - Yes, I will indeed. I had him in mind following his recent request for broken aluminium parts but didn't expect to be going to him so soon with a hole in my block! See below ...

 

@IanL - Thank you for that, looking at it I think that might be the kind of thing that the original repair was done with. It seems to have lasted 10 years. It appears to be something like an epoxy with a high level of metallic content, it's certainly tough to scrape away. I'm being careful not to remove any additional good metal at this point. I'll bear it in mind as a possibility.

 

@Mankee - Unfortunately you were! I should have taken more notice of what you said. You were spot on. Due to the high metal content of the patch, when I cleaned it up before it actually looked like metal and I missed the fact that it had been patched at all. Became a bit more obvious when the edges lifted though! I know a bit more now about the engine than I did back then. When I built my spare engine I ground the block myself and I took it very gently, offering the starter motor up for a trial fit step by step. Looking at the block on the installed engine, they have certainly gone quite a bit deeper than I found I needed to.

 

@Ed White - Hi Ed! I read your earlier posts re aluminium welding. They stuck in my mind as I managed to wreck a sump on a raised cat's eye on my first day of Caterham ownership. The car was running far too low, I hit the brakes while pulling off the A1 into a right turn central lane, compressed the front suspension and ding. Bye bye sump.

 

Anyway, do I remember correctly that your workshop was in the Nottingham area? We are only 20 minutes from Nottingham in Burton on the Wolds near Loughborough, so it would be easy to get the car to you.

 

At the moment I'm just carefully scraping back the patch to clean metal to get a good look at what I'm actually dealing with. I haven't got it all cleaned back yet but there is a definite elliptical shadow emerging which looks like where a bit of over-enthusiastic grinding has touched the side of a cylindrical drilling.

 

Once I've got it cleaned back I'll take some detailed photographs and maybe we can have a chat as to whether it looks like something that you would want to tackle and what would be involved, or whether you can recommend any alternatives. I'm guessing it would at least need the engine out for access, and probably quite a bit of stripping back.

 

My general approach to things in life is NOT to bodge them and I do intend to keep the car for the long term (hence the spare engine build) so I would prefer as "proper" a solution as possible. If that's an engine-out welding job then I may just go for it.

 

I've had enough scraping for one night. At least now I know where the oil is coming from I stand a chance of fixing it. I just need to find that persistent rear suspension clonk now ...

[Ed White]

Hi, yes we are in heanor, Derbyshire. I'd want the engine out ideally. Regards, ed

[6speedmanual]

http://www.precision-welding.co.uk/

here

These people are good too, and would almost certainly want the engine out also.

 

Good luck with it.

 

Peter

[elie boone]

If you want it done properly you will have to take the engine out, but if you can find someone who will weld in situ unplug ECU and alt. to avoid damage.

I would try and make a piece of alloy that fit over the hole and glue it in place. You could make a proper fix when the engine has to come out for some other reason.

[revilla]

OK, decisions ...

 

The engine's got to come out. Whatever I do, it'll need the engine out.

 

In the garage I've got an identical spare engine I built over the winter. I ran it all up to temperature again this evening. It sounds lovely. Smoother a quieter than the one in the car. No leaks, no rattles. Runs up to temperature and then cools as it should. Wasn't planning to put it in yet ... but why not? It's going in.

 

I shall then overhaul and rebuild my current engine as this year's winter project. I can pick up a used bare block quite cheaply, do the grinding and conversion, then get an engine reconditioner to give it a proper acid dip and deep clean for me. Shouldn't cost much more than that, just gaskets bearings and anything else untoward I may find. The rebuilt engine can be wired and plumbed up to my test trolley and be kept as a running spare (for the next time ...).

 

Ed, I'll BM you re the old block.

 

I'll start a new thread (or two ...) for any questions I have re the engine transplant as it's really a separate subject. It really should be a one-in one-out job as I built the spare engine as an exact duplicate of what was installed.

 

Thanks for all comments and suggestions as always.

[revilla]

Well here is the hole now that I've cleaned away all the epoxy that was bodged over it. Lovely isn't it? a.k.a. how NOT to grind a K Series block!

http://www.revilla.plus.com/Block%20Hole.jpg

[Jonathan Kay]

Well... it's better to know.

 

I hope that's just shadow to the left of the rib...

 

Jonathan

 

Edited by - Jonathan Kay on 11 Aug 2014 15:05:45

[revilla]

@Jonathan - Yes just shadow, I used flash which was probably unnecessary.

[Jonathan Kay]

Thanks.

 

I look forward to hearing what an expert welder will say and do.

 

Jonathan

 

Edited by - Jonathan Kay on 11 Aug 2014 15:57:37

[AJC]

Probably something along the lines of "You see that big skip over yonder?,cob it in there".

[oilyhands]

If you key the surface then Devcon would probably make an effective repair.

 

Oily

[Birkin S3 ZA.]

If it was mine I would weld it in place, the hard part is getting the oil out of the aluminium.

over time it soaks in deep and can take a bit of heating cooling and cleaning a few times to get it clean.

also the better machines can be set to etch the material more as you weld to keep it clean as you work, slowly weld the sides and get a good clean weld around the hole then join the sides to close the hole.

Chris

 

[Slipper man]

Interested that you ran the spare engine up to temperature without putting it in the car. How did you do that?

[Tony Whitley]

I've ground those ribs off on a couple of engines without realising there was an oilway behind

[revilla]

@Slipper Man - See

😬

 

When I built the spare engine over last winter, I was fully expecting to need to keep it in good running condition out of a car for many years. The plan was to have it as a long-term replacement for when I finally wore out the engine in the car. Little did I know that it would be in the car a few months later.

 

In order to be able to test it and to turn it over every now and again I built a complete test trolley for it complete with:

 

1) A full cooling system which mirrored that in the car, including expansion bottle, MG TF radiator and thermoswitch controlled fan.

 

2) A complete engine loom. I built this from scratch myself but to be electrically and dimensionally identical to the one in the car so it too could be used as a plug and play spare for the car in the long term future.

 

3) MEMS3 ECU, 5AS immobiliser (to keep the MEMS3 happy, but again all programmed up as a matched set so I could use as spares for the car if needed), MFRU, battery, battery conditioner connector, OBDII diagnostics port.

 

3) A replica of the relevant parts of the main car vehicle loom in order to allow it all to be powered up. Basically all of the wiring for the instrumentation, switch gear fuel pumps, battery and fuse box terminated in the correct plugs to connect to the engine loom.

 

4) Instrumentation including ignition light, alternator warning light, water and oil temperature gauge (switchable), oil pressure gauge (mechanical) and switches for ignition, start and fuel lift pump.

 

5) Fuel system including a tank made from a 5 litre plastic can with motorcycle tyre valves fitted as supply and return attachments for rubber hoses, a Bosch injection pump and a Facet lift pump (only needed to prime the main injection pump if the "tank" is standing on the floor below the level of the pump, as the main injection pump was really designed to be immersed in the fuel tank and is a lot better at blowing than sucking) plus appropriate filters.

 

6) Exhaust system comprising a standard Caterham collector with lambda sensor and a stubby silencer plus supporting brackets. I resisted the urge to add a chrome tailpipe.

 

7) Caterham engine mounts. Again VVC spec so I have them as spares for the car.

 

I started the engine up and ran everything up to temperature every couple of weeks, checked it was all happy with no funny noises, leaks or DTC codes. It would run indefinitely on the trolley as it warmed up to 85C and then just sat there with the fan cycling on and off, even on a hot summer day.

 

Once the old engine has been sorted, either by repairing or replacing the block, I will give it really good going over, rebuilding or replacing anything that isn't A1, and then it will be installed back on the trolley as the spare. Hopefully this time it will not be needed for many years!

[AJC]

10/10 For that............but its crying out for a chain to drive the wheels somehow,thats your next job 😬

[Slipper man]

Brilliant!!

[revilla]

@Tony Whitley - It's actually the channel for one of the head / through bolts, which doubles up as an oil return channel from the head back down to the sump, so it's drilled or cast quite a bit wider than the bolt itself. It is actually not far below the surface at all by the time you've ground enough of the rib away to fit the starter (I've compared this engine with the spare I built and there's only a few millimetres difference in grinding depth), so you need to be careful to only take away as much as is needed. How the original builder could have managed to grinf it that far into the channel without realising though is beyond me. I think I would have stopped when a crack started appearing!