Classic cars forum & vehicle restoration.

[fiatguy23]

So im restoring a 1923 fiat 501, and I've had it running for about a year now, although not being on the road yet. Its only done little trips around the yard. But, lately I have noticed the engine was slowly gaining oil, the level visible by a sight guage and meter on the side of the sump. Expecting the worst I pulled the filter out (only way to actually inspect the oil) and sure enough it was milky! What a horror, I had completely rebuilt the engine too!! im hoping it is somethining as simple as the head gasket, as the head bolts hadn't been retensioned after it had been run in.

So, assuming it is this and everything else is fine, what is the best way to remove the watery oil from the engine? I don't really feel like pulling the sump as to do that the entire engine must be removed. It didn't seem like there was too much water in the oil, it was a dark grey colour so not a real white milky colour yet, thankgod! I had also noticed water bubbling out around a few head bolts, also indicating it needed to be retensioned. Is this right?

Brodie.

[peter scott]

Hi Brodie,

If you let it settle the oil should float on the water and if you drain the sump you'll find that the water comes out first. As to any emulsion left in the crankcase I'd just run the engine with a detergent oil and it should clear it.

Be careful not to apply too much torque to your head studs just in case you have a similar problem to mine.

I had this problem a couple of years ago due to a cracked top deck.
http://www.scottpeter.pwp.blueyonder.co.uk/new%20page%2015.htm

I hope your water source is easier to repair.

Peter
_________________
http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon

[fiatguy23]

Thanks for the tip peter. The engine had been sitting for close to a couple of weeks before I drained it out but it was still mixed in with the oil. I am really hoping its an easy problem to source, and a cheap one at that! I'm a uni student so time and money is scarce!

I am contemplating getting new head bolts for the car, the old ones are 90 odd years old and I just have this horrible feeling that one is going to break :/

[peter scott]

Hi Brodie,

I think you will need to take the head off to establish where the leak is from.

Peter
_________________
http://www.nostalgiatech.co.uk
1939 SS Jaguar 2 1/2 litre saloon

[fiatguy23]

Update: Took the spark plugs out and cylinder number three looks nasty! Both inlet and outlet valve have rusty water seeping past the stems and from what little can be seen through the spark plug holes is not a pretty sight.

Thankfully the valves are not seized, and the engine would still run fine apart from this major defect. Heres a link to when the engine was running

http://www.youtube.com/watch?v=YPssKzlhkCw

We spoke to our mechanic who helped us rebuild the engine, and he (unfortunately) suspects a cracked head. So, following his advice we are leaving it sit over night with the radiator full of water and will turn it over with the starter with the plugs out in the morning. If water sprays out, then that means a cracked head, or block.

[buzzy bee]

Hi

Great video, so sorry to hear the bad news! She started so easily on the handle in the video, wish they were all like that!

Cheers

Dave

[MVPeters]

Not to question yiur mechanic, or Peter's, advice, but I'd be very tempted to carefully snug the head bolts down first.
There's a recent thread on two different ways of doing this & two different opinions as to which is correct.
It could, if you're lucky, just be a leaky head gasket between the water jacket & #3 cylinder.
_________________
Mike - MVPeters at comcast.net
2002 MINI Cooper 'S'

[Jim.Walker]

The best way to detect leaks is to pressurise the cooling system. Kits are made for the job, but it is relatively simple to modify a radiator cap for the job. Never pressurise beyond normal pressure cap level or only 2 or 3 psi. if an unpressurised system or the water pump seal may be blown off its seat.
Rotating the engine until both valves on the offending cylinder are closed should reveal whether the leak is in a port or the combustion chamber.
We once had a problem where a casting pin-hole in one of the ports was causing a problem. If the engine happened to stop with that valve open it flooded the cylinder.
Jim.
_________________
Quote from my late Dad:- You only need a woman and a car and you have all the problems you
are ever likely to want". Computers had not been invented then!

[P3steve]

If the water is coming past the valves then being a side valve means its unlikly to be the head gasket it might be worth pulling the cover off the valve chest to see whats happening there and be very carefull about putting any pressure in the system as a lot of vehicles of this period have open vent cooling systems and were never ment to be pressurised so you could end up blowing some gasket that was never ment to take any pressure.
_________________
If the world didn't suck we'd all fall off

[fiatguy23]

Hmm, I'd be hesitant to pressurise the system as P3steve said, because it is an unpressurised system anyway so it may do more harm than good. Looking through the spark plug hole the tops of the valves can be seen as well as a little of the top of the block and all is rusty, the fact that water is running down both the inlet and outlet valves of cylinder no. 3 leads me to think that it isn't the valve stems leaking, it seems pretty coincidental otherwise that both on the one cylinder are leaking.

When I get home from work tonight I will crank it over and see what happens, I had a look through the hole this morning and as far as I could tell no more water was in the cylinder than there was the night before. If no water sprays out when it is cranked I will nip up the headbolts and see if that provides a fix, this was suggested by our mechanic too. Fingers crossed!

[roverdriver]

I do hope that the cylinder head only needs tightening. It is possible that the head cracked in between the running on the video and now, but IMHO it is a little unlikely.

One word of caution, I once assembled an engine in very low light conditions. It ran perfectly, but blew the head gasket after only about 50 miles. When I removed the head again, I found that some greasy rubbish had lodged on the gasket thereby causing a leak. The grunge must have fallen onto the top of the motor just as I was lining up the cylinder head.

Re-pressure to locate a problem, a useful tool is one of the older spark plugs that have removable porcelain. Take the porcelain out, and replace it with a tyre valve. Turn the crankshaft so a cylinder is on the compression stroke, insert the pseudo spark plug and apply air pressure.

A hiss from the exhaust indicates exhaust valve problems, from the inlet manifold it will indicate inlet valve problems, lots of air (there should be some) from the oil filler shows the rings are suspect, and bubbles in the radiator mean a bad head gasket or possibly cracked head.
_________________
Dane- roverdriver but not a Viking.

[fiatguy23]

The thing is, I start the engine up regularly, probably every two weeks and it always ran fine, although running rough for a minute or so from cold. I just assumed this was carby related.

We cranked the engine by the started motor tonight with the plugs out and no water sprayed out, a good sign I hope. We also examined another engine head and block that we have. On the car it is weeping water from the head bolts, but the only way it could really happen is if the bolts aren't tight enough as they do not screw into the water chambers, hence allowing water to come past the gasket and up past the bolts.

I shall keep you posted

[MVPeters]

Fiatguy
You're certainly thinking along the right lines.

Just a comment on pressurizing: all you need is a couple of pounds of air, as Jim pointed out. A bicycle pump or gently-used car foot pump will do just fine. If you can put some brightly coloured fluid in the engine, like bright green anti-freeze, it will help.

& just a note on the head bolts: if the head has ever been skimmed, or there's a washer missing from under the head of the bolt, it's possible that the bolt can 'bottom-out' in the threads - which gives the impression that the bolt is tight when it really isn't. On the Austin 10, the centre bolt is a bolt (!), the rest are studs. Mine (40+ years ao) kept blowing gaskets between 2&3 until we replaced the bolt with a stud, washer & nut.
_________________
Mike - MVPeters at comcast.net
2002 MINI Cooper 'S'

[fiatguy23]

Thats a good point mike, both the head and the block were machined during the rebuild so that could very well happen. There are washers under each bolt but perhaps introducing a second one wouldn't hurt.

I would have to block the overflow pipe in the radiator if I were to pressurize it but thats well worth a thought!I am also thinking of doing that diy sparkplug cylinder pressure thing mentioned by roverdriver, it would be interesting to see how 'even' it is between the cylinders.

[Julian]