Lotus Elan

Dave Bean stroker pistons?

PostPost by: Plus2soon » Wed Mar 29, 2017 10:41 am

Hello Everyone,

I'm rebuilding my engine and planning to go the 711M /1700cc / Q420 route. Block, 1600 crank 3,06" strok, new 5,23" Carrillo rods are already on my shelf. I like to keep the tall deck height for strength reasons and found Dave Beans so called stroker pistons for 83,5 mm bore and 1,46" compression height made to just this purose! My enginge builder have not used these pistons earlier and he asked me to fin out what rings DB uses. I have asked them, but no answer so far. Also I like to know if they are directional, i.e. have pin offset. I have got indications that CP Pistons do not have offset pin and if they supply DB the risk is I get non offsets pistons from DB.

Does any one have any input? Are there any other supplier of this piston spec without need to custom make them? Any help much appreciated :)

Johan Wintzell, Sweden
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PostPost by: SimonH » Wed Mar 29, 2017 11:23 am

Hi Johan,

These ones from Burtons sound similar.

http://www.burtonpower.com/accralite-fo ... fl114.html

Cheers,
Simon
Last edited by SimonH on Wed Mar 29, 2017 3:56 pm, edited 1 time in total.
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PostPost by: Plus2soon » Wed Mar 29, 2017 3:35 pm

Thanks Simon,

I tried the link but could not get it work. Had a look into my old Burton catalouge back from 2013 and only found the "1600 X-Flow conversion" pistons (FL114) which are about 1,76" CH i.e. taller then originals. I need a shorter compression height then original at 1,46" to keep deck height intact combined with 5,23" rods (BDG). Is there a new piston at Burton?! Maybe I can find it through the web...

Thanks /Johan
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PostPost by: RichardHawkins » Wed Mar 29, 2017 6:26 pm

Johan,

I believe a stroker engine is about 12mm taller than the standard engine. I am currently struggling with bonnet clearance with a standard engine in my S4 Elan. How do you find the exta room for a taller engine?

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PostPost by: rgh0 » Wed Mar 29, 2017 7:16 pm

The height you can set the engine at the front is determined by the carb to footwell clearance. With a talll block 711M engine you just set the block lower by slotting the engine mounts as needed to maintain the head at the same height in the car. The sump is off course lower.

cheers
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PostPost by: Plus2soon » Thu Mar 30, 2017 11:52 am

Richard,

I will sort that out as Rohan describes, all though I have a pair of scraped standard engine mounts which I will convert to superflex polyurethane 1" 80 grain bushes. Here you find instruction video for a Europa application, same mount but upside down ;-)

https://www.youtube.com/watch?v=QdnSkwT_Fco

The visual change from orginal is minimal, but you end up with a cheep, fail safe solution. When fabricating the mounts you can chose engine height as you please.

Cheers Johan
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PostPost by: ceejay » Sun Oct 22, 2017 6:32 am

Hi folks, just like to make a comment re the urethane modded engine mounts. I too went down this path a few years ago during the rebuild/restoration of my Elan S2.

I spent many many hours doing just what was described/detailed in the video, the new mounts all fitted in great, and then one day the first test drive arrived... well, I was astounded with the amount of vibration caused by the modified and very firm engine mounts, I drove all of two kilometres, then returned to the workshop to begin the job of removing them to put the standard engine mounts back in.

If I was to offer anyone a bit of advice about this engine mount mod, the urethane or poly bushing material needs to as large as is physically possible to put in the engine mount bracket, as you still need some flex in the mounts.

I will revisit this mod again sometime in the future and try something different, because the standard items do fail to quickly.

If you are currently rebuilding/restoring an elan or Europa and have already carried out this mod, and not yet carried out any test drives, then be prepared for a very different driving experience, I found the NVH or Noise Vibration and Harshness to be totally unacceptable.
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PostPost by: Foxie » Sat Oct 28, 2017 7:54 pm

Plus2soon wrote: Had a look into my old Burton catalouge back from 2013 and only found the "1600 X-Flow conversion" pistons (FL114) which are about 1,76" CH i.e. taller then originals. I need a shorter compression height then original at 1,46" to keep deck height intact combined with 5,23" rods (BDG).

Johan


I'm using Dave Bean 1.13" compression height 85mm pistons and 82mm crank with new QED Lotus block, built last year. Going very well :)
68 Elan +2, 70 Elan +2s
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