mg tf 160 bad head gasket

The big end shell is worn but in a normal way..the crank is probably good but check!
Short pistons..no wonder they like to rev.
I wonder if someone broke a ring whilst replacing them at some time.
Personally I would have left the liners in place unless scoured.

You are far enough on to do a great job of rebuilding it now and the satisfaction you will get is enormous. Well done.

that is quite worrying and I would like to figure out exactly what exactly caused the chip. my one theory is that the liner expanded at that section and the piston started making contact and eventually chipped. But yea, Whoever put this together previously was a bit of an ape and made a lot of little mistakes like using silicone glue to assemble the head and stripping a few threads so not completely unlikely that they broke it. The liner bore looks completely fine at least (will get a picture when I'm tinkering again). I got the suggestion of welding the missing material back on the piston and sanding it to the correct shape. Is this a viable solution?

Thanks!!! haven't removed the liners yet but I did rotate the crank to get access to the piston bolts as I was planning to remove them to clean the water channels a little (They seem to be a little seized and I think the previous owner used some head gasket sealant which is gluing them a little).

Do not even remotely try to weld up that piston!
I will leeave it at that.😉

wrote:

Do not even remotely try to weld up that piston!
I will leeave it at that.😉
 

I agree totally, DON'T attempt to weld up the piston!

Top marks for wanting to have a go but id add my voice to the others, best replace rather than try to repair that piston. Piston repair should only be attempted within a very advanced engineering workshop where they can check and replicate the exact metallurgy and join seamlessly to avoid creating a stress point. It's really only ever worth it if the type of piston is otherwise entirely unavailable.

No, that's a bad idea! I've seen videos of poorly equipped workshops doing remarkable work, that though is a matter of "needs must if the devil drives". I'm of the opinion, as with the rest of the lads, that your missing piece was missing before the head was put back on. If it had broken whilst running (Why/how) it would have left evidence of its departure. Order spares & rebuild.
M

I'm pretty sure that the 160 pistons were specially hardened to cope with the increased power. This could be a rogue. 
In any case, they have 160 stamped into them on the piston top face.


Edit:- Scrub that, I think I can see 160 on your piston... 
 

Mexiiiii wrote:

Finally got around to removing the piston and can properly see the the damage, was actually pretty straight forward

 . Struggling a bit to get the liners out so I'm soaking them in penetrating fluid. 
It's got the number "135" stamped in the side. Could this be a piston from a 135 engine?(or are they the same and it doesn't matter?

 

 

 

David Aiketgate wrote:-
For some reason the 160 pistons do have 135 on the side. But as above, have 160 on the face.

 

This is of course the story of my life........Pissed n broke! 🤣
I'm sure many of you have been in the same boat!

Thanks a bunch, you awesome folks! This is my first time using a forum, and I’ve never been so happy to be told how close I came to screwing things up. You’ve all been a huge help! 
I'm going to make an order from the UK once I've gotten my shopping list finished then it's hopefully just a few days of assembling. I'll post a video of it once it's all back together (if it runs ;P)

Hi Mexiii
You seem pretty capable of getting this thing running again but I will offer a few tips if you have no written guidance.

Replace that piston and replace the rings on all of the pistons. Check the ring gaps once installed, there will be info in the ring pack. Don't assume they are "factory" gapped.
For instance ...info can say for Road use 15thou...or for Race use 40thou...you need to check the gap so they don't expand too much and nip in the bore and break. The compression ring is the important one.
Spin the rings around so that the gaps are about a third of the circumference away from each other.
Once the pistons are ready to be fitted in to the bores deglaze the bores with 400grit wet dry lightly to remove the varnish and allow the new rings to bed in.
Smother the rings with assembly grease..many types on Ebay...and carefully fit in to the bores with the pistons facing the right way. 

Replace the Big end bearing shells.

Clean the surfaces in the conrod and the cap and press in the new shells on to a clean conrod surface. Do Not use assembly grease on the back of the shells..it will effect the torque of the con rod and cap.
Once the shells are in place then lightly grease the bearing surface and the crank journals with assembly grease. Do not use grease on the conrod and cap mating surfaces where they are bolted together.
Refer to the MG manual for the correct torque settings for the bearing caps.
For instance with forged Eagle rods they give you 3 different torques setting for using the bolts dry..with oil..or with assembly grease. I am fairly sure MG will say lightly oil the bolts and give you a torque figure. CHECK.
Cleanliness is your friend when assembling an engine. It will smoke from the assembly grease on start up but will burn off quickly.

If you refurbish the head be sure to use assembly grease on the camshaft bearing surfaces!
I am pretty confident you will end up with a nicely running engine.
Good luck!