12g940 head

[horrace]

that is very kind thank you, i have sintered rockers i think already now, following further investigation! and ill see if i can get springs from my local motor factors and if not ill take you up on that offer

[bmcecosse]

If not the triple groove collet - then what are they ???

[horrace]

they are the small collet type def not 3 groove

[horrace]

panic over whilst scrabbling around on the workshop floor i found the collett just the new springs to get then its all back together! had a go at the exhaust throat with a die grinder as you rightly said it is restricted by the exhaust valve shoulder.

[bmcecosse]

Be sure to wash out ALL the crap...... Well done finding the collet. I was going to send you one - but needed to know what type.

[horrace]

had a good wash out with petrol diesel and then thinner followed by brake cleaner then dried and oiled on the necessary surfaces before giving a nice lick of paint, just drying in front of the fire now, mrs has hardly said a word! i appreciate the offer of the collet. thanks and from i think declan for the springs but id rather chuck a set of new ones in...
i tried to get the spring from minispares but they wanted me to confirm what kind of cam i had, i assume its standard as its a 1098? i dont think it was fiddled with before i had it.. got hold of another engine yesterday and saw the different kind of rockers. mine def sintered.

[horrace]

well the head had taken a bit of a back seat until today, i whipped the old 1098 one off the 1098 block (any takers for a 1098 unleaded head supplied by esm? its done approx 1000miles)
so the new 12g head is a bit different.... the head gasket when put it on the block doesnt have 2 waterway holes where they should be, which i thought might be a problem... until i looked at the head, 2 of the water ways in the head are brazed closed! so no water passes throught there any way???? is this ok ???
one of the water ways is slightly shrouded by the gasket, i know we have touched on this before, and i think what i intend to do is slightly grind away at the edge of the block so the water can come through a little easier at an angle... ok????
the pics show the shrouded hole. the 1098 gasket on the 12g head with the brazed up holes ( there are 3 holes but flash has hidden one)and the 1275 gasket on the head showing the brazed holes covered all look good to you?[frame][/frame][frame][/frame][frame][/frame]

[bmcecosse]

Don't grind anything - thin lick of grease on both sides of the gasket and get ON with it!!

[moggydriver62]

The 1275 M G heads over here had brass plugs in some of the coolant holes.
If you overheated them the plugs would move .= Instant water leak.
To fix you knock out the plug,tap the hole ,tapered pipe thread. Use a steel
pipe plug,install same with red locktight.Dont overtighten. Face cyl head.

[horrace]

ok ok im gonna get on with it! just been a bit busy but missing the driving so maybe this weekend but the mrs has got me cutting logs so unless i can sneak away... i thought i read that someone had ground away the hole so that water passed easier?? not necessary then?

[bmcecosse]

Cutting logs ??? Oh dear.....

[horrace]

no logs = no heating = unhappy wife & dog

[linearaudio]

ok ok im gonna get on with it! just been a bit busy but missing the driving so maybe this weekend but the mrs has got me cutting logs so unless i can sneak away... i thought i read that someone had ground away the hole so that water passed easier?? not necessary then?

That isn't a waterway, it is the oil feed to the rockers. I did indeed chamfer mine as it seemed a nice thing to do, but the flow rate to the rockers is not going to be adversely affected if you ignore it- most people happily do so!!
Don't worry about those brass plugged holes etc- as i have noted before, after 10,000 hard miles, mine hasn't shown any inclination to overheat or do nasty things due to the altered water flow rates!
As it says on the front of the "Hitch-hikers guide to the Galaxy" (and also the front page of the instructions for my Arcam surround system installation book)- DON'T PANIC!
If the valves don't hit the block, the head doesn't foul the waterpump top, the battery tray is thumped locally to clear the heater valve, and you don't get your fingers trapped dropping the head on, then you are laughing, or at least will have a huge grin on your face from the increase in power (mostly noticed to start kicking in just where the standad engine fades out, around 4000 )

[bmcecosse]

The little hole at the front edge is the oil feed - and it's completely open in that shot. Don't worry about it. I find the extra power is there ALL the way up the range - but I still have the standard 1098 cam in that engine.

[horrace]

managed to get out of the logs.... had to go xmas shopping instead!!!!!!! making slow progress when i get time, below are are a pic of the sintered rockers, they still dont line up perfick, but is this ok? the rockers line up right at the edge of valve, you can just see the champfered edge of the top of the valve... i have overcome the bashing the battery tray by slightly enlarging the water tap fixing holes which allowed me to twist it round enough to clear the tray. im hoping i will be able to do the same to the thermostat housing[frame][/frame]

[bmcecosse]

Obviously the rockers are not perfect - but that's how MG Rover decided to do it - and it's the reason the sinter rockers are so wide. By all means line them up so they are better centered on the valve stems - but MG Rover decided what you have is good enough. I had no problem with the thermostat housing - I simply used the curved section from a bottom hose to join the stat to the rad.

[horrace]

right update....... head on and started first time, very surprised!
only other thing i had to do was cut a notch out of the engine steady plate where its bolted to the head as it was fouling the heater tap.
the top hose from rad to head looks a bit cack as alignment is not great, will prob get better hose soon.
now ........ it seems the engine is running a little rich - black sooty plugs, i have wound the carb nut right up so that the spring on the waxstat jet is compressed as much as poss. which am i right in saying is as lean as it can get, or have i got it round the wrong way?
also i just remembered i have done exhaust and inlet at 15thou would this matter? and or affect it?

Merry xmas! only 1 sleep left.........

[bmcecosse]

The gaps won't matter - you should torque the head down again anyway after the first heat cycle - and then reset the valve gaps, 12 thou inlets and 15 thou exhausts. Maybe the needle is too far up inside the piston - worth checking.

[linearaudio]

Oh yes!- Don't forget to cut a notch out of the engine steady bracket so it clears the heater tap
What needle do you have? As BMC (Merry Christmas from a loyal reader!) says, check that the jet mounting collar is flush with the bottom of the piston when you tighten the clamping screw. When you take the damper pot off to check that, see how the jet position looks, it should be a little under-flush with the surrounding brass sleeve. You may just have been screwing the wrong way! Screw inwards/ clockwise to richen, and the reverse to weaken. Or maybe your timing could be too retarded?

[horrace]

i have retorqued the head and then i did the gaps at 15 thou id best set them again!
im wondering if the jet is worn as it is the carb that was on the pick up when i bought it 3 years ago so god knows how worn it is prob good practice to replace any way? i got a new needle from manilow when i got the freeflow system i will check see what it is. wht /how would the needle be too far up the piston