The Instruction for an Ammco surfacing hone is to use copious Ammco oil.

The instructions for a Ritch brand rigid hone state to use kero for finishing, followed by oil and 8 parts kero to polish.

Cutting is most rapid with oscillation as reqd for the cross hatch and with copious liquid.

Another source for a rigid hone reommends viscosity of 7.5 mm mm/sec, however that relates.

Ring manufacturers state that the bores should be scrubbed with soap and water until a white rag stays clean

I had a set of Jowett liners rebored by a practioner who claimed to have a suitable jig. The result was .003 out of round. He said he would refund if I could do better. So I spent a few days adjusting my super crudely made Indian lathe and did a set. I got my money back.

Finished with the Ammco hone with oil in kerosene.

If filing nails is too tedious a primitive version of the telescopic gauge is not hard to make. Working to one meaurement standard reduces errors which can quite easily stack up to .001. Hence the value of the feeler test.

Location: Auckland, NZ

Hi Martin & Renaud

Thanks for the endorsement of my measuring method. Hope I am not being a bore but I have just completed my survey and have found the following:-

All cylinder bores 2.2285" +- 0.0005 i.e. newly bored with minimal ovality or barrelling.

Piston - Top dia at piston ring location - 2.218"
Skirt dia parallel with gudgeon pin - 2.223"
Skirt dia 90 deg to gudgeon pin - 2.228"

i.e the skirt has 5 thou ovality

With the piston in the bore, there is absolutely no rock at 90 deg to the gudgeon pin but rock due to the 5 thou clearance in the plane of the gudgeon pin.

My question is, should there be between 4 and 5 thou clearance between the piston skirt and the bore at 90 deg to the gudgeon pin? i.e do I hone out the bores by 4 to 5 thou to give this clearance? Also, honing out the bores will increase the ring gap to at least 15 thou ( 5 thou x 3.142). Existing ring gaps between 10 and 13 thou (as supplied with the pistons)

All urgent responses will be much appreciated as I wont start honing until this is clarified to my satisfaction.

Location: About 40 km SW of Limoges

Tony, suggest you read all the posts in detail from the beginning.

Can readily detect .0002 difference in bore size with telescopic gauge or fitted nails, but accurately transferring and establishing the absolute length is tricky.
Feeler clearance is the ultimate test (assuming thin)

The side clearance is important; the piston expands more in that direction, and there is no give. And it helps accommodates crank flexing.

I do not know the recommended clearance for split skirt supplied when new but probably not more than .0015 with a feeler. Even a true .0005 should not be very tight to hand crank

.005 is racing clearance for a solid skirt piston.

The pistons must oscillate freely on the gudgeon after it is clamped.

Location: Auckland, NZ

HI Tony,
If you have split skirt Pistons those Sizes are spot on
if solid will need an xtra .0015

Hope That Helps Colin

Location: TINOPAI NZ

So another weekend of dodgy engine building comes to an end.

Just to make things clear, this is typical of the quality of scrap that I'm working with..............



This particular engine has donated its pistons, which have cleaned up surprisingly well, and is going to provide a matched pair of timing gears.

I ordered a tub of Timesaver Lapping Compound, which arrived the following morning. I'm very impressed; it only took a few minutes to ease the very stiff big end, so I gave the others, which were still a bit lumpy, a light application, with very satisfactory results.



As I still had some mixed Timesaver - which isn't cheap! - I decided to lap the flywheel (from a sixth engine) to the crankshaft with it and cleaned up the taper very nicely.



I struggled a bit finding a serviceable set of correct main bearings. Most of them appeared to have been buried for several decades and were seized solid. normal attempts at cleaning failed miserably. I eventually resorted to holding the inner race in the lathe (1913 Drummond "B"), while holding the outer race with a bit of wood and flushing with paraffin and oil. Most of the muck went up the workshop wall, but it worked and the bearings now run smoothly.

Location: Herefordshire, with an "E" not a "T".

Brilliant!

Location: Wales

Wonderful.
Takes me back 50 years to poverty stricken times.

Location: Bristol

Great stuff Martin. Your posts have inspired me to buy even more A7 junk at a recent auction to mix with my own pile that has been festering under the bench in the hope of creating something that can rattle out a good few hundred miles!

Unless the goo was just dried preservative grease, I am not sure that the resurrected races will be a success.
I dunno about mains but in most other auto applications any roughness is apparent. All rolling race surfaces need to be perfect for smooth running.
Almost any clearance wear in the roller bearings leads to rumble.
Parts from slightly worn roller races can sometimes be mixed to achieve a very close clearance, but can be hard to assemble. The a.c races can be shimmed but overdoing threatens the lip.

Both with Austins and others it always troubles me the way so many parts are ruined by rust and corrosion. Once any bearing surface is corroded it is rendered largely unfit for serious mileage. Parts reusable by the patient are rendered useless. And rebores, regrinds etc are unnecessarily triggered. Parts need to be preserved in grease; oil soon dries off.

Love Martins lathe with useful apron platform. Can it be accurately dated? Straight out of my fathers 1920s Model Engineer mags. Was it originally round belt drive? From a treadle? I wonder how many modern equivalents with diecast and nylon gears, fancy belts etc will be around in 90 years. The oil can also a museum piece.

I like what appear to be copper vice clamps. A device unknown to most commercial “mechanics”. It is what old h.w. cyls are for.
In most of the commercial garage workshops I have been able to explore, not even sheet steel clamps are to be seen anywhere. Nearly every
Seven dynamo shaft sports vice marks on the bearing journals.

Location: Auckland, NZ

Hi Bob. I'm not sure what the gunge in the bearings was, but after removing it the balls, rollers and races all appear to be unmarked, so fingers crossed!

Of my £100 budget for the rebuild, £65 or so is earmarked for a new set of piston rings - I only managed to recover 5 out of 16 - so buying new bearings isn't an option.

The lathe is a Drummond B - direct grandparent of the Myford 7 still very popular with model engineers. We've found the serial number and it's an early one, first half of 1913 according to http://www.lathes.co.uk/drummond/page5.html . Amazingly, after 104 years it still has a full set of change wheels and other accessories. It's worn, but adequately accurate. At some point it's been motorised courtesy of a pre-war Berkel meat-slicing machine!

The oil can came from elsewhere, but cried out to go with the lathe.

The copper vice jaw covers were the first thing that I had to make when I started the practical side of my professional engineering training. My mentor, Mr Cornelius, was very old school and wouldn't allow anything important anywhere near a vice without them.

Location: Herefordshire, with an "E" not a "T".

Bob,

You can buy reproduction oil cans here ........

http://www.hetheringtonlamp.co.uk/oils-cans-pourers/

Jeff.

Location: Almost but not quite, the far North East of England

Thanks Martin

Now you have mastered the hone, with that platform on the lathe you will be all set for mass production rebores.The problem with lathe work is that it can be more intriguing than Sevens...and safer.

Location: Auckland, NZ

Location: Herefordshire, with an "E" not a "T".

If anyone gets reeeeeally stuck finding an Ali welder then I can do it. I'm down near Cardiff airport.
I've welded new lugs onto lots of A7 nose pieces.

No charge, other than postage etc.

Rob

HFH200 @ hotmail. co. uk

Many thanks for the offer, Rob.

Location: Herefordshire, with an "E" not a "T".

Progress on the engine rebuild has been slow recently, but anyone who follows our Facebook page https://www.facebook.com/Martin-Prior-and-Sons-Motor-Works-1473477006309584/?ref=bookmarks will know that we've had our hands full with a couple of customers' RPs.

Anyway, I now have to confess to embarrassing ignorance. I'm planning to do some serious assembly of the engine over the weekend, but I can't for the life of me remember which way round the rear main bearing oil thrower should be fitted. I'm not even certain that there IS one on either the RP or the PD.

Should it be set up as in the first photo, or the second?

Anything else that I should know?!





Thanks!

Location: Herefordshire, with an "E" not a "T".

It should be like the second photograph, remember though that it goes inside that cover plate, not outside

Martin,
Take the ali plate off and then fit the washer between rear main bearing inner race and flywheel boss. The way round is as in bottom photo. Make sure that the oil thrower has a bit of a dish in it at its internal bore so that this dish is compressed between bearing inner race and flywheel boss as you tighten up the flywheel nut. Just get your ball pein hammer and tap out the dish shape on an old bearing of suitable bore size. The idea is that the thrower rotates with the crank and chucks the oil out and down the hole in crankcase and steel rear main bearing cartridge back into sump. So make sure the holes line up. I am doing the same job at the moment but getting frusrated because I can't find the front bearing retainer washer I removed 3 days ago.
Dave.

Location: Sheffield

Thanks, gents! All very clear, simple and logical.

A combination of the '33 Parts list and Mr Woodrow had conspired to confuse me!

Location: Herefordshire, with an "E" not a "T".

Hi Martin,

Sorry I'm a bit late to the party, I've been attempting to retire, whjich is proving a challenge as people don't want me to pack up, so I'm still doing the work, but with the staff I had!

I thought I'd share with you the fact (which sounds like an urban, or in my case rural myth) as the block really did come out from under a hedge in the village, that one of the best engines I ever had benefiited from rusted and badly pitted bores that after honing the pits seemed to hold a bit of oil, it never smoked and went like a train.

Good luck mate that engine will be a winner, even though it'll probably sound like a Maxwell House tin full of bolts!

Location: Near Bicester, Oxfordshire

Thanks for the encouragement, Ivor.

Having sorted out the rear main arrangements, this afternoon's frustration has been the discovery that the camshaft gear pulls tight against the face of the bronze bearing on what is probably the last half-turn of the nut.

This is far and away the best pair of gears that I have, so I guess that my only option is to fractionally ease the back face of the hub - unless anyone has a better idea.

Retirement? Ah, there's a nice thought. Some of my contemporaries have reached that point. My current estimate - honestly - is that I'll have to keep going for at least another 30 years. I'll only be 89 by then!

Location: Herefordshire, with an "E" not a "T".

Hi Martin,

Just a quick point, and hope it helps.

The rear oil thrower is one of the most important parts of the engine.

Its good to get it the correct way round.

But more important is what it's there for.

The thrower traps between the bearing and the flywheel.

If it traps to soon the flywheel will come look in use.

If it doesn't trap then the rear bearing will be free to spin on the rear main.

Which is why so many cranks are undersize on the rear main bearing.

Lap your flywheel in carefully. And get the interfearance correct.

Tony.

Location: Huncote on the pig

The original fit tolerance is very small. The blueprint which appeared in post Crankshaft a year ago shows 0 to + .00025. According info kindly provided by Tony Press, in 1964 tolerance for a standard bearing was -.0003 to +.0002, so some bearings may never have been tight (except due unmounted out of round). Currently 0 to - .0004.

Many cranks have had bearings fitted many times. In my car at least 7. As I have encountered with other makes, lazy “mechanics” may have eased the shaft slightly to simplify assembly/disassembly.

And with an easy fit it only takes a metal chip to briefly lodge sometime down the ages to trigger spinning.

The few throwers I have seen were plain. Needed stretching slightly to grip shaft. A thin neoprene washer/gasket could be inserted.

As a matter of interest, what is exact finished dia of Phoenix journals? Are they reground after nitriding? Or just polished?

And on a different tack, the groove in thrust surface of timing gear is the main oil supply to the timing gears.

Location: Auckland, NZ

Thanks, everyone, for the advice and suggestions.

The rear main situation is now sorted.

After much thought, I decided to turn about 0.004" off the back of the camshaft gear hub and that now has a couple of thou clearance from the bearing face.

Unfortunately, in playing around with this, I let the rollers from the camshaft centre bearing drop out. Fitting the little sods was bad enough with the camshaft out of the engine, but with it in, it's proving almost impossible. Any helpful suggestions?

Location: Herefordshire, with an "E" not a "T".

It's one of the great pleasures of Austin seven engine building.
Copious quantities of grease might stick them in. Or, you could find an old outer race, cut in in half and use that. Tied together with a bit of wire it will retain the rollers and push out of the way as the cam is fitted.

Martin. You'll have to take it out again.

Cam and grease in the freezer. Stick the rollers on with the cold grease then put an elastic band round them. Then refit

Location: not north wales any more

Quite a few people have asked me about progress on the rebuild of the scrap-bin engine.

Paying work has taken up most of my "spare time" recently, but we've made some progress. The main engine assembly has been completed; it turns over on the starter and has pretty reasonable compression.

The moment of truth is almost here. If I can arrange a quiet weekend, I shall sort out and fit a set of serviceable ancillaries and then.........?????

Location: Herefordshire, with an "E" not a "T".

Hi Martin

I see the new engine has solid engine mounts. Is this as the rest of your fleet?
Some claim notably more harsh although I found with thin rubber washers added, much the same.
A problem is that any mods raise the engine relative to the radiator.

Location: Auckland, NZ

Hi Bob.

I specifically wanted to build an early '33 engine and actually swapped a rubber-mounted crankcase for this one.

I have to admit that the rubber-mounted variety is more user-friendly. Years ago, I made the mistake of improvising this on my solid-mounted RP, only to find that the engine had almost completely detached itself from the chassis half-way up the motorway between Worcester and Birmingham!

Location: Herefordshire, with an "E" not a "T".

The Frankenstein engine lives!

We finally got everything together this afternoon and attempted a start.

We hoped to record a few pops and splutters. What actually happened was not quite what we expected!

Unfortunately, I have no idea how to upload a video to the Forum, but it can be seen on our Facebook page, Martin Prior and Son's Motor Works.

Location: Herefordshire, with an "E" not a "T".

This should work for the video Martin...


https://www.facebook.com/1473477006309584/videos/1873511362972811/

Great stuff ! See Video/Facebook for more extensive comment.

Location: Ferring, Worthing, West Sussex

Location: Herefordshire, with an "E" not a "T".

well considering that has no exhaust yet, that's pretty darn good, isn't it?!

Location: NZ

The Frankenstein engine is now running very nicely, smoothly and with good compression.

The issue I'm having is very low (even by A7 standards)oil pressure. The pump is just about lifting oil into the gallery, but that's about it. I'm getting possibly 1/2psi cold.

With the oil pressure gauge pipe disconnected, a pathetic dribble weeps out.

Before I launch into major dismantling, what might I have missed?

Location: Herefordshire, with an "E" not a "T".

Hi Martin, if you have cut your own gasget for the pump to c/case joint.....did you punch out the hole for the oil gallery as well as the obvious one for the two bolts, easy to miss, but hope you haven't ! I,m sure you have put the vanes in the correct way round with chamfer at the top. If you have fitted new vanes did you carefully check they didn't stick when pushed right in? I had this a few months ago and on checking found one of the vanes was .007 tapered this was enough for it to stick in on a complete revolution. IanM

Thanks, Ian and Charles.

I think that I can rule out the gasket, which definitely had enough holes. The dribble of oil would seem to confirm this.

The vanes COULD be the wrong way up. I was interrupted just as I was about to insert them last Saturday and I may have lost track of what I was doing. I'd have thought that even if they are incorrectly fitted there'd be a bit more pressure with a cold engine...........or maybe not?

I was hoping that someone might suggest the pressure relief valve! During the same interruption I mislaid my carefully-cleaned ball and spring and quickly grabbed a set from another junk engine. By then, I was in a hurry and may well not have checked and cleaned them very thoroughly. I think that's where I'll start.

Location: Herefordshire, with an "E" not a "T".

Similar issue recently turned out to be an early rear camshaft bearing in a late crankcase - all pressure lost past the 1/8" gap...

Engine had run like that for many years apparently.

Thanks, Ruairidh. I think I'm probably OK on that one. Presumably there's a different part number. Where would the 1/8" gap be?

Location: Herefordshire, with an "E" not a "T".

The difference is the external diameter of the bush, a hard one to spot if installed as the outwardly they are identical.

Another recent problem was the oil gallery behind the pressure relief valve totally blocked with gunge.

Only worth considering the above if you are certain the pressure relief ball is seated correctly and pump vanes installed corrrectly.

Thanks, Ruairidh.

I should be OK on the rear camshaft bearing. That came out of a '34 engine (with some difficulty) and was a nice snug fit going into the current crankcase.

The crankcase had been pretty thoroughly cleaned and all of the oil passages appeared to be clear.

As soon as customers permit, I'll take a look at the relief valve. Hopefully, that'll be where the problem lies. I certainly hope so, as the sump is now well sealed to the crankcase and completely leak free. I really don't want to have to take it off again!

Location: Herefordshire, with an "E" not a "T".

The gauge is ok?

I have never had an air bubble in the pipe to the gauge but I suppose it could happen....

Simon

Location: On a hill in Wiltshire

Thanks, Simon. The gauge is an unknown. I'd primed the gallery and the gauge pipe with oil before starting the engine to minimise the risk of air locks. Because I wasn't getting a reading, I disconnected the pipe at the engine, and almost nothing came out, so it definitely looks like a lack of circulation.

Location: Herefordshire, with an "E" not a "T".

We have oil pressure!

I checked the relief valve, but no joy there.

Off with the sump and the oil pump base and was greeted with the sight of a lovely pair of chamfered vanes. Bugger. Turned them round, put the whole lot together and immediately clocked at least 10psi.

What an idiot.

The interruption that led to this cock-up was a scam phone call from some overseas crook improbably calling himself "William". I am happy to say that I was quite spectacularly rude to him.

Location: Herefordshire, with an "E" not a "T".

Well done Martin, I suppose it warrants a trip to the pub for a well earned pint.