Lotus Elan and Lotus Elan Plus 2 Forums

I'm fighting off a bad cold & sore throat and feeling achy and on top of that its a bit chilly this morning in my garage. Fire up the propane heater, take two Tylenol and get motivated as I want to get the twin cam running today. Armed with a number of insights from forum members (Thank You) I show Drew the comments and we decide to tackle a methodical plan of going through each area that could be causing the twin cam not to run.

I removed the valve cover and confirmed that the cam timing was correct (it was) with each cylinder at TDC. We also confirmed that this really was a new rebuild on the engine as the entire head, cams, head bolts and chain were all very clean and not worn.



Then we double checked the spark plug wires from the distributor and the location at each plug. Hand cranked the engine to line up the timing marks on the pulley and the timing chain cover. Ensured we were at 12 degrees TDC. Confirmed the spark plugs were gapped properly as well as the points. Turned the engine over to see spark at the plugs and at the points. All good.

We must have spent10 minutes turning the engine over and making slight adjustments to the distributor when the starter motor started pouring out smoke. Immediately disconnected the battery terminal and checked all the wiring. Pulled the starter motor, which was hot as the dickens. Funny, it looked brand new. Traced all the wiring and confirmed that everything was intact. Strange. Wonder what caused that? We checked the solenoid and thought it might have gone bad. I had a spare so we installed it. The starter motor had cooled off, we put 12 volts to it and it ran so we reinstalled it. Tried to start the car, the ignition switch would not turn the starter on, but the button on the bottom of the solenoid did. The starter motor started smoking right away. Battery disconnect again.

Now we were wondering if there were wiring problems behind the dash. Unbolted the dash, removed the crash pad, dropped the steering column and pulled the dash out as far as possible. The wiring seemed in fairly good condition besides the double brown wires connected to the ignition switch, one of them had clearly melted and after looking at the wiring diagram determined it was for the electric window motors.

Figured the starter motor had gone bad (how we don't know, anybody have a new starter motor burn up?) so we installed another started motor I had from my S1 and cranked away.






The rear weber carb kept getting small backfires but the engine would never fully run. It acted like it wanted to but just wouldn't start. Pulled the plugs and changed them to NGK BPR7EIX (there were Champion N7YC in the engine). Gapped all the plugs, pulled the distributor and checked the gap, closely inspected the distributor and everything was as it should be. Reinstalled everything. Turned the engine over. Nothing.

We pulled the webers from the intake manifold. Found the first problem, one of the metal spacers didn't have the round rubber gasket in it. Sucking too much air. While the carbs were off, we inspected the intake valves to insure they were seating and nothing was bent. It all looked brand new. Just to make sure it wasn't the carbs, I had another set of webers from a twin cam that I knew ran well (just smoked a bit of oil) so we swapped out the carbs and reinstalled them.





Rechecked all the wiring again, and guess what.......two of the plug wires were mismarked and needed to be switched. Turned over the engine and it started on the second try and ran like a top. ARGH! Six hours of labor, one burned our starter motor, swapping carbs and the engine is running like a top. Drew and I looked at each other in bewilderment. How did we mess that up so many times?

Spent some time tuning the carbs until the engine purred like a cat. Sounds great!

Well, the original weber carbs needed to be rebuilt anyway as they had been sitting for a long time so now that we have them off the car that will be next. Then we will tackle a few other electrical gremlins like no tach, why the ignition switch won't turn over the engine (probably a faulty relay), replace the melted brown window motor wire, test the window motors and who knows what ever else.

And the crash pad and dash needed to come out anyway because we have to install a new windshield and moldings.

Boy am I still feeling dumb about the crossed wires ! I took two more Tylenol and went to bed.

Epic....but glad you got it sorted.

Regards
Richard

The twin cam block in my S4 has the following serial numbers;

Right Side: T 25291
Left Side: 701M6015A

Can anyone provide some insights to this block?

Glen, the first number is that of an engine fitted to a Federal Elan Sprint in late 1971. The prefix T is for a Big Valve, Stromberg Federal engine. Engines in the 252 & 3 ## range tended to go into Sprints which came off the production line in Oct/Nov 1971.

As you have told us, your car's title says Elan Sprint, though we know it left the factory well before the Sprint concept was dreamt up. It did so with engine no. LP16086.

It seems clear that your S4 has had the engine from a later Sprint fitted to it by a PO. The engine no was usually scribed into the bulkhead end of the cylinder head, under the web between the two cam carriers. Since it is a Weber head, my guess is that it will have come from yet another Elan!

Tim

Tim, the story of this car is all piecing together. The engine and trans came from a Sprint that was wrecked. The S4 is a very low mileage car that needed an engine. The PO wanted to build a Sprint with with the parts from two cars. He had Jerry Mong build the weber head for the Sprint block as he wanted a weber version, not a federal car. I'm still perplexed that it's titled as a Sprint,

Thanks again Tim for the additional details.

Hi Glen
Glad to hear that you got her running. I had the same issue with two of the leads on the wrong cylinders and I'm sure we are not along!

Your cylinder head would appear to be from an earlier engine as it has the additional castings/webbing in the spark plug wells.

I'm sure someone on here could tell you when they stopped making those heads.

Good luck with sorting out the wiring.

David

Rohan is working on an excellent paper that sorts through the twin cam heads. This is what he has on the Type 1 head, which appears to be what you have Glen, as David points out:

"Type 1 Heads ? First production heads, by now they are the same for the Elan and Cortina
and were die-cast by Williams and Mills and machined by JAP and introduced February 1963.
They had half-moons down the centre well and square reinforcing blocks on the inlets and a
centre rib in the spark plug well between cylinders 2 and 3; it is not known how many of
these produced. At some stage Lotus changed back to sand casting but it is not clear if this
occurred with the change to the Type 2 style heads at around engine LP 5332 in late 1965
(earliest engine number Type 2 head located so far) or prior to that time within the Type 1
head production run without changing the basic casting style. I would need to see more type
1 heads in the LP1xxx to LP4xxx range to see if any change in casting method can be
identified. The key identification feature of the Type 1 head is the half-moon protrusions into the
centre spark plug well. The inlet tracts on the Type 1 head were smaller in diameter than the
later Type 2 head and less suitable for race porting so it is rare to see one on an historic
race car of the period now. Another early Type 1 head had a boss in front of the No1
spark plug. The development sand cast heads and later Type 2 sand cast heads have this
boss."

It is not all that surprising that a Weber head in the US would come from one of the earlier iterations of export Elans. June 1968 is the earliest Stromberg engine I am aware of, so your head Glen likely comes from a pre 68 Elan.

Tim

David and Tim, appreciate the additional insights. As usual I am learning more about all the unique aspects of the twin cam cars and the history of Lotus manufacturing during the early years.

Your comments got me thinking more about the twin cam heads and to be honest I never paid attention to the numbers on the back of the heads. So of course I had to go look to see what I could find out as I currently have four heads in my garage (three attached to engines).

The S4 engine has these markings:

26E311 (the first 1 could be an "L" but I cant tell)
WM
LM8 WP


The spare engine has these markings:

26E3_1 (the space is an unknown, I cant read it)
WM
LM8 WP


The S1 engine has these markings (this is a replacement engine)
LF
2752 129_ (the space is an unknown, I cant read it)


I have a spare head and these are the markings:
BVB11L
064


Clearly the first two engines have the older model type 1 heads and the second two are the "newer versions" type 2 heads. But the numbering is so different on the last two. Any reason why?

Glen,

If you are interested, the original engine from your Elan S4, engine number G16086B was found fitted in a 1965 Elan S2 that needed restoration, and that was in Ontario, Canada in 2013.

Andy

LotusArchives wrote:Glen,

If you are interested, the original engine from your Elan S4, engine number G16086B was found fitted in a 1965 Elan S2 that needed restoration, and that was in Ontario, Canada in 2013.

Andy

Andy, any idea which Federal Sprint T25291 came out of? I'll give you 3 of the 5 digits, you fill in the rest -02xxK

Andy, Thanks For the info on where the original engine is for this S4. Phil, you seem to know which car my Sprint engine came from ......... Details?

Certified Lotus wrote:Andy, Thanks For the info on where the original engine is for this S4. Phil, you seem to know which car my Sprint engine came from ......... Details?

No, just want the vin of the scrapped car for completeness of the federal elan register...

Full day of Elan work in my Lotus garage on Saturday. Drew and I started early and a bit later Chris came over in his '67 Elan to perform a leak down test. Always good to have a garage full of Lotuses and interesting mechanical stuff going on.




Drew brought my Weber's back after taking them to his shop last week and stripping them down for a complete overhaul. He found that one carb had a whole different set up than the other. Amazing. Here were the discrepancies:

1. Main jet: 115 needs to be 120
2. Air corrector jet: 200 needs to be 155
3. Idle jet: 45 F9 needs to be 50 F8
4. Needle valve: 200 needs to be 175



The plan for the day was to install the windscreen on my S4. I had bought the car with it out, but it came with all the parts. The windscreen molding looked to be in very good condition but had this waxy coating on it from being stored for 15+ years. Drew spent a while scraping all that off while I tackled getting all the old black silicon off the windscreen edge. Once he got the molding clean, we let is soak in 102 degree F water for half an hour to soften it up. Tried to fit in on the windscreen and realized it had shrunk by almost two inches. Pulled it slowly to stretch it and got another inch out of it, but not enough to make it work. Plus the rubber was still very hard. Made the decision to order a new one and wait until new week to install the windscreen.




While we were working on the windscreen, Chris was preforming his leak down test. He had very good results and will post them separately.



It was lunch time so we took a short drive to the local sandwich shop. Nice cool fall day.




After lunch Drew and I tackle the brake and clutch master cylinders. Remember, this car has been off the road for 15+ years. The PO told me he put silicon fluid in the brake and clutch hydraulic system for storage so we drained and cleaned out the masters then pumped lots of new brake fluid thru to flush it out. The brake system seemed to work after bleeding, but we have major questions about the master cylinder. Both the shop manual and Bucklands book don't show the type of cylinder we have so I will need to do some more research. I sense the reservoir and cap are not OEM so more parts t be ordered. The clutch was completely shot. The slave was frozen (I had a spare new one so we installed it) and the master stopping pumping after about 10 minutes of use. Another part to order.



With all the wheels off to bleed the brakes, it was evident that the PO spent a good amount of time restoring the mechanical parts of the car. Everything was clean and repainted. A real time machine. Did I mention there is only 8000 miles on the odometer?



I have a long list of parts to order for next weeks work. And I sent out the starter motor to have it rebuilt.

Here are some detailed photos of the of the suspension, brakes, hubs and undercarriage of the S4. To the credit of the PO, he did a very nice job restoring everything.

Certified Lotus wrote:The brake system seemed to work after bleeding, but we have major questions about the master cylinder. Both the shop manual and Bucklands book don't show the type of cylinder we have so I will need to do some more research. I sense the reservoir and cap are not OEM so more parts t be ordered. The clutch was completely shot. The slave was frozen (I had a spare new one so we installed it) and the master stopping pumping after about 10 minutes of use. Another part to order.

DSC06852.jpg

Glen, do a search here on SOVY... there's quite a bit of info...