My side valve wont start, but has spark and fuel

[Anzaclad1951MM]

I have a old side vale MM series low light that has been asleep as a parts car for 3 years now and have decided that it is far to good and rare as a donor car and have decided to make it live again.
So here is the deal, it is not seized, has spark at plugs, plenty of flow of fuel to carb, everything has been cleaned and stater motor turns over. But yet it wont start up?
Could it be suck valves? Last owner said it got a ''Bit Hot'' last time she used it.

HELP!!!!!!!!!!!!

[Anzaclad1951MM]

Oh also distributor is firm and is not loose and the correct plugs are in it and to my understanding the ignition sequence is correct.
As it turns over, about every 4th turn it will make a ''piffft'' noise.

[bmcecosse]

Is there any compression? As you turn it with the handle - do you feel 4 equal compressions? It is indeed likely to be both stuck valves - and stuck piston rings. Frankly - I think it will be better NOT to start it - take it out and clean/inspect/measure everything. 'Starting' it will only do damage - and achieve exactly what even if it does start?

[Anzaclad1951MM]

Yes the compression feels poor and uneven and for that reason alone I have not turned it over too many times in fear of damage, The idea of getting it going was that were it lives at present, Is a shed at the bottom of my property a little 'down hill' and was going to get it up on its own steam to my garage. But on hearing you say that, I will go with my initial gut instinct and tow it up to its restoration garage and strip it down and inspect it.

[bmcecosse]

The clutch will almost certainly be seized on anyway - and the brakes......

[Anzaclad1951MM]

So here it goes on progress, Motor taken out and to my surprise all valves are happy and free and doing what they do, plus they are in fantastic condition, and so are the piston rings with cylinders like mirrors, with no pits at all.
There condition has come at quiet a surprise, especially considering,On the other hand, the head gasket was fried, and when the water was drained from it we found that there was a thermostat choked with what only could be described as a thick lumpy yellow Vaseline vomit. Oil in water when it over heated?
I have come across Vaseline deposits before in old dirty sumps, but not encased all over a thermostat, this could explain why it got hot last with the previous owner who had it as a road worthy car up till 2008 until before he passed away and has been asleep since.

[bmcecosse]

Could explain the problem then - just as well you didn't start it! I would check the rings are all free -and of course have a look at the bearings....

[mike.perry]

Series MM head gaskets are prone to blowing at the back of the block behind the centre rear head stud where there is very little gasket behind the stud.
There are a lot of poor quality gaskets around which do not fit properly.A good quality head gasket should have a seam around the edge and the water passages, and should drop smoothly down the head studs on to the face of the bock, not have to be tapped down studs. Also make sure that you use a Series MM gasket not a Morris 8 gasket which does not have water passages on either side of the distributor drive. Check that the head gasket set contains a thermostat housing gasket.