Another day building the Mini 1275 engine

We spend another day this week showing you what’s involved in building and machining a mini 1275 engine

[@theo_korner]

Something in my mind tells me you need to make a couple of videos together with the channel called "the workshop". Best collab on KZbin.

[@darrellhendrix5502]

Nothing like having one of your regular pieces of equipment down for maintence/repair and having to use something else to make you appreciate your primary machine. Love your videos and your sharing the ups and downs of the business.

[@normanstephens5391]

Enjoying the content, as usual. I'm no Mechanic/Engineer but have in my younger life. Striped down several engines on vehicles I owned and those of friends to replaced Main Shells. Big End Bearings and Piston Rings (like for like) Standard. Re Bores x2.Went to the likes of you guys. People watching will get a Feel.. For Time & Labour Costs if they ever get a bill for any such works done to their vehicles. See you in the next one. 👍👍

[@tsedge99]

Really enjoying seeing the process, thanks.

[@Captain_Scarlet_SIG]

Great stuff more please 👏

[@oneselmo]

An engineer named David Vizard published a book called "Tuning the A Series Engine" that is full of information on these engines. Lot's of performance mods. Unfortunately he never did one on the B series engines as well.

[@woodrimcars2324]

Really enjoyed this one before lunch and to see the M3 motor behind the red press.

[@flwryvv]

Really interesting, thanks for posting.

[@patwheeler9291]

There was a Churchill service tool introduced in the 1970s to dismantle and install gudgeon pins, remember using it on Ital engines. Have you ever seen one?

[@J_I_Was]

I'm really loving all the details and all the videos

[@michaelclarke3684]

Thank you really enjoyed this week

[@trevormansfield6740]

Could you show the crankshaft polishing process the next time you do it please 👍

[@mooney0086]

More on the actual doing, 👍🏻

[@skylinefever]

I have heard that you need to measure your replacement pistons anyway, they could vary a few ten thousandths of an inch. Then when the engine is honed, each bore is honed a little differently to match each piston.

[@bobawatsit]

fully floating with buttons or spring retainers ..... semi floating press fit or pinch bolt 3 common ways I know of and not two

[@mikepickett3277]

Excellent stuff p, I’ve built many, many A type engines in my time. Well done, keep it up

[@TheBillzilla]

Looks like has a good rod /stroke ratio.

[@blackbirdxx928]

Those have to be the longest roads I think I have ever seen...lol I assume the stroke is much more than the bore? The crank looks plenty stout to...at least compared to most of the american made engines I have put together. Takes serious skills to hone and get the hole consistent from top to bottom. We have one of those sunnen deals with the digital display and as per the way it was explained to me the machine is able to sense a tight area in the bore by the amount of load on the motor and compensate for it automatically...makes it stupid easy the get every hole within 2 tenths of a thousand. Just finished putting a 455 olds for a buddy who used a local machine shop to bore the block. I ran a dial bore gauge down each hole...every hole was 2-3 tenths out of round and 5 tenths taper...good thing he bought re builder rings..lol. At least he got the clearances close enough...4-5 thou. for cast pistons is the number. Motor in a jet boat always runs cold...150* or less most of the time. Set one up with normal clearance is a good way trash piston skirts.

[@paulbrend6541]

seeing that thumb nail of mini pistons and rods brought back a bad memory from over 30 years ago, took my 1275 cooper S rods and new pistons to an engineering shop in Barnstaple with a name of Barum Engines or Barum Engineering to have old pistons removed and new pistons fitted as the gudgeon pins are press fit and i did not have a press at the time, came back to me with new pistons fitted but 3 bent con rods , as you imagine i went straight back to show this engine shop and guess there reply ( not us mate ) even when i showed the marks were the rods had been clamped in a vice, the engine had been running fine before just was fitting omega pistons, be careful out there its not easy to find a good engineering shop as i found out over many years of building engines

[@grahamreid827]

Enjoying the Mini rebuild, had a full race S in the past running a straight cut box, great fun, you didn't mention the gas flowing of the cylinder head you mentioned in answer to previous comments, was this done, otherwise don't see the point in doing all the other work with the cam

[@Oh-Jay52]

SC/CR Box ooooh that sounds nice ...

[@JapsDmz]

2 questions, 1. Is the blade getting engine work..? 2. Why cant you press the pins back in..? Loving the content aswell. Reminds me of work lol...

[@martyncotton5740]

👍👍

[@Icetea184]

Hi. I’m loving this mini engine build… I’m in the process of doing exactly this at home. 1275 engine rebuild. Could you make a list of the parts your putting in? I live in Denmark, so I have to order the stuff online. Or maybe you could give a good deal on it.

[@SJLAutomotive]

Can’t keep up with you on the videos Lee - Keep up the good work! I guess that Mazda 4 Pot is very similar to the Ford Duratec.

[@WickedTRX]

Do you check valve seat pressure and adjust the installed height of the spring?

[@williecosgrove]

another day TRYING to build an engine 3rd time round

[@BarumEngines]

Thanks for the view again 👍

[@watomb]

I don’t understand how you balanced that engine I always thought you had to get the weight of each rod and piston. Then attach weights to crank shaft to check balance. Good video

[@thewholls7176]

I would’ve thought you’d balance the crankshaft on its own and the flywheel and clutch is a separate assembly that way in the future if you change the clutch you can re-balance that with the flywheel again otherwise technically you have to take the crankshaft out and start again…..???

[@redpill3145]

Very Good mixture of videos, is there any chance of a vid about improving bhp without remapping

[@justinsheldon5015]

With going through all the work in balancing, do you weight balance the pistons as well ? Its a quick and easy job to do and would complete the bottom end. Minis always suffer centre main bearing wear more than the others. You can get a centre main strap to strengthen it up. Built many mini engines in the past and A plus rockers arent the best. I found some original Cooper S ones, which I fitted offset bushes in, which is a mod to increase lift. They are pressed in and then you drill the oil holes through the bushes. I also thought the A plus was an 11 stud head, with a stud near the thermostat. Maybe I just didnt see it. Single point injection isnt great but can be big money to change.

[@jackcameback]

Question, that crank spinning machine thing, how can you run the cranks spinning with no lube? Loving the vids BTW!

[@alvydasurbonas8913]

my guess because it runs on the rollers not just slipping on some metal supports

[@Tomoose1985]

There needs to be some friction or the thing wouldn't turn!

[@nickimperialengines2559]

I machine a fair amount of mini's. Ive had problems with the small end of the rod mot having enough interference with the pin. Usually around 6 tenths. I've even taken to closing the hole by electroplating nickel into the small end then i can hone to get 12 tenths interference. Is this something you've found?

[@Oh-Jay52]

I dont know much about fine tuning vehicles , but 2 questions for you knowledgable ones if thats ok ? 1, If you balance a lightened flywheel or comp clutch on one engine , will it be ok to use on another engine with crank balanced to same specs as 1st one ? or is it not that easy ? 2, Do the manufacturers know you will be balancing their Items , so leaving them no need to have to balance before you buy ?

[@blackbirdxx928]

Dont know about minis but I work on american v8s mostly for high performance marine use. A flywheel for an internal balance motor like a 396/427 chev will always come balanced neutral and an externally balanced motor like a 454 will always come out of balance to the proper spec. All balance correction is done with the crankshaft with either drilling or adding heavy metal. I cant see a manufacture selling a flywheel that would need balancing right out of the box, that would mean it would be necessary to have to tear down a motor just to use one of their flywheels. Same goes for pressure plates. I have tried rotating the pressure plate on the flywheel to see if it changed the overall balance and it changed so little it didnt much matter. Dont know if that applies to a mini but I have no reason to think that it would not. Balancing the entire assembly is a good thing but not doing so is not necessarily a bad thing.

[@Oh-Jay52]

@@blackbirdxx928 Sounds and looks technical but i get what you mean , I suppose wallet and preference sometimes dictate eh :)