A series budget engine rebuild

[garellikatia]

Hey guys, 

Thought I'd document my first engine rebuild, or more like refurb. 

I have a running classic mini that I'm building up a spare engine for.

I'd consider myself to be fairly competent at spannering, and can do jobs like heads and clutches etc... so thought I'd give this a bash. 

It will be nice to get my son involved too while he's young. 

I managed to get a 1098 A series engine for £60 which has a chipped valve. Without a gearbox. 

It's pretty much in 3 pieces and I've started tidying bits up starting with the head.

I've had some great advice on here regarding the Pitting on the valve seats.  So I will be recutting the valve seats and fitting new guides.

Initially I had plans to bore it out and fit a fast road cam and uprated pistons etc..m etc... 

But I've now decided3 as this is my first rebuild I'm going to simply put it back together and replace only things that need replacing. 

That way if I mess up, it won't be too hard on the wallet. 

Here's some pictures of when I picked it up and a few of the head once I'd cleaned it up. 

Next step will be to assess the crank and see if it needs a regrind. 

 

 

[Stinkwheel]

Looks like it'll be a good project, following.

Looks like youve got two heads there as well, are they both the same type?

[garellikatia]

4 minutes ago, Stinkwheel said:

Looks like it'll be a good project, following.

Looks like youve got two heads there as well, are they both the same type?

Thanks mate, yes both the same type. 12g202. One looks to have been ported and work done on the chambers, but as you pointed out the valve seats are quite worn. I also have a 1275 head. 

This again will need work. On the plus side I've contacted a well known mini guru near me and he's going to charge £35 plus Vat to cut new valve seats on the 12g202 head

 

[paolodivichio]

Following with interest, I'm fairly sure my mini is going to need an engine rebuild soon, the gearbox already needs rebuilding!

[garellikatia]

4 hours ago, paolodivichio said:

Following with interest, I'm fairly sure my mini is going to need an engine rebuild soon, the gearbox already needs rebuilding!

Ah nice! Will be interesting to see how all the gearing work 

[garellikatia]

So before I started on the engine I had a few jobs to do. Pretty much fit a new rebound stop, some shock absorber bushes and torque the hub nut. I always do the washer method when dealing with CV nuts. Whereby I remove the conical washer and replace it with a flat one. Then I torque the nut fully. I then remove the washer, replace it with the correct conical washer  then I torque again. 

[garellikatia]

Managed to get a bit more  stripping done on the engine. The primary gear needed taking off and luckily I had the puller for it . (I love old tooling) I made sure to fit an old crank bolt in the nose  as I didn't want the puller to mash the threads. It would have probably been OK but didn't want to risk it. Anyway the primary gear needs renewing it's very chewed up. 

The crank looks quite pitted. I'm  not sure what to look for in terms of that so any advice is most welcome. Cheers

[garellikatia]

Bit more stripping and I found that the two dots don't necessarily line up on the timing gears. I'm doing some research into this but in the meantime I'm going to mark where they currently line up, Just in case I need that for future reference.

[Stinkwheel]

Blimey, that primary gear does look rough, never seen one like that before. Nice to see you getting stuck in so quickly

[garellikatia]

1 hour ago, Stinkwheel said:

Blimey, that primary gear does look rough, never seen one like that before. Nice to see you getting stuck in so quickly

I know Hahaha!! Wonder what the past owners been doing with it. Thanks mate it's been great back in the garage tinkering

[comfortablynumb]

Following with interest.

We've just discovered that a 'rebuilt' 998 engine that's in the van mk2 son is putting back together doesn't have any oil pressure 🥺

Looks like we'll be using you as a Haynes manual then......

[somewhatfoolish]

Is this from the rare prototype subaqua mini used by Cousteau and you've rescued it from the sea? 🤣

1 hour ago, garellikatia said:

 

 

[garellikatia]

Hahahaha must have spent some time in Scotland hehehe 

[garellikatia]

1 hour ago, comfortablynumb said:

Following with interest.

We've just discovered that a 'rebuilt' 998 engine that's in the van mk2 son is putting back together doesn't have any oil pressure 🥺

Looks like we'll be using you as a Haynes manual then......

Ohhh don't say that, it's my first time 😯  😂 

[garellikatia]

So I've got the crank and cam out. I'm not sure what wear I'm checking for really. But there's obviously scoring on the crank.

 

It looks as though it has the original crank shells so it must not have had a grind previously. 

There's a lot of scoring on number 4 piston. The bores actually look really good considering , so may just get away with a hone. 

If I go for a rebore I've been quoted £50 for the first cylinder then £20 for the following ones. So £110 for the Job if I chose to go that way. 

Guess for now I'm going to clean the block up. 

 

 

 

[garellikatia]

Oh yes and ignore the bunch of followers. I'm going to put a new cam in so will replace them. 

[Marshall2810]

No way is it your first time doing this 🤯

[garellikatia]

1 hour ago, Marshall2810 said:

No way is it your first time doing this 🤯

Don't know whether that's a good thing or a bad thing 😯 😂 

[Surface Rust]

Only one way to learn!

Watching with interest, I've got a 1275 I took to bits before my first child was born 10 years ago that I need to rebuild.

Place bets on me remembering how any of it went together!

[Marshall2810]

9 minutes ago, garellikatia said:

Don't know whether that's a good thing or a bad thing 😯 😂 

My apologies, it was a complement. To be that organised in your approach to it was just impressive. I wish I has your patience and organisational skills!

[garellikatia]

4 hours ago, Marshall2810 said:

My apologies, it was a complement. To be that organised in your approach to it was just impressive. I wish I has your patience and organisational skills!

No apologies needed, really appreciate your kind words, cheers

[garellikatia]

Just looking at the piston bores. They're smooth if I run my finger in there. But still might air on the side of caution and have them rebored. 

Luckily my son still had a load of empty sweet bags left over from his birthday and they've made perfect bags for parts. 

 

 

 

[garellikatia]

5 hours ago, Surface Rust said:

Only one way to learn!

Watching with interest, I've got a 1275 I took to bits before my first child was born 10 years ago that I need to rebuild.

Place bets on me remembering how any of it went together!

Absolutely,  we'll surely nows the perfect time,  maybe they can get involved too?

[High Jetter]

15 hours ago, garellikatia said:

Thanks mate, yes both the same type. 12g202. One looks to have been ported and work done on the chambers, but as you pointed out the valve seats are quite worn. I also have a 1275 head. 

This again will need work. On the plus side I've contacted a well known mini guru near me and he's going to charge £35 plus Vat to cut new valve seats on the 12g202 head

 

Barg!

[garellikatia]

Not much progress today. Just removed the engine number plate. Easy enough to do. Maybe not the smartest idea but it won't match the V5 anyway

but the main reason is that I'm going to hot Caustic dip the block. As Caustic reacts violently with aluminium,  I thought it was necessary. 

Also removed.the core plugs so the Caustic gets in all the nucks and crannies. I will then rinse it off and use electrolysis to remove the rust once the grime has been removed 

 

[garellikatia]

Block and a few other grubby bits have been in a Caustic solution for 12 hours now. Will probably end up having the jet wash it properly clean to remove the sludge but it seems to be working OK. 

 

 

 

[lisbon_road]

The crank doesn't look too bad in the pictures.  Man in a machine shop showed me how to check for ovality using a vernier, which isn't accurate enough to do a proper measurement but will show if there's a difference ie ovality.

Pistons look done for really.  If you need new pistons, might as well get it rebored - that's just an opinion.

I think we have a time served machinist here @Talbot

Good luck - looks like good progress.

[garellikatia]

Ahh excellent,  thanks for your help. I'll check later for irregularities.

Absolutely, I'm definitely tempted to have it rebored. 

I've also asked on a well know mini forum. Great to get as many opinions ,and loving the learning process!

Cheers 

[tooSavvy]

@garellikatia.. "I've also asked on a well know mini forum. Great to get as many opinions ,and loving the learning process!"

Good on you 👍

You'll never be short of 'enthusiasm for spending other people's dosh' 🤣

Among all the wise words will be nuggets of true vision..... THEY will save you a pile ££ 😉

..... I've knocked up my fair share of IMP motors, using scrappy salvaged parts. Rebored @930cc with scrap pistons .. £60 all 4.

Cord ridge-dodgers rings fitted [upside down] in the pistons as they were much cheaper than stock...

Ahh....... I'm well past all that now, AVAS!

🚙💨

[Homersimpson]

The dots on the cam gears should point art each other with an imaginary line drawn between the crank and cam as the diagram on this thread.

 

https://www.mgexp.com/forum/mg-midget-forum.3/68-1275-timing-gear-setup.3378750/