Lotus Elan

S1 Élan Rebuild - My Story

PostPost by: collins_dan » Tue Jun 09, 2015 5:56 pm

I converted to narrow springs with the body still on, I used allen headed bolts to install the strut fully assembled with springs and resilient mounting on top. I am not sure if you will be able to remove them in one piece with hex headed bolts, like it appears you are using, but it sure makes things easier if you can. Just a thought. Dan
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PostPost by: CBUEB1771 » Tue Jun 09, 2015 8:53 pm

Certified Lotus wrote:Spoke with TTR about the old rear rotors not fitting with the new drive train parts. They told me they have "heard this before" so I ordered new rear rotors (and a few more parts on my list). Couple more days until they arrive and then I should be finished with the final drive assembly.

I wonder what part I need next and haven't thought of.........


I recently had a similar problem with new rear discs and outboard drive shafts from TTR. In my case the problem was clearly with the discs because the three bolts holes were slightly undersize and the unthreaded shank of an AN bolt would not pass through. I only had to open the bolt holes in the discs a few thousandths of an inch and then everything went together nicely. Fortunately I have a good collection of reamers for this kind of job, using a twist drill would have made a mess of the bolt holes in the brake discs. I also noted your comment about there not being an invoice on the outside of your parcel from TTR with the new inboard bearings. It must have been a rough day at TTR, I have never gotten anything from them without having all of the correct paper work on the outside of the box.
Russ Newton
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PostPost by: Certified Lotus » Wed Jun 10, 2015 9:15 am

John, Dan & Russ, thanks for your input and suggestions. I had a funny feeling that trying to mate old parts with new ones in the drive train was going to cause an issue so no real surprise that the bolt holes didn't align on the old rotors. I should be getting the new ones today from TTR. They were very responsive to my phone call on Monday as I got a shipping confirmation via email right away. Stuart and Tony at TTR have been great to deal with.

To clarify about the shipping documents, TTR had all the copies of the invoice in a clear plastic sleeve on the box. I have no idea why customs called me and said there were no documents and had me get a copy via email. When my package arrived with the documentation attached I wondered if they just didn't turn the box over to look for it.
Glen
65 Elan S2 - 26/4055
72 Europa - 74/2358R
69 Elan S4 - 45/7941
64 Elan S1 - 26/0379
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PostPost by: Certified Lotus » Wed Jun 10, 2015 9:48 am

Long conversation with my engine builder yesterday. They are perplexed at the "standoff" at 6800 rpm on the dyno. Took the head off the engine and found out the valve keepers were not all the same thickness and there was zero clearance on two of the intake valves. New parts being ordered. Another delay. So much for my three week marathon rebuild plan.
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65 Elan S2 - 26/4055
72 Europa - 74/2358R
69 Elan S4 - 45/7941
64 Elan S1 - 26/0379
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PostPost by: billwill » Wed Jun 10, 2015 11:27 am

You do know that the normal engine is not supposed to go faster than 6500-6575 RPM don't you?

I'm not an engine expert, but I've gathered from this forum, that unless you have uprated crankshaft and conrods, valvesprings and bearings you are likely to break the engine by making it go faster than 6500 RPM.
Bill Williams

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PostPost by: rgh0 » Wed Jun 10, 2015 11:58 am

As Bill says using the standard crank regularly beyond 6500 rpm is going to ultimately end in tears. Use it beyond 7000 rpm and you will back to your engine builder sooner rather than later.

150 hp at 6500 rpm on road fuel is about as good as you will get on a 1600 cc twink with a standard crank and good head and cam and exhaust. How drive-able that 150 hp is depends on the type of cam used and how well setup the rest of the engine for your intended use.

Strange to have no clearance on two inlets after a short run on the dyno as the clearances once set right do not generally change unless the valves were not seated properly in the first place. Valve retainers of different thickness are unusual and I have never seen it in a new set from any of the normal suppliers, they don't affect the valve clearance anyhow.

Without knowing the cam or springs your using its hard to comment on whats going on at 6800 rpm but you should not really be dyno testing a standard crank engine at these revs in any case. This card from Dave Bean has been a friendly reminder to me over the years :lol:

dave bean.jpg and


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PostPost by: oldchieft » Wed Jun 10, 2015 3:10 pm

I think if the collets settle into spring caps you lose the clearance and the cam follower acts on the spring cap.

Maybe what happened here?

I always like to ding the the valve stems with a soft drift a few times to settle them.

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PostPost by: Certified Lotus » Wed Jun 10, 2015 5:40 pm

I was waiting for a response to 6800 rpm ;-)

The instruction to the engine builder was a mid range torque engine that was to be used on the street using pump gas and wanted it to be bullet proof. Will probably never go beyond 6300 rpm (unless I do something stupid).

Magnaflux'd the crank, all good. New Pistons, rods, valves, springs, bearings, modified oil system, ported and polished, etc, etc.

When he told me that he couldn't get the engine beyond 6800 rpm I was shocked. What are you trying to do, blow it up before I get it? Was told not to worry, he knows how to set these engines up.

As this shop builds lots of competition engines I'm taking them at their word. I'm waiting for the final results and the Dyno run with me there. Any day now, any day.........
Glen
65 Elan S2 - 26/4055
72 Europa - 74/2358R
69 Elan S4 - 45/7941
64 Elan S1 - 26/0379
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PostPost by: PaulFinch » Wed Jun 10, 2015 6:00 pm

Sure, if you try to rev a standard bottom end to 7.5k it's going to go bang. Standard valve train won't like it much either,

My engine builder (who has a successful 35 years experience with racing twin cams) assures me a well prepared standard crank will go to 7.5k. Assuming ARP bolts and steel rods are used.
The cause of failures on over revved twinks is more often than not conrods and big end bolts. He refreshes one engine out of a brabham single seater every 18 months or so which has been using the standard style crank without problem for years.

I believe Vizard agreed with this 7.5 limit for a properly modded heat treated crank. Of course one could argue if you're going to go to those lengths you may as well go steel!
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PostPost by: pharriso » Wed Jun 10, 2015 6:23 pm

You're doing this at Marcovicci Wenz Engineering right?

Your bill must be huge!! :roll: :roll: :roll:
Phil Harrison
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PostPost by: Certified Lotus » Wed Jun 10, 2015 6:32 pm

Paul, that's what I was told. Not that I'm ever going to go anywhere near 7K. The rods and pistons are all custom. High strength bolts. Top end will handle abuse with the entire valve train and cam setup being built accordingly.

Phil, engine being built at Quicksilver Racing. And sadly, yes, it's a big ticket to build it right.

As I said in the beginning of my opus, I bit the bullet hard. If I'm going to go through a complete rebuild, this is the way I do it.
Glen
65 Elan S2 - 26/4055
72 Europa - 74/2358R
69 Elan S4 - 45/7941
64 Elan S1 - 26/0379
12 Colin 30 - Lotus Racing Kart
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PostPost by: Craven » Wed Jun 10, 2015 7:22 pm

Ask him to put his reassurance in the form of a written guarantee.
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PostPost by: Certified Lotus » Wed Jun 10, 2015 8:21 pm

Yeah, good luck on that. I have had lots of engines built over my lifetime. Have never been able to get a real guarantee.
Glen
65 Elan S2 - 26/4055
72 Europa - 74/2358R
69 Elan S4 - 45/7941
64 Elan S1 - 26/0379
12 Colin 30 - Lotus Racing Kart
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07 Exige S - Fast Road/Track Car
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PostPost by: rgh0 » Wed Jun 10, 2015 8:40 pm

Sadly I have seen to many people who were told by "experts" that a standard crank is good for 7500 rpm being towed in off the track with a busted crank !

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PostPost by: Certified Lotus » Wed Jun 10, 2015 8:56 pm

Agreed on that Rohan! I don't abuse my engines. It's the reason I have them dyno'd with a plot printed out. Look at the torque curve and figure out where to shift. Of course the danger is a steady curve all the way up to the breaking point.

As I'm not tracking this car there is no reason to hold the rpm's at the threshold of danger. Just be careful not to accidentally down shift or miss a gear at high rpm.

Anyway, it's all speculation. Will see what happens in the first season of driving. Need to get my S1 back on the road first !
Glen
65 Elan S2 - 26/4055
72 Europa - 74/2358R
69 Elan S4 - 45/7941
64 Elan S1 - 26/0379
12 Colin 30 - Lotus Racing Kart
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