Lotus Elan and Lotus Elan Plus 2 Forums

¡WOW!

Henry, what is the colour code for the Cosworth red on the engine? the Polished panels are looking sensational, I'm being tempted to do the same one ours.... Vaughan

I don't know, Vaughan, I just used off-the-shelf POR15 Engine Enamel, MG Maroon. Looks about right, though.

Sorry got it wrong

I read the logbook entry as KAR 965C.

Indeed, both registered at Hertfordshire in the first half of 1965.

Progress, and a temporary halt.

Crankshaft and oil seal installed (using the BestGasket GraphTite rope seal product). The crankshaft was in good shape and only required polishing, so found some nos vandervell bearings in the same +20s as I removed. All torqued up and ready.




Ran into an issue with tappets, though. Having discovered a couple spots of corrosion on the face of one, I'd ordered a replacement set - but didn't notice until fitting that the head has an OD of 21.5mm where the ones that came out have an OD of 20.5mm. Found this as I tried to fit the camshaft and realized the tappet next to the central boss for the camshaft wouldn't seat fully.

Unfortunately, I've only been able to locate 21.5mm head tappets, so off to the machine shop to get my new set turned down to size.

Looking good!

On rebuild, my existing camshaft was very tight on rotation at 2 points. After fully inspecting the bearings (new) and the camshaft, identified some indicators of stress on the rear journal that had it very slightly out of round - so, in search of a replacement. Does anyone have an old stock A2 camshaft laying around they'd consider selling, or have any leads?

SENC wrote:On rebuild, my existing camshaft was very tight on rotation at 2 points. After fully inspecting the bearings (new) and the camshaft, identified some indicators of stress on the rear journal that had it very slightly out of round - so, in search of a replacement. Does anyone have an old stock A2 camshaft laying around they'd consider selling, or have any leads?

Contact Tony Ingram, https://www.lotus7.com/Home.html
or Jay Ivey, https://iveyengines.com/
Either may have something for you if no one here has one available.

Best of luck in your search.

SENC wrote:On rebuild, my existing camshaft was very tight on rotation at 2 points. After fully inspecting the bearings (new) and the camshaft, identified some indicators of stress on the rear journal that had it very slightly out of round - so, in search of a replacement. Does anyone have an old stock A2 camshaft laying around they'd consider selling, or have any leads?

I'd be looking at the bearings not being totally round - they are a pain to get in and to stay perfectly round.

Have you tried the camshaft in back-to-front to see if the marks appear on the front bearing? It would perhaps tell you whether the cam is bent, or the bearings are slightly pinched.

Cams are very difficult to bend. If you've ever tried to destruction test one you'd know what I mean. I cut a slot halfway through a cam and tried to break it with a hammer and I lost! I was actually cutting the cam down to use one of the bearing surfaces as a bearing installer. That started my journey to finding that cam bearings are a pain to install. I've had a proper tool made and even then, they give trouble, particularly the centre bearing.

If it turns out your cam isn't bent, and the bearings are OK then you may have got a bit of block distortion. I wouldn't worry too much if you only need to slightly scrape a bearing just to clear a high spot. You just want the cam to rotate by hand so that you don't get a bearing spinning in the block when the engine is running.

If you've got a spare Lotus T/C jackshaft knocking around you could try that in your block to see how that behaves.

It's all good fun, isn't it?

Didn't you have a rod go through the side of that block?

Thanks Dan. I sent a note to Tony last evening, will reach out to Ivey, too.

I did, Rob, which certainly could support a block distortion theory,, and Alistair's suggestion of using a tc jackshaft is a good one for testing. Don't think I have one, but may be able to out my hands on one. I also need to inspect the old bearings that came out to see if I can id unusual wear that might help tell the tale. Other than the idle/low end issue related to the weak valve spring, the engine was running quite well and smooth, so that makes me question block distortion.

Inserting the cam, it spins freely as it enters the 3rd bearing. When in the right place, it begins to bind at 2 (opposite) points and that lasts for btw 1/8 and 1/4 turn before freeing. Push it on through until the face of the camshaft is against the face of the block, and it spins freely again. This is what led us to looking for an out of round condition and any possible cause. I would not have picked it up, but have a very experienced mechanic who is helping/guiding me identify clues/markings on that journal consistent with stress - all about the midpoint of the journal, which seems to match up the shaft binding when in the right place but spinning when shifted forward or back.

While he is experienced and highly competent, he is not a Lotus specialist, so does not have a lot of experience specific to this engine - so as always, I covet the input and recommendations of the folks here.

Jackshaft bearings are a real pain. I tried fitting several sets, the centre bearing is a problem and truth be told, I was never happy with any of them. Fortunately I found a local (well 50 miles away) engineering company that could not only press the bearings in properly but then hand scrape the bearing. The jackshaft turned smoothly and I have excellent oil pressure. Maybe it's worth trying to find a machine shop that can do this?

Have you checked the camshaft in V blocks for bending? They can and do go out of shape.
A quick blast with a blunt air chisel on one side of the shaft changes everything!