MG Metro cam and 12G295 head related query

[814XUW]

Hi all,
I recently fitted an MG Metro camshaft in place of the standard 1098 camshaft on my 1098, along with a matching oil pump and duplex chain kit. The engine is also currently sporting an HIF38 carb on an alloy manifold.
My problem is that since fitting the cam the performance is no better, in fact it's very definitely worse. I must have fitted around 30 timing chains and check them all each time with a straight edge across the dots each time. It may well be that I've cocked up there, but on the advice given on this forum I noted others saying it wasn't necessary to time the cam and that the dots would be fine for a road engine. If I take the front end off again to double check the chain placement is it in fact necessary to time it with a dial guage and timing disk, and if so to what figure? The other problem seems to be getting a new dial guage that reads in imperial - not metric!
My other more straight forward query is regarding the 12G295 head I'm currently rebuilding - am I correct in thinking I need a good quality 1098 spec gasket or do I need a different one?
As usual, many thanks in advance.

[panky]

You will need a 1275 head gasket along with the other mods, ie making sure there's enough clearance between exhaust valve faces and block, heater take-off and steady bar bracket.

[814XUW]

Really? I thought that was only necessary with the 12G940 1275 derived heads?

[panky]

Sorry mis-read you post

[philthehill]

The set up that you have installed should improve the performance markedly.
Timing with the dot on the cam pulley and the mark on the crankshaft pulley aligned is more than satisfactory.
You do not need an imperial dial gauge as it make absolutely no difference whether you measure the piston TDC or cam degrees in imperial or metric. You will need a 360 degree timing disc to bolt to the crankshaft though.
The timing data/details for the MG Metro camshaft is given in Vizard's book on Tuning the 'A' Series.
If you do use a dial gauge it is best to use two and their respective stands.
See picture of my 1380cc during setting up of the cam timing.
One dial gauge is sat on the top of the piston to determining the position of the piston TDC and the timing disc is then adjusted to zero degrees; the other is sat on a push rod to determining the max lift of the cam lobe at the manufactures specified degrees.
This setting is only the base setting and the cam timing may need to be adjusted after road testing or dyno testing.
Having a vernier cam drive helps get the camshaft timing spot on and is well worth the money.
You do not need to use a 1275cc head gasket when using a 12G295 head just a good quality 1098cc one..[frame][/frame]
Sorry but I cannot get the photo to be the right way up.
Here is a link to an imperial dial gauge and stand:

http://www.ebay.co.uk/itm/0-1-DIAL-GAUG ... V-sc3FGKuA

[814XUW]

Phil,
Thanks for that. I've been reading some posts about cam timing that uses a set figure of lobe lift (measured in thou) hence the assumption an imperial guage is the one to get!
Engine is still assembled, so assuming I can find TDC with a drilled-through-and-bolted spark plug I should theoretically just need one dial guage (be it metric or imperial) just to see when the lobe is on full lift by the rocker/pushrod? It's somewhat academic as I'm struggling to find what to set it to! I will have to dust off my yellow bible and find out.
I like the idea of a vernier adjuster but they are quite dear, stupidly passed one up that was cheap second hand. I might whip the front end off and but an offset key to sort that one out.

I hope it's something simple like the cam timing and I've not been sold a dud, I may pull the cam out again and check it actually is a Metro cam (as I was sold it) and check it's not, for sake of argument, a standard 998 cam or something else slot drive. If all else fails I do have a Kent 270 cam as well, but I feel that would be a little overkill on a road going motor(?).
Thanks as always for all advice.

[panky]

The MG cam has a 1/4" groove machined into the shaft after the number one lobe. There's an excellent guide to identifying cams on the Minifinity site, written by AC Dodd.

[IslipMinor]

I would not fit a 270 or 276 cam in a 1098, they need well more than 6,000 rpm to give their full performance, and 6,000 is the practical limit for a 1098 engine.

The setup that you have should give a real increase over a standard 1098 performance. What pistons do you have? They will need to be flat-topped with a 12G295 head to any decent compression ratio, unless you have seriously skimmed the head - have you? What results do you get with a compression test?

[philthehill]

Full and correct TDC can only be found by using a dial gauge and a timing disc.
When the piston is at assumed TDC the crankshaft can still turn through several degrees without the piston seemingly to up or down the bore.
If the camshaft timing is to be correct - true TDC has to be determined.
I am not an advocate of the offset woodruff key as the cross section of the key is reduced the more the offset and the wilder the cam more stress is put on the woodruff key.
See the little yellow book for camshaft identification.

Panky - MG Metro Cam - Vizard says 1/4" groove after the third lobe ??????

Even if you have another camshaft fitted the motor should still pull well as the timing of the 'A' Series camshafts are not that different (see little yellow book) it is just that the MG Metro has the camshaft timing advanced about 4 degrees over the rest which seems to suit the 'A' Series even on a completely standard cam.

Have you checked that the rest of the replacement parts are compatible with each other i.e. timing, needle/carb spring?

[814XUW]

Panky - will check.
Islipmimor - +20 standards. The head has been skimmed by a fair margin already, and is currently being skimmed further. I should point out the head is not yet fitted to the vehicle, and never has been, still on a standard 1098 head at the moment.
Compression is at 190 on all cylinders.
Phil - I understood a fairly foolproof way to find actual TDC was to put a form of blockage into the bore, bring the piston up so it touches said blockage (in this case a spark plug with a bolt in it), monitor figure in timing disk, turn crank back round in the opposite direction and note that timing mark, and using this method you can divide the space the piston hasn't travelled by two and set the crank there for TDC, are you not an advocate of said method?
I think a woodruff key would suit my purposes being a road engine with a reasonably mild (in the grand scheme of things) cam.
I did not know the Metro cam specifically is times differently, perhaps that's my problem.
I've retimed it, reset mixture, then extensively road tested and tuned (50 miles a day 6 days a week commute - lots of opportunities for doing so) and got it to the point where it pulls on the flat more or less about as well as the standard cam did, but it is very poor at the first sight of a hill.

[panky]

I know Vizards word is normally gospel but AC Dodds article has a photo showing the groove between 1st and second lobes. There is another section that describes a 2A948 profile that was fitted to very early MG's but this cam has three raised rings after the third lobe - confusion somewhere.

[philthehill]

This is the process I use when I check for absolute TDC - I bring the piston up to assumed TDC and then turn the crankshaft through 20 degrees forward - note the distance travelled down by the piston on the dial gauge. Bring piston back to assumed TDC and turn crankshaft 20 degrees backwards - note the distance travelled down by the piston on the dial gauge. Repeat process and adjust the timing disc '0' degrees until the degrees turned and the piston travel are the same when the engine is turned forward and backwards by 20 degrees. '0' degrees on the timing disk will then indicate true TDC.
Your process may give a similar result but as I like to be exact I would not use any other method to determine exact TDC.

[philthehill]

Panky
I have not found the photo but found this link.

http://miniclassic.yuku.com/topic/1729/ ... C-DBOR77cs

AC Dodd states that the MG Metro has the 1/4" groove after No: 1 lobe.

Found this on 'e' bay:-
http://www.ebay.co.uk/itm/MG-metro-cams ... Sw44BYI3fe

Checked Vizards book again and it does state '1/4" Groove after 3rd lobe' - Confusion does reign!!!!
Phil

[panky]

Here's the link to AC's article

http://www.minifinity.com/forum/viewtop ... 82&t=95092

[oliver90owner]

I've found TDC on my tractors and Landy by a slightly different way.

Rise to the same DTI readig on both sides of TDC, marking flywheel against a fiducial pointer for each point. True TDC is then exactly central to those two marks when aligned to the pointer. An angle timing disc can then be attached if/as needed.

RAB

[philthehill]

Panky
Many thanks for the link.
Now added to my favourites bar.
Phil

[RobThomas]

I checked a later Midget 1098 in the shed (10CC serial number with bigger journals and 295 head) and the pistons as fitted were not flat topped but not as deeply dished as the 1098 Minor. Filled with oil to the brim and covered with dead spiders, hence the lack of a photo.

[Declan_Burns]

Panky,
Here's a timing disc for you to print off and play around with.

Regards
Declan[frame][/frame]

[silloyd]

You may find this useful as well.

[panky]

Brilliant thanks to you both. I'm getting a lot from this thread and hopefully the OP will too