David Brown Knocking

[cobbadog]

I may have mentioned this elsewhere in the Forum but a couple of weeks ago when loading David onto Lorry's back a bearing knock sound started. So after last weekend I unloaded everything off Lorry the Flo off David's carry all and parked David in his house. I noticed no knocking noises this time but I only need to hear them once and it is get inside and find the problem. It was all too obvious as to what the problem is. After dropping the sump and big end caps I started using the Vernier callipers to measure all things 'big end'. Well the good and bad of it all was there is 0.006" wear on 3 of the 4 big ends. This is enough to loose oil pressure which was a big problem when we first drove David and obviously was the instigator of the problem I have now. Well that is how much wear there is on the crankpin journals I do not know how much wear there is on the slipper bearings until I can measure new ones up so I am guessing it is now way passed time to do something to fix it properly. I am now in the process of stripping David apart, right apart to get the engine completely out so the crankshaft can get a grind, new bearings supplied and then keep looking at all the other obvious parts that wear like, pistons, rings bore not to mention the things that go wrong with the head as well. So many $$$$$$ later David will be back together and going again, sometime. I now have to search for parts availability like the bearings and gaskets and head gasket etc. If none here in Oz I have to search Pommyland. So here is a pic of David right now as I type this thread. It is sad to him in pieces and so close to our Rusty Iron Rally. I have been in contact with a couple of people who should be able to supply my needs but I need to know exactly what I want before we talk about availability and costs. I still have to remove the steering box set up, fuel tank assembly, clutch housing, head off and governor system before lifting the engine. So much to do and so much to remember how it goes back together. I don't want a rear steer Cropmaster or something silly like that!

[wee-allis]

Hi John,

Sorry to hear of David's dilema.  As to sourcing parts, the best guy I have found for early DB parts is Max Curtis in Bainsdale Vic. on 0428 658 653. He did have a tractor service business, and since he retired, he now does bits for the old girls from home. I have used him for many years and he is very helpful in sourcing parts.  If he doesn't have them, he can get them in for you.

I have a VAK1A,(sort of), it is from the grill to the clutch and from there back it is a '53 Cropmaster. I also have the bones of an early Maggie model, so if there are any bits I can help you with, let me know.  I gave the head away some years ago and the block has been cracked in half by frost, but you never know.
Good luck, Steve

[cobbadog]

Hi Steve,
Thank you so much for the contact details for Max Curtis. One of our Club members mentioned his name too and said that he is very helpful. Thanks also for the offer of some parts from your early maggy model, I certainly will keep that in mind as I keep removing bits from ours. As I am slowly removing bits I keep finding things and then all of these questions come to mind. I found out yesterday about the 'water distributor' that is now missing in our engine head but a few people have said that it is not needed anymore. I am pleased about that as stainless reproduction ones are at a premium price. Since driving the tractor over the last couple of years in some good hot days the water temp has been rock solid and never has risen above normal temperature range and this is using a new gauge. Actually I have problems even using the radiator blind to get the temp to rise when it is just standing still, I actually have to drive it to get temps up. I have also just been given a tip on how to do a simple test on the engine oil pump to get an idea on its real condition. "Put it in a tub of petrol and spin it by hand" If it pumps petrol it is good and will certainly pump oil. Apparently an "old school" trick.
I won't be taking much more off the tractor this week as we are going away for a short holiday. Once we get back it will be 'full on'' with the removal of everything else and then getting the engine to the reconditioner already stripped and ready for his clean up and inspection and results of what he finds.

[cobbadog]

Hi Steve,
Now that I am back from a brief holiday I have stripped down David almost to the point that I can lift the engine. All I now need to do is double check the timing marks on the cam to the crank (just to be sure) disconnect the shaft in the gearbox to the clutch plate and undo all the blots around the engine block. Something that I found yesterday afternoon is the idler gear that goes from the crankshaft across to the governor. My gear has some very strange marks on the teeth as if something had fallen onto it and has worn the teeth in a funny pattern. On that old engine that is cracked is that gear available? If so how much would you like for it?
So far everything else looks quite good. I was told a simple test for my engine oil pump was to put it in a container of petrol and spin the driven gear. If it pumps petrol it is more than good enough to pump enough oil. Mine throws the petrol out quite well so I am guessing all my oil pressure was going out past the bearings.

[cobbadog]

Hi Everyone,
This is where David is at end of day today. The engine is completely stripped out except for the crankshaft and the liners for the bore. Tomorrow will be attending to the clutch section and removing all of that so the block can then be undone from the frame and lifted out, at last.
Everything that I have done today has been a bit of a challenge. Firstly I wanted to check the tappet clearance before I remove the rocker gear to get an idea of what the tappet clearance is when it is cold, only a hot setting is offered in the manual. Well they were all over the place and no two were the same, so maybe one of them was right and all the others wrong. This showed up another problem that took some researching, valve timing. Yep, just like any other four stroke engine I have had apart there was the traditional centre dot marks, one on the crankshaft gear and two on the cam gear. Now for the big issue they don't line up at any TDC position on any cylinder. The only time they lined up was when the pistons were in mid stroke, half way up or half way down the bore, how bloody delightful! So I hit the Service Manual I have and it goes into great detail about aligning the centre dot marks "UNTIL" you get to the second last paragraph where it says; 'where new gears have been fitted all of the above does NOT apply' and then goes on that you now have to point both keyways downwards so that they are both parallel with one another and this is the correct timing position. BONUS! Once I had the engine in that position all things came together even the timing mark on the flywheel. Then it was all ahead full to remove the rocker gear, pushrods, cam followers, cam head and pistons.
So now David looks like a dragster without a "guidance system" (steering).
I have also discovered that the threads on the big end nuts n bolts appear to be BSB (British Standard Brass). A 3/8" diameter shaft on the bolt with 26 TPI. The Whitworth 55' pitch thread gauge fits snuggly. I can't find any other thread that matches it.
More fun tomorrow.
Cheers Cobba.

[Scott]

Hello Cobba.
Good to see progress is happening.
I know of a 6 cylinder Lister that'll fit well in that gap left when you remove that dirty old block. David would go well at tractor pulls then with 110hp sitting in the front.

Cheers then
Scott

[wee-allis]

Hi John,

Good to hear you are getting into the project.  You will have so much satisfaction when you finally get it going again.

As to the gear you need, it is free to a good home, as are any other parts you may need. I just need the time to get it out for you and into the post.  I've been doing seven days a week lately, and have the job of organising the collection and removal of a recently deceased club members engine collection, probably this coming weekend.

I will get to it in the very near future, but will keep in touch to let you know when I do.  Please send me a PM with your address.

Cheers, Steve.

[wee-allis]

Hi John,

Just letting you know that I found ten minutes yesterday afternoon to remove that gear you wanted.  It looks o'k and I will post it to you.  Just give me a ring on 0418 439914, any time to give me your address for posting.

Cheers, Steve.

[cobbadog]

Well everything is out of the tractor that needs to be out. I have roughly cleaned the parts that are going to the reconditioners and then started on the other parts. So in the meantime I had a little trial fit of our Scuttle Plate after not having one since we have owned this tractor. Now all we need is an engine to push it all around.

[cobbadog]

A very big thank you goes out to wee-allis (Steve) for being so very helpful in supplying a replacement idler gear for the engine rebuild on our David, it is in excellent condition. I finally got all the necessary parts into Taree for a clean up and assessment yesterday. So sometime next week I should have a list of parts to find and costs involved. Hopefully it won't be as bad as I am expecting.

[cobbadog]

Well here we are at the 'find a part' department. There has been good news on the Head with little work being required. Typical surface grind for the main flat area also had the ports re done as it has always burnt out manifold gaskets. It only took 0.060" of machining to get a good surface again. Valves lapped back in and waiting for new welsh plugs and it is done. The crank needs -0.020" right through the mains and big ends and appears that big ends are available but not sure about the mains. So far the feed back has been that it is unknown if the diesel engines use the same main bearings as the petrol/kero.
DOES ANYONE ELSE KNOW PLEASE?
I had the liners pressed out and they are not suffering with any electrolysis which is good but the bore has a slight bit of wear but good enough to just hone and re ring it. So I need to find a supplier of rings to suit the standard 3.625" bore size but I do have to measure the rings widths as they apparently changed over time. Gaskets are not a problem and I can make most of the new ones but will be buying the new head gasket and manifold gasket as well as the front and rear main oil seal cork gaskets which are a square section of cork at a certain length.
Can anyone offer me the torque settings for the mains and big end bearing as well as the head and for the cylinder block to frame torque settings. I have the settings for the tappets but it is a HOT setting. I find this strange as you can't set them HOT when you have just assembled the engine so a COLD setting would be good too please.
Cheers Cobba

[cobbadog]

I have got the feelers still out and awaiting responses for the main parts I need. In the mean time I am continuing to clean up bits and have started making the new gaskets that I know I can make. I bought some 3/8" square "A" grade felt for the front pulley seal and made it up and have it installed in the plate that bolts onto the timing gear cover and the pulley goes through. I need to buy some thinner oil gasket paper 0.15mm thin for going between the cylinder block and tractor frame, but this is not expensive either. The only gaskets that I know I must buy is the head and the manifold gaskets. I tried before to make the manifold gasket using the type of paper with aluminium in it and I made a real mess of it. So for the cost of buying one I will save a lot.

[wee-allis]

Hi John,
As far as your tappet settings, I would set them at + 1 thou cold for start up and then set nthem hot to specs.
Cheers, Steve

[cobbadog]

Thanks for that tip wee allis. I am also curious about this 'water distributor' in the head. At the moment there is not one in there and so far even on a tractor trek on a hot day water temp has never risen nor has there been any pre-ignition which is apparently a side effect on not having one. It looks as is I can easily buy one out of Pommyland at a price but don't know if I really need one.
Any thoughts out there ?

[cranky crank]

Hi,
When you look at the david brown book it shows the tube has small slits in it which appear to direct the water around the valve seat area. I put a croppy together for a mate who was putting it to work .The old tube come out in bits but was enough to get an idea on its shape. We ended up getting a bit of copper pipe and squashed it slightly to make the shape to fit snugly in place in the head and used an angle grinder with a thin blade to cut thin nicks for the water.
It is still there and the tractor is worked hard with a slasher.