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Chris's Mkiv Basket Case restored to glory


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15 hours ago, mpbarrett said:

Can you see what the slave cylinder and actuator are doing?

Nope. It’s a concentric slave cylinder in the bell housing. No portholes…. I did suggest taking a (careful) holesaw to it. Wasn’t entirely joking!

Engine is a fresh build. We did check that there is still some endfloat ie input shaft not bottomed out and leaning on it, and there is a just a little float - as there should be.

Getting it running so easily was boost, especially once the cooling system seems good and it’s running very nicely once ITBs balanced up. 

Not being able to drive it and start the mapping process is frustrating though. Reckon this by one might need a RR session to do the top end though  - going to be rapid I think.

 

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Yes, real pain. Cheap endoscope connected to mobile phone/tablet are useful. You may be able to poke it into the bell housing and have a look. The one I have is the diameter of a pencil.

Edited by Mark
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12 hours ago, Nick Jones said:

Yep, maybe be worth trying to twiddle the prop. Pretty sure you won’t be doing by hand though…..

Fear the box will have come out. It went in on the engine, so we don’t actually know if it can come out backwards. May actually be easier to pull the lot…..

Different box I know but it is possible to turn the box by hand in gear on the clutch on my Spitfire.

It's a long box so getting it out backwards may be tricky. At least if you do have to take the whole lot out together it will make checking the clutch easier I suppose 

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All pulled out again…. At least two issues. 
 

Firstly the spigot bearing is unhappy. This damage has occurred in less than 60 seconds of fairly low-speed running (when started in gear). Apparently it was assembled as an interference fit in the crank but running fit on input shaft. It’s possible the bore closed up when fitted to the crank. Certainly it picked up on the input shaft and spun it in the crank.

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Also….. the friction plate is a bit thick for the pressure plate and the whole lot was being over-stroked due the larger m/c….

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Backside of diaphragm fingers did that. Didn’t hear anything!

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The spigot bush is the worry. Looks like the rest is fixable with a slightly different parts combination.

Don't understand how the spigot bush got so bad so fast. Implies misalignment but all other measures seem ok….:huh:

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17 minutes ago, Nick Jones said:

The spigot bush is the worry. Looks like the rest is fixable with a slightly different parts combination.

Don't understand how the spigot bush got so bad so fast. Implies misalignment but all other measures seem ok….:huh:

My suspicion with the spigot bush would be radial misalignment rather than angular given your epic milling efforts. Wouldn't take much. Pondering how you would check that as we're not talking much in the way of offset.

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23 hours ago, Escadrille Ecosse said:

Oh.... sub optimal :sad:

Sub-optimal indeed!

I suppose to test the 'spigot closing up' theory you could whip the flywheel off, press the spigot into it and see if it still has a running fit on the input shaft when loose. If it's tight to fit on there then perhaps that's your issue. Or is the input shaft nose too chewed up to confidently tell you anything?

Also, apropos of nothing gearbox-related, but I was doing a bit of research on wheel fitment and a post of yours from a while back came up. Does Chris' car have the old Formula Ford 5.5J steels on the back and the late 1500 5Js on the front? I've bought a set of split rim centres I plan on using with custom barrels to get a lightweight set of 6Js on my car with 185 or 195 tyres, and was wondering about fitment. Lots of posts online saying that X or Y wheel/tyre rubs, but neglect to mention whether it rubs on the outside or inside! Were the 5Js necessary on the front for outside arch or inside arch clearance?

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12 minutes ago, BiTurbo228 said:

Also, apropos of nothing gearbox-related, but I was doing a bit of research on wheel fitment and a post of yours from a while back came up. Does Chris' car have the old Formula Ford 5.5J steels on the back and the late 1500 5Js on the front? I've bought a set of split rim centres I plan on using with custom barrels to get a lightweight set of 6Js on my car with 185 or 195 tyres, and was wondering about fitment. Lots of posts online saying that X or Y wheel/tyre rubs, but neglect to mention whether it rubs on the outside or inside! Were the 5Js necessary on the front for outside arch or inside arch clearance?

Personally I like the steel 5.5Js. Back in the day they were still fairly easy to get hold of and were a lot cheaper than alloys. Also remakably tough/ fixable. And in my opinion they look good and suit the cars.  I am fortunate in having eleven of them (one did get totalled in a racing incident) and a set of 5Js as well.

My experience.

Steel 5.5J with 185/60s fit OK at the back of the Mk4/1500 Spitfire with the longer halfshafts, and with std rotoflex setup.

With the earlier cars they can rub on the flange of the arch with the long halfshafts unless the flanges are turned up. Can be a bit tight with rotoflex too. OK with the short halfshafts though.

5.5J with 185/60s fit at the front although they do extend a little beyond the arches at static height. Full bounce the tyre wall can touch the flange of the arch, especially on the earlier bonnets which all seem to have a wider flange. Under certain extreme loads, ie full opposite lock and bump some very square tyres can kiss the bulkhead. 185/55s are OK in this situation.

190s can contact the bulkhead at full lock, static ride height. Never tried the 190s at the back but I suspect that with certain offsets the tyre could contact on the inside or outside edge.

Not had issues with the steel 5.5J with 185/60s on the inside front or back. Nor with 185/55s.

But given the clearances with the steel 5.5s you would want to check with the inner diameter of alloys around the rotoflex uprights/dampers and front discs especially if going wider.

There are 6" wheels out there in 13 and 14 inch diameters. But from memory of discussions on these wider and/or larger dia wheels (we're going back many years now) I think that these didn't allow tyre widths any larger than 185 and offsets are critical.

Better memories/experience invited.

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14 hours ago, BiTurbo228 said:

Does Chris' car have the old Formula Ford 5.5J steels on the back and the late 1500 5Js on the front?

Yes. As does my GT6. This works due to the roto rear end having something like 2” (!) less track than the front wheels. This madness means that the early narrow track square-tail cars look, frankly, ridiculous on the original 4.5”/155 combo. It also means that it is really hard to come up with a single wheel/tyre combo that fills the arch at the back without catching at the front. Hence the “stagger”. Though not a true stagger as the same 175/70 tyres are used all round. There are also 6mm spacers at the back. 

These particular 5.5” wheels don’t fit at the front. Too much offset. Worse than the 6” 100+ cross-spokes (currently on mower!!) which do nearly fit.

IIRC the 5.5” wheels come in at least two offsets. The factory option ones, which is presumably less to fit at the front (I had a set on my Herald for a while, could have used more poke at the back) and the formula Ford ones, which I suspect are what I have now.

Mine came from a fella who bought a set of 5 (one neither round nor straight), had them all (badly) powder coated and was then surprised when they didn’t fit his Dolomite! 

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Thanks folks, exactly the sort of info I needed.

I've found elsewhere that the stock 4.5J and 5Js have ET22 (0.88" to be precise), with the two varieties of Formula Ford wheels being ET16 and ET9.5 (3/8"). I'm assuming it's the 3/8" offset ones you have Nick as they were so wildly out at the front, and the 16mm ones you have Colin as they seemed to just about fit (though I note you seem to be running slightly smaller rolling circumference tyres, which would help with clearance a little). I think there's stampings on the face of them which should make it obvious.

Judging by that, ET28 on the front and ET7 on the rear should be somewhere around right. Now I just need to work out just which bit they measure the distances from on split rim barrels as there's a potential 12mm error if they do something weird!

Anyway, enough distractions from your gearbox woes, helpful though it may be ;) 

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On 8/27/2024 at 3:32 PM, BiTurbo228 said:

Thanks folks, exactly the sort of info I needed.

I've found elsewhere that the stock 4.5J and 5Js have ET22 (0.88" to be precise), with the two varieties of Formula Ford wheels being ET16 and ET9.5 (3/8"). I'm assuming it's the 3/8" offset ones you have Nick as they were so wildly out at the front, and the 16mm ones you have Colin as they seemed to just about fit (though I note you seem to be running slightly smaller rolling circumference tyres, which would help with clearance a little). I think there's stampings on the face of them which should make it obvious.

Judging by that, ET28 on the front and ET7 on the rear should be somewhere around right. Now I just need to work out just which bit they measure the distances from on split rim barrels as there's a potential 12mm error if they do something weird!

Anyway, enough distractions from your gearbox woes, helpful though it may be ;) 

Tidying up in the garage after (yet more) fibreglassing and thought I'd have a look at the wheels. Turns out I have more 5.5s than I thought and the 5s are away (remember flogging them now).

Anyhow. All my 5.5s are ET16 which makes sense as 175/70 foul the bulkhead. And there isn't space for 195/60 even if I wanted them which I don't as they are a bit too wide for the 5.5" rims

Regards tyres, width/aspect ratio is important and I would recommend to do some checks before dropping serious wedge on split rims. There really isn't too much space around the front

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  • 2 weeks later...
  • 4 weeks later...

It is. It’s actually been ready for trial for a little while but it’s exit was blocked by a non-functioning Skoda….

As well as sorting the clutch (we hope!) he’s also tweaked the gear selection mech which now feels spot on.

Apparently auto-tune was not working it’s usual magic so now we have to work out why…..

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