Head gasket

[sudburypaul]

Having been feeling rather smug recently for changing a head gasket successfully on my 803 engine I now find I have the tiniest weeping of water coming from the joint at the front cylinder (alternator side). This is accompanied by a sometimes more smokey exhaust - light greyish in colour. As yet it does not appear to have affected the engine's performance and the radiator is still full. I've not needed to top up since the refit about 3 months ago. I have checked the plugs on all cylinders. They are all slightly sooty and much the same in colour, but this was after a few minutes idle from cold.
My question is, is it safe to re-torque the head down again, and if so can I just do the two front nuts where the leak appears to be or should I be retorquing them all. I imagine the answer is do them all as at least then I'll know whether they will need doing or not and to be safer and not affect any of the others unduly.

Paul

[mike.perry]

Did you clean the surfaces of the head and block properly, especially around the bases of the studs?
Re torque all the bolts in the correct order.
Are you sure that the water is not coming from the water pump and blowing across?

[sudburypaul]

Yes, all got a good clean up and dressed around the studs. Will check around the pump first before I retorque

Cheers, Paul

[bmcecosse]

Torque them in sequence (and in small steps) to 44 ft lbf. Have you retorqued it since you fitted the gasket? And then - reset the valve gaps to 12 thou inlets and 15 thou exhausts....

[sudburypaul]

Firstly checked my wrench settings, which were at 40lbs as per the Haynes manual from the last time I did this, so that was what they were torqued up at. I reset it to 44lbs and torqued again. Not quite so bad - less leakage evident but stil a bit smokey at operating temp or after a good rev at standstill.

I'll give it one more go but will still order a new gasket just in case. That said, I'm not sure just how sensitive my wrench is, as even though I increased the poundage most nuts seemed to be at 44lbs anyway. Tracked down to where it appears to be leaking, just below the first offside stud point on no.1 cylinder (no.9 stud). Though this doesn't necessarily suggest where the blow is I imagine.

Cheers, Paul

[Neil MG]

I suspect the water leak and the smoke may not be connected. Not sure if this is in any way an 803 issue, but mine does tend to smoke on start up - noticeably so if I have just parked on top of a mountain pass! i.e. after sustained high revs in 3rd up a steep hill. I put it down to the lack of effective valve seals and maybe slightly worn valves. The high revs help put more oil up in the rocker box.

If you have water getting into a cylinder you would probably have a clean spark plug! It also sounds like you may be running a little rich, I notice that my car is also a little more smokey on choke. Your plugs should be a nice coffee colour.

[bmcecosse]

It's just a little weep - will probably dry up. Did you make sure all the studs were firmly seated before fitting the new gasket - and did you apply a thin wipe of grease to both faces......? It's not a blown head gasket. And - you should never leave the torque wrench set - always wind it back to zero when finished with it.

[sudburypaul]

Thanks for all this folks.

Will check the valve guide issue by getting it running up to temp and remove the oil filler cap and see what smoke comes out the rocker cover with a good rev. I'm hopeful it is just a weep and will pass - there is no real leakage as such, just a tiny speck 'puffing' from the seam on the corner of the casing/head. I'll keep an eye on it, but is running fine for the moment. Yes, I think it may be running a bit rich too: Not used the choke all spring/summer and plugs still a bit sooty, but could also do with a good run to blow out the cobwebs. Will put the wrench back to zero too Learning something new every day...

Paul

[bmcecosse]

It's definitely too rich if it starts without choke from cold.......

[Bazzalucas]

I recently replaced big end bearings, valve seals (modern viton type on the inlets, hopeless rubber rings on exhaust), piston rings and of course, head gasket. Ran it up through several heat and cool cycles, then retorqued head bolts. I put between 75-100 miles of routine varied driving on it, with no smoke, problems or leaks, 50+ psi oil pressure, and ran nice and cool. Then I took it on a 120 mile round trip, including a stretch on the motorway of about 30 miles at around 70 mph. Within 5 minutes of high-speed driving the OP dropped slowly but steadily until it hung around 30 psi and stayed there for the remainder of the trip. On the drive home, I started from cold with 60ish psi, then it dropped again to 30 not very long afterward. Worse yet, about 10 miles from home it began burning oil, until by the time I reached my driveway I was leaving a pretty impressive cloud behind me.
No nasty noises from the engine, no leaks, no over heating.
I have not done a compression check yet (too dispirited- just drove it in the garage and closed the door behind me), but I removed the vent pipe from the crankcase breather and tappet cover and it was puffing merrily away. Did I overdo my budget semi-rebuild with my high-speed dash down the freeway? (and yes, I did hone the cylinders and cleaned the piston ring grooves to within an inch of their lives). Any thoughts, however discouraging, would be welcome.

[daveyl]

On the subject of leaking head gasket. I recently changed my gasket and found that it was leaking near the front of the head (by the engine serial number).
It appeared to be seaping out of the gasket. It might be worth checking all around the area where you see the leak. Thermostat housing, hoses, temperature sender. The fan can blow the water backwards and can appear to be the gasket.

[Neil MG]

Bazzalucas, that seems like a pretty short running in process and it sounds like you might be using the wrong oil! First of all it's generally accepted that you should be using 20w50 and not synthetic. More important is the quality of the oil. There are some who are happy to use the cheapest available, but that is not the best policy for long higher speed journeys when you need to maintain oil pressure. It must be classic oil with ZDDP. ZDDP has been removed from most oils because it can damage catalytic converters but is essential for older push rod engines such as ours. Different oils have been discussed on other forums with some measured effects on oil pressures after prolonged high speed driving. There is a company on your side of the pond called Kendall that supplies a highly recommended oil. Other guys over there use ZDDP additives. Here it seems that Valvoline VR1 20w50 is highly recommended specifically with respect to maintaining higher pressure when hot. Hope it's not too late...

[bmcecosse]

I would say the low oil pressure and smoke etc simply indicates that the half-hearted rebuild was a waste of time. A NEW oil pump is always needed (esp as your engine may still have the old 3 lobe pump fitted - modern pumps are 5 lobe and much better) - and frankly, pressure that low tells me the crank needs a regrind, so may as well rebore and fit new pistons too. Then - run it in carefully for 500 miles before doing more than 50, then work up the speed over the next 500 miles. Make yourself a period style 'Running In - Please Pass' sticker for the back window....... All new Minors came with one - perhaps someone still has one and can put up a picture ?

[Bazzalucas]

Ah, thanks...there goes any hope of someone saying, "Oh, it's just a fiddly relief valve". I guess I knew the answer before I asked, but hoped against hope. Anyway, for what it's worth (very little), I always use 20w50, a motor factor "own" brand, so not sure about the content of ZDPP, etc.
The engine is an early 70's Midget 1275, so don't know how many lobes the oil pump has- not enough, apparently
I did the change-of-underwear 'rebuild' because I left the engine in situ. Obviously, there is an engine-out complete rebuild in the near future. Sigh.

[bmcecosse]

I don't believe all that ZDPP stuff - a 1275 will have at least 4 lobe pump, so not quite so bad. Obviously - your engine will soldier on for quite a while - and some on other forums claim 'magical' results by pouring in a can of STP. Might be worth a try! Also - make sure the engine breather(s) is(are) connected to the carb inlet so there isn't any pressure build up in the crankcase - which if present can push oil up past the rings making the blue smoke........

[Bazzalucas]

I have breather pipes from the rocker cover and timing chain covers, T'd and feeding into the carbs in the factory spots.
I will try some "Magic Moose Whiz" of some sort- what have I got to lose now?

[sudburypaul]

Daveyl you've described exactly where the leak appears to be. I'm confident enough (famous last words) that it is coming from the gasket as can actually see a speck of water being blown out from the join right at the point of no 9 stud (it is very small) and have checked for other damp around the pump etc, which seems dry.
As BMC says I'll just keep an eye on it for a while and hope it dries up. I will be weakening the mixture too, so hopefully the smokiness under revs will reduce, and give it one more retorque to see if I can squeeze it together any further. Clearances are set for 12 and 15thou for inlet and exhaust respectively but will reset to be sure once retorqued.

Just a lack of indicators to solve then. No winkers, no operating light, no nothing. New fasher unit on the way as the old one has one very wobbly spade connector. If that doesn't work I'll be turfing up on the electrics forum...

Cheers, Paul

[bmcecosse]

Just join the wires together - do the indicator lights come on (obviously won't flash!) when you set the switch to left and right........

[Bazzalucas]

Finally got few minutes to do a compression check on my 1275: 150+ psi on all four from cold. How does that compare to what it ought to be? I took a peak inside and saw that each cylinder wall was shiny with a thick coating of oil. What hopes have I that the rings will eventually "bed in" and the oil burning will stop? C'mon, someone throw me a bone!

[MarkyB]

Did you glaze bust the bores at all?
How about cleaning out the ring grooves?
Some rings are marked and must go a certain way up, how much wear was there on the bores? A lip at the top you can catch your fingernail on is too much.

No bone yet