10 replies to this topic

[new_van_man]

I am attempting to rebuild a 1.3 MG metro engine. I have never done this before, so hopefully this will be a good learning curve for me as well all those who also want to learn how to do this.
So heres the engine after removal from car looking very sorry for itself.....

Here is the block......


Here are a few close ups of the bores not sure how well these have come out



Head gasket seems to be missing a bit


Here is the head. Should the valves look like this? and a few close ups of each valve.





I am going to take the clutch and flywheel housing off tomorrow or the day after and separate the gearbox.
Once this is done i be taking the engine to the machine shop to get them to measure it and let me know if needs reboring and new pistons or if i can get away with just a hone and new rings. I will also be reconditioing the head well the machine shop will do most of this also.

I intend the engine to be a reliable and efficeint motor, i dont want to go above 1293 if indeed i have to have it rebored. I am not attempting to try and tune this to any degree partly because of cost. However, if there are any cheap mods i can do to improve power such as exhaust, best gear ratios. I assume it is a leaded head altho i have no idea. I have not used it for 7 years and when i put in car when i used it i just put unleaded in and it seemed ok! It was only 85 quid then so i wasnt too fussed. Hopefully i havent knackered it up.

I currently have the 21251 pistons in the block which i think are low compression. Would there be any gain (assuming I have to buy new pistons and rebore is required) in upgrading these to to the 21253 (high compression pistons? Does anyone know the advantages or disadvantages of doing this. I assume more cost more power.

Also do the photos of block and head show any thing sinister. I was a little concerned that the head gasket had disappeared bewteen two of the pistons. Is this normal?

Any help much appreciated.

[Jordie]

could always smooth out some of the roughness in the cylinder head, either DIY or machine shop. I dont mean taking loads of material out or a completely smooth surface. Some of the casting ridges and roughness can be smoothed out easily, same can be done in the inlet manifold and exhaust manifolds.

Looks like its blown the gasket between the middle two, sometimes happens. Check to see if the head and block are flat and skim if required.

[new_van_man]

No updates as yet, awaiting flywheel puller and a few bits from mini spares......

But i do have a question. You know sometimes when an A series engine has been left for a while the clutch siezes on and you have to turn engine over to get it to break free.

Will this cause me problems when i try to take the clutch and flywheel off using a puller? I reckon it is a dead cert that it is seized on. Will this mean a new clutch and flywheel and how easy will it be to separate when off engine?

any help as always much appreciated.

Hoping to get this off tonight if bits arrive today more pictures to follow then off to machine shop with it.

[Guess-Works.com]

If it has 21251 piston already in there, then it's already been rebuilt once, may already having a rebore, check the tops of the pistons for a +.020 or similar... ( actually just looked at the pictures and you can see the STD mark ) but 21251 pistons are not standard Rover pistons and an MG metro would have had the equivalent to the 21253 piston from manufacture.

The Head is a leaded MG metro head, but looks like it's been running a little lean ( hence the light grey deposits ), personally I would only get the head checked and refurbished, the head is good as standard.

The flywheel and clutch come off the crank as a complete unit, if the clutch is seized then it'll be the plate to the flywheel and pressure plate, not the crank.

[AndyMiniMad.]

Im pretty sure thats been rebuild before as the pistons in an Mg engine are these.



These were in both of my mg engines when i stripped them.

Am deffinately going to watch this as im also rebuilding mine as a 1380 just now and can nick some of your ideas, ha ha,

Good luck

Andy

[new_van_man]

If it has 21251 piston already in there, then it's already been rebuilt once, may already having a rebore, check the tops of the pistons for a +.020 or similar... ( actually just looked at the pictures and you can see the STD mark ) but 21251 pistons are not standard Rover pistons and an MG metro would have had the equivalent to the 21253 piston from manufacture.

The Head is a leaded MG metro head, but looks like it's been running a little lean ( hence the light grey deposits ), personally I would only get the head checked and refurbished, the head is good as standard.

The flywheel and clutch come off the crank as a complete unit, if the clutch is seized then it'll be the plate to the flywheel and pressure plate, not the crank.

I take it then it is possible too that block has been skimmed hence no engine number tag? Unfortunatley i dont know when or if its been rebuilt.

Would you leave the block well alone then? There is slight rim around top of bores but bores generally look ok. I havnt measured them as yet. Not sure best way to do this. If I measuere the bores ring gap and it is too large i.e needs reboring am i better off replacing with 21253 pistons then. Will this cause compression problems as i read somewhere i need to consider this esp if block has been skimmed previously. Intend to refurbish head for definate and convert to unleaded. Previously just ran it on unleaded..... How can you tell it is leaded? Size of valves?


thanks for help.

Gearbox will be on its way to you if i can get it separated for a check and refurb if thats ok

[AndyMiniMad.]

Once you have cleaned all the old gasket residue of the block and head you should be able to tell if the head or block has been skimmed by the tell tale marks. Unfortunately I have lost the photo I took after mine came back from being skimmed, but the cut marks are unmistakeable. I had ten thou taken off the head and five thou off the block. When I put the head on the block after the skim they were so well matched that i could not lift the head back off and had to slide it off. It was oiled and for some reason they just stuck. There is probably some techy physics thing which would explain it.

[Guess-Works.com]

How can you tell it is leaded? Size of valves?

If it's a std head, then yes, no big valve unleaded head was ever made... when the conversion to unleaded fuel began ( circa 1989/90 ) the big valve MG head was dropped and all 1275's, mini, metro, maestro and montego, used the same valve sizes, 1.3" inlet and 1.15" exhaust.

Edited by Guess-Works.com, 02 July 2010 - 01:11 AM.

[MiniLandy]

...There is probably some techy physics thing which would explain it.

Indeedy, due to the intermolecular forces present in the oil, it has cohesive properties. Same reason water droplets can hang from a ceiling.

Mmmmm a level chemistry...

[AndyMiniMad.]

...There is probably some techy physics thing which would explain it.

Indeedy, due to the intermolecular forces present in the oil, it has cohesive properties. Same reason water droplets can hang from a ceiling.

Mmmmm a level chemistry...

Nice, I always wondered about this but never thought I would get the answer on TMF. But zzzzzzzzzzzzzzzzzzz all the same.

Edit. coudnt spell zzzzzzzzzzzzzzzzzz

Edited by AndyMiniMad., 02 July 2010 - 03:53 PM.

[Teapot]

Bump ... bookmarked this to follow progress. Any updates please?