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Re: Restoration of a '71 Sprint

PostPosted: Tue Jun 21, 2022 9:21 am
by Andy8421
Greg,

Thanks. I had looked at those, probably a bit over engineered for the Elan, but the principle is what I had in mind. I am a bit concerned they put a twisting moment on the lift's arms, but my lift is rated for 3000kg, and with the Elan at around 750kg, I probably have capacity to spare.

Here is the link to the manufacturer:

https://mohawklifts.com/automotive-lifts/specialty-items/tire-engaging-adaptors/

I have CVs to replace the donuts on the Sprint, and plan to use poly bushes in the suspension arms, so there shouldn't be any 'mechanical' damage by supporting the car with the wheels at full droop for an extended period. I am less sure that the 50 year old glass fibre won't creep about - I could imagine finding that the doors won't open after I lower it, so I am still keen to support it on the tyres when restored.

Andy.

Re: Restoration of a '71 Sprint

PostPosted: Wed Jun 22, 2022 6:45 am
by Roland
Andy,

My 2 post Twin Busch lift is rated at 4200T. The elan never had any impact of my wedge anchor bolts because it really is not stressing these lifts much. It was my Freelander 2 that backed off two of my anchor bolts slightly.

I have posted before on poly bushing my car. I don't think this exercise is helped by the poly bushes on the market that are commonly used on older Lotus's. The first two manufacturers I tried did not fit my front wishbones which are original to the car.

The third set I used was from Super Pro, I have run Super Pro bushes on my two older 911's for some years. They are probably a market leader and they have a technical capability in terms of bush design. I think the material is better and they fitted properly. Note on the front you will need to put large spacer washers on the inside of the wishbones to ensure the bushes don't migrate/move. This means that you will need spacers at the outer ends as well (top ball joint, damper & trunnion).

Roland

Roland

Re: Restoration of a '71 Sprint

PostPosted: Tue Jun 28, 2022 9:38 am
by Andy8421
Roland wrote:Andy,
My 2 post Twin Busch lift is rated at 4200T. The elan never had any impact of my wedge anchor bolts because it really is not stressing these lifts much. It was my Freelander 2 that backed off two of my anchor bolts slightly.

I have posted before on poly bushing my car. I don't think this exercise is helped by the poly bushes on the market that are commonly used on older Lotus's. The first two manufacturers I tried did not fit my front wishbones which are original to the car.

The third set I used was from Super Pro, I have run Super Pro bushes on my two older 911's for some years. They are probably a market leader and they have a technical capability in terms of bush design. I think the material is better and they fitted properly. Note on the front you will need to put large spacer washers on the inside of the wishbones to ensure the bushes don't migrate/move. This means that you will need spacers at the outer ends as well (top ball joint, damper & trunnion).
Roland

Roland,

Thanks. Feedback like this is invaluable.

Andy

Re: Restoration of a '71 Sprint

PostPosted: Tue Jun 28, 2022 9:57 am
by Andy8421
I'm planning a road trip 'up north. I haven't been doing a great job of updating this thread, and have been active on a few Lotus related projects. I will try to get the thread up to date.

I have had:

- the front and rear calipers rebuilt by Classicar Automotive, who did a great job. I had planned to buy a plating kit, and do everything myself, but after the hassle of rebuilding the calipers for my S3 racer I thought I would give the professionals a try. I will post pictures later.

- the seats blasted, powder coated and re-trimmed by Frank at Option 1.

- Stainless 'ladder frames' made by Spyder to replace my rotted frames (not a job I am looking forward to).

I need to travel north of London to Bromsgrove and to Peterborough to pick up the seats and ladder frames. I thought I would stop by Longstone and get tyres fitted to the wheels I bought a few years ago from Sue.

While I am at it, I have thought of going via Sue's on the way home to pick up larger parts where shipping is a problem. I had thought that picking up a dashboard, carpet set and hood would make sense. I haven't stripped the car yet, and I am sure I will have a laundry list of parts to obtain when I do, but are there any other obvious parts that I should try to get while I am out?

Thanks,

Andy.

Re: Restoration of a '71 Sprint

PostPosted: Mon Jul 18, 2022 11:08 am
by Andy8421
A couple of updates. Moved the car into the garage I will use to strip it down. Some pictures:

The sad engine bay as it appears prior to work starting.
Engine.jpg and
Engine bay prior to strip down

Re: Restoration of a '71 Sprint

PostPosted: Mon Jul 18, 2022 11:10 am
by Andy8421
More pictures:

Interesting markings on the carbs.

Carb.jpg and
Carb engraving

Re: Restoration of a '71 Sprint

PostPosted: Mon Jul 18, 2022 11:18 am
by Andy8421
Another picture, not great I am afraid. The autofocus wasn't sure what to aim for. The inlet runners appear to have been polished, or are all inlets like this? It is hard to find pictures on the web of unmolested heads.
Valve.jpg and
Inlet runner.

Re: Restoration of a '71 Sprint

PostPosted: Mon Jul 18, 2022 1:03 pm
by Roland
Andy,

The inlets on my head haven't been touched to my knowledge and it is basically a cast finish. There is slight evidence of some slight reworking just on the bottom edge for 1/2" into each inlet, I suspect it was to correct some slight misalignment. Yours look much smoother than mine so they must have been worked on.

The engravings on your carbs seem to indicate chokes, main jet and air jet have been changed from factory, assuming they reflect what is actually fitted in the carbs.

Roland

Re: Restoration of a '71 Sprint

PostPosted: Mon Jul 18, 2022 1:54 pm
by Andy8421
Roland,

Thanks. I have done a bit more digging, and as far as I can see the jets / choke match the numbers engraved on the outside of the carb.

I don't know much about camshafts, but in an earlier thread about this car, a poster recalled it was fitted with Cosworth L1 cams. I have measured the base circle (24mm) and lift (10.75mm) of the cams and this would seem to be approximately consistent with the L1.

I have found a posting in an old thread of recommended carburettor settings for the L1, and 34mm choke, 135 main, 165 air correction are in the same ballpark. I will have a go at measuring the cam timing (if I can figure out how to do it) to see exactly what it is.

Regarding the ports, I have a faded receipt from the late 70s that references 'gas flowing', but it is difficult to read anything else.

Andy.

Re: Restoration of a '71 Sprint

PostPosted: Mon Jul 18, 2022 4:12 pm
by types26/36
Here's a couple of Cosworth L1/L2 spec sheets that may be of interest to you.

Re: Restoration of a '71 Sprint

PostPosted: Tue Jul 19, 2022 5:46 am
by Andy8421
Brian,

Thank you very much for this. I have been searching around for details on the L1. Burton say this:

Very popular rally/race camshaft. Best power band between 4500-7500rpm. To check for piston to valve contact, ensure there is a minimum clearance of .200” (5mm) between the valve head and piston at TDC.
Power Band: 3500-7500rpm

Valve Lift: 0.398"
Duration: 306° inlet
Timing Figures: 47/79/71/55
Inlet/Exhaust Full Lift Position: 106° ATDC
Inlet Valve Lift at TDC: 0.130"
Exhaust Valve Lift at TDC: 0.127"
Valve Clearances: .010" inlet/.010" exhaust
Durations quoted at .010” / .25mm checking height.

Which is similar, but not the same as the Cosworth sheet. Very interesting the 4 degree difference in recommended timing. As always seems to be the case with Lotus, there is inconsistent information available.

Assuming they really are L1 cams in the engine, in spite of "Best power band between 4500-7500rpm", as far as I can remember (its been long while since I drove the car), it was fine to drive on the road. It did have a 'coming on the cam' change in intake noise as the revs picked up, but as this was my first Lotus, I thought they all did that.

Andy.

Re: Restoration of a '71 Sprint

PostPosted: Tue Jul 19, 2022 6:49 am
by reb53
Hi Andy,

" so there shouldn't be any 'mechanical' damage by supporting the car with the wheels at full droop for an extended period."

Interestingly, when my Sprint was at the repair shop 30 odd years ago it was left lifted, with the wheels at full droop, for several weeks.
When finally back on the road, having been repaired by me, both left and right rear wheel bearings failed almost immediately.
I keep pretty good records and each failed well before its time, and at different mileages.
I had, and still have fitted, the much maligned Rotoflexes, and I concluded the heavy, and constant, pressure they imposed on the bearings was something the bearings didn't like.

By the way, is Hugo still in the rocket business ?
Peter is still with Rocket Lab, the solar panels he personally made recently are now well on their way to the Moon !
Ralph.

Re: Restoration of a '71 Sprint

PostPosted: Wed Jul 27, 2022 11:35 am
by Andy8421
Bit of an update. Managed to get the engine out. Thanks to all who over the years have posted guides to removing the engine and how to avoid the major pitfalls. No problems encountered at all - which given the car hadn't been run for at least 10 years, and the engine hadn't been out for at least 35 years is quite a relief.

I took the coward's way out with the exhaust manifold and cut it up with oxy acetylene. The manifold was junk anyway, and the studs look completely rusted, so I figured this was the best course of action.

IMG_3042 - Copy.jpg and
Engine out

Re: Restoration of a '71 Sprint

PostPosted: Wed Jul 27, 2022 12:03 pm
by 661
Don't blame you for chopping it. It's a pain.
TTR have just made a slip joint one which makes life a doddle.
Is that another Elan in the shed?

Re: Restoration of a '71 Sprint

PostPosted: Thu Jul 28, 2022 8:29 am
by Andy8421
661 wrote:Is that another Elan in the shed?

Page 1 of this thread has a picture of the 'stacked Elans'

It's a HSCC spec S3 that I bought fully prepared about 20 years ago. My racing days are probably over, but my youngest son has shown interest in pursuing the hobby.