1098 10cc engine

[philthehill]

The Midget camshaft is little better than the standard Minor camshaft. The best cam for a 998cc engine is the old 997cc Cooper camshaft Pt No: 2A 948 or one with similar timings. I had a 2A 948 camshaft fitted in my 948cc Minor engine which was bored out to 998cc and fitted with Powermax pistons. It was also fitted with twin HD 4 (1.5 carbs) LCB exhaust with an improved 12G295 head. It also had a lightened flywheel and stronger clutch and not forgetting the Cooper S steel duplex timing chain set up.
It went like the proverbial off a shovel.

img069.jpg (326.12 KiB) Viewed 1722 times

[shivey]

Nice engine,won't the 1098 rods be to long with 950 crank the metro 998 ones are 3 inch ? i'm using mini pistons..I've got quite an assortment hoarded over the years...

[philthehill]

All small bore connecting rods are 5.75" between centres. Therefore the 1098cc rods will fit.
The reason for fitting the 1098cc or Cooper connecting rods is that it gets rid of the pinch bolt which can and does fail.
The gudgen pin in the 1098cc and Cooper connecting rods (& pistons) is fully floating and the gudgen pin is secured in the piston by circlips.
Unless you have 'A' Plus 998cc pistons which are an interference fit in the rod small end all other 998cc gudgen pins are secured in the piston by circlip.
If you are building a out and out 998cc competition engine with fully floating small ends you can substitute the circlips with Teflon buttons to keep the gudgen pin in place.

[shivey]

Thanks for that

[shivey]

Phil,I have been checking up on ARP studs now the are straight 7/16 mine are 7/16 then have a larger shoulder the thread is 15/32 into the block just under 1/2 inch the shoulder is part of the bolt,i've been told they are grade 8 studs been talking to a friend who checked with mg owners club, he has the same engine but not stripped

[philthehill]

That shoulder looks more to be the main cap locating ring.

Unfortunately I do not have a 10CC engine to compare with.

All I can suggest is that you try a normal 7/16" main cap bolt screwed into the block and see what the fit is like.

The MOSS web site quotes the same part number 12A1910 for the main cap bolt which is suitable for the 948cc and 1098cc main caps including the 10CC engine.

[shivey]

I'll get one stud out after,the guy from mg said it was part of the bolt one off's.we will see

[shivey]

Phil it isn't a dowel slight countersink only for stud to bottom onto

[shivey]

image of stud

[philthehill]

Thank you for the photos.

Did you try screwing a normal 7/16" UNF bolt in the block?

All the main bearing cap bolts I have are 7/16" UNF and are waisted under the head of the bolt.

The after market main bearing cap studs are waisted as per your studs.

I have no alternative explanation as to why you have studs instead of bolts and will go back to my original theory in that the bolts have been changed to studs at some time in the past.

Currently this is the nearest I can find to your studs - note the waisting.

https://www.minisport.com/kenmsa33-arp- ... per-s.html

[shivey]

Mg sussex list these nuts as standard but thats all they could tell me,don't know anyone else who stocks them,i've since been on mg midget forum and had 2 replies from America both say that is what was on the 100cc engine,i have a10cg engine here there is no room to get the 10cg dowels in ???

[philthehill]

I have found these on the ARP web site.

https://arp-bolts.com/kits/arpkit-detai ... ordID=1229

I will point you once again to Peter May Engineering who will be able to provide you with a definitive answer as to what is fitted either bolt or stud to the 10CC main bearing caps.

Note: The waisting of the main bearing cap bolt or stud is there to allow for any variance in the concentricity of the hole in the bearing cap.

The main bearing caps are located by the dowels not the bolt or stud. The bolts or studs are under tension forces not shear forces.

[shivey]

10CG AND 10 CC CAPS dowels would never fit in you can hardly see the slightly larger hole required for the10cc stud I'll contact Peter May after easter i'm in no hurry and i din't want it coming to pieces...thanks

[philthehill]

Thank you for posting the above phot.
I am afraid I cannot suggest any thing more.
All I will say is that those studs you have do not look to be long enough and the nuts do not look man enough to hold it all together.
Please post on here any feed back you have from Peter May especially part numbers.
Phil

[shivey]

I personally wouldn't consider fitting lock tabs on reassembly. They compress and distort too much. Follow the advice of APT for the thread treatment and torque load figures. For example, I discard the lock tabs on flywheels and use blue loctite on the threads. If you do the same, check the bolt thread length is not too long without the lock tab. These critical bolts are all Grade 8. Incidentally, the 10CC motors use rods of an improved design over the 10CG motors and can be lightened quite a bit. Shot peening is quite good after machining but you may need to have them checked for trueness afterwards.

This is the reply I had back from mg forum froum AUS not US Thanks fo all the help I'll keep posting...Glyn


message from US Don’t lose those center two studs, re-use them. ARP studs/bolts do not have the special sleeve (width) that the 1098 crank central bearing cap needs!

[philthehill]

Found this on 'e' bay with good photos of the main bearing caps and yes studs with similar nuts to those supplied by West Sussex MG.

https://www.ebay.co.uk/itm/Reconditione ... Sw7eleE-bq

[shivey]

Amazing Phil,found a pdf on SC parts cat. these studs are the same as the cooper s i tried to copy onto here but it does'nt allow me41 8305 Stud main bearing cap - short. . . .
41 291617 Stud main bearing cap - long .
42 18650 Nut main bearing cap. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

[philthehill]

Then the Cooper S studs in my post above and which are available from MiniSport will do the job nicely. They have the enlarged dia at the lower end of the stud as per yours.

https://www.minisport.com/kenmsa33-arp- ... per-s.html

They also have the precision ground washers I mentioned above and the best quality nuts.
You do not need locking tabs with these fastenings but you do need to follow closely the fitting instructions as torqueing up the fastenings is not the same as for standard BMC items.

I have used ARP fastenings for holding together my 1380cc engine.

Phil

[shivey]

Got to the bottom of it 970 and early 1275 found pdf copies of bmc parts ive got the one for 10cg kept from the garage i worked in years ago out of stock at the moment but will order thanks a lot

[shivey]

found the original AKD3153 BMC parts manual shows no 8 for stud 14 for nut ..the nut is the same no as i've had new,can't post the diagram it's to big,wont allow me,how do i make pics smaller ? thanks