Old Bill

Thanks Barry. Might be worth a go.

Looking at these photos this morning, I have just realised that there are ten more tubes in this plate compared with the one I counted before placing my original order! Will have to get some more tubes as well. Oh well. That's a job for later. I am on Dennis radiator castings today!

Steve  🙂

I have been pressing on with threading gills onto tubes and have completed 111 with 15 to complete. Unfortunately, I am short of gills and so must order some more. It is an unfortunate break but at least it will give my fingers a rest! When I take the tubes back, I will see if I can get some pictures of the dipping process.

Dad has taken Barry's advice and has spent a lot of time salvaging the tube plates. Fist job was to remove the bottom tank from the chosen core.

Looks like the mice managed to get inside the tank!

He then attacked the tubes with the disc cutter.

This rad had been buried next to one of the Peerless chassis somewhere down on the south coast. As a result, the core was very rusty and full of filth.

The plates don't look too bad.

He attacked the muck with a nylon brush in the drill which was quite effective.

A few odd gills remain soldered to the plate so I will have to get them off later.

The soldering is curious. I wonder if those tubes at the edge were a repair job at aome time?

All cleaned up and ready to have the tubes drilled out.

Dad is coming to visit soon so he will bring them up for me to finish. Should save a few quid in brass anyway!

Steve   🙂

I have been over to Grantham today to see CPA Radiators and pick up a set of tubes and gills for the radiator. They can do 15/16" dia and turned the lot around in two weeks from order so I am very pleased. They can also do 15/16" square gills if anyone needs them.

13000 gills which I now suspect is not enough! Oh well.

126 tubes.

I had to try one! All is well and I just need to put the hours into the remainder.

Must get on with salvaging the tube plates so I can return the lot to CPA for soldering up. More progress!

Steve  🙂

26 minutes ago, radiomike7 said:

Would metric cap screws be a good starting point, they are available in UHT 10.9 and 12.9 versions?

We could start with commercial bolts but I don't think I would try gr 12.9. They are not good under fatigue conditions and suffer from stress corrosion cracking. I don't think SCC would be an issue inside the engine but it is definitely a fatigue sensitive application.

Thanks for the thought!

Steve  🙂

22 hours ago, Asciidv said:

Why is it not possible to re-use the existing tube plates?

Hi Barry. Thanks for the steel guidance. It is what I had in mind.

Now that you suggest it, we really should see if we can salvage the original tube plates. It will destroy some scrap and save a quite a few quid as well as using original parts. Will have a go the next time I go down.

Steve   🙂

Thank you for those leads, gentlemen. Very much appreciated.

I have had a nice weekend in Devon. Worked on the lorry and Mum cooked a splendid roast dinner so it was all pretty good!

As always, we are doing lots of things at once. The main target, though, is to get the engine back together and safely in the chassis, out of the way. The blocks were next in line for some treatment. They had been painted Ferguson grey over the rust and suffered a variety of thread problems. Two manifold studs in one block had been 'Helicoiled' 3/8" Whit where they had been 3/8" x 18 NS originally. Dad made up two replacement studs for these, Whit one end and NS the other.

The other block had a stud sheared off and two UNC studs wound into the NS thread at a funny angle. Ouch!

We started off by giving the blocks a preliminary clean. What a filthy job that was! We then decided to tackle the 1/4" threads in the top face which hold the water manifolds down.

These proved to be 1/4"x27 NS threads. Four of them were stripped so I Helicoiled them 1/4"x26 BSF instead working on the basis that with such a short thread, it wouldn't make much difference which proved to be the case.

For those of you unfamiliar with the 'Helicoil' process, it is a fiendishly clever way of repairing a stripped thread. In the kit, there is a special tap which is the same pitch as the thread to be repaired but larger in diameter. This is used straight in the stripped hole. On removal, a 'thread insert' which looks like a spring but is diamond in section, is wound into the hole using the tool in the kit.

Winding the insert in. The far end is pushed out with the other tool and the insert re-creates the correct thread form. No workshop should be without them!

The broken stud was much more of a pain. We fiddled about for ages until I made up a drilling jig to hold the drill in the centre. Once drilled through, I ran the UNS tap down and all was well.

Dad made up some new studs, NS both ends for these holes and Whit one end for the two on the other block.

Dad then gave it a proper clean ready for painting.

In the mean time, I tried fitting the con-rods to the crank to see how good they are. All are usable without further adjustment although they are by no means new. There are no shims fitted so I couldn't tighten them without either re-metalling or machining the caps back so I think we will live with them as they are.

One concern though, was that several of the big-end bolts look a bit iffy. I think we shall have to make some replacements but what sort of steel should we use? I would value your thoughts please.

The other interesting thing about them is that each rod has two long bolts and two short ones. The long ones have the split pin hole in the same place as the short ones. Does anyone have any thoughts as to why this might be? The only thing I can think of is that they dip in the oil and splash it around a bit more. This is a splash lubricated engine but they do seem a bit odd.

More planning as I went back and measured up another radiator core.

CPA Radiators in Grantham have the tool for these gills so I have ordered 13000 and 126 tubes. I hope to visit them shortly and pick up the bits.

Now I must get on with the tube plates!

Steve    🙂

That tank is remarkably like the Dennis tank. I guess it was an available standard of the period. Dennis mounted the tank with the filler on the rhs and the sump and tap just outside the tank saddle so just the same as in your manual. All looking very nice. You will be out and about next year!

Steve 😁

Thanks for that Tomo. I'll give them a try.

Here are our lovely new springs. 48 hours between order and arrival for a bespoke product is pretty impressive!

I measured up the best original and then sent:

Free length

Number of coils

Wire size

Bore and specified ground ends

He came back to me and said that he didn't have exactly that wire size and would this do instead? It is all fairly uncritical in this engine so we have taken what he had which I think was 0.218" instead of 0.213".

If only the valves could be so easy! I have an expanding reamer which I shall put through all of the guides which started out at 7/16" bore. I shall work up until they are all the same size and 'clean'. Dad's new guide replaced an original which had been drilled through 1/2" dia so he has drilled that 7/16" to give me somewhere sensible to start. Once I have a known size, I shall draw up the valves and ask G&S valves of Godalming to give me a quote. If I am lucky, there will be something similar they can modify and the price will be reasonable. If they have to make them from scratch I suspect that they will be a bit eye watering! We shall see.

Steve 🙂

Thanks. I did look at the terminals to see if there was any discolouration but there were no signs. We are going to Quainton on the 30th so will have to see how it performs then.

Steve  🙂

First job on the blocks was to strip them down a bit more so the bronze valve plugs wee unscrewed. Surprisingly, they were not very tight.

Top of the valve now visible.

Under the plug is a very narrow copper-asbestos washer. Does anyone have a source of these? The FWD needs some new ones too.

Rummage under the bench and pull out my modified and extended valve spring compressor. Isn't it nice just to have the tools to hand?

Squeeze up the spring.

These valves have a cross-slot in the bottom with a wedge so this was wangled out with the pliers.

Once out, they all went into the wash tank. That was a good investment too.

The valves are a bit variable with some worn more than others. The seating surfaces were OK but the shanks of some are very corroded.

This head has seen better days too so we have decided to replace them all.

Spring seats will all fight again.

The springs would function for a while but I expect we would have failures due to the corrosion dimples so we have ordered replacements from Tested Spring Co. I placed the order on Tuesday evening and they have arrived this evening! Amazing service.

The guides are all showing signs of wear with one exceptionally bad. I plan to run the expanding reamer through them all except the bad one which Father has replaced.

First get the old one out. Interestingly, it was held in with countersunk screws rather than being an interference fit.

Chuck a piece of cast iron and off Father went!

A nice new valve guide  ready to fit.

Next job is to get them all the same size and then draw up the replacements ready to order. That will be a job for me.

Steve   🙂

I took the hint after that and tempered them back a bit. I wasn't expecting it to get quite that hard!

Steve    🙂

Thanks Barry. You must have a bit of old blue rope. I don't think it comes in any other colour!

Thoughts have turned to tappets and followers. Fortunatey, Father started on the job some time ago by cleaning them up.

Unfortunately, some of the tappets were pretty poor.

And two of the followers had seen better days as well.

Dad set to and turned up a new set of tappets.

Which I case hardened and quenched in oil.

The remainder cleaned up nicely.

But two of the followers definitely needed replacing. The axle for the roller was trapped by a cross-ways pin which I drilled out before pushing the axle out.

The oil way arrangement is interesting. This hangs down inside the crank case so splashed oil can run in.

I turned up two new rollers from silver steel and then hardened them before reassembling.

Unfortunately, the axle was a bit tight and when I pushed it in, there was a 'snick' and a broken roller. Bother!

I turned up another with a bigger hole in the middle and set about reassembling it.

The pin was secured by riveting over.

Ready for reinstatement!

Cleaned the tappets and fitted Father's new nuts.

Back in the engine!

And fixed down with another load of UNS nuts made by Father.

Time to think about the blocks.

Steve  🙂

All looking very nice Andy. Better than working!

This is the Howes and Burley we have on the Dennis for comparison. We were even more fortunate in that it is WD marked!

Cheers!

Steve 

We both managed to get down this weekend so we took the opportunity to turn the engine over. Now the flywheel was in place, it was just too much to manhandle.

The engine hangs from its mounts so they had to be fitted before we could put it in its stand. Tim blocked it up so we could insert the bolts.

In the mean time, Father had cleaned up and painted the pivot casting.

This went in with the repaired bolts without a hitch.

Then the other end which also went well.

When the mount had been removed, we noticed that a lock nut was missing. I picked a nut to copy and sketched for Dad who made a new one. Unfortunately, one of the nuts was a joker and slightly bigger AF. Of course, I picked that one to copy! Oh well.

The new nut works OK and matches the joker so all was not lost. 5/8"x16tpi UNS this time. We have spent a fortune on new taps and dies but at least they are all sharp!

Front mount pivots on a plain pin.

And into the stand where we can do some real work!

Dad has made up the three replacement studs with the large thread, the oversize thread and a standard one.

They fitted nicely.

Push rods, tappets and blocks next.

Progress at last!

Steve  🙂

The engine beckons! I have just had a nice weekend in Devon and we have made some good progress. We got the crank case up on the stand and Dad carried on with the cleaning.

This engine mount bracket remained. It is secured with two bolts with round heads. To secure them the bolts have 'feathers' drilled into the head. The first bolt undid.

You can see the feather under the head. The second broke off which presented an interesting challenge as the heads are counterbored into the crank case.

The solution was to cut a slot in the end of the bolt so that it could be held with a screwdriver whilst turning the nut. Much to my relief, this worked!

The feather is 1/8" diameter, drilled straight through the head.

Casting removed and another cleaning and painting job to do!

The oil pump hangs on four bosses on the side of the crank case. One stud was present, one missing, one boss had a stripped thread and the last boss, a lump missing from the casting. Fortunately, the casting is thick enough just there that I could drill and tap it deeper ready for an extended stud.

The thread was tricky, of course. 3/8" x 18tpi UNS just to trip us up! The stripped thread was simply tapped oversize.

With the crank case looking good, it was time to look at fitting the crankshaft. First stop, the bearing caps which had a piece of felt laid into them to seal against the sump.

Looking good!

The moment of truth.

Looking good but what about the timing?

Good thinking Dad. Fortunately, the gears are well marked.

Caps were nutted and tightened and the crank shaken to see if there was any play. Fortunately, there was no radial movement at all so we simply tightened them right up and pinned them. Unfortunately, two nuts were missing but we did find a pair of replacements, 1/2" x16tpi UNS just to keep us on our toes!

The engine mount bolts were all designed with feathers but most were missing or loose and needed some attention. New bits of rod and some Loctite did the trick.

Making sure that the corresponding holes were clean.

Ex-US Liberty B chassis I think.

2 minutes ago, super6 said:

Poor electrical connections also generate heat via arcing, presumably there would be other symptoms though

When I fitted the heat shield, I did look for signs of arcing but the terminal was quite clean. I wonder if it is something to do with the modern volatile fuels? If we had been running lean, I would have expected the engine to boil up as well but it all ran very well. A bit of a puzzle but one for Tomo to look out for.

Steve 🙂

On 7/12/2021 at 10:16 AM, Rangie said:

Is there an external water supply or is there a reservoir/drip-valve sitting in the top of the generator assembly?

Alec.

Hi Alec.

Yes, there is the water tank and valve arrangement inside. What you can see is just the casing. I'll dig out some pics shortly.

Steve

Thanks Tomo and thanks Barry. I assumed that the knobs would have been a Phenol-Formaldehyde thermo-set and would have had to get a lot hotter. Only 150° is a bit more reassuring although it is probably not good for the mag itself. Something to keep an eye on.

Andy, what would you do to the timing? I have it set to fire on TDC when fully retarded but could probably advance it a bit more.

Steve  🙂

I have been able to give the pistons some workshop time today to finish them off. First job was to drill angled radial oil holes just below the bottom ring. They were puzzling me a bit until I realised that this wonderful new mill of mine has some interesting features!

Eight radial holes were drilled using the dividing head to index them. All successful!

Last machining job was to drill and tap the holes for the gudgeon pin securing screws. 3/8" x 18 UNS this time. One good thing about these odd threads is that all of my taps and dies are brand new!

I turned up the screws (one per pin) and now only have to fret out some tag washers to lock them in place.

Somethine else we managed to do last weekend was to fit the bump stop springs. Dad has painted them so it was just a case of removing a U-bolt from the front axle and slotting them in.

The U-bolts were replaced where they just trap the springs. This will allow them to rattle which may become annoying in time!

Now back to the engine.

Steve  🙂

We had the great good fortune to be invited to the Shuttleworth Flying Day at Old Warden last weekend and took the lorries.

We had a super time and was our longest run to date with the Thorny. On inspecting it later, we found that the HT leads were beginning to bubble and one of the magneto terminals had melted which is a bit concerning.

The magneto is very close to the exhaust manifold but is exactly the one (Simms SR4) called up in the parts book and, as far as I can make out, has been installed exactly as it was originally. There is nothing I can do to move it further away so I have bent up a piece of aluminium and made a heat shield which I have bolted to the main shield.

I don't like deviating from factory build but see no option here if I am not to suffer a failure on the road. We have not seen any signs of a shield in the old photos but surely they must have suffered the same issue. Very curious.

Steve   🙂

On 7/6/2021 at 11:00 AM, Tomo.T said:

Mike kindly turned up the missing plug

Hi Tomo.

It is all looking very smart now! Did Mike include the plug extension to block the hole in the end of the suction tube and give it some support?

Easy to miss if you don't know!

Steve 🙂

 I have just had a few days in Devon where I have seen what Father has been up to and been able to pick up the lorry once again. You may remember the piston castings we had poured.

Father machined the ends and the bore and then took them to a pal who machined the gudgeon pin holes for us.

He then turned up a dummy gudgeon pin and bored a block to fit it.

After mounting a piece of steel on the face plate and turning a spigot to fit the piston bores, he set up a piston with the dummy gudgeon pin and used a draw-bar to pull it back onto the plate.

This left it firm enough for me to turn it.

Father had previously rescued the rings from the original pistons and we deem these good enough to re-use so I cut the grooves to suit.

The diameter was turned in steps ranging from 4.507 at the crown to 4.515 dia at the skirt. Hopefully this time, we won't have the seizing problems that we had with the Thornycroft!

A quick try in the bore just to prove a point!

Almost complete and require only some radial oil holes just below the bottom rings.

Time to start thinking about the rest of the engine!

Steve 🙂

You are very kind Barry. I have just returned home from Devon where I saw the castings for the first time and have brought them back for machining. I must say that I am very pleased with them. It took Ben, at the Bridport Foundry, a whole day to make the moulds but his efforts were worth it. I have just put the patterns on the shelf ready for the next time someone does a Dennis Subsidy lorry!

Steve  🙂

Radiators are an expensive game! Did you make the patterns Duncan?

Steve 🙂