9 replies to this topic

[LukeClassicMan]

Hello!

I am a 21 year old who has grown up with minis both new and okd, and now have my 1980 austin-morris mini with the standard 998cc engine with a HS4 carb.

Though the car has no information, ive managed to figure out that the car, being at roughly 73,000 miles, seemingly has not had anything done to the engine. Of course I would assume usual perishables have been sorted but nothing regarding a rebuild. Driving her, though she is reliable, and has been roaded at 32hp, she feels tired compared to other 998 minis.

I have been researching parts costs and also asked around regarding rebuilds from known companies, and I wanted to ask, Is it possible for someone like me, albeit given time, to do this myself? Or is it worth biting the bullet and saving up to have a more known company sort it?

[absx2]

The 998 is a great little engine and 32 bhp is not that bad on the rollers and if it`s running fine and not smoking and using oil I would leave it alone as the old saying goes " if it aint broke don`t fix it " applies here as there seems to be a lot of people that rebuild engines for the sake of it.

 

A compression test would tell you if you need to look at reconditioning the cylinder head which is a job that would get you started on engines and would most likely perk up the performance a bit without digging too deep.

 

I recently pulled the head from a genuine 100,000 mile 998 that was running fine to fit an unleaded head with hardened exhaust seats for a friend.

There was a tiny ridge at the top of the bore and the valves on the original head were choked with carbon and although the exhaust seats were pitted it still measured 170 PSI across all cylinders before I removed it.

 

The car felt like it had a different engine after the head swap that was due to the exhaust valves and ports not being full of carbon.

 

Incidentally the engine doesn`t use any oil and the oil stays clear on the dipstick for at the first 1000 miles and is changed at 3000.

If there was any wear to be concerned about on the bores the oil would go dark on the dipstick very quickly due to piston ring blow by so nothing to be gained at this point by throwing money at it.

Yes it has wear but ...................:)

[Lplus]

Hello!

I am a 21 year old who has grown up with minis both new and okd, and now have my 1980 austin-morris mini with the standard 998cc engine with a HS4 carb.

Though the car has no information, ive managed to figure out that the car, being at roughly 73,000 miles, seemingly has not had anything done to the engine. Of course I would assume usual perishables have been sorted but nothing regarding a rebuild. Driving her, though she is reliable, and has been roaded at 32hp, she feels tired compared to other 998 minis.

I have been researching parts costs and also asked around regarding rebuilds from known companies, and I wanted to ask, Is it possible for someone like me, albeit given time, to do this myself? Or is it worth biting the bullet and saving up to have a more known company sort it?

For a plain rebuild you can do it yourself with the help of a Haynes manual and a selection of youtube videos.  For a modified engine you might be better getting a professional do it.  Mind you in that case you won't learn anything useful.

 

If it still has good oil pressure at 73000 and doesn't burn oil, it could be a head job might refresh the performance without a major stripdown.

[mab01uk]

Ultimate Mini engine Builder is a good place to start to see what is involved in an A-Series engine rebuild.

No longer available on DVD but can be seen in link below on YouTube.
Over 4 hours video with Mini racer Bill Sollis:-

Edited by mab01uk, 04 November 2024 - 09:37 AM.

[Cooperman]

You can easily learn to do it, and we are all here to help and advise.

You will need to buy, beg and/or borrow some tools, but nothing unusual.

If you do decide to DIY, come back on here and we can list the tools you will need to strip it down (and put it back together). Then we can give you a strip down sequence & procedure.

Once it's in pieces we can tell you what to inspect/measure which will lead to a list of parts. If you get the TMF discount from Mini Spares you'll save a lot and you will need to find a good local machine shop (as for recommendations).

When it's all completed and running, you will know that it's been rebuilt properly, you'll be proud of the job and you will have developed some new skills.

Once again, we are all here to help. Go for it!

[Designer]

Hi Luke,

 

As Cooperman says but posting pictures on here perhaps at each stage would be a tremendous help for those with the knowledge when giving you advise.

Above all enjoy your Mini and enjoy working on it.

 

Paddy

[Spider]

I wouldn't discourage you from doing this but for your first, I would suggest having someone who is experienced in engine building do it with you. There's so many small details items that are simply not covered by the workshop manuals that to the untrained eye are easily missed or simply overlooked.

 

As for books, while the Haynes and similar manuals show and explain strip and re-assembly steps, they seldom explain procedures and why things are the way they are, faults etc. A general engine reconditioner's book aimed at collage students can be helpful here, one I can highly recommend though I think is out of print is the ACL Engine Manual.

 

If you have a bit of time on your side here, I'd also suggest finding a used running engine, strip that down , clean, inspect and reassemble only replacing gaskets & seals etc but not going to the expense of reconditioning it, then run it again (preferably for a few miles), this will give you a feel for many of the parts and lead the way on particular tools you'll needs and techniques for disassembly (without damage !!) and reassembly.

 

Reconditioning an engine 'for real' is not a cheap process and there are no short cuts. I've done countless engines and gearboxes over the last 40+ years. In my view, based on my experience and training, I will say that a reconditioned engine includes the intake system (so an overhauled carb at least here), cooling system (radiator overhaul, new water pump), ignition system and in the case of the Mini, a very thoroughly cleaning of the gearbox, this often involves stripping it to be sure it's clean 

 

I wrote up the page below a while back to hopefully give some appreciation of what you might expect from a machine shop (and not all shops are alike ! Some are good and some are just glorified butchers.)

 

https://www.theminif...gine-machining/

 

[alpder]

I wouldn't discourage you at all. But do know in advance what you're getting into... because the trouble with engine stripping is the old "where to stop?" question. Once you've done all the work to get the thing out and take it apart, it makes very little sense to put a worn engine back together again without having a rebore and new pistons. And, while it's at the machine-shop being rebored you may as well get the shop to tinker with the compression ratio and skim the head appropriately. And, while they're working on the head it makes sense to at least replace any worn valve guides. And, of course, check it has hardened valve seats. And, maybe push the boat out and have a little gas-flow work on it? Then you start wondering are the cam bearings worn, and what cam do I want anyway? And if I change the cam should I change the rockers too? And, having changed the cam, you'll consider adding adjustable timing gear to get the best out of it. As for the gearbox, it'd be madness to strip down without at least changing the baulk rings. And then should you reuse the old transfer-gear bearings? And what about all those other needle rollers in there, should I replace those too? And, while you're tinkering with cams and compression ratios, you might fancy a change of final-drive ratio. Then, during rebuild, you'll have to check and set the end-float on various parts, which means obtaining the correct £shims. And, after rebuilding it all, do you want to stick the worn old distributor back onto it, or instead have a reconditioned one - maybe with a different curve? And, really, there's absolutely no point doing all this work and not reconditioning the carb. And, finally, you may want a freer-flowing exhaust and air filter. Then, having made so many alterations to the engine, it'll run like a complete dog until you take it to a rolling-road and get the fueling and timing set up properly.

 

If you love tinkering, and have the budget, then go for it. Or if the engine/box clearly has issues that require a strip-down then really you're forced into the job anyway. But if you're a bit uncertain and would rather work in bite-sized chunks, then start on the outside and work inwards, one thing at a time... rebuild the carb, have the distributor checked, change the exhaust, move on to a bit of head work... all these things are quicker and cheaper than a full engine rebuild and - so long as you keep in mind the final configuration you want - the work won't be wasted if you do decide to press on into a full rebuild.

 

Another approach is to buy a second engine/box, and work on that. You can then keep driving the car until you're ready to drop the replacement engine in. With a bit of patience and a hand ready to click "buy it now" on ebay as soon as a reasonably-priced one appears, you can have a bare 1275 A+ with box for £600-£700.

Edited by alpder, 05 November 2024 - 11:03 AM.

[jonlad]

 

Another approach is to buy a second engine/box, and work on that. You can then keep driving the car until you're ready to drop the replacement engine in. With a bit of patience and a hand ready to click "buy it now" on ebay as soon as a reasonably-priced one appears, you can have a bare 1275 A+ with box for £600-£700.

 

I came here to say this! Keep the car running but get a second hand engine to strip and rebuild at your leisure. that way you can and not be pressured to get the car back on the road. Good luck!

[sonikk4]

 

 

Another approach is to buy a second engine/box, and work on that. You can then keep driving the car until you're ready to drop the replacement engine in. With a bit of patience and a hand ready to click "buy it now" on ebay as soon as a reasonably-priced one appears, you can have a bare 1275 A+ with box for £600-£700.

 

I came here to say this! Keep the car running but get a second hand engine to strip and rebuild at your leisure. that way you can and not be pressured to get the car back on the road. Good luck!

 

 

There are a lot of 998's out there that would be ideal to buy cheaply and then use that to learn rather than use your running engine now. Gives you more time and less pressure to complete as mentioned. Then you will have a handy spare.

 

My very low mileage 998 i took out of my Clubby will be stripped down for a full inspection at some point in the future as he is 50 years old. Some minor inprovements will be made at that point but ultimately kept as a spare plus he is Paddys original engine.

 

Mkae sure you have some decent tools, a good torque wrench, a flywheel puller and find a reliable machine shop to do any surfacing / reboring etc that maybe needed.