19 replies to this topic

[dansalter]

Hey there, i'm rebuilding an engine that is currently in pieces in my garage its a 1989 1275 metro engine with a 12g940 head and is suspected to be a GTA engine, is there anyway i can check??

I have a few questions before putting it back together

Firstly, what is the largest bore i can go to without changing the pistons?

I have heard people talking about a 2.7 final drive which makes the car better on motorways.. any details on this would be great as i am likly to be doing a fair bit of this in the future.. are they hard to fit or expencive? where do i get them from??

I have no idea what 1.5 rockers are and the difference from standard but are the worth getting?? again any details would be great.

Skimmed head.. how much can i take off?

MG Metro/SW5/kent276 Cam does anyone know whats best?

Anyone think of anything elce i should do while it is in pieces?

what HP can i expect from the engine?

and once it is in how should i brake the engine in?

any replys much appriciated.. Danny

[Nightrain]

Hey there, i'm rebuilding an engine that is currently in pieces in my garage its a 1989 1275 metro engine with a 12g940 head and is suspected to be a GTA engine, is there anyway i can check??

I have a few questions before putting it back together

Firstly, what is the largest bore i can go to without changing the pistons?

I have heard people talking about a 2.7 final drive which makes the car better on motorways.. any details on this would be great as i am likly to be doing a fair bit of this in the future.. are they hard to fit or expencive? where do i get them from??

I have no idea what 1.5 rockers are and the difference from standard but are the worth getting?? again any details would be great.

Skimmed head.. how much can i take off?

MG Metro/SW5/kent276 Cam does anyone know whats best?

Anyone think of anything elce i should do while it is in pieces?

what HP can i expect from the engine?

and once it is in how should i brake the engine in?

any replys much appriciated.. Danny

Firstly Im guessing your not sure what a rebore is, the bore is the bit the pistons go up & down in. So if you rebore you make it bigger so your present pistons will no longer fit. So you can't rebore it without fitting matching pistons.

2.7 final drive, keep a eye on ebay or the for sale sections in the various forums.

Skimming the head depends on the rest of the spec of the engine, but you shouldn't really need it as the GTA had 10.4:1.

All those cams are much the same besides the 276 which is crap in a 1275, you'd be better of with a 286 if you want something racier than the MG/SW5.

Depends on which RR you use, they can be made to read whatever you like in the real world 60-70bhp.

There are lot's of differing advice on breaking engines in, I have always used 100miles change the oil, upto 500miles 3000-4000rpms (varied) and then increasing the rev's until about a 1000 miles by which time Im using max rpms. Others opinions will vary on this.........

Edited by Nightrain, 02 August 2009 - 02:22 PM.

[Retro_10s]

suspected to be a GTA engine, is there anyway i can check??

if you can chuck the full engine number up on here we can de-code it for you.

[Nightrain]

If you can see the cam, it should be a MG cam in the GTA. There's a quarter inch gap between the first and second lobes from the timing chain end.

Attached Files

•  MG_Metro_Cam.jpg   19.29K   4 downloads

[dansalter]

Thanks guys

Firstly Im guessing your not sure what a rebore is, the bore is the bit the pistons go up & down in. So if you rebore you make it bigger so your present pistons will no longer fit. So you can't rebore it without fitting matching pistons.

i thought you could take a certain amount off and use larger piston rings, i knew you couldnt take much off without changing the pistons tho. am i right in saying that?

if you can chuck the full engine number up on here we can de-code it for you.

there is a plate on it with the code 12HE25 118658
and the block itself has WFM 1024 N W
the head is a 12g940 with 23E9 and an N

are the 2.7 final drives hard to fit because i don't want to go taking all the gears off and not being able to put them back because it looks scary =[.
but the guy who i brought it off said that it had the gearbox partly rebuilt.. how do i check what the final drive ratio is atm because i have no idea what i'm looking at when i look into the gearbox.=s

[dansalter]

unfortunatly it did not come with a cam wich is why i'm looking at getting somesort of fast road cam.
thanks anyway tho.

[SolarB]

i thought you could take a certain amount off and use larger piston rings, i knew you couldnt take much off without changing the pistons tho. am i right in saying that?

'Fraid not. The piston is a close fit and needs to be to ensure it stays parallel with the bore. Rings are there only to control gases and oil.

[samsfern]

ignore whoever said a 276 cam is crap in a 1275, i have one and its excellent, improves driveablity, and is great fun!!! and has a fairly smooth idle

[dansalter]

hmm, thanks for that guys i'll have a think about it.

anyone able to give me information on if it is a GTA or not?

there is a plate on it with the code 12HE25 118658
and the block itself has WFM 1024 N W
the head is a 12g940 with 23E9 and an N

[Cooperman]

If you look at the figures for the MG Metro cam and the Kent 266 they are very, very similar. Now, as the MG Metro cam is, arguably, the finest road cam ever produced by BMC/BL/ARG/Rover, it follows that the 266 is also great. The 276 is about mid-way between 266 and 286 and I have used it on road-rally and historic engines with good results. For example, I did a Frog-Eye A-H Sprite with an 1100 cc engine and a 276 cam with a 12G295 head and, set up with all the other bits you would expect to see on a rally engine, like twin H4's, it gave 75 bhp a the flywheel at 6000 rpm. A 1293 Historic Rally spec engine with the 276 gave 92 bhp at 6200 rpm with a V-Max head. I know that's less than the same engine would be with a 286, but it is much easier to drive on snow and the first event for that car was the Historic Monte Carlo. My own rally 'S' gives about 115 at 6400, but it has a 286 and everything else possible within the historic regulations. It's 'orrible to drive on the road though and below about 3300 it just doesn't go well at all. Over 4500 - wow!

[dansalter]

Thanks Cooperman, i always thought the 266 was for the 998 but you would still say i should get the MG Metro cam?
or would a 276 still be usable on the road?

i'm still wondering about how hard it is to change the final drive to a 2.7 and ideas anyone?

[Pauly]

Will need to lock the gearbox up. Remove the diff, disengage the selector in the box by removing the coller on the right of the selector, if you remove the output covers (either side of the diff housing) you will see it, then you need to select 2 gears putting 1st/2nd syncro into either 1st or 2nd then 3rd/4th syncro into either 3rd or 4th. Then you need to remove the pinion nut (on speedo end of box, remove the speedo housing) then swap the pinion gear over (a diff should come with the matching pinion). You can now refit your new diff.

If you buy the pale blue haynes manual (one before the darker blue) it has the full gearbox strip down in there, but you dont need to strip the complete box to change a diff.

Paul.

Edited by Pauly, 02 August 2009 - 05:17 PM.

[Ethel]

A 2.7 diff could work against sporty cams, without extra cc's you need extra rpm to make much more power.

[dansalter]

hmm well is there anything i could do inorder to increace the 'motorway expericence' if you like. such as just changing the 4th gear? or just dropping the ratio a little rather than to the 2.7 to be honest i still don't really know what the final drive ratio is..

i'm sorry, i don't understand much about gearbox's.

[Nightrain]

Count the teeth on the crownwheel (big gear in the diff housing) and pinion (small gear the crownwheel engages with). Then divide on it to the other, that will give you the ratio.

Too all those who like the 276 explain to me why, where does the power come in and go out. In my personal experience it comes in about 2500rpms and is all done by 7000rpms. Giving a powerband of 4500rpms, where as a 286 comes on cam at the same 2500 and is still pulling at 7500rpms. Giving a powerband of over 5000rpms................

Comparing how a cam works in a different engine is just a fools game, the 1098 having such a long stroke has totally different parameters.