Classic cars forum & vehicle restoration.

Rdover · Joined: 26 Nov 2007 Posts: 413

The last bits arrived yesterday and a couple of hours in the garage paid dividends.

The engine has now been repainted, the gaskets all made to fit, the inlet manifold polished and the flange sleeve smoothed out and everything is ready to fit and test which I hope will happen this evening. The copper washers are a perfect fit so I'm confident compression will be as good as it can get.

I can heartily recommend Dobson Gaskets ....

Photo of the engine, painted, with valve caps and gaskets all in place

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Richard

kevin2306 · Posted: Wed Apr 23, 2014 4:50 pm Post subject:

Looking great, cant wait for the first fire up!

kev

Rdover · Joined: 26 Nov 2007 Posts: 413

kevin2306 · Posted: Wed Apr 23, 2014 7:32 pm Post subject:

Rdover · Joined: 26 Nov 2007 Posts: 413

Sometimes knowing the problem is a relief.

After weeks of fettling and fixing and changing and testing the car is not a jot better than it was, in fact it is worse. Hamish (VCC guru) came round again to assist and we double checked:

ignition timing and points - all okay
fuel delivery and carburation - again okay
compression - absolutely fine
valve timing - changed from 10d atdc to tdc and it ran like a bag of nails

The conclusion is that the cam has worn. This is a new experience for me but I've been told that once the hardened surface of the lobes on the cam wear through the ongoing deterioration can be quite rapid and it is the front face (lifting face) of the lobes that are most prone. This would mean, logically, that although the engine will run and the valves will lift to a decent height they will not stay open for very long (in fact decreasingly so) resulting in massively reduced power.

Given that when I have the engine set 'by the book' it runs at its best, and that over the last 200 miles it has got progressively weaker (even though I've found other problems along the way) the cam is the last thing to look at. This requires the radiator and front crossmember to be removed, which means I either have to remove the wings or cut them to allow the retaining bolts to be removed!

Although I'm very disappointed to not drive the season opener in Dumfries, I am excited at the prospect of fixing the engine once and for all and having the chance to have a new cam profile designed to maximise the power. The Dumfries weekend will see us run as tail-end-charlie and the Alldays will be up and running brilliantly again in time for the Strathmore Extravaganza at Glamis Castle. If its not the cam then I'll have a nervous breakdown.

Photos and rebuild info will follow .....
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Richard

kevin2306 · Posted: Mon Apr 28, 2014 9:50 am Post subject:

what sort of cost is involved in getting the cam re-profiled?

kev

Rdover · Joined: 26 Nov 2007 Posts: 413

Rdover · Joined: 26 Nov 2007 Posts: 413

And things move on .....

I got the endoscope into the engine and the cam is so badly worn that each time it runs it is getting noticeably worse and the metal from the lobes MUST have gone somewhere. I checked the oil and it is just a bit more glittery than it should be.

I've been advised that if I'm going to the effort to take it 75% apart I may as well go the whole hog and get it done properly. This means losing an entire season's events (I'll still go but not be driving) and spending many thousands I don't really have. It will mean, however, that I'll have an engine that is 100% perfect making top power and still totally reliable and will never need touched again.

I'm gutted on one level but also relieved I know the problem and have no choice as to what to do.
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Richard

roverdriver · Posted: Wed Apr 30, 2014 11:16 am Post subject:

Sorry to hear how bad the shaft is, but at least now you know! When that is sorted, and having done all of the other fettling that you have achieved, I believe that the Alldays will settle in to give you plenty of faithful service.

Good luck,
Dane.
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Dane- roverdriver but not a Viking.

PAUL BEAUMONT · Joined: 27 Nov 2007 Posts: 1281 Location: Barnsley S. Yorks

I am sure that this problem is both annoying and worrying, but as an engineer it is also fascinating. How do you go about establishing the design, not only of the lobes but also all the bearing journals, oil ways, sprocket fixings etc. Sounds like quite a challenge.
Had a quick Google and Newman cams look like a good place to start.

Paul

Rdover · Joined: 26 Nov 2007 Posts: 413

PAUL BEAUMONT · Joined: 27 Nov 2007 Posts: 1281 Location: Barnsley S. Yorks

Just an opinion, but 6-8mm of valve lift does not seem to be out of place to me!
Paul

Rdover · Joined: 26 Nov 2007 Posts: 413

colwyn500 · Joined: 21 Oct 2012 Posts: 1745 Location: Nairn, Scotland

Impossible to make any meaningful contribution after you have followed all this through so thoroughly but is there a possibilty that the cam-followers themselves are worn through the hardening and gradually reducing valve lift?

Rdover · Joined: 26 Nov 2007 Posts: 413

Diagnosis confirmed and wasn't the embarrassing "you did check the exhaust wasn't blocked"

Cam AND cam followers are very worn. The surfaces are grey and mottled, cam follower rollers are loose and scored and jamming. Engine is coming out tonight to be taken asap to the engine specialist for partial stripping and checking. Once we know what's needing done they'll fix what's needing fixed and I'll get a box of bits back to rebuild myself.

I know I should get the whole engine stripped but it is only the cam side of things that's worn so we'll start there. I'll save £000s by re assembling myself.

I'm steeling myself for a HUGE bill for the cam.
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Richard