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cylinder bore wear


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Whats going on here???

Similar marks in three other bores.

Weirdly not on the thrust or opposite sides

Front of bore 1, and 5

rear of bores 4 and 8 so the very front and rear of the engine??

Not measured them for roundness yet

Compressions were OK

1 160

2 158

3 164

4 160

5 164

6 162

7 165

8 158

20210420_153041.jpg

20210420_154044.jpg

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Are the pistons fitted with the correct orientation in those affected cylinders?.... 

1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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No - no coatings.

1996 Esprit V8, 1998 Esprit V8 GT, 1999 Esprit S350 #002 (Esprit GT1 replica project), 1996 Esprit V8 GT1 (chassis 114-001), 1992 Lotus Omega (927E), 1999 Esprit V8SE, 1999 Esprit S350 #032, 1995 Esprit S4s, 1999 Esprit V8 GT (ex-5th Gear project), 1999 Esprit V8SE ('02 rear)

1999 S350 #002 Esprit GT1 replica

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Posted (edited)

Hi Michael.

It was a development engine with 400 hrs on a dyno and had never been in a car.

i got the engine with damaged valves and no ancillaries.

I stripped the engine to check the internals, had the heads rebuilt with new valves and guides Turbo's etc and have done 15000 miles  with it in my car over 11 years.

Tappy noise( like a lifter) developed three years ago and i have been trying to pinpoint the cause since then

Cam followers were replaced last year made no difference.

In addition earlier this year i noticed buzzing from the oil cooler pipe, so expecting this to be a broken oil pick up pipe i decided to rip the engine out before it did too much damage.

Only thing found on strip down is excessive slack on the timing chain which could cause the tapping ? slapping when the engine was on light load/no load

Never burnt oil but there is oil in the boost pipes ( i suspect from oil level blocking the turbo drain lines)

Engineering shop just confirmed the bores are fine with the honing marks still evident in all bores top to bottom.

Going to have the rotating assembly balanced before i rebuild it but i would have really liked to have found something broken then fix it before rebuilding it.

?

 

 

Edited by alanlambert
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you guys from England have the most interesting stories of where you source your parts😆  It's becoming a dream of mine to go and visit some of you😂

so the Shop found no out of round of the cylinders and so far the pistons have not been pulled out. It will interesting to see what the cylinder liners look like on the outside as well as the pistons and rings. 

So you will have them re-balance with new rings and verify the piston wrist pin holes have no abnormal wear, meaning the pistons where not slapping around?

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Yep was a bit of luck,

an ex colleague of mine called one day and said he was stripping out a warehouse in West London ready for a new tennant and he found a red engine on a pallet on a mezzanine floor and he knew i was a petrol head.

It had been left by the outgoing tennant .

The previous occupants of the factory was AC cars who had decided to relocate to Malta.

The design engineer was John Owen who was previously the lead design engineer at Lotus developing the V8 engine.

I tracked him down in Malta and asked him about this engine and he told me its history

When he left Lotus he took with him the old development engine with a view to producing AC Cobras with Lotus V8's in.

They made two but were not popular (doesn't sound like a V8) so didn't pursue the lotus engine route any further

Turns out when they left the unit they didn't have any way of getting the engine down to the ground to transport, so they left it there.

We didnt have a crane so improvised

John died in 2012 😪

One piston out so far, all OK and yes the con rods will come off the pistons for match weighing checking and all balanced.

The crank looks to have been internally balanced but while its out !!

 

 

IMGP7751.JPG

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After thinking about this and it makes me really want to buy a borescope to stick down my bores and see how my Self-tuning has made my cylinders looks. 

Too much fueling from my initial startup tune together with an accidental water syphoning from water/meth tank in the very beginning has had me wonder. 

Then theres the fact I dont use the Knock sensor or the factory "rough road" sensor mounted on chassis to eliminate possible detonation, I rely simply on taking baby steps in the tuning. 

Question, are you using knock sensor on your tuning computer?

 

 

 

Edited by v8GTmac1
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  • 3 weeks later...

Found bit of movement in some of the small ends, so ordered new bushes

Slight rumble in the bearing on the accessory belt tensioner. Bearing isnt replacable 🙄

Dont want to pay over £300 for new tensioner and pulley so found that its used on loads of American V6's

Ordered a new pulley for a 2004 Ford F150 V6, 😀

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That explains what’s happening there. 

Does it add up rhatvthe poay is only on that cylinder?

 

good job on the pulley, learned something new. 

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I do purchase from SJ, but could only find the pulley with the tensioner, at about £280 plus.

No problem with the pick up pipe just a small heap of sealant material sucked to the gauze but not enough to restrict flow, so dont know what the cause of the vibration was.

Pressure relief valve moves freely and always had good oil pressure 🤔

 

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