What to check/prep on an unknown engine ?

[JohnD]

Egret,

The "Christmas Tree" on the gearbox drain plug magnet may not be as bad as it looks. It's the magnet that forms all those fierce spikes - wash it in engine cleaner to remove the oil, and wipe some off on your fingers.  You'll probably find that  away from  the magnet they are the finest metal dust you could imagine!     But the quantity, and the loose tooth indicate a fairly well worn gearbox.   If you're rebuilding the engine, get an estimate for a 'box rebuild  (I'm not brave enough to DiY!) while you do the first.

John

[Nick Jones]

4 hours ago, egret said:

Also a bit of a christmas tree on the magnetic transmission sump plug and a syncro tooth in the oil that came out.  I'm hoping this will be fine as it worked acceptibly before, so with new oil it shouldn't be any worse, maybe even a little better.

Picture looks fairly typical. As John suggests rubbing it carefully between fingers (splinters/shards!) will likely show it all to be very fine. This being the case you can call it general west rather than gross damage. Finding synchro baulk ring teeth (brassy colour?) is a first for me but as you say, if it worked before it’ll likely work again and even appreciate fresh oil!

5 hours ago, egret said:

The clutch release bearing pin (that the alloy fork rotates on) is missing, that's on order, but this likely prevents the new years day target being hit.

Assuming you mean the pin that provides the pivot between bell housing and fork, they do frequently fall out. Surprisingly the clutch quite often carries on working after a fashion. There is supposed to be a spring clippy grippy thing inside the fork that holds it but gravity usually wins in the end. Don’t fit the new pin without a new clip, you’ll just loose it. Better yet, buy a long bolt (5/16” UNF, though M8 likely fine too and easier/cheaper) with an unthreaded shank long enough to pass right through the bell housing, then it can’t fall out and you can put a nyloc nut on the bottom to stop it climbing out too.  You may need to reduce the head size a bit (even if you buy a cap-head) so it will still turn in the bell housing as needed.

[Escadrille Ecosse]

Certainly been busy.

Reminder to me to get my finger out on my Spitfire.

Given the atrocious quality of the cheaper replacements and eyewatering price of the better ones I created a mould and made my own from fibreglass.

Took the opportunity to get rid of the redundant tray carried over from the Herald/Vitesse which makes it a far easier job to fit insert under the dash. Lined with heat reflecting foil rather than the bulky glass wool bag which helps air circulation round the box.

[Mark]

Very nice !

[egret]

More progress, Moss managed next day delivery!  So gearbox is back together, cylinder head assembled, engine is on the workbench. I've taken the timing cover, chain, front plate, and bridge off, I think everything is dismantled as much as it needs be other than the rear oil seal.

I realised that the clutch which came with the mk3 has different splines to the gearbox, so I'll be reusing that assuming it's ok.

My extremely festidious machine shop (dad) is operating much quicker than usual as I've been updating him on progress so he's getting on with the aluminium spacer for the trigger wheel.

Photos:

Oil gallery, looks clear and clean to me

Old 1500 head on left, new head on right

Inlet valve with a bit of work on the back face.

Exhaust valve as new then with first pass of a stone on the back.

First cut of the Ali backplate (making a trepanning(sp?) tool was the intention, but I worked faster than expected)

Ali in the lathe getting a cut to match the pulley shoulder.

Edited December 29, 2023 by egret

[JumpingFrog]

For the clutch, the 1500 single rail clutch can be used but it's bigger and uses a heavier flywheel which IMO isn't really suited to a small-crank 1300.

You need to find a Toledo 1300 or Marina 1300 fine-spined 6.5" friction plate. The cover is the same as for the coarse spline clutch plate. It was fitted to both these cars for only a few years so they aren't common.

Original part number was GCP244. I'll admit that I've hoarded a few of these for my own cars over the last few years, usually when they come up on eBay for not much money.

These are basically the parts you want, another seller has a compatible Laycock friction plate listed, but I've personally not had great success mixing Laycock and Borg & Beck clutch parts.

https://www.ebay.co.uk/itm/155237548033

There is apparently a company reproducing them, I've not tried myself and they are considerably more expensive than NOS, but I guess at least don't contain asbestos:

https://www.ebay.co.uk/itm/122810443314

 

[Escadrille Ecosse]

Or our 'friends' at Rimmers. But they want £96 plus a £50 exchange surcharge.

https://rimmerbros.com/Item--i-GCP244

The 1500 spitfire clutch is an oddball unfortunately. But other alternative is to redrill your existing 1300 flywheel for a 'normal' 7 1/4" diameter clutch fitted to the Ford Escort, etc. which has the correct fine spline. Readily available and more suited to a breathed on 1300 than the 6 1/2".

[egret]

Penny has dropped on another issue. The bronze bushing in the end of the crankshaft is smaller in the 1300 than in the 1500. I assume the 1300 originally had a 3 rail box with a smaller input shaft,  simple measurements seem to imply the 1500 (single rail box) is 15mm diameter and the 1300 (3rail box) is around 12.5mm. Does anyone have tricks to remove these bushes? Dad's keen on the idea of making a puller, but I've not attempted to remove them yet, so will try the grease and drift trick in case they aren't in that tight

[Escadrille Ecosse]

I've always managed to get them out using an appropriately sized digit from my collection of ten encased in a Marigold glove. With maybe a bit of penetrating oil first to help soften up any dried gunk. Worth a try first.

With the original RV8 rebuild the bush was a bit reluctant but a wall anchor did the trick to grip it and then just levered it out.

[Nick Jones]

Wet bogroll or wet bread works as well as grease and is an easier clean up. They aren’t usually very tight. 
 

Don’t remember having that particular problem though - and I did stick a Dolly 1500 OD box in my Herald initially onto the original 1200. There were many unintended consequences but that wasn’t one of them….

[egret]

Nick, your recollection is correct! I've spred disinformation on the internet, sorry!

 

Both bushes are, in fact, identical. I'm not sure where I got the idea that my clutch allignment tool fitted into the 1500.  To be completely clear, both driveshafts are the same diameter.

What is different is that the bolts holding the 1500 flywheel in place are larger diameter and length.  So I'm waiting for dad to make some tophats to allow the 1300 crankshaft bolts in the 1500 flywheel. These will centre the bolts and provide washer area to make sure the bolts clamp effectively. I think I'll lose 1 thread in 16 engaged threads and the torque is less than I'd expected at 46lb/ft so I dont think it needs longer bolts.  I'll torque up with care and see how it feels though.

Other bits of info:

A drift and some hot glue got the bushes out without any difficulty.  The hot glue got in behind the bush and stuck to the drift allowing it to pull out very easily.

The 1500 clutch is a larger diameter than the 1300 so you can't just swap friction plates.

Both flywheels are about the same at 6kg.  Doesn't look like the inertia will be that much different either.  But as said above, the clutch is a good bit bigger so probably does add some inertia to the assembled thing.

1500 is the one with the shiny friction surface, on the left.

[rogerguzzi]

Hello 

         I am not sure I would fit the smaller bolts to the heavier flywheel ?

Plus if I did use top hat bushes I would make them a press fit into the flywheel

Plus I machined my flywheel all over to remove all casting marks and the balance was near perfect when check at the balancing works and maybe 500grams lighter (i can not remember may have written down ?)

Roger

[Nick Jones]

I used the 1500 flywheel on my 1200 and made spacers (not top-hat) out of some random (but very conveniently sized) tube found in the garage. Can’t say I liked the method but it worked and nothing bad happened. I note that at least a couple of the usual suspects sell spacers for this purpose!
 

My conversion was done in a rush in a somewhat unplanned manner, in someone else’s garage, over a weekend, having been forced by a clutch failure. It was my only car at the time. There were many challenges to be overcome (some of them in a less than ideal way) and the lasting memory was that the overdrive was initially utterly unusable as the propshaft was so far out of balance it was impossible to exceed 40mph without car and driver being shaken apart. This made the 200 mile maiden voyage back to London something of an ordeal.

[egret]

I'm keeping bolts matched to the holes in the end of the crankshaft, so using the 1500 flywheel leaves them a rattling fit in the holes in the flywheel. I'm hoping that the stud and flywheel recess will locate them accurately. The inserts I'm having made will be there to prevent the bolts bending and to give a larger clamping area. I'm assuming (hoping) the balance of the clutch, and the engine are done separately, so the balance should not be out.  I'll report back on how this pans out.

There is a rebuild in the future (bottom ends balance), so resolving these issues properly will be part of that work.  It seems like the larger clutch diameter seems like a good tradeoff for longevity vs the added inertia, but I've nothing to back that up beyond a wild guess, so I'll happily hear opinions on this!)

[Escadrille Ecosse]

1 hour ago, egret said:

I'm keeping bolts matched to the holes in the end of the crankshaft, so using the 1500 flywheel leaves them a rattling fit in the holes in the flywheel.

That's what Nick and Roger's were alluding to.

Rimmer Bros (yeah I know) do a kit of bolts and sleeves to allow the 1500 flywheel to go onto the 1300 crank. Unusually they are not taking the mick with the price.

https://rimmerbros.com/Item--i-RL1512

1 hour ago, egret said:

The inserts I'm having made will be there to prevent the bolts bending and to give a larger clamping area

The sleeves/inserts aren't attached to the flywheel and won't improve the clamping on it.

1 hour ago, egret said:

I'm assuming (hoping) the balance of the clutch, and the engine are done separately, so the balance should not be out.  I'll report back on how this pans out.

That'll work out fine.

Regards the way forward with the flywheel clutch there are basically three options here

1. Fit the 1500 flywheel with the sleeves and stick with the potted 1500 clutch. This has an oddball shallow clutch cover that sits on the raised ring on the flywheel and only fitted to the 1500 Triumph engines. So no commonality with other 7 1/4" clutches which means longer term greater cost.

2. Fit the 1300 flywheel and get the better bolting and get a standard 6 1/2" cover and small spline friction plate.

3. Drill the 1300 flywheel to take a universal 7 1/4" clutch which comes with the right 7/8" 20 spline centre and is compatible with the Spitfire release bearing.

In my view taking everything into account (especially given your plans for the engine and car) long term option 3 is the best and option 1 is 'least best'.

It's what I would and did do for my car. Even paying a machine shop to redrill the flywheel it works out cheaper because the clutch is not Triumph specific so you have a lot more options with suppliers.

[egret]

Thanks for all the excellent advice.

To clarify my plans, the top hats should act as spacers with integral washers (i.e. they won't be the full depth of the flywheel holes). I'll lose some threads, but the without the washer parts the bolts will only bear on flywheel at the points of the hex's. 

Given my brief is to get the car back on the road I think I'll keep the plan as is, but I'll look to get the 1300 flywheel machined to accept a more generic 7 1/4" clutch as you suggest. I'll swap this in when I pull it all to bits again to get the bottom end balanced nicely.

A 7 1/4" clutch looks close to the original mounting holes though on the 1300 flywheel. Did yours look like this when you did it? The image below isn't great, as it doesn't quite overlap the holes, but it's really close.

Edited January 1, 2024 by egret

[Nick Jones]

With the top hat solution you propose (which has its plus points), be aware that the spacer material needs to be hard enough not to deform under the clamping pressure of the torqued up bolt and subsequent heating/cooling cycles and other external forces as that will effectively loosen the bolts and reduce the clamping force/friction between flywheel and crank which is the main way that torque is transmitted.  Anyone who has suffered HGF after using shiny new, but soft, washers under their cylinder head nuts will be familiar with this disappointment.

Edit: there is a 4th solution to add to Colin’s list, which is to redrill and tap the 4 holes in the crank to the larger size.  This is a machine shop job and given that the engine is already assembled, not likely your favourite option…..

[rogerguzzi]

With the top hat solution you propose (which has its plus points), be aware that the spacer material needs to be hard enough not to deform under the clamping pressure of the torqued up bolt and subsequent heating/cooling cycles and other external forces as that will effectively loosen the bolts and reduce the clamping force/friction between flywheel and crank which is the main way that torque is transmitted.  Anyone who has suffered HGF after using shiny new, but soft, washers under their cylinder head nuts will be familiar with this disappointment.

I agree with Nick they must but a Good Grade Steel and I would still make them a press fit 

Perhaps use a large High Tensile bolt for the Steel? (10.5/12.9 or what ever the numbers are!)

Roger

[egret]

That's a really good point about deformation of washers, thank you. With that in mind I've just had a chat with the lathe operator and given that the rimmers kit doesn't seem to use longer, or larger headed bolts, we've decided to forgo the washers and just go with tubular inserts. These will support the bolts and keep them from deflecting when tightening up.

Option 4 had crossed my mind and you are correct, I'm not all that keen to take it all apart again. Also our seems like a bit of amutilation to a fairly rare part.  I feel like replacement flywheels can be made more easily than crankshafts, so machining a flywheel feels less damaging to triumph heritage than machining a crankshaft.

[Escadrille Ecosse]

Good stuff and fair enough given where you are.

Fitting the larger clutch on the 1300 flywheel is fine. The friction plate basically misses the bolt holes. Having said that the shop that did mine filled the redundant holes with staked inserts and gave the whole thing a light skim to clean off the wear and corrosion.

You can also remove a little weight from the back of the flywheel to lighten it. Concetrate on the outside but make sure you leave enough of a land for the ring gear.

Looking forward to seeing this thing run again

[JumpingFrog]

I think the ultimate solution is both the larger clutch on a 1300 flywheel with the crank and flywheel enlarged for 7/16 bolts. But in your current situation probably the 1500 flywheel with inserts is good enough for now.

The original 3/8 bolts are a known weakness and it's not unheard of for them to come loose. I don't think it's much of a mutilation to the crank, certainly I plan to do this to my engine...

Off topic, but interested to know if there are any potential clearance issues with a larger clutch and earlier bell housings? Although I know op has a single rail so shouldn't have issues.

Edited January 1, 2024 by JumpingFrog

[Mark]

Did have a lightened flywheel come loose on a tuned 1500 Spit engine whilst on a rolling road (Original flywheel machined down) over revved by the operator, another story. Makes a horrible noise. Fortunatly no real damage. Had an extra dale fitted in the end of the crank, new bolts & locktite. Balanced 1500 engine, rev limiter set at 6500 took it there fairly regularly on the track, no other issues in my ownership.

[JohnD]

I've no knowledge of this mod, or its consequences.   But I was at Mallory Park when a non-Triumph's flywheel let loose as it went under the foot bridge over the start/finish straight.

HALF the flywheel ended embedded in the underside of the foot bridge!  I have a photo somewhere.

A flywheel at speed has enormous energy.  

John

[Escadrille Ecosse]

Lots of energy in a flywheel. Although a complete car has even more.

Overrevving (whatever the definition is of that) CAN be a bad thing. But flywheel failures are a lot less common that a lot of other more serious failures, which are in themselves less common than no significant failure at all.

Man bites dog...

The phrase man bites dog is a shortened version of an aphorosm in journalism that describes how an unusual, infrequent event (such as a man biting a dog) is more likely to be reported as news than an ordinary, everyday occurrence with similar consequences, such as a dog biting a man.

The phrase is attributed to Viscount Northcliffe (and a few others), a British newspaper magnate "When a dog bites a man, that is not news, because it happens so often. But if a man bites a dog, that is news.

The result is that rarer events more often appear as news stories, while more common events appear less often, thus distorting the perceptions of news consumers of what constitutes normal rates of occurrence.

The phenomenon is also described in the journalistic saying, "You never read about a plane that did not crash."

Diversion over...

None of the mods proposed are in themselves dangerous. 1300 small cranks Triumph engines are very good.

A 1300 small crank engine is very much not the same as a 1500 crank engine in terms of dynamic response at elevated RPM and the effect of a lightened flywheel on that response. Or indeed a non-specific non-Triumph engine in the heat of a full on race.

Check the stuff is in good condition and do things up properly. And Loctite won't hurt. They'll be fine. Just as Mark says.

 

 

[egret]

The flywheel has a races which locates on the crankshaft, rotational orientation is set with a dowel pin, so the bolts are there to keep is all together and provide the friction to resist the torque rotation from engine power and rpm changes.

I'm happy what I'm doing will be ok for now, it'll have a very careful assembly, some loctite, and proper torque.

This leaves the 1300 flywheel ready for some machining as/when I have the money and when I take the engine out again to balance the bottom end. Given some of the points here I might even get the crank machined for larger bolts too.