Lotus Elan

Bill's 26S

PostPost by: bill308 » Sun Jun 05, 2016 10:54 pm

This is the early part of a journey. I'm building a road version of the Lotus 26R, but optimized for the street. Since there are no rules or race organizations to comply with, I will take some liberties for the benefit of mankind. :D

This is a light weight TTR body and 26R chassis coupled with a 1930 cc all aluminum engine, tranny and final drive. The car will be fitted with full road gear in the spirit of a true GT, but I will endeavor to come in at a very low weight. The engine output is 190 bhp and 165 lb-ft torque. The tranny is a Voights modified T9 5-speed with custom BGH gear set giving a 2.66:1 first gear and a 0.82 5th gear. This gear set is midway between the Lotus close ratio and semi Close ratio gear sets but with a useful overdrive. The final drive uses all aluminum castings and a Quaife ATB with a Burton Power 3.54:1 CWP, so cruising should be relaxed and acceleration should be exhilarating.

Some photos to bring you up to speed.
Attachments
dsc01079-s1.jpg and
Body and Chassis in crate as delivered by TTR
dsc01129-s1.jpg and
Engine on stand 190+ bhp, 165 lb-ft torque
dsc01228d.jpg and
Light weight body on roll around stand
dsc01229d.jpg and
Light weight body on stand
dsc01258d.jpg and
Engine in chassis
dsc01317d.jpg and
Unmodified Y-bulkhead of TTR 26R chassis
dsc01321.jpg and
Modified Y-bulkhead grid to fit speedo drive. Divisions are 0.1 inches
dsc01323d.jpg and
Modified Y-bulkhead
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PostPost by: el-saturn » Mon Jun 06, 2016 5:26 am

.......................wow; this is a real mouth full!! good luck sandy
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PostPost by: gjz30075 » Mon Jun 06, 2016 9:17 am

Subscribing, to keep up with your build. Interesting! First gear shouldn't be a problem with that kind of
power and torque.
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PostPost by: ken ob » Mon Jun 06, 2016 10:59 am

Looking forward to seeing this progress.

Ken
Slightly confused by everything since the invention of the wheel.
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PostPost by: Stevie-Heathie » Mon Jun 06, 2016 12:49 pm

Will follow your progress with interest. Good luck :-)

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PostPost by: seniorchristo » Mon Jun 06, 2016 12:50 pm

It's great to see you're making progress Bill! Have you decided on your seats yet? I may be visiting Conn. in August. Hope to stop by and visit.
Good Luck
Chris :)
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PostPost by: Certified Lotus » Tue Jun 07, 2016 10:16 am

Bill, can't wait to follow your progress on this build. I'm sure I will learn a few things!
Last edited by Certified Lotus on Tue Jun 07, 2016 3:50 pm, edited 1 time in total.
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PostPost by: bill308 » Tue Jun 07, 2016 3:06 pm

Thanks for the well wishes everyone.

Hi Chris. No decision on the seats yet. I look forward to your visit in August.

Hi Glenn. I hope we all learn something during this adventure.

Today's task was to separate the tranny from the engine which is out of the chassis. When Peter Marcovicci did my engine I didn't have a clutch cover for the dyno pull so we used one of his along with the dyno exhaust system, but my headers. Now I have a new clutch cover to match the co-axial throw out bearing supplied with the Voights kit and it's time to get it balanced. I took Tilton flywheel off the engine and brought it, along with the clutch cover, a spare 6-bolt crank, and the flywheel bolts to Precision Automotive in Simsbury, CT, USA. They will supply the clutch bolts then balance all pieces in this order: the crank, flywheel, and then clutch cover. They tell me the pieces should be ready in a week or two and they balance to 1/10 gram. They told me Winston cup cars balance to a gram or two but they go the extra bit just to be sure.

Bill
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PostPost by: john.p.clegg » Tue Jun 07, 2016 3:24 pm

Bill

Don't know too much about balancing but "a spare 6-bolt crank" makes me think?

John :wink:
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PostPost by: 1owner69Elan » Tue Jun 07, 2016 6:39 pm

Would love to see the dyno curve on your engine if you can post it.

Been interested in the various other build outputs achieved in hp and torque vs rpm, especially for a road car, since my recent build. I ended up with 181 hp @6900 and 143 torque (pretty flat torque from 4000 to 7000), 1700 cc.

Not sure of road manners yet as car rebuild still in progress.
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PostPost by: bill308 » Tue Jun 07, 2016 11:52 pm

Hi John,

I actually have a couple of good 6-bolt cranks. I believe one crack checked and is reground 0.020 and 0.030 undersize. The other is crack checked and is reground 0.010 and 0.010 undersize. Let me know if you have any interest.

Hi 1owner69Elan,

I'm embarrassed to say I only have part of the data for run 18. I'm trying to get the rest of the data.

I plotted the partial data I have in Excel as all I had was a partial table.

Bill
Attachments
dyno-run-18.jpg and
Partial data from Dyno Run 18. Early runs were hindered by unknown ignition timing as the trigger wheel was set one tooth off and we were hampered with 2-dead timing lights on first run.. I was definitely on a budget, so we cut short the tuning process. In hindsight, I think we could have gone with more aggressive cams. CR was kept modest to run on pump gasoline. blends. We built for livability and drivability. Time will tell all.
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PostPost by: EnfoKen » Sun Jul 03, 2016 3:15 am

Nice, I'm looking forward to seeing this completed.
http://thegaragista.com

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PostPost by: bill308 » Tue Jul 05, 2016 11:12 pm

Hi Ken.

It's going to be a big job to do it right, but I'm going to try. Love your web site.

I talked to my engine builder last week and he said that the reason there is little dyno data below 4.2k rpm is because of his test methods and dyno limitations. It seems that to get peak power and torque points he has to set an initial heavy load and he doesn't want to load the engine heavily at low rpm. Set the load too light and he won't be able to define the hp and torque peaks. Dyno run 18, for which I have plotted the available data, was one of the last runs made and is representative of all the late runs. Early runs were hampered with ignition timing issues, so are of no value.

The other thing we talked about were the specifics of my engine. So far I report the following:

Bore: 89mm
Stroke 77.62 mm
Intake cam: DBE 104; lift 0.440 in; l[email protected] 0.140 in; lobe center set a t102-105.5 degrees; cam closes at 104 degrees.
Exhaust cam:DBE 114; lift 0.420 in; [email protected] 0.115 in; lobe center set at 104.5 degrees; cam closes at 114 degrees.
Intake valve: DBE D-production, 1.625 in diameter
Exhaust valve: DBE D-production, 1.375 in diameter
Main bearing clearance: 0.0018-0.0021 in
Rod bearing clearance: 0.0018-0.0020 in
Thrust bearing clearance: 0.003-0.012 in
Ignition: 32 degrees total

I still want to ask about:
piston to cylinder clearance and ring types and gaps

Anything else I should know and document?

I came to the conclusion that the clutch cover I purchased and balanced is not correct for the Voights assembly I have, when I started to check the geometry of the throw out bearing relative to the clutch cover. Specifically, my cover doesn't have a bearing platform, as it is a finger type, so is incompatible with the installed throw out bearing. It may be possible to find a different throw out bearing, for the Ford concentric slave cylinder Voights uses, but I think it is better to bite the bullet now, and just get the appropriate clutch cover, balance it, and install it.

Anybody need a finger type 170 ftlb capable clutch cover, balanced, but never used?

The Tilton, aluminum flywheel I have is proving to be a bit troublesome. When bolted down with the 12-crank bolts, to 55 lbft torque, the aluminum plastically deforms (Poison's ratio effect), closing the bolt hole slightly, and causing some gauling, the transfer of some aluminum to the retaining bolt shanks. Both the engine builder and Precision Auto in Simsbury, CT, USA, the balancer, advised me to clean up the bolt holes with a tapered reamer, to restore flywheel retaining hole clearances. While I have a hand reamer, this seems a bit crude. When installed, a bit of antisieze should be applied to the underside of the retaining bolt heads and I think also the bolt shanks. These bolts are to be torqued to 55 ftlb.

I checked that the T9 transmission shaft is not too long, which could destroy the thrust bearings, and found there was plenty of margin. I have a diagram if anyone is interested.

The custom (bespoke) shock absorbing, twin tube, drive shaft from TTR, is in and came with a T9 output shaft and UJ installed. Also included, were the fixings for the final drive, the breather, fill and drain plugs and sealing washers. I need to get the new clutch cover installed so I can do a dry fit of the complete drive train. Once the suspension and steering are trial fitted and the chassis is fitted, then it's off to the powder coaters to get the chassis and suspension arms coated.

I purchased TTR 26R upper front wishbones and I was thinking of installing the Spyder adjustable bushing carriers. Now, I'm leaning toward stainless steel, PTFE, rod ends with protective boots. TTR told me they had a lot of trouble with protective boots in the past, but there is a local outfit to me, that manufacturers rod end boots and I'm determined to stop by and see what they recommend.

TTR recommended suspension settings:

Front caster: 4-degrees
Front camber 1-1.5 degrees, negative with 1-degree preferred for street use.
Front toe-in: 3/16 inch overall, measured at the rim
Rear camber: 1-degree negative
Rear toe-in: 1/16-inch each side measured at the rim

I'm still looking for some S2 items if anyone can supply these, please PM me.

heater cable complete
Smiths fuel gage FG2530/71
Smiths ammeter AM 2300/01
S2 dash

I need an S2 dash. I will probably have a custom one made up because some items, like the lamp vacuum switch, will not be needed as I will be using 26R, fixed lamps with probably Hella Bi-Xeon lamp modules, that are small in diameter, so they can be mounted high in the headlamp openings, resulting in a light beam that should not be chopped by the head lamp opening,.

Bill
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PostPost by: nmauduit » Thu Jul 07, 2016 8:59 am

bill308 wrote:I came to the conclusion that the clutch cover I purchased and balanced is not correct for the Voights assembly I have, when I started to check the geometry of the throw out bearing relative to the clutch cover. Specifically, my cover doesn't have a bearing platform, as it is a finger type, so is incompatible with the installed throw out bearing. It may be possible to find a different throw out bearing, for the Ford concentric slave cylinder Voights uses, but I think it is better to bite the bullet now, and just get the appropriate clutch cover, balance it, and install it.
Bill


thank you Bill for the detailed insight regarding build specs. In case of any use to you, the Lotus 5 speed clutch system has a bearing without platform, and from that perspective may be a quick fix option (provided thickness is appropriate) - got mine from QED (179 pounds/in Helix http://qedmotorsport.co.uk/qed-shop/lot ... ompetition ) but should be available from all reputable Lotus vendors...
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PostPost by: rgh0 » Thu Jul 07, 2016 9:42 am

Burtons have AP racing clutch covers with a suitable torque rating. They have covers with both the bearing platform per 4 speed Elan and covers without as used by the 5 speed Plus 2 and other later Fords. Details of install height are provided. Burtons can also supply matching AP racing pressure plates but I have used other local plates ( Excedy) as they are half the price and appear to be not significantly different and perform well.

cheers
Rohan
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