Low compression on cylinders 1 and 2

[alan.barker]

What's the marvel mystry oil is it like "Redex" an UCL (upper cylinder lub).
In the long distant past when people filled up them asked for a few shots.
It could have been sticky Rings or sticky Valves.
Good luck and better than pulling the Head off.
Alan

[2cams70]

I’ve pulled quite a few engines down that have been sitting around in less than ideal conditions for a long time. Usually what happens is that the ring grooves in the piston corrode. The white aluminum oxide corrosion deposits push against the rings and the ring then seizes the piston in the bore. Aluminium corrodes preferentially to the iron piston rings. Sometimes the bore itself does not show a lot of corrosion but it’s the corrosion of the piston around the ring grooves that’s the main problem. Probably at least some damage has been done to the engine but if it seems to run reasonably well then depending on how fussy you are you may decide to just leave as is and see what happens. If you can get a camera in the bores it may be worth a look to see what the bores look like and determine whether there is any bore rust or any bore scuffing that has occurred from operating with the rings having been partially seized

[alan.barker]

Stephen,
If i was you restoring a car that has been standing since 1976 i would remove Engine. Remove Head, remove Sump (will be full of old oil that's turned to treacle),
If on original Bore size deglaze and buy NOS Pistons from Sjsportscars very cheap.
Polish Crank and fit new Vandervell Shells.
For me this is not an expensive exercise and good preventitive maintenance. Cheaper in the long run with an unknown Engine.
Personal choice but that's what i do.
Alan

[2cams70]

If it were me personally I'd just suck it and see. Provided it runs OK, compressions are reasonable and it isn't pissing oil and coolant (flashing red signs - water pump, water pump!) everywhere due to dried up seals I'd try to leave it alone. Of course change all the fluids and filters and flush the cooling system as best you can. If it's been sitting a long time with coolant or worse plain water in the system the radiator and block will have a fair amount of silt in them.

Simple things you can do as I mentioned is to have a look in the cylinders through the spark plug hole with an inspection camera if you feel so inclined. Another thing I'd do would be to remove the cam cover and check the valve clearances. Whilst the cover is off check the cam lobes and followers. This is another area where you typically get a layer of surface rust if the engine has been sitting a long time.

If there's damage due to long term inactivity it's already been done and running the engine as is isn't going to significantly worsen the ultimate rebuild cost unless you do something stupid like keep using it whilst it's obviously showing signs of distress - eg. overheating due to having a silted up radiator or making strange knocking sounds.

Insofar as old oil sitting in the sump is concerned my experience is that it doesn't turn into treacle just by itself. There needs to be pre-existing circumstances such as a leaking head gasket existing when the engine was last used allowing moisture to mix with the oil. I've drained oil from engines that have been sitting for a very long time and it has always flowed out and appeared just as it would have done 20 or 30 years prior

[alan.barker]

The last +2S130 i bought i dropped the Sump to find 1 cm of Sludge in the bottom.
The car had not been used for 24 years.
When i said treacle i meant sludge in bottom of Sump. When you drain the Oil this stays in the Sump.
I wish you good luck and no problems whatever your choice.
Alan

[2cams70]

Every engine that you pull down that hasn't had regular oil changes, run mineral oil all it's life, and covered a fair mileage usually has a layer of sludge in the bottom of the sump. It's not there necessarily because the engine has been in storage a long time.

You should of course watch the engine oil pressure and check for anything unusual. In particular check that the pressure is not too high as it could be indicative of a sticking pressure relief valve in the oil pump.

[alan.barker]

"Trying to resurrect S2 been standing since 1976".
Difficult for me to understand the way of thinking not to remove and refresh like i said.
Alan

[2cams70]

Of course it would be best to pull it down especially if the ultimate aim is to do a complete restoration.
If however the budget does not permit or the intention is just to get it running I would not be too concerned running the engine as is provided it is not showing any obvious signs of distress (and that of course is very important).

[StephenT]

Thanks again for all the suggestions.

Ultimately I will pull and rebuild the engine. My goal for now is to make this a drivable car. This will give me the opportunity to evaluate the other systems and respond to their needs.

I have rebuilt the brake calipers and replaced the rubber hoses, master cylinder and rotors. I have replaced the rubber donuts (the least enjoyable project). I have rebuilt the fuel pump and carburetors. Now the engine runs (to some degree). I still need to get the carbs dialed in. I have installed a new clutch master cylinder and have a new clutch slave cylinder to install (I hope the clutch is in a serviceable condition). So I should be very close to actually driving the car. Which will give me a chance to evaluate other areas of the car. Plus it will give a certain feeling of accomplishment before I start tearing things apart.

Thanks,
Steve

[mbell]

I still need to get the carbs dialed in.

My guess from your result is that the two carbs are quite out of balance and need balancing. So I would start there, balancing make quite a difference to engine running at idle.

[StressCraxx]

For those questioning my advice to use Marvel Mystery Oil, I completely understand. I never liked "mouse milk" additives in my cars at all. I once managed the lubricants program for a large west coast oil refinery. We didn't use third party additives in our 4200 pumps, turbines and compressors in the plant.

That said, our recip compressor rod packing boxes(a series of 3 piece segmented carbon rings with a surrounding garter spring) would frequently leak sour gas from the dirty process despite the use of a nitrogen purge and oil lube on the boxes. If the compressor rod boxes were found to be leaking we would have to stop the machine and repair them. We discovered debris that plugged the packing boxes was soluble in Marvel Mystery Oil. Pumping MMO into the purge taps immediately cleared the packing boxes of debris and re-established adequate sealing. I've used MMO on other engines including a 907 in a Jensen Healey we resurrected from the dead after replacing it's timing belt. YMMV

As far as the OP driving the car until he knows all of the issues, it's a fair decision. I did the same on my '67 Elan S3 for 4 years, then rebuilt it.

[alan.barker]

Hi Stephen,
not to look on the dark side but i bet the Clutch is stuck to the Flywheel after all those years
I think you will be pulling the Engine earlier than planned. Remember to get the Flywheel resurfaced no matter how good it looks.
Have fun
Alan

[StephenT]

The clutch being stuck has been in the back of my mind for a while. I just ordered the hydraulic line for the clutch, so I should know more soon.

Steve

[mbell]

You can often free a stick clutch in situ. My car had possibly been laid up for 20 years and had stuck clutch I managed to get it with out removing anything. There are free threads on here with different approaches you can try.

[StephenT]

Thanks, I may be searching that topic soon.

I put some of the Marvel Mystery Oil in all cylinders yesterday afternoon. I will see if it made any difference later today or tomorrow. I will report back with my findings.

It’s been said many times but I want to repeat that this group is an invaluable resource. Without it I would be muddling my through all of this. So thank to all that muddled before me and are now taking the time to share their experiences.

Steve