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65 Lotus Seven S2


SENC

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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?

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  • 3 weeks later...
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  • 3 weeks later...

She's back on her feet and full of fluids.  Turned over without plugs to get fuel in the carbs and saw the oil pressure gauge start to move,  so the battery is charging overnight and will see if she starts tomorrow.  Well wishes and final words of warning or advice are welcomed!

 

 

IMG_20211023_175047.jpg

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Started up and ran well!

 

I do have an issue, though, a whirring when the clutch pedal is fully depressed. Halfway and I'm getting engagement, no whirring, but depress further and it whirrs.  New clutch, pressure plate, release bearing (good quality NOS) and spigot bearing.  I suspect it is the release/throwout bearing, which would be engine back out to replace - but since it it NOS I'm may run it a bit to see if I get lucky and it is just old grease that has hardened and that softens up over time.

 

Made a poor decision to try to back off the clutch rod nut to see if that would assist. I should have known the result, but wasn't thinking clearly. As you might guess, a little extra clearance was just enough to allow the piston in the slave to get to the tapered exit and to jam :cry:.


Fortunately I was only a mile from home so my son picked me up and I gathered a spare and some tools and a bleed bottle and did something I could not have done on my Elan (without ramps or blocks) - a roadside slave cylinder swap. That got me home. I'll recheck all that this week, and maybe get to a break-in drive next weekend. Not how I wanted to spend the afternoon, but happy with a running engine that seems healthy - and I'm going to be cautiously optimistic I won't have to pull it back out for another throwout bearing swap.

 
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Had a nice, 70 mile break-in drive yesterday, and the little car ran very well. My old, spare clutch slave held up quite well, and as I started my journey home from the back country roads I'd been using for accel/decel I noticed the bearing noise was reduced. By the time I got home it was non-existent, so maybe got lucky on that one. Oil pressure was right on the money throughout, and engine temp stayed on the low side thanks to a 70 degree day and running without the bonnet.

I took a shorter, 5-mile jaunt today to warm the oil back up before changing the break-in oil for regular oil, and ran strong, still no clutch noise and, more importantly, no smoking.

I'm getting a little exhaust popping on lifting off the accelerator after a 3k-5k WOT pull, so some tuning is next on the list - but plugs looked decent and the engine sounded good and pulled hard, so perhaps not too far off.

About only "negative" so far is a fair amount of engine oil draining from the filler cap (it is a breather, too) and pooling on the top of the rocker cover - enough that running yesterday without the bonnet resulted in a fine mist on the windshield from the air flowing over the engine at speed. I'm hoping that 50 weight will be less prone to do so than the lighter 30 weight break-in oil. But will work on a baffle if not, and not a big worry overall - the dipstick showed little to no loss on the day.

Glad to have it back to a state it can be driven, and hoping for a few more weeks of good weather to do so. Thrilled the La Nina may mean a milder winter, so also hopeful for scattered opportunities throughout the winter. Thanks to all who contributed advice and guidance along the way!

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Blessed with spectacular 70° weather allowed a couple drives this weekend, after changing the 79°-30' butterflies for 78° butterflies, on Keith Franck's advice.  This effectively moved the 1st progression holes downstream by .5mm, which made all the difference in the world in the transition, eliminating the popping on decel while maintaining a nice idle.  I have a little more tweaking to do, but think I'm getting very close to finding the right balance now.

My 20 y-o daughter, home from college, got her first ride in it - all smiles and giggles as we accelerated through curves!  I'm not embarrassed to admit to giggling every time I drive it, too!

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  • 3 months later...

I have been to several LOG events and would be planning to go to this one as well except it conflicts with our British Invasion weekend in Stowe VT.   This is very unfortunate because we would prefer to do both.   

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Finally got tools and cars relocated in a new storage and "toy shop" space a friend and I have taken, so can get back to tuning and tweaking on the Seven (and back to valve and shim dx on the Elan) - but one step forward and another back...

 

Took the Seven for a bit of a drive yesterday to reset my thoughts on how it is running, and though the engine is running pretty well I had a clutch slip when shifting to 4th at high revs from 3rd.  Was able to replicate and identify the slip is only at higher revs, >4k or so.  As it is a new (old stock) clutch disk and pressure plate, I'm thinking I either have some oil/grease contaminating it or that the release bearing is bad.  You may recall that, upon getting  it back on the road, I had some bearing noise upon full clutch depression that stopped after a hundred miles or so. As it was a NOS bearing, I had hopes that old, dried bearing grease had just needed to warm and soften, but I'm questioning that now.  Either way, I suspect I'll need to oull the engine again to fully diagnose, though I may try to look around with a boroscope to see if anything obvious sticks out.  I'd welcome any other thoughts.

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About the crankcase pressure, is it broken in yet? Is the road draft tube installed and taper to the rear or is the end square cut? Was there a pan baffle/windage tray? Standard volume pump? Thicker oil doesn't drain back to the pan as quickly so you probably have more in the valve cover than if you ran something thinner. Too late now, but a common mod during building is to smooth internal surfaces and radius oil returns to aid flow back to the pan. Glypt was often used to coat internal surfaces for a slick, oil resistant surface.

I see you have a borg and beck pressure plate. These have higher ratio levers (5-6:1) than modern diaphragm spring pressure plates (effectively 3.5:1) and are slower to fully clamp the clutch after a shift. I'd try a little more time between foot off the clutch and applying throttle before another tear down. If only we could pump fresh synthetic grease in NOS release bearings.

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Thanks MV8!  I'm definitely going to drive it a bit more before pulling it, so will see if I can duplicate the symptom well after a shift, good recommendation.

 

Re oil on the cam cover, I'm pretty certain now it was splash rather than pressure/spray.  The piece of tin I fit into the filler neck to block a direct line from the filler hole to the underside of the cap has prevented any further leaking through the cap.  I have not yet refitted a road draft tube to the breather tube in the block (the breather tube I have is not a great fit for the road draft tube connector), but it seems to be breathing OK even without that bit of venturi pull.

 

 

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