SM head

[Kre1979]

I'm in process of replacing the head gasket on my SM, what is the best way to pull it down, torq it half way down then for full amount? Am I right in saying 85lb is correct ?

Many thanks
Kev

[dexta roadless]

I would take it in three steps eg 30, 60 and 85

[Kre1979]

Thanks for your help.
Who puts the gaskets in dry and who uses a sealant?

[henk]

I have put a dry gasket between, and put a small amount of sealant just above the place where the engine number is located. This seems to be a place where the gasket can leak a bit.
Make sure you clean bolts are running smoothly in the clean holes.

[Kre1979]

Which sealant is best? I'm really struggling to get my head to seal. Only small amount of water seeping from the gasket on the exhaust side.

[henk]

I have used bleu sillecone sealing.

[liam]

I had the same problem .I got a new gasket and used a little silicone sealer on the block and head faces on the water channels and I have had no more leaks so far,just go easy with the sealer ,it only takes a tiny amount .It is a common problem and has being discussed here before,hope this helps.

[Pavel]

Try Blue Hylomar in a spray can - great stuff for heads.
Pavel

[Kre1979]

Thanks for all the info, I've got the head back from being skimmed and just lapping/fitting valves. Does anyone know if there is much difference between power major cranks and SM cranks as the previous owner has told me he fitted a PM crank in my SM, the tractor does vibrate at certain revs more so than you would expect. Any thoughts?

[Nick]

If a different crank has been put in, it is possible that the flywheel wasnt put back quite in the correct place. As i understand it, all engines were balanced from the factory, so if the flywheel is ever taken off (to replace the crank etc) it should be marked and put back exactly the same so it stays balanced.

[Brian]

Crank is the same throughout the range, only the very early tractors had a cast crank. You cannot get the flywheel on wrong as you have large and small dowels and the timing marks must be right.

[super6954]

Hi
Just a thought here If the tractor by some chance had what is thought to be a power major crank put in was the crank that was fitted a cast one with the two dowels the same size, and it was not the right crank for the power major. Maybe the guy that did it didn't notice. this would give a balance issue as the hole in the flywheel would not be matched in metal quantity by one fitting peg if that makes sense.

Or it is the right style steel crank but it has 2 small pegs fitted. I did a clutch in a live drive power major once and the flywheel would go on both ways with the two pegs the same size, I only found out when i checked the timing before i pushed her back together and it was 180 degrees out,I thought the pegs where different to when i fitted the flywheel on .
The other thing could be one of the three locking tabs from the centre bolts is missing there was a guy on here a while ago had a picture posted and one was missing. that would cause a problem too im thinking.

If the tractor has a duel clutch (live PTO) fitted I have seen the tread and nut break off one or more of the pins that hold the springs in the clutch cover too . I have only seen this on non running tractors I scrapped and dont know if it through the balance off when it was running.
Maybe Brian could answer on this as he must of come across this in his working career before.
There is so much mix and match on these old majors these days and guys messing around with things that have no idea half the time, I guess any of the above could be possible , taking it apart may be the only way to really know whats going on sadly
Regards Robert

[Brian]

Rest assured that if a cast crank had been fitted to a Super it would ge in two pieces by now. They broke in the Kerosene versions with less compression than a diesel.

Clutch problems are a more likely cause of vibration and of course, if no dowels have been fitted but if the flywheel is in the wrong place, the timing will be out as Robert said.

If you have a problem, check it out before this happens!!!!!

[Kre1979]

After having the head skimmed, I re lapped the valves back in, new seals etc, re fitted the head, reset the valve clearances( to how I think is correct) the engine ran fine, wurst no vibrations. Drive today to a ploughing match, again fine with no vibrations, the same during the ploughing. Shut off for lunch, etc then driving home, vibrating like hell, almost giving me white finger through steering wheel? It's very confusing and puzzling now.
Not sure what to try/do next ?

[BearCreek Majors]

Hmmmm….apparently the crank and remaining parts are correct our you would most likely have the vibration all the time, so I would have to think something is loose and causing bad harmonics/vibrations. I’m assuming it does this whether running down the road or sitting in the yard, and that it’s not a miss or dead cylinder as you should notice this by lack of power, smoke, being able to hear it missing in the exhaust. Things I would check, flywheel/clutch assembly, harmonic balancer on the front of the crank, broken fan blade, slip the fan belt off to see if it goes away. Loose bolts in the bell housing, loose bolts in the engine mounts. Does the problem go away if you hold the clutch down? Is there oil pressure issues, I have seen engines run with a broken crank and they do vibrate like a bitch, usually the first indicator is a drop in oil pressure.
Good luck and keep us posted.

Pat

[Kre1979]

Cheers pat,

Yes it vibrates when sat in the yard. Makes no difference if the clutch pedal is depressed. The chap who I bought it off did say that he had to shim the timing gear to the crank, so that might be first place to look I will still check valve clearance as it needs double checking now it's run in.

[Brian]

There are two sizes of crank where the gear fits, sounds like he may have put a later gear from a stepped crank onto a straight crank, if he has and it has started to move, you need to get that sorted ASAP and not run her.

If that gear cuts the key it can cost you a new block and camshaft. If the cam shaft stops in the wrong place it can be hit and broken by No.3 con rod.

[Kre1979]

Ok Brian thanks :-/ he said he shimmed the gear on so it was tight. I have another engine lined up as I haven't been convinced with this engine.
Kev