Doris NP Super Dexta rebuild

[Dextrous]

Also you will need to lock the crankshaft somehow to prevent it turning whilst you undo the pulley, unless you have an impact wrench (and toughened box spanner). I made a long spanner which I bolted onto the pulley bolt holes. This worked but I later discovered my pulley had a hairline crack (spotted by an eagle eyed reader after I posted a photo on here!) by the key way. I can't help wondering if the spanner attached to the pulley was the cause. Better to lock the crankshaft itself rather than the pulley, so maybe bolt your spanner on using the flywheel holes.

Thanks for the tip ben - this is what I have come up with to lock the crank - I found a long UNF bolt to fit in the flywheel flange bolt holes and this rests on the engine stand. I have a long bolt in the alignment hole in the flange and have packed them both out so they don't damage the engine stand and both take a share of the load.


The spanner was a problem, my mate had a 1 5/8 AF socket but its not quite deep enough as the starting handle ratchet/dog protrudes, however he did have a 1" whitworth cranked ring spanner. The correct size across the flats is 41.28mm or 1.625" while the 1" BSW is 42.42mm or 1.67", so not a lot in it. Here's a shot of the spanner on the nut and the socket that is not quite deep enough hanging off of the water pump studs. I can't see why they have a starting handle dog on the nut in the first place, with the compression of a diesel engine and needing to crank it upwards of 100rpm then its nigh on impossible to start with a handle - unless you know differently ( I guess a Formula 1 style starter might do it!)


The lugs for the fan bolt holes get in the way of the spanner, probably fine with the correct 1 5/8" AF spanner but with the slightly larger 1" whitworth then its important that the lugs are closer to the spanner in a clockwise direction, not like in the following picture as pulling on the spanner tends to push it off the nut and could damage the pulley.


I gave it a quick go on my own, I put a strap under the engine hanging off the hoist and couldn't budge it with downward pressure and lifted up the engine and stand with upward pressure and the strap removed. The ring on the spanner stops the usual farmers method of slipping a scaffold bar over it. So I have enlisted the help of another neighbour who has muscles on his muscles and is used to stubborn nuts on big machinary while I have the centre of the nut full of WD40 type stuff. Its safer to have 2 when giving a stubborn nut some welly I have a few ideas of how to move the little tinker

[russelm]

I removed mine once the sump was off, I packed pieces of wood between the crank throw and the block to stop crank rotation.

Cant recall the socket size (I am fortunate enough to have loads of big scokets upto and includinga 75mm one!) but I seem to remember them being around 10-12 pounds on ebay

[Dextrous]

Thanks Russell

The spanner worked - to the point it bent the bolts stopping crank rotation but not to the point it removed the nut.

So sump off and packed the crank with wood, top tip! I can now vaguely remember my dad doing that when we did the A series engine up on my first mini.

However the nut won't budge, the spanner slips before enough torque is applied. Round one to Doris

There is no tab washer on it - we had a good look with torch and poked it with the screwdriver, we've had the "is it a left hand thread" conversation when doubt crept in and decided no

My neighbour has gone looking for big sockets and box spanners in his old barn and my mouse pointer is hovering over the buy button for the correct box spanner

Cheers
Andy

[tom lad]

hi m8

A T enginiering is generaly very good for bolts tools ect.
on A6 nr brock / preston ish , prob not that far from u ? 01995 650058
very helpful guys , well used to muppet farmers askin daft questions ,just like me

[Dextrous]

Thanks Tom

I'll bear that in mind

I've ordered the correct box spanner. I'm away now for a couple of days so it should be waiting for me at the weekend when I can swear at the nut some more

Cheers
Andy

[russelm]

If you are still stuck then let me know and you can borrow the socket I have which fits.

[Dextrous]

Thanks Russell

If the box spanner doesn't work I'll take you up on that, my folks don't live far from Nottingham and I'm at a wedding in Lincoln soon so will probably work logistically too.

Cheers
Andy

[Dextrous]

Good news, the nut came off Box spanner arrived, a bit rough for £16, needed a bit of filing to remove swarf and burrs. Using a bar through the holes was useless as the holes are too small for meaningfull leverage. Used a very large plumbing wrench on the other end of the box spanner with a 3 foot length of scaffold bar before it would move. Used a block of wood in the crank to stop counter rotation.

Other progress, refitted PTO shaft after making a new gasket then removed PTO selector and replaced the o-ring. Made a gasket and replaced the PTO selector shaft and housing. Used hylomar univeral blue spray gasket sealant- far better than the tube.

Removed valve springs and valves etc. just about ready to dip the head in phosporic acid to remove scale but will probably do it along with the engine block so need to finish stripping it first. Used my new stud extractors to loosen the head studs in the block, very nice.

I also took out the brake pedal assembly after swearing at the woodruff key for a while. Next job is to replace the seals for the brake pedal shaft and the then tackle the oil seals in the bell housing/gearbox.

Probably no more time this weekend as I'm looking after the youngest daughter while the eldest goes to London with the GF.

Is the clutch operating rod supposed to be that shape?


Cheers
Andy

[Bensdexta]

Is the clutch operating rod supposed to be that shape?

Good work.

My rods are pretty well straight.

[Dextrous]

Thanks Ben - I'll make sure they are all straight

I didn't get anymore done today except take tools I borrowed back to my neighbour and pick up the injectors he has refurbished for me - very nice. All tested and atomising nicely

Sorry about putting them on a copy of the Daily "hate" Mail but we were right out of toilet paper The mother in law to be brings it around when she babysits so I can't complain...

Cheers
Andy

[Kiwi Kev]

Thanks Ben - I'll make sure they are all straight

I didn't get anymore done today except take tools I borrowed back to my neighbour and pick up the injectors he has refurbished for me - very nice. All tested and atomising nicely

Sorry about putting them on a copy of the Daily "hate" Mail but we were right out of toilet paper The mother in law to be brings it around when she babysits so I can't complain...

Cheers
Andy

Andy
What was the answer to 18 across
Keep up the good work on the Dexta.
Kiwi kev

[Dextrous]

Thanks Kev - 18 across was "burglary" - see below I've had an attempted break in, first they cut through the back of the downstairs barn, even though the main sliding door is never locked, but then I don't leave tools lying around, they are all locked away. They tried to jemmy the door of one of my store rooms but I use steel security doors with multiple internal bolts. Good news, nothing stolen, bad news, door is £150 but with pallet deliver (very heavy) and tax it is just over £260 and my insurance excess is £250 so no point sticking a claim in

The door doesn't look badly damaged but the bolt clearances are such that it will never be right, the GF was complaining the door was too stiff before the jemmy attack.

How they got in


The door they tired to jemmy - damage half way between handle and floor



No idea when it happened, I only found out when I went to turn the compressor on to use my air tools to take the rest of the engine apart


Regards
Andy

[pbufton]

Nice to hear in this case they left empty handed! As round here, the general consensus is if they want it, they'll have it any which way

[Bensdexta]

I didn't realise the Super engine has a different oil strainer to the Standard.

My oil strainer is part of the cover that bolts on underneath the sump.

[Dextrous]

Nice to hear in this case they left empty handed! As round here, the general consensus is if they want it, they'll have it any which way

Yes. I'm very pleased the toerags didn't get anything However no time for complacency so I'm welding heavy gauge mesh that you use for reinforcing concrete, the one bigger than A142, inside the boarding to the steel frame of the barn. Unfortunately I didn't have a MIG welder so I had to buy one of these, purely coincidentally it has a very low current setting of 15 amp which is perfect for tractor bodywork

Picking up an argonmix bottle next week. Will be able to weld mild and stainless - I also make my own brewery kit which is mainly stainless so it will get some use.

If anybody in the UK wants cost effective steel security doors, try here.

I'm also buying a couple of these video cameras. I already have all the gear for logging pictures and video to a server etc. - turning into an expensive event however I live in a rural area, police can't be everywhere, I travel a lot so need the piece of mind.

To pay for it all I may have to cut back on our wedding costs next year, maybe go to church on a tractor instead of a limo - I do believe somebody on this forum did this a few years ago

Cheers
Andy

[Dextrous]

My progress has been delayed slightly by the attempted burglary, fitting a new door and some video cameras etc. However I got a full day of tinkering today and managed to get a couple of hours of tractor time. I cleaned the cyclinder head up then deciced it needed the rust and scale in the water galleries cleaning out

Here's the head before cleaning


Here's it in the phosphoric acid bath


And here it is afterwards


The difference doesn't show up too well but most of the gunk has gone in the smaller galleries, these were nearly closed up on the head face. Not having done this before I didn't want to overcook it so probably pulled it out a little to early.

I used 2 litres of 42% phosphoric acid diluted in 10 litres of water at 76 celcius. By the time I dropped the cold block in it, the temp was down to about 45c. I left it for about an hour giving it a scrub now and then. I then washed it in hot water twice, immerising it completely before drying with a cloth and covering it WD40 immediately then a further coat of oil a little later.

Valve guides will be done soon and while this is happening I'll strip down the block. I didn't waste the acid water, I have some rusty old bit of swinging drawbar bracket in there for the night.

Cheers
Andy

[Mark]

Nice thread on the rebuild of another old Dexta girl (Doris). You might try the caustic soda on your head. I had mine cleaned with this at the local Machine shop, block to. It did wonders for all the gunk inside the little holes and hard to get to areas. Keep up the good work, will be keeping and eye on your rebuild, nice thread.
Mark

[Dextrous]

Thanks Mark

I haven't had time to do much to Doris myself recently however I have had the valve guides fitted and valve seats recut at the local agricultural engineers shop so the head is more or less ready to go.

I have just received a new toy to play with, I have some tractor time coming up tomorrow so will strip down the rest of the block ready for new sleeves and pistons and practise with the MIG if I have some time left


Cheers
Andy

[Mark]

Interesting old tools you have lying about. What are they used for, can't see them all that good to tell what they were made for. Nice welder you got there to Andy.

[Dextrous]

Hi mark

Here's some closer photos of the old tools, they are presses of some description, my farmer neighbour has brought most of big old tools up to my workshop on the condition that he can use them at will. Works great for me as he's a tool maker at a local aircraft factory and part time farmer so I get use of his big farm toys, loader, bobcat etc. and he gives me advice on using my lathe and milling machine - win - win

The presses are made in Birmingham and Stockport, one is operating using the lever, the other wth the quick thread you spin the handle round



Evidently this is a flypress, I've found similar called no3 and no4 on the web, it has 1A at the bottom so this may be a no.1A? it has serial number 1307 on the other side.


Can't find much on the web on this one though.


Cheers
Andy

[Mark]

I like looking at old tools and finding out what they were used for. Sounds like you have a sweet deal with your farmer friend. Nice to have such a good neighbor!
See ya
Mark

[ol'Blue]

Love your shop.... And it looks like you have scored a nice welder.... One piece of advice I might share on the welder... When the power and speed are correct for the material your welding, the sound of the weld will sound like nylon material being ripped...Too much speed and the wire will push back at you, too little speed and it wont make a nice continues fillet....I like to run as hot as I can on the current to provide good penetration. Remember listen for the sound of the weld... if its right it will sound like a pair of nylon undies being ripped intwo...

dave

[Kiwi Kev]

When the power and speed are correct for the material your welding, the sound of the weld will sound like nylon material being ripped...


if its right it will sound like a pair of nylon undies being ripped in two...

The sweet sound of success

[Dextrous]

I've been told it sounds like frying bacon when you get the wire speed, current, travel and gas all about right, however ripping nylon knickers appeals to me a bit more

I've only had chance to have a quick play so far, I won't show you the first 5 minutes, just the second attempt, I did manage to get one part where it sounded something like a ripping gusset The left hand side weld is I think my best, and when I turned it over it had penetrated to the other side just before I blew a hole out on the edge


other side with penetration of the left hand weld looking better


I didn't have much scrap metal in the shop but I should have some more this weekend, I should have some 0.9, 1.0, 1.2 and 2mm sheet and some 4mm angle to play with so I can play with 0.6 and 0.8 wire. The MIG goes down to 15 amp so I should (I repeat should!) be able to weld the 0.9 without blowing too many holes. I also have a proper peashooter flow meter coming so I get the gas flow right at about 6 to 10 lpm inside with no wind, dont want to waste expensive Argon.

I'm writing down the welder settings at each metal thickness when I get the feeling I'm somewhere close. I think I still have a long way to go before I attempt anything on the SD cowling! Tips appreciated!

Cheers
Andy

Cheers
Andy

[tom lad]

hi
those tools are great
the fly press / threaded one would i think be ideal for riveting . Things like the discs on a plough . usefull tools and better built than anythink u'll buy today .

keep playing with the welder m8 , i learnt alot on a evening course at collage , u'll learn quicker being shown, and it all comes easyer with practice

i'd prob reccomend running it on a 16 A blue round plug rather than the standard 13 A 3 pin to make full advantage of ur power / duty cycle .
my argon /co2 is a 2 gague type looks just like you're , works fine , i'd stick with it tbh .

as you say u can see ur good penertration on that weld , with spot welds u could have filled the hole . no need to use the timer , or poss drop power a midges . the gap between the two plates has helped penertration too .
for fun then take the jionts to the vise and abuse with a big hammer , that will show strength .
all the best
tom