Smoking Rover not the good kind

[eggman]

So here is my new problem. I have a 1971 series IIa that was given to me by my brother in law. It hadn't run in 34 years and I went over it and changed all rubber hoses/seals all fluids and turned it over with the hand crank to lubricate all parts and then started it. It ran rough but that was to be expected. Then I noticed that when it warmed up the rover smoked like a fiend (oil smoke). I took off the head thinking the valve guides might be bad and while out had the exhaust valve seats replaced with hardened seats (all of this was done by a business reccomended to me that has done rover work before aslo found out that it is a 8:1 as stamped on the head). I reinstalled the head and torqued the bolts as described. Started up the engine and initially had some black smoke and then took it for a ride around the neighborhood and by the time I got back the oil smoke was back and just as bad. Before dismantling the head for the rebuild the compression was 140's on all four cylinders (cold engine). I am stumped! Could the rings be bad and only showing problems when warmed up and should I test the compression after the engine has warmed up to see if they change? I pulled the oil pan and cleaned out the sludge in the pan and replaced the gasket and then used 20W-50 oil for high mileage vehicles. Believe me any and all advice is helpful. I have been working on this rover for a year and would like to get it in running and take my patient wife for a drive.

[Alk-3]

could it be running rich enough to blow smoke? how do the spark plugs look?
have you run it long enough to see if the oil level actually goes down?

[SafeAirOne]

Is it smoking all the time or just at certain times, like during engine braking?

Oh, and the compression checks shoud be done with engine at operating temperatures.

Is there a PCV system installed on this engine?

[LaneRover]

Is the smoke coming out the tail pipe or is it in the engine bay?

[eggman]

SafeAirOne, it is smoking all the time once the engine is warmed up, yes it has a PCV system and no I haven't changed the diaphragm, that is next on my list of things to buy, I have a weber carb coming to replace the zenith that was original to the vehicle, and I will post the compressions values later today. Lanerover, the smoke is coming out of the tail pipe. If I could upload the video from my iphone of the maiden drive I could give you the example of the smoking it is doing. I havent run it long enough to notice any oil loss I'm afraid the neighbors will run me out if i run it that long! Again thanks for all the help.

[eggman]

So here are the results and they are not good:
Compression cold - cylinder 1-120 2-125 3-120 4-95
Compression hot - cylinder 1-25 2-20 3-40 4-30

So obviously a problem but is it a head problem (just rebuilt) or a ring problem? If it is a head problem is there a way to check the head specificly? If there is then i can bring it back to the shop and get them to fix it. This sucks! Wondering if I just shouldn't pop for the RN head but I may need to still fix the rings! HELP!

[stomper]

wet compression test. add a teaspoon of oil into each cylinder and then recheck compression. if the numbers go up, it is the rings. if they stay the same, then it may be a valve issue.

My 1000 mile away guess? rings are toast. the oil has to be coming into the cylinder from somewhere, and it is most likely from the rings.

[Alk-3]

I agree with stomper. You can do a leak down test to figure out what the weak link is. I bet it's rings though, if you've just had the head rebuilt.

[LaneRover]

I agree on doing the leak down test - any chance the valves are too tight and need to be re-adjusted? Did you shave the head at all when you had the work done?

[Alk-3]

correct me if I'm wrong, but even if the valves were too tight and not closing all the way, that would create a low compression situation but it would not cause the smoking. the valve guides might, but they would have to be very bad indeed. If the head was rebuilt, I think it's very unlikely the guides are that bad.
I think the only real likely cause is bad rings, as lng as you trust your rebuilder that the guides were in fact replaced.

[Alk-3]

I had another thought.. can you start up the motor and then check the crank case breather pipe for blowby?
With compression that low, it should be significant, and shouldn't take too much to determine the rings are bad.

[eggman]

I will do the leak down test and let you know but I am heading out of town and won't be able to do it until I get back. Has anyone heard of checking the head by turning the removed head upside down then pouring a small amount of gas to see if it leaks past the valves or valve seals? Thoughts, smart or stupid? Lane I didnt shave the head and I don't know if the shop did but I can check the paperwork and talk to them. What would be the signs of a shaved head? Alk-3 I will check the breather then also because I will have to start it and get it up to operating temps to leak check the compression! Again thanks for all the help! What would we do without the internet? Oh yeah drink beers with friends and talk about rovers!

[Alk-3]

if you are going through the trouble of pulling the head again, I would just take it to a shop and have them check it out for you.
burning oil has not got a whole lot to do with a head though, generally, I don't think. it's possible the valve guides are leaking, but they would have to be leaking a lot to cause oil to be seen in the exhaust at the level you are describing. Also, with compression that low, I'd be willing to bet you are dealing with bad piston rings/wear on the bores etc.
if you pull the head, you can lap the vales to seat them, but again, I really doubt this is your problem.

[eggman]

so I finally got the time to do a leak test. here are the numbers:

compression cold 1/110 2/100 3/115 4/130
compression hot 1/50 2/72 3/50 4/45
compression hot with oil added 1/102 2/115 3/120 4/120

tell me if I did it wrong but I added the oil and then turned over the engine until the pressure gauge on the compression tester reached its maximum. This took maybe 20 rotations of the engine, basically ran the engine til the pressure no longer increased.

On a good note I replaced the Zenith carb with a new Weber and the rover runs great just some pesky black smoke when I goose the throttle. I plan on doing the ring job and I would like to change over to the electronic ignition but I am unsure of what I need. Any help with any aspect of the ring job or the ignition swap would be appreciated.

Thanks,
Dan

[eggman]

pulled the pistons after removing the ridge and here are the pictures, I need to know what everyone thinks, are they burnt out and require new pistons or are they normal and go with them. This is the first time I have done this so I dont know what a piston with
98K miles on it should look like.

Thanks68816882

[SafeAirOne]

The fate of the pistons is determined by the cylinder wall-to-piston clearances and any out-of-round tolerances specified in the bible, providing there are no obvious reasons to discard the pistons (cracks, excessive wear, etc...).

...Unless you're doing a 'down-and-dirty' re-ring job and not bringing it back within spec otherwise...

[Alk-3]

based on all you have said, it's the rings that are worn, not the valves etc. now it's up to you to decide how to correct the problem.
it sounds like you did a compression test, not a leak down test as such.
a leak down test involves setting the piston to top dead centre, then pressurizing the combustion chamber of that piston with an air compressor and an adaptor for the spark plug hole. you then measure how fast the pressure releases itself, and you can listen to various parts of the engine to see where the leak is occurring. if you hear it when you listen through the tailpipe, it's the exhaust valve, through the carb it's the intake valve and through the crank case breather means it's the rings.
I think it's safe to say you have a ring problem though, without needing to do the leak down test.

[albersj51]

Marks right. Unless the piston is cracked its fine and can be reused, unless the bore us now oversized/out of round. In that case, in needs to be bored X amount over and new pistons/rings fitted. The only true way to confirm this is with a micrometer, which I would only
trust to a competent machine shop. However, if you end up pulling the motor, you might as well rebuild it with new bearings, rings, seals, etc. then you'll know its good for the next 40 years

[thixon]

pulled the pistons after removing the ridge

Thanks68816882

Explain what you mean by "after removing the ridge."

[I Leak Oil]

The only way I wouldn't replace those pistons is if I were ONLY putting in new rings. Pistons are cheap...Do you want to be here again in a short time?

Those don't look great but measuring them and the cylinders will be a better determining factor.

[SafeAirOne]

Explain what you mean by "after removing the ridge."

Presumably on the tops of the worn cylinder bores so that the pistons can be removed in an upward direction.

[eggman]

Thixon, the ridge I was talking about was the the ridge caused by the rings wearing the cylinder bore and where they don't wear (top 3/4" of the bore or so) was removed with a ridge reamer rented from the local auto parts store. I then honed the cylinder and cleaned the bore til no residue showed up on a white towel. I would take out the whole engine and do a complete overhaul but the money is just not there right now to do it. I plan on using a cylinder bore dial gauge measuring the bore at four spots around the cylinder and then moving up a half inch and then measuring again til I get to the top then comparing them to see if the bore is out of round. If it is (anyone know the tolerances?) I will have to get it bored by a professional. As for the pistons I was contemplating getting our hosts piston tops only not the connecting rods to save some money or just the rings. Thoughts? And thank you for all the insight!

[Partsman]

Replace the connecting rods too, also don't forget to replace the bolts as well, I had to replace the engine on my first Rover because I went the route you outlined here, the number 3 rod broke right where the bolt goes through, and I blew a hole right in the side of the engine, I had to replace it. Don't use fatigued parts, they'll cost you money in the long run.

[thixon]

Eggman,

Gotcha. Sounds like you have it covered. I was worried you did something crazy like went in with a die grinder or something. Sorry, no offense meant, you just never know what people will try.

[eggman]

Thixon,

No problem! Like I said I'm doing this the first time and any and all help is appreciated. I don't want to make a mistake that costs me a couple thousand to fix just cause I didn't listen to the knowledge base on this forum.

Again thanks for all the help to everyone!
Dan