1098 modifications

[bluegrass]

I am going to be using my 1098 saloon as my everyday car and want to make some light modifications to the engine to give it a little more 'go'.

The engine needs a rebuild, so after much reading on the forum, I think I'm going to do the following:
(I'm spelling it out here and quoting some other forum members because I'm new to all this and want to make sure i"m understanding everything correctly and haven't missed anything. Thanks in advance for any corrections/input.)

I just bought a 12g940 head and an hif38 carb on an mg metro inlet manifold from ebay.

i will fit the head with a 1275 gasket, and get an AAA needle for the carb.

I understand i need to adjust the Valve stem gap on the head to 320 thou clearance from the cylinder head face to the exhaust valve head whilst not touching the inlets.
(Whatever amount the exhaust valves are sunk - I need to then put a shim of that thickness under the exhaust valve springs to retain the correct spring compression using flat washers. At very worst the valves could be sunk by 40 thou, but often much less is required - even zero! )

I will find and fit normal lift 1275 sinter rockers rather than keeping my 1098 ones . Where can I get these and what do I need to look out for when finding some..?

I need to file/grind some metal off the top surface of the water pump to make sure the head can seat down without fouling the pump.

I need to adjust the thermostat housing...Is it best to use this?
http://www.jagspares.co.uk/Morris/PartV ... perpage=10

I need to modify the heater valve stub/ adjust heater tap. With this?
http://www.minispares.com/Product.aspx? ... 696&title=

I will fit new shell bearings and oil pump. Any particular type?

I will fit a single timing chain with mini tensioner rather than duplex and get the rounded cover for it.

Find and Fit a crankshaft damper. Which one?

Set valve gaps to 15thou and check every 3 months

Is it worth finding and fitting an Mg metro cam whilst the engine is apart, or is the standard 1098 one ok?
If fitting mg metro cam fit new cam followers:
http://www.minispares.com/shop/classic/ ... spx?100103

A friend has an ital 1300 exhaust manifold I can have. Should I use it and will it and a bigger exhaust make much difference?

Which air filter is best? I don't want a much louder engine.

Will a different diff make much difference and will the increased hp handle it...if so, 3.9 or 3.7.....I will at some point be fitting a tow bar to tow a small light camping trailer so need to keep that in mind in terms of low down pulling power.

That's where I'm at with it. Any suggestions or corrections much appreciated. My first job is to clean and service the head and carb once they arrive next week.




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[bmcecosse]

Pretty much got it there blue.. it's not anything to with the valve STEM - just the distance from valve head face to cylinder head face. What does the head have right now? You will 'get away with' 300 thou - but I think 320 is safer. MG cam is well worth while if you can find one. But the standard cam (inspect the followers anyway) is perfectly ok in this engine because you don't want to go over 6000 revs. The shimming under the exhaust valve springs doesn't need to be an exact science - I just used handy washers. My Trav pulls a 3.7 final drive very well with that engine spec. Just look out for excessive wear in the sinter rockers - if the pads are worn you can 'stone' them back to profile. I fitted a 3 branch manifold (NOT an LCB which is only for more'wild' camshafts) but frankly didn't notice much improvement.

[bluegrass]

Thanks for the info, I'm getting there, slowly. I don't have the head yet but will take measurements when i get it.

I found these , do you think they fit the bill?

[bmcecosse]

Yes - these are fine - think of that 3.7 final drive as an 'investment' .....it will always hold that value - or indeed go up.... BTW - a 1249 tpm Mini speedo gives EXACTLY correct miles and speed when used with that 3.7 ratio..and 155 X 14 tyres.

[bluegrass]

Perfect, Thanks!

[bluegrass]

Things are moving on a pace! I have been buying "bits"!

So I now have the following parts:

Standard 12g940 head
hif38 carb on mg metro inlet manifold
3.7 diff (These seem to be getting expensive)
marina exhaust manifold (offered to me if I need it)
mg metro cam
mini timing chain/tensioner and fittings.

I am still looking for 1275 sintered rockers, and the timing chain cover. Thanks 'BMCECOSSE' for the mini speedo tip. I am looking into that...most on ebay don't have a clue what 'tpm' their speedos are. The hardest thing seems to be finding the right one.

I will leave the timing chain and cam until i rebuild the engine, but the rest I shall start working on once I receive it all.

One question I'm still contemplating is the air filter. I don't want a loud engine, so don't want to go down the K&N route...I'm wondering what alternatives there are along a more quiet line but still effective.

As I get on with things I'll post up some pictures, and most likely ask some questions. The head and carb will be first on my agenda to sort out.

My car is away having other 'works' carried out at the moment, but hopefully I can prepare things so that I can just bolt everything on when I get it back!

[Declan_Burns]

I find that my 1408 tpm speedo is very accurate running a 3.9 diff and 145 tyres when compared to a sat nav.
Regards
Declan[frame][/frame]

[bmcecosse]

Yes - you do have to 'teach' the Mini lads where to look for the tpm figure. That may be a record price for that 3.7 final drive !!! Be sure to get the right oil pump to fit the MG cam. Others have simply fitted the air cleaner assy from a Mini/Marina/Maestro/Princess etc to get a quiet inlet flow.

[bluegrass]

~Yes, an interesting night on the 3.7 diff front. Its a long story, but I somehow ended up with two!

Some people invest in coffee/gold/stocks and shares. Forget about that, the smart( ) money is on diffs!

I would like to add a 'cheaper' 3.9 to the 'collection' ready for some future diff comparison experiments!

[bluegrass]

On the oil pump front, which is the correct one?

[Declan_Burns]

There is another way of correcting your speedo.
Here's two photos of the prototype step up gearbox that I made for the MG which is needed when the CWP is exchanged.
It sit's on the back of the speedo. Ratio 1.2 : 1
Regards
Declan[frame][/frame][frame][/frame]

[bluegrass]

A very neat looking unit Declan. Maybe you should produce a kit with different cog sizes for different final drives. From what I've seen of your upgrades and mods, you could do good business selling a few mod kits.

Out of interest did you ever try a 3.7 diff in your car, or just go straight for the 3.9?

[Declan_Burns]

Bluegrass,
I have never tried the 3.7 diff but I am currently setting up another 3.9 with a new CWP and bearings as the 3.9 I bought and fitted howls like the banshee. Yes there is oil in it.
Regards
Declan

[bmcecosse]

You definitely have too much time on your hands Declan..... Neat job of course, as always !

[bluegrass]

I've just taken delivery of a 3.7 diff (ebay)....The fin with the bolt hole for the brake pipes is broken off. Is it easy to repair or should I send it back?
Thanks

[Declan_Burns]

Bluegrass,
Can we see a photo and also a close-up photo of the gearing? Can you measure the backlash?

Regards
Declan

[bluegrass]

Hi Declan, yes I can take some photos. How do I measure backlash?

[Declan_Burns]

Bluegrass,
Here's how it is done.
http://www.youtube.com/watch?v=Ouq67Fyt5K8
Regards
Declan

[bluegrass]

That's a good video Declan....I can't set that up unfortunately as I don't have that gear here, but I would say at a very rough guess 1 mm of backlash..I'm loading up some pictures of the diff now.

[bluegrass]

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