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Engine is dead - compressions through the floor


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Ran the compresisons checks tonight

worst cylinder had only 98psi - best was 118... :( .. so no S'stone for me.

Fair to say engine is pretty goosed - so time for a new engine - will speak to Gary Kemp and John Welch re an uprated engine/turbo package whilst also looking for someone to do that elusive 383 stroker conversion.

Aim now is to have a strong pakcage by Jan/Feb - tested and ready for first race in May. I've set aside a budget of no more than 10K to achieve that aim. :(:P

:(

It's alive.. alive!!!..

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Ran the compresisons checks tonight

worst cylinder had only 98psi - best was 118... :( .. so no S'stone for me.

Fair to say engine is pretty goosed - so time for a new engine - will speak to Gary Kemp and John Welch re an uprated engine/turbo package whilst also looking for someone to do that elusive 383 stroker conversion.

Aim now is to have a strong pakcage by Jan/Feb - tested and ready for first race in May. I've set aside a budget of no more than 10K to achieve that aim. :(:P

:(

I'd be interested to know what failed, share the pics.

Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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I'd be interested to know what failed, share the pics.

Still got to do proper exploratory work but she felt rough as a dog when turning over - very wheezy.. 3 cylinders looked shiney shiney.. some scoring from initial peer down but we decided to call it a day.. :P

basically a boost pipe was cracked so car overboosted while the chargecooler failed - inlet temps reached 90 degrees and afr crossed 14.7 under load.

It's alive.. alive!!!..

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Garry Kemp is advertising a hot new S4 motor complete as an exchange in the Parts section for less than

Proud recipient of the LEF 'Car of the Month Award' February 2008

"Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and loudly proclaiming: "Wow, what a ride!!"

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Ran the compresisons checks tonight

worst cylinder had only 98psi - best was 118... :P .. so no S'stone for me.

Hi - just a minor point here, was your compression test done with the engine warm and the throttle fully open? I forget the min psi for the engine (120?) but you need to test with a warm engine and open throttle otherwise the reading will be lower than expected.

Regards

ALan

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Hi - just a minor point here, was your compression test done with the engine warm and the throttle fully open? I forget the min psi for the engine (120?) but you need to test with a warm engine and open throttle otherwise the reading will be lower than expected.

Regards

ALan

Those are all good points.

Another thing that people neglect is that at higher altitudes, the compression will be lower. my compression at 5300ft is lower by 11psi IIRC.

Still, it sounds like Jon's motor is gone. It has ceased to exist. It is an ex-motor. If has gone on to join the choir invisible... :P

Travis

Vulcan Grey 89SE

My Lotus Photo and Projects Album

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It was a cold engine - throttle full to the floor..? Car sits near sea level - ambient temp about 23 degrees C.

can someone confirm that the compressions quoted are those of a deceased engine - I'd h8 to miss a track day for being over-cautious but nor do I want to take a engine that wil likely let go.. suffice to say I've spent a good few hrs over last weke replacing and fixing and this morn car should be going to the dyno.

Mechanic buggered off as presumed engine dead - he looked down one of the bores and 3 were shiny shiny which I believe is also not a good sign..? He used a digital tester but we didn't do a leak-down test.

John Welch recommends a rebuild between 130-145psi but I want to know if the engine would survive the day.

Edited by M Blur

It's alive.. alive!!!..

altimeter.gifsai.gif

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It was a cold engine - throttle full to the floor..? Car sits near sea level - ambient temp about 23 degrees C.

can someone confirm that the compressions quoted are those of a deceased engine - I'd h8 to miss a track day for being over-cautious but nor do I want to take a engine that wil likely let go.. suffice to say I've spent a good few hrs over last weke replacing and fixing and this morn car should be going to the dyno.

Mechanic buggered off as presumed engine dead - he looked down one of the bores and 3 were shiny shiny which I believe is also not a good sign..? He used a digital tester but we didn't do a leak-down test.

John Welch recommends a rebuild between 130-145psi but I want to know if the engine would survive the day.

Lotus' minimum spec is 140psi (at sea level, hot). Cold you might expect maybe 3-5 less... But that 98-118 is pretty bad. It'll probably run, just not make much HP, and smoke...

Travis

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John Welch recommends a rebuild between 130-145psi but I want to know if the engine would survive the day.

I think a valve job may be in order at those pressures not a reuild. :P

Luke Colorado, Super Spy.   -  Lotus Owner No Longer

1987 Zender Widebody 560SEC | 1994 Lotus Esprit S4 | 2013 Honda Fit EV (#269)

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but if I did no work to it it could let go - yes? - full day - GP circuit - full throttle for long-periods of time - may hit 150+ in 5th easily.

You can drive Honda with lower compression thatn that for 100,000miles... It just won't be making more than 80hp.

At race speed with a turbo, I don't know how long it'll last??? If it went pop recently, which prompted you to look at compression... Then it may go bang soon?

Travis

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reckon you're right - think Garry Kemp would prefer to take a runner in exchange even if poorly rather than a box of bits from a piston going bye bye at 160..

Yeah, the biggest worry is probably oiling. With the lower compression you'll be burning oil, possibly pressurizing the crankcase... all sorts of problems. If you were to run low on oil during the race/event, that's probably the worst that would happen. With low compression I doubt you be making enough hp to damage or stress parts, except from a lack of oil.

Travis

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My Lotus Photo and Projects Album

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