Mike Macartney

REPORTS ON A 1914 HUMBERETTE RESTORATION

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Mike, I was just thinking that would it be better to make a jig to hold the crank at the bearings than in the lath?  I would think it might flex the flywheel by putting pressure on it from end to end. You've said that it's quite heavy and it would require some pressure to just hold in the lath. I was thinking of a jig with a vee cut in it so it would self center itself. Then use the jig to go off of for your dial indicator. Just a thought. Mike

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Mike' I'm curious...was the engine man you went to see perplexed by the blind holes?

 

jp

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Hello Mike,

Been following your rebuild with great interest. Your bottom end is almost a copy of my pre 20 Harley’s. Can I offer the following. The shafts should be on V blocks close to flywheels to reduce flex. Then check if flywheels are parallel . If not gentle leverage can fix. Now check the run out and adjust with one end of crank pin not torqued to allow movement with a blow from a copper hammer to flywheel.

I freaked out with the taper being pressed in flywheel in a press! They can disintegrate with too much pressure in taper take care here. We clean taper perfectly, no trace of oil etc., make sure there is full taper contact ( there is a theory that a light fine emery removal of glaze is good?) Then torque progressively to max 80 ft/lb .

Hope this helps, Spend a little time setting up and reduce your stress. Been there done that. love watching your posts. 

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5 hours ago, colw said:

Been there done that.

 

But have you worn the T-shirt and eaten the pie?!? :)

 

I do very much appreciate your help and comments.

 

5 hours ago, colw said:

I freaked out with the taper being pressed in flywheel in a press!

 

I was very apprehensive about pressing the taper into cast iron flywheels, with the hydraulic press, I did not use too much pressure. I had been recommended to do this by a member of the Veteran Car Club  who owns a Leon Bollee  and a 1910 Morgan. I quote :-

 

"When I assemble flywheels, I insert the timing side mainshaft  and put it under a press and push it in with 4 tons pressure ---------- and then, after adding the drive side flywheel, aligning the assembly, aiming at better than 0.0005” on the shafts, I give the drive side mainshaft a nip of 4 tons, to bed the flywheels onto the tapers, better than can be achieved by just tightening the nuts".

 

5 hours ago, colw said:

Can I offer the following. The shafts should be on V blocks close to flywheels

 

After reading your post this morning, I attempted to try and mount the shafts on V-blocks, using my lathe bed as the stand. I could not get the V-blocks high enough to clear the flywheel and con rods. I gave up and came indoors to read your post again. I may have to make a stand to mount the assembly on.

 

5 hours ago, colw said:

Then check if flywheels are parallel . If not gentle leverage can fix.

 

I had been trying to work out with the dial gauges whether or not this was a problem. They are a few thou out of parallel, but this maybe due to my machining of the 4-faces of the flywheels?!?

 

5 hours ago, colw said:

We clean taper perfectly, no trace of oil etc., make sure there is full taper contact (there is a theory that a light fine emery removal of glaze is good?) Then torque progressively to max 80 ft/lb .

 

I will try your method. Thanks again for your input. Regards Mike

 

12 hours ago, JV Puleo said:

Mike' I'm curious...was the engine man you went to see perplexed by the blind holes?

 

No, he has worked on early engines before and fitted pistons in blind bores for me previously. I did not realise he was still in business, I thought he had packed up and retired due to ill health, he also used to build our Jaymic race engines. When I went to see him on Tuesday I asked him about the problem of honing out bores and getting a taper. He said he had only ever had the problem with Rolls Royce engines! They seemed to be harder towards the top of the bores. Your comments would be appreciated Joe.

 

16 hours ago, Mike "Hubbie" Stearns said:

I would think it might flex the flywheel by putting pressure on it from end to end. You've said that it's quite heavy and it would require some pressure to just hold in the lathe.

 

It  actually doesn't need hardly any pressure from the tailstock to hold the flywheel between the centres. The heavy bit is lifting the crankshaft assembly up onto the lathe, it's that what 'knackers me". I think I am going to take your advice and make a jig. Thanks for your ideas Mike.

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I've only ever bored one RR engine and that was a '29 PI and I didn't do the work. I have honed them but just to break the glaze. I'm afraid my RR expertise ends about 1930. I never liked the PII much - and only worked briefly on three of them. The same with the 20-25 and 25-30 although I owned a 1934 20-25 and did take the lower end of the engine apart. Generally I prefer the Ghost, the 20HP and the early PI's. I may even be able to afford a 20HP some day (provided it's in wretched condition)!

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Mike,

Hadnt given much thought to effect of machining. Let’s overlook that for now. Isnt the current aim to get the shafts running in line “as one”. The V blocks if aligned on a dead flat surface should do that if crank pin is just loose and your set up can relax. You can carefully rotate and check either end of each shaft for runout with crankpin just slightly tightened, hopefully they will be near spot on, then slowly torque the crank pin and recheck the shaft readings. If they change when torqued it’s the flywheels out of parallel. Let’s cross that bridge if needed. My thoughts are if pins both run with only minor deviation I would not worry about face of flywheel being slightly out ( could be your machining) as the effect will only be balance and these old things were never balanced as we now think and expect. Perhaps someone like Joe might like to comment on my ideas as I am neither engineer or mechanic just self taught.

Good luck mate, this is a patience job.  Col ( Brisbane Aus.)

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22 hours ago, JV Puleo said:

I've only ever bored one RR engine and that was a '29 PI and I didn't do the work. I have honed them but just to break the glaze.

 

The reason I talked to Martin, the engine man, about the possible taper when honing a lot of material of cylinder bores, was that you had mentioned to me about it previously. When he said that he had only had the problem twice and it was with RR blocks, I put 2 and 2 together and made 6! As you had worked with RR cars in the past I assumed that was where you had come across the problem.

 

15 hours ago, Col Wright said:

Mike, Hadn't given much thought to effect of machining. Let’s overlook that for now. Isn't the current aim to get the shafts running in line “as one”.

 

Yes Col, I am looking at making some sort of jig to mount the crankshaft assembly on the table of my milling table. I will let you know how I get on. Thanks again for your advice. Mike

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It seems ages since I have posted anything about how I am getting on with the Humberette, although I believe it is only a few days.

 

The calculations below may not be of any use to non Humberette owners, although, they may be of use to Humberette owners looking for replacement pistons for their Humberette engines in the future.

 

PISTON CALCULATIONS FOR HUMBERETTE ENGINE
             
  STANDARD ORIGINAL HUMBERETTE PISTON FORD ZETEC PISTON 24003 STD
  Measured Measured   Measured Measured  
  by Micrometer by Vernier Use for Calcs by Micrometer by Vernier Use for Calcs
  inches inches inches inches inches inches
Standard bore diameter is 84.25 mm (Ford 84.8 mm)     3.317 3.3386   3.339
Top of piston above top of gudgeon pin hole N/A 0.901 0.900 N/A 0.900 0.900
Gudgeon pin diameter 0.515 0.515 0.515   0.812 0.812
Half the diameter of the gudgeon pin     0.258     0.406
Therefore top of piston above gudgeon pin centre is:-     1.158     1.306
             
             
Height of piston top above top ring 0.138 0.142 0.140 0.294 0.288 0.290
Therefore height of top of top piston ring from gudgeon pin centre     1.018     1.016

 

Below are a few of photos of the pistons.

 

2516.thumb.jpg.9f1c3527fcaff988a742fbfcbf3f8784.jpg

 

2515.thumb.jpg.d1417dbfbec2374e01f2fab7bbe5f164.jpg

 

2514.thumb.jpg.736d74f49289445a1c00dff4b45b89bc.jpg

 

I have yet to draw out the bronze bushes that I need to make to fit to the Ford piston to the Humberette con rods.

 

The Ford piston will slightly increase the compression ratio as the extra height of 0.147" which equates to 6.71cc's.

 

I have given myself a bit of a break from the crankshaft assembly alignment for the time being and have been thinking about some machining I need to do to aid me.

 

2501.thumb.jpg.96eaa1ccce2324ed6b745a69f1017128.jpg

 

This is a plug that screws into the jug from the top, above the centre of the cylinder bore. I puzzled over the thread diameter and TPI as it seemed to be 3/4 x 17 TPI. It looks the same as the thread for the nuts for the big end pin? I tried one of these original big end nuts on the plug.

 

2500a.thumb.jpg.64aec45985db1789d08b4173fd0acaab.jpg

 

It fitted perfectly. Now, what thread is it?

 

2502.thumb.jpg.99bd132eefa26f3d0628f656ccb9bde7.jpg

 

It seems to be either 3/4" or 19mm and the pitch seems to be 1.5mm.

 

2503.thumb.jpg.f25051e7c740dd251df9beb115e5d0b0.jpg

 

2504.thumb.jpg.ef4b646355eda31e6924a1572bbb2bc2.jpg

 

2505.thumb.jpg.3a580969e800f49a7523fdd7abfa65f0.jpg

 

The thread form appears to be Metric (60 degree) rather than the Whitworth thread form of 55 degrees.

 

I do not have the gears, to cut metric threads on my big lathe, I also can't, at present, cut metric threads on my Myford lathe. I took the plunge and ordered a M19 x 1.5 tap and die, at great expense, it had to come from Germany. On arrival of the die . . . .

 

2509.thumb.jpg.5d5bb58958001182baec7ad7695cdfaa.jpg

 

I tried the die on the blanking plug and . . . .

 

2510.thumb.jpg.17f1daa975470c62957227017b13496a.jpg

 

. . . . also on the big end. It fits like a glove!

 

Now to get the extra gears I need for the Myford, so I can cut the metric threads on that machine. I think that this has answered the question as to what thread form Humber were using at this period in time on this engine.

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Yes Roger, the die was £45 and the tap was £25. As they say "It's only money". They also say "You can't take it with you". Although I am working on a design for a coffin with panniers!

 

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6 hours ago, Mike Macartney said:

Yes Roger, the die was £45 and the tap was £25. As they say "It's only money". They also say "You can't take it with you". Although I am working on a design for a coffin with panniers!

 

 

I've heard you can't take your money with you but you can take your tools... right? 

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I hope so. The worst part of traveling is that I feel naked without access to my tools.

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13 hours ago, Luv2Wrench said:

 

I've heard you can't take your money with you but you can take your tools... right? 

A few people are even taking their car with!

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What was the first thing I saw when I opened the newspaper this morning?

 

2517.thumb.jpg.34cca196bd88c0b7df06601f563247e9.jpg

 

I hope it's not an omen!

 

Roger, it is not too much of a problem for you take your, tools and model cars, but Joe would need a few big trucks!

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Since my last post a friend in Australia with a Humberette has emailed to say that his engine has developed a piston problem. Kevin uses his Humberette a lot for rallies in Australia. His next rally is in April next year. I have found some more of the Ford pistons, that I bought for me, so I have now 4 pistons to modify to fit Humberette jugs. Kevin was the first Humberette owner I ever had contact with. I 'met him' via a member of this AACA forum. He helped me a great deal with loads of information when I first got my Humberette. It will be nice to return a favour.

 

IMG_8823.thumb.jpg.50b78eaa0726c4199fdb0478754186e9.jpg

 

The damaged piston out of Kevin's Humberette.

 

It's not as bad as the last engine problem he had . . . .

 

IMG_8824.thumb.jpg.35b08a2846b4a81dcd218ddb5aaa8f9e.jpg

 

. . . . when the engine broke a valve.

 

Since his emails and the limited time Kevin has to get the engine back running, I have been drawing out and working through what I need to do to modify the modern Ford pistons. There are a couple of points I need some help with.

 

1870256256_PISTONGUDGEONPINBUSH.thumb.jpg.0cb104a09e8f17e6e87cc9c60dc41490.jpg

 

If I am going to fit bronze bushes into the alloy pistons to reduce the size of the gudgeon pin (wrist pins) to the size of the Humberette gudgeon pins. How much larger should the bronze bush be? Presumably the bushes should be a tight fit? I tried looking it up on the internet but I got baffled with too much technical stuff.

 

Here are some photos of my Humberette piston and the Ford piston I am going to modify.

 

2514.thumb.jpg.79e8e6c41e680671d674fe184a62b1f5.jpg

 

2515.thumb.jpg.d70e87f5837d7071f456a28cd9152133.jpg

 

2516.thumb.jpg.479eb655d29bdb7a541991df82fc63e7.jpg

 

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I would try for a .001 to .002 press fit in the piston. What is the diameter of the wrist pin? It is likely that an off-the-shelf bushing will be fine as they are usually made to be a tight press fit. You would just have to get an ID that can be machined to fit the Humberette pin. Look for oil holes in the for piston boss...these will have to be drilled after the bushing is in place unless the original Humberette piston did not have them.

 

I should have read your specs first... it looks like a 21mm OD bushing is .012 large. You'd have to take .010 off the OD. That would be doable in the lathe but you'll need a mandrel to hold the bushing. After the OD is machined it should be possible to hold the bushing in a 21mm collet to ream the inside. 5C collets don't compress much but .010 is within their range. You want a tight "push" fit on the wrist pin.

 

I don't know about using circlips...the ID of the clip will probably be larger than the diameter of the Humberette pin. I'd look into those teflon plugs that are used in racing pistons. I forget what they are called but you end up with floating wrist pins which minimizes the wear on them.

 

Another possibility would be to make new, larger pins and ream the bushing in the connecting rod. That would completely eliminate the wear and the larger pins would be better. Those original pins look mighty small to me.

 

A further edit....could you ream the hole in the piston to 21mm. That would allow the use of an off the shelf bushing...then the inside could be reamed to a standard size - like 15mm, the con rod reamed to match and new pins would be easy.

Edited by JV Puleo (see edit history)
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On 12/16/2019 at 8:07 AM, Mike Macartney said:

 

PISTON CALCULATIONS FOR HUMBERETTE ENGINE
             
  STANDARD ORIGINAL HUMBERETTE PISTON FORD ZETEC PISTON 24003 STD
  Measured Measured   Measured Measured  
  by Micrometer by Vernier Use for Calcs by Micrometer by Vernier Use for Calcs
  inches inches inches inches inches inches
Standard bore diameter is 84.25 mm (Ford 84.8 mm)     3.317 3.3386   3.339
Top of piston above top of gudgeon pin hole N/A 0.901 0.900 N/A 0.900 0.900
Gudgeon pin diameter 0.515 0.515 0.515   0.812 0.812
Half the diameter of the gudgeon pin     0.258     0.406
Therefore top of piston above gudgeon pin centre is:-     1.158     1.306
             
             
Height of piston top above top ring 0.138 0.142 0.140 0.294 0.288 0.290
Therefore height of top of top piston ring from gudgeon pin centre     1.018     1.016

 

Below are a few of photos of the pistons.

 

 

 

2515.thumb.jpg.d1417dbfbec2374e01f2fab7bbe5f164.jpg

 

 

 

So it looks like 1.306 - 1.158 = 0.148, or about 0.15 inches so the top of the Ford piston would be too high relative to the wrist pin. 3.76 mm.

 

So the TDC volume would be smaller by (pi/4) (84.7)(84.7) (3.76) in cubic millimeters = 21,181 mm cubed = 21 cc

 

Has it been decided this is close enough? Will the increase in compression ratio be modest?

 

Edited by mike6024 (see edit history)

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How is the pin, the OEM pin, held in position in the Ford piston? There is no provision for a circlip. Forgive my ignorance. I don't get it.

 

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On 12/16/2019 at 8:07 AM, Mike Macartney said:

The Ford piston will slightly increase the compression ratio as the extra height of 0.147" which equates to 6.71cc's.

 

 

can you show me how you got this? I came up with something very different.

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Joe, Are these the type of bushings you are recommending?

 

https://www.mcmaster.com/bronze-bushings

 

I have looked on UK sites and not found anything to suit the size of bushing I need. I also looked on the McMaster site above and still couldn't find anything the right size. The bushings need to be able to be made to fit a 13.1mm (0.516") gudgeon pin, which is the size of the Humberette pin. The OD of the bush has to be a press fit into the Ford piston gudgeon pin hole that is 20.63mm ( 0.812"). Yes, I could ream the gudgeon pin hole in the Ford piston to a larger diameter, but still I can't see any 'off the shelf' bushings that are a suitable size. I am happy to machine the bushings out of solid if I have to.

 

I will take a couple of photos to explain why I think the standard size Humberette gudgeon pin can't be enlarged by very much.

 

I am not sure about the 'Teflon piston wrist pin retainer buttons'. There would be a lot of gudgeon pin sticking out of the side of the Ford piston. I will post a photo later that should explain the situation. It is still early in the morning here and I have yet to face the cold weather and get up to the workshop.

 

Yet another chest infection has put me back a bit this week. The antibiotics and steroids have started working, felt a lot better yesterday, now at last I should be able to get up to the workshop again.

 

10 hours ago, mike6024 said:

How is the pin, the OEM pin, held in position in the Ford piston?

 

To answer your question I will have to see if I can find out. Thanks for pointing it out to me.

 

I have just looked it up and here is the answer:

 

Zetec rods are an interference fit with the gudgeon pin (the rod is made red hot so it expands over the gudgeon pin, when it cools off it clamps the gudgen pin extremly tight). The only way to seperate them is to press the pin out which will damage the piston.

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Hello Mike,  It looks as if you have a thoroughly thought out plan for your piston issue and the pin dilemma.  On another subject, could you take a picture of the front side of the Crestmobile chain drive rear axle.  I have a question that could be answered with a picture.

Al

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2 hours ago, alsfarms said:

On another subject, could you take a picture of the front side of the Crestmobile chain drive rear axle.

 

Al, you will be disappointed with the photos!

 

1375790873_Crestmobile07-05-2014a.thumb.jpg.ee8c5c799790fec351884955576b2c23.jpg

 

No chains - it's got a differential and shaft drive to the epicyclic gearbox that is bolted to the diff.

 

IMG_8031.thumb.JPG.a247ae0c96026d3f873093d4ddeef16c.JPG

 

Sorry I can't be of more help to you.

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Yes, it does sound as if making them from scratch is the best solution. I would turn the OD and ream the centers. You need a 33/64 reamer (.51562) or you might go up to 17/32 , make new pins and ream the connecting rods. You can get drill rod (silver steel) easily enough and that will do for the pins without any modification.  If the bushings are reamed in a collet the holes in the pistons are probably perfect so it is likely they will just press in and be fine without trying to ream them together although that would also be a good thing to do. To do it successfully you will need a "pilot reamer" but if you are working to a standard size that might be available.

Edited by JV Puleo (see edit history)
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Thank you so much for your advice Jo. It is very much appreciated.

 

These photos below may help explain the pistons and gudgeon pins a bit better:-

 

2519.thumb.jpg.d2f662d00753530a36bbe142d2da2068.jpg

 

The small end is quite small where the bushing is. The photo shows the Ford gudgeon pin sitting on the Humber small end bush.

 

2520.thumb.jpg.cef38b47d234f835547013397121b8e7.jpg

 

This maybe a better view.

 

2521.thumb.jpg.54096c6e391ac294174d855f9a78abed.jpg

 

This shows the difference in length of the gudgeon pins.

 

2522.thumb.jpg.df3a4664467e2a33f35e95235229187d.jpg

 

This is the Humber gudgeon pin sitting in the Ford piston.

 

2523.thumb.jpg.589af6b26c9726809b629a90f09b9948.jpg

 

This shows the amount of standard Humberette gudgeon pin sticking out of the side of the Ford piston. I think the Teflon buttons are out of the question with these pistons.

 

I will have a practise making a couple of trial bushes first to see what accuracy I can get. I was hoping not to change the gudgeon pin diameter from standard, but I could go up to 14mm, like I did with the other end of the smaller con rod. Using a pilot reamer would be good if I can find one at a reasonable price.

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The pins are interesting. It looks as if they were intended to float and had brass end to keep from scoring the bores. I don't see why you couldn't use those or make new ones to the same design. The only purpose of the teflon plugs is to prevent the pins digging grooves in the bore so anything you do to prevent that will accomplish the same thing.

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