SENC

What type 40DCOEs? Mine are type DCOE-2. The type and individual carb numbers may give some clues as to whether they may be original to the car (the numbers may not be sequential, but should be in a similar range). Lotus sometimes recorded carb numbers, but even if they did not record them for yours you may be able to piece information together from others that helps you determine if yours are in the right ballpark for your year and chassis number. Lotus recorded the cab numbers for mine as 222xx and 221xx

Confirmed my brake master is 5/8 and clutch master is 3/4, for what that is worth. I have no reason to believe that is not the original orientation, but who knows for sure what a PO has done. I've found Lotus literature that says the clutch should be 3/4, but have also seen contradictory evidence. Regardless, I dont thing either size would contribute to your problem. It is definitely a "strong" clutch pedal with a 3/4 master. I tried to look back on some old threads and notes, and it looks like the incorrect push rod length may have been a master cylinder rod length issue rather than a slave cylinder rod length issue. You mentioned a new clutch master, so it may be worth checking it's rod length and comparing that to the old one. Non clutch related, you might check your gearstick turret. If that turret had unwound itself at all, it may not be putting the lever in exactly the right places. I had this issue after my rebuild - I'd neglected to add a little threadlock after adjusting gasket thickness to get it situated correctly and engine vibrations had unwound it just enough to keep me from selecting gears.

I think you're OK with 5/8 master - lots of debate on whether 5/8 or 3/4 in various places. Slave should be 3/4. It may be worth checking the length of your slave cylinder rod. These apparently came in different lengths. I dont remember the correct length offhand, but lots of discussion on lotuselan.net about this topic.

The below may help id your head...

You may or may not find you need a bigger fan - I have an original small fan on mine and it seems to do the trick when idling in traffic as long as I keep water flowing periodically. That said I don't have the oil cooler you have restricting airflow when driving so yours may have different needs. Re clutch bleeding, like our Elans the rotational angle of the slave cylinder and location of the bleed screw can cause issues with air in the slave itself. On my Elan I added a length of brake hose and fitting and effectively raised the bleed screw to near the master - which made for much easier bleeding and ensured air from the slave reached a higher point. The Seven is open enough I haven't felt the need to do that. I also found that the pumping action when bleeding agitates the fluid and introduces air throughout, that then finds its high point and stays there. My solution to that has been to use a board to hold the clutch (or brake) pedal fully down overnight after changing fluids. This seems to give the air a path out to the master cylinder. A top off in the morning and I've yet to have a problem. If your problem is air in the system, perhaps this will help.

That is the way I read it. For mine, the 116e/120e variant it calls for a 1/8" advance, so I settled on the outside edge of the right side of the markings on the case (rather than between them). That said, a contemporary HLR newsletter on the cosworth engines I indicates a 1/8" retard - and, of course, cams could have been changed - so I'd use the manual as a general guide to get started and running then tweak from there as gap/dwell and carbs are adjusted.

Sorry, I didn't mean to imply dwell was in there - I meant to point to the timing advance. Yes, I think you are correct on dwell. https://vintagetechnologygarage.groups.io/g/sidedraft/topics and, specifically, the thread of back and forth on mine a couple years ago... https://vintagetechnologygarage.groups.io/g/sidedraft/topic/tuning_advice_65_seven/74580852?dir=asc

Be sure to check the dwell, then readjust timing as per the manual. I found that much more accurate than setting gaps via feeler gauges. I really struggled with carb tuning until I got some help from Keith Frank on his iogroup page. Perhaps due to wear, my butterflies were closing a bit too far and covering the first progression hole (this was resolved by swapping butterflies for a set with a different angle edge bevel). Not at all suggesting you'll need to do this, just that Keith is extremely helpful diagnosing problems.

When the timing mark is at the pointer, you should be 10°BTDC. The mark on the smaller wheel my be for TDC? Pretty sure that's the case on the Elan.

So your rise is about 1.5", roughly double mine. The pictures may be deceiving, but the top of your radiator looks to be higher than the top of your cam cover. The top of my cam cover is a bit (maybe 1/2-1") higher than my radiator. Is your radiator sitting down in the chassis mounting holes (with top hat style bushings)?

The top hose? I can't remember off the top of my head - seems like I searched for a bit for what it came off and found another British car of that era and then found a NOS hose. If that's the one you're talking about I'll see if I can get lucky and find an invoice for it. This might be it... https://bpnorthwest.com/triumph/radiator-hose-upper-spitfire-62-to-78-gt6/?gad_source=1&gclid=Cj0KCQjwsPCyBhD4ARIsAPaaRf1OLe4nEubif6utMAYrZo2ME68CRHeaZytA6J2t7LO76VPTHoiuCZkaAlTIEALw_wcB Or this... https://www.ebay.com/itm/190848712318?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&mkscid=101&itemid=190848712318&targetid=&device=m&mktype=pla&googleloc=9010076&poi=&campaignid=20394324446&mkgroupid=&rlsatarget=&abcId=9317262&merchantid=6365194&gad_source=1&gclid=Cj0KCQjwsPCyBhD4ARIsAPaaRf1qfqrAFgZSJzYmNR7t0s9bnBvLJ_864xc6cmZ23RW0cWvJruxYgL0aAk_6EALw_wcB

Was at my shop some today so took the opportunity to take some measurements - maybe something here will help you in evaluating your system. The bottom of my swirl pot is roughly 1" below the bottom of the radiator inlet pipe. My swirlpot outlet is about 1/4-1/2" above the bottom of the pot - so overall rise from the bottom of the outlet inside the swirlpot to the bottom of the radiator inlet pipe is roughly 3/4-1". As the cold level of water in the swirlpot is about 1/2", it requires a rise of roughly 3/4-1" before unpressured water would flow to the radiator. My swirl pot is about 4" diameter, so if my math is correct it only needs about 7 ounces or less of water to get enough rise to start unpressured flow. Our cooling system holds about 12 pints, just under 200 ounces - so thermal expansion takes care of most/all of that rise at 200F (93C). Ie., it wouldn't take a lot of pressure on the downstream side of the pump or suction on the upstream side of the pump to get and keep circulation flowing. I'm still confused why you don't get visible inflow into the swirlpot at higher than idle rpms. Perhaps measure the level when cold and observe the flow immediately upon start-up. Is the pump pushing up water to the pot (with rpms) when cold but not getting high enough in the pot to flow to the radiator. Is the pump eventually sucking air from the radiator and "running out" of water to push? Other measurements - my swirlpot inlet is about 2" higher than the swirlpot outlet. That puts it an inch above the radiator inlet. The top of my swirlpot is about 1/2" above the top of the cam cover. The design of my swirlpot would naturally flow water from the inlet pipe around the opposite side of the pot, and directly towards the outlet pipe, so even before a rise in water level would send a good bit of water to the radiator. If your rise from swirlpot outlet to radiator inlet is larger than mine and you determine the swirlpot needs to be elevated, it shouldn't be difficult to machine an aluminum or brass spacer/riser to fit between the head and the swirlpot inlet flange.

I want to say that there is a very slight incline from my swirlpot outlet to radiator inlet, but it isn't much. Without looking at it in person, I'd guess the incline is less than the ID of the outlet - and that any rise in water to/above the outlet inside the pot results in flow to the radiator. I'll post a couple of pictures for comparison. I've been trying to think through whether/how that is contributing to your circulation problem. Presumably it worked at some point so I'd think it would be ok - but perhaps minor efficiency losses due to restricted water paths, pump wear, etc. are combining with a marginal design to result in your outcome? Considering the water level in the swirlpot during your video - can you estimate where that is in relation to the high point in the connection between the swirlpot outlet and radiator inlet? Ie., is that high point above the water level in the pot? If so, I could see that being an issue. The water pump pushes what it can through the engine and to the pot until it reaches that level, but if (at that level) gravity doesn't force water back to the radiator the pump would quickly run out of water to push. Perhaps the post-rev gurgle you're seeing is the result of a little vacuum created upstream of the pump through the radiator trying to suck some water through? Or opposite, a release of some air from the radiator due to back pressure? I'll be interested to hear today whether your radiator appears to have very little water in it today as it did yesterday.

While you have it off, run a hose into the inlet - would at least give you an idea of what a strong inflow of water should look like from the top. Perhaps it is internally baffled in some way and you wouldn't see obvious flow as in mine.

A longshot, but the cap on your swirlpot isn't a high pressure or malfunctioning cap that is blocking the overflow tube, is it? Wondering if there is any possibility that air pressure is building up in the swirlpot and keeping water from flowing up to it. I'm doubting this since you've run it without the cap at least long enough to see/video activity in the swirlpot but just a thought to consider.

very strange, I'm at a loss - unless the swirlpot inlet itself is blocked, it seems either a 2nd bad pump (unlikely) or maybe just enough blockage in the engine to prevent high enough flow to get up to the pot, but not enough to prevent water creeping through.

Interesting design, though I'd wonder if it would be as effective removing air as the more vertical design. Regardless, that wouldn't be your problem I don't think. Looking at the design, I'd expect to see a gush of water coming from top left of the video on increase of rpms. As you've described, the video shows that isn't happening - it does look to me like the outlet is attempting so suck water out upon decel. That leads me to believe the outlet to radiator to pump section is ok and trying to do it's job, but from pump to swirl pot inlet isn't. I'd rig a hose to the pump inlet and remove the swirlpot to see if some hose pressure gets water up through the head. If not, you could open the drain on the block - if it flows there you may have increased the chances it is a head gasket resteicting flow or clog higher up - if not it would suggest a blockage in the block. In the head gasket idea, I do recall from searching for mine that not all are designed the same - any chance of pictures of that gasket from last rebuild?

I just remembered you mentioned the swirlpot is homemade - maybe a picture of that too? Is the design similar to this? Inlet from head to high point on the pot, outlet to radiator at the low point? I'd be tempted to remove the swirlpot and turn the engine over to see if it shoots water up as expected.

Odd that you're seeing surge when lifting off the throttle, almost like backwash rather than water coming in from the top inlet pipe. Am I interpreting correctly?

1 - I generally wear a pair of Gokey moccasins - just a leather bottom with no outsole. Works well, looks pretty normal otherwise. Soft soles are thick/firm enough for comfortable pedal work - just don't walk a mile on gravel in them. 6 - there are fiberglass sleeves out there that work for this purpose, just Google for them. Not the best looking things in the world but available in different sizes so you can find something that works and slip it on when taking your daughter.

Smaller crankshaft pulleys were used frequently by racers to reduce wear in the water pump - and as they were almost always above 3k rpm it would pump just fine. Here is a closer shot of my crankshaft pulley and timing marks. I'm not with it right now, but it appears they are roughly on the same plane.

Agree with MV8 on the relative sizes - I didn't notice your measurements before. Mine is similar to the picture MV8 posted - I can grab some actual measurements if you'd like. I believe the crankshaft pulley is 4" diameter and the water pump pulley slightly smaller. EDIT: my memory was right and wrong! My Elan has a 4" diameter crankshaft pulley, but my Seven is 4.75", as MV8 estimated. My water pump pulley on both is 4.25" If you have the 4" crankshaft pulley you're definitely losing some efficiency at the pump.

Yeah I didn't think about that but you're right, I couldn't do what I suggested either. Maybe you can get a hose into the swirl pot and directed towards the outlet. Something to see that you can force water up through the engine and to the swirl pot.

The perplexing thing is you were seeing flow into thw swirl pot at higher rpms (though higher than expected), so there must be at keast some flow. You mentioned that on disconnecting everything you discovered the radiator was empty. I'm sure youve double checked the top hose for blockage and thag water flows through the radiator well. The other thing that comes to mind is an airlock within the engine - that expands when it gets hot and fully blocks circulation. In the Elan I learned to be sure to always make sure it is nose up when draining/refilling coolant. Apparently these engines are known for getting air pockets in the back of the block when nose down or even level. Perhaps park it nose up overnight then refill from the swirl pot - or better yet remove the top hose from the swirl pot and add water through the radiator until you see it (hopefully) rise up into the swirl pot.