1098 Engine modifications

[John.n]

managed to get a 12g940 head off ebay. looks in good shape but I will see when it gets here.
Item number; 380557087811
what rockers do I need to go with this head? 1275 rockers?
does the standard thermostat fit straight on? not that I can get the one off the original head...
do I need the 1100 head gasket or something else? 1275 gasket?

I have taken the waterpump off the block and found what looked like a silicon gel round the whole pump and bypass. not sure what it was but it had blocked the whole pump up. no idea how it was still allowing water to circulate. now it is all cleaned up it is forming small white spots all over. not sure if i should just replace the water pump?

Regards,
John

[bmcecosse]

1275 gasket and rockers. Or re-arrange the standard rockers on the shaft so they act directly over the valve tips.. The water pump is rotting - it will be fine once it's together with anti-freeze in the system.

[John.n]

rotting... sounds good. guess its just electrolitic reaction.
I'll see what I can do with the rockers when the head gets here.

Regards,
John

[Nutts]

For what it is worth,
My back ground is mini's and I have always told people if your not doing a lot with the brakes then don't do a lot with the engine.
I would think a moggie is worse as weight is more to stop.
Although oil pump, possibly twin timing chain, clutch plate and bearing are all things that are more difficult with engine in.
Peter

[Tomz]

I'm following this closely as I have got myself a 12g940 head as well, so I can turn my Morris into a fire-breathing monster!
Thomas

[bmcecosse]

You may be in for a slight disappointment there .....

[John.n]

been fitting the timing gears and chain this evening. ended up fitting a single row chain, may regret this in the future but it can be changed without removing the engine. found the old tension rubber bands had gone very hard compaired with the new ones that I have fitted. just need to clean the muck off the timing cover when I get chance and refit it with a new seal.

I have still got the engine upside down and found what looks like a dowel with 2 opposing flats cut into it. spotted it in the opening where the cam followers should go towards the flywheel. I know it was not there the other day as I was cleaning this area. What is it? I did accidenty pull the cam shaft out of place when test fitting the timing gears.

Regards,
John

[Tomz]

You may be in for a slight disappointment there .....

I'm sure my expectations will be fully met!



Thomas

[John.n]

I don't Doubt It!

[bmcecosse]

Dowel with two flats - no idea - you'll need to give us a picture...

[John.n]

havent got a picture at the moment, sorry.
it is a dowel about 20mm long and 5mm in diameter with a 15mm flat machined on to opposing sides of the diameter.
could it be something from the oil pump?
need to take it off anyway.

Regards,
John

[bmcecosse]

Is it the pin drive out the end of the camshaft????

[John.n]

Got the 12g940 in the post today!
I will measure the valve clearence when I get chance.
is it possible to refit this once the pump is removed or have I got to remove the camshaft?
Regards,
John

[bmcecosse]

IF that is what it is - the cam would need to come out - but actually - it seems a bit small....take the oil pump off and let's see a picture of the end of the cam... Check the 940 carefully for cracks between the valves... it's not unknown.....

[Tomz]

Hi, do both valves of the 12G940 head have to be sunk for a 1098 engine? How much? 1 mm?

Thanks, Thomas
P.S. John, I don't want to hijack your thread, I just thought my questions fit to your topic. Please let me know if I should open a new thread of my own!

[bmcecosse]

Only the exhausts -and only if necessary to give 320 thou clearance from valve head to head face. But yes - 40 thou sink will guarantee safety as long as using standard lift camshaft (up to and including MG Metro) and std rockers.

[Tomz]

Thanks bmcecosse,
although that certainly wasn't the last question!

I found this interesting old thread on heads: http://www.mmoc.org.uk/viewtopic.php?f= ... 8&start=15

[bmcecosse]

It's a great head - but if buying one - check for cracks between the valves....

[John.n]

I will be checking for cracks between the valves then. measured up the valve depth and I will need to cut the valve seats back. just had a quick look on ebay for a suitable tool and found this;
http://www.ebay.co.uk/itm/RDGTOOLS-30MM ... 51a3989588
seemed the cheepest 30mm one I could find

just got a set of 1275 rockers to go with the 940 head.
p.s. Tom dont worry about sealing a thread! if its a similar project then you may think of something I havent! makes sense to have all the info in one place rather than refering between the two anyway.

Regards,
John

[John.n]

what damage would a blown head gasket do to an engine block? I have seen one for sale locally and it has had the gasket blow between 2 and 3 cylinders.
are 1100 engines known for cracking in this area? would a skim at a machine shop possibly solve the problem or will this cause problems fitting pistons?
Regards,
John