Engine frozen

[jaxonedy]

Morning
I had not used my MM for a while-laid up in garage, I had forgotten I had replaced the heater hoses, and refilled with water!

Went to turn over the other day, but engine was frozen-my plain stupidity

The engine blew a core plug-I lifted the head appears to be no damage, so I decoked, repaced head gasket,core plug, changed water, oil etc

The car restarted well, but appears a little noisy, with evidence of water in the oil, I believed as it is an iron head and block there should be no damage, and none is evident

Any ideas where to look next?
Thanks again
Eddie

[bmcecosse]

Well - if it's losing water - it may have cracked the head or the block. Blowing out the core plugs unfortunately doesn't relieve all the pressure of ice expansion. And cast iron is extremely susceptible to cracking by ice - it has almost no elasticity - it just cracks.

[jaxonedy]

Thanks
Stripped the head again, had a close check, looks like no damage, so I will replace the gasket again as it appears to be separating, although it is new, and give it a try. Will flush the oil to make sure there was no residual water, as the first oil change was when the car had not been run, to remove the worst of the contaminated oil
Any tips welcome

[bmcecosse]

Oh well - fingers crossed for success! Maybe the water evidence was just condensation due to the ongoing miserable weather.

[jaxonedy]

Thanks again

[jaxonedy]

Apologies I am poor at diagnosis!

Stripped the head again, no water in oil this time, on restart the car starts but will not rev, I have examined the cylinder head, no damage, the pistons appear fine, just a slight track around top of the bores, and engine turning easily

I removed, examined the valves, no damage and re-ground in

Still running poorly, I tried a compression test on 2 cylinders, and gave up! the tester registered fluctuations in compression, up to around 80psi on the dial but did not sustain, and the needle continued to drop to zero

Can you remind me of the valve sequence inlet/exhaust etc, just in case I have mixed up, any other ideas are great, I am loosing faith in my abilities
Thanks

[bmcecosse]

First thing is to check the valve gaps - set inlets 12 thou and exhausts 15. Use 'rule of 9'- so when #8 valve os down you adjust #1, when #7 is down - adjust #2 and so on. And from the front - the valves are EX IN IN EX EX IN IN EX. Then -for a compression test - you want engine hot (maybe difficult in your situation - but run it for a few minutes if you can) - then all spark plugs out - fully charged battery - and throttle held open. Put tester in #1 and crank it till the reading is steady - at least 5 or 6 seconds of cranking. The gauge should hold the reading to allow you to read it - then you reset by pressing a release button - and repeat for all 4 cylinders. Then come back with the results!

[jaxonedy]

Thanks again
Away from home till Friday-will give a try at weekend

You are a great help again
cheers

[jaxonedy]

As a confirmation before I start, are the exhaust valves the smaller (dished)valves?, it is a 948 cc engine

If I have mixed the valves am I better to order new?

Any tips in grinding in the valves, I have had trouble with the sucker sticking to the dished valves

Thanks again

[linearaudio]

I am sure someone will throw their hands up in horror, but I always grind my valves by gripping the last 1/4" or so of the stem in my cordless drill, and spinning the valve slowlyish with light pressure applied by pulling on the drill. Yes- the exhausts are the smaller ones, for all normal purposes I wouldn't be worried about inadvertantly mixing from one cylinder to another as long as they all lap in nicely!

[bmcecosse]

You need to poilsh up the heads of the valves - by spinning them in an electric drill - and holding emery paper against the flailing valve - beware the fingers! And yes - electric drill 'grinding' is fine!

[jaxonedy]

Thanks Team
I have the engine back in now, the bottom end appears fine, no apparant wear, except a very slight ridge around the top of the bores
Will relap the valves etc, charging battery, will give it a re-commision tomorrow, and may be back for help

First engine rebuild- all fingers crossed
Thanks