Lotus Elan

Fast Road Twink: Two Engine Builders, Two Recommendations

PostPost by: Stevie-Heathie » Mon Feb 06, 2017 12:55 pm

Thanks Jon

Your power and torque curves are just what I'm after (does this mean I am admiring your curves???).

You're the second to suggest the Sprint cam (or QED Equivalent).

I've decided not to decide until the head has been pulled and my builder can advise on the state of the valves and seats etc. If I do indeed have larger "big valves" already then the Sprint / 360 cams would probably be the preferred approach.

Thanks for sharing.

Best
Steve
1967 S3 SE DHC
1970 +2S (RIP - went out in a blaze of glory in 2001)
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PostPost by: jono » Mon Feb 06, 2017 4:34 pm

Hi Steve,

Just to add, my TC started as a SE spec engine. The existing cams were re ground to 360 spec by QED on an exchange basis (much cheaper than new off blanks).

I had the head re worked and larger valves fitted to inlet and exhaust. Vernier pulleys were used to get the timing 'right' my engine guy timed them 'for torque' (the witchcraft is beyond me).

That said I had to completely strip and re build the engine after only 80 (eighty) miles due to a myriad or errors by the builder - head gasket, water pump and other things. Oil that looks like cafe latte is not nice to see.

I'm no expert but I managed to do that and now have a very nice engine (except for oil leaks which I am shortly going to pull the engine to deal with).

So, don't rule out doing it yourself (but get a specialist to do the head - I would recommend Paul Exon but others might say otherwise). That way you can be meticulous in a way that a commercial builder might not be due to time/cost constraints.

Just my two 'pennorth'.

Jon
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PostPost by: Stevie-Heathie » Fri Mar 17, 2017 2:13 pm

UPDATE MARCH 2017

I took the Elan to Rawles Motorsport in Alton, Hampshire last week to get a proper baseline power run done on their rolling Road. I was pleasantly surprised at the result. 93bhp at the wheels so call it 110bhp at the crank. Nice flat torque curve, A/F between and 11 and 13. Pretty much bang on for an SE (I was amazed) but a bit smokey.

Armed with my dyno print outs I went to see Max at Max500 in Guildford and we had a good discussion about where to go next. He pulled the head and found:
1. Big Inlet valves
2. Regular exhaust valves
3. SE Cams
4. Bit of play in valve guides (hence the smoke?)
5. Head may have been skimmed once but only lightly. Face nice and flat.
6. Generally good nick.

So we've decided to:
1. machine and sort out the valve guides (to reduce the smoke!)
2. clean up the porting a bit - remove the burrs.
3. Install QED 420 cams and the necessary 55 springs - if the piston cut outs are deep enough to provide the necessary clearance. (QED 360 cams if not - I'm not up for a bottom end rebuild as well at this stage!)
4. Install vernier timing
5. Sort out timing & rejet carbs as necessary
6. Drive around grinning like a fool (hopefully).

Then I'll go back to Rawles for final set up and another power run to see what we've managed to achieve.

Stay tuned folks, and thanks for all the advice so far.

Steve
1967 S3 SE DHC
1970 +2S (RIP - went out in a blaze of glory in 2001)
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PostPost by: LorraineLH » Fri Mar 17, 2017 5:20 pm

Look forward to hearing the results from this, hope it goes well.
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PostPost by: Stevie-Heathie » Tue Apr 11, 2017 8:46 pm

UPDATE - APRIL 2017

Well I'm delighted to say that Max turned around my engine in under 3 weeks and I've had the car a couple of weeks now.

In summary the engine work was:
- Clean head
- Remachine valve guides
- install QED 420 cams, with necessary 55 springs etc
- install vernier timing
- re-jet webers
- new valves
- bed in valves
- set timing and tune

Wow, what a difference. I'm delighted. The engine feels transformed. Pickup is faster and both the power and torque have been improved significantly. The engine starts much better (first time from cold!) and smokes less. Still occasional blue haze but not a concern.

Exhaust note sounds better too - more "raspy" if you know what I mean.

Car is very noticeably quicker now - so much so I can scare my myself in it (is this a good thing? :shock: ). A proper pocket rocket, the performance is now in balance with the exquisite handling, which is what I was after from the outset.

The carbs aren't quite set up perfectly - but lumpy 1700-2000rpm, but hopefully they will rectify on the RR at Rawles when I go in few weeks.

I'll be fascinated to see what the dyno run at Rawles will reveal, I'll be sure to share the "before" and "after" plots here.

Best
A Happy Stevie
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PostPost by: gibbon » Wed Apr 12, 2017 7:40 am

Very interesting reading thank you.

Would it be possible for you to add rough costs of what you've had done?

Looking forward to reading about the next rolling road session.
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