Engine rebuild project following blown piston

[F1 LOTUS]

This close-up shows a little bit more of possible damage?

And from the piston picture I would guess the gradual melting/erosion of the crown led to the oil-ring failure as it doesn't look like anything big got past the compression rings?

[paulwatkins]

This sounds like a very plausably explanation I must say. If you look at the spark plug pic on page 2 of this thread, there is a considerable amount of metal 'missing' from the centre electrode.
Maybe fatigue, or possibly damaged during insertion? Who knows?

I will have a much closer examination of the valves and surrounding area tomorrow - especially at the areas F1 Lotus has indicated.

Thanks for the excellent support guys!

[delta]

A typical melt-down- coursed by injector failure - as seen so many times before.

The intense heat from the lean burning + the spark it self can easely melt the tip of the sparkplug, but also crack the insulation due to heat expansion of the metal tip it surrounds.

So this seems to be a consequens of the injector failure, and not a fault by it self.

As the piston has melted, there is a huge risk that the high temperature on the cylinderwall has created some ovalety, which can not be corrected by honeing, so check very carefully.

Also the marks on cyl 4 seems very deep.

All in all, I suggest you go for the rebore an oversize pistons, even though it's expensive.
Delta

[F1 LOTUS]

[stevieshag]

Hi Paul,
whats the latest.
how were the valves etc, have you decided to go for an oversize piston.

[paulwatkins]

The engineering company called around yesterday morning. Unfortunately, the honing repair did not remove all the damage to the no2 cylinder wall. That means a re-bore of all cylinders is required. He was unable to complete the re-bore yesterday, because the bore diameter needs to be calculated from the actual piston diameters, so I need to get hold of these first. I have decided to go for the +0.5mm oversize pistons and rings.

As delta indicated on previous responses, I will also replace the injectors

[stevieshag]

Hi Paul,
not so good news then, do ya wannna borrow my engine hoist, & have a look at my injectors, i dont mind a trip out to drop any of it off.

stevie

[paulwatkins]

Hi Stevie,
I'd like to take you up on your offer mate. I'll pm you my contact details.

[stevieshag]

Good to chat to ya on phone, found this firm who service injectors, didnt think the price was too bad at £18 each.. they got couple of movies too showing processes..
http://www.pineport.co.uk/p_injector_servicing.html

[paulwatkins]

Hi Steve, thanks for the info. I'll give them a call later. Also found some local firms which i'll try.
Cheers, Paul

[GeoffSmith]

Bloody hell Paul, sorry to see it turned out this bad for you.

Any recommendations on the engineering company guys?

I have at work but it's obviously a bit late for you now. Sorry, I've been on holiday.

Good luck with the rest of the work.

Geoff

[paulwatkins]

Cheers Geoff, hope you had a nice hol.

Had my injectors back from servicing today. The flow rates, after being refurbed, are 85 - 87 - 84 - 85.
This certainly shows that there is something not compeletely right with no2 set up. I am going to replace the no2 injector.

delta - would these readings confirm your original thoughts on the problem? Its a shame they didn't give me the flow rates before the cleaning. Do you think I have found the source of the problem?

[delta]

delta - would these readings confirm your original thoughts on the problem? Its a shame they didn't give me the flow rates before the cleaning. Do you think I have found the source of the problem?

The max. difference is less than 4% and can not have create the problems you had, and must have been much higher before cleaning. (10% diff. would not be critical, so you might have had a diff of more than 50%.)

The Q here is what the flowrate is surpose to be. I don't know, so you need to ask a specialist about that.
Delta.

[paulwatkins]

delta, I was a little bit annoyed that they didn't have the 'before cleaning' flow readings for me. I did ask them to!

I think stevieshag has got some spare injectors which I am hoping to use. The service company has said they will test the flow rate of a replacement injector for free. It will be interesting to compare the flow rate readings.

Unless I can get the flow rate information from someone who knows! Anyone know?

[stevieshag]

injectors in the post.
stevie

[paulwatkins]

Just an update.
I've had the spare injectors from stevieshag tested and they have found a suitable replacement for my dodgy one. The flows on all injectors will now be very similar.

I have ordered the parts that I need from SJ Sports - new pistons, rings, gaskets, studs, nuts etc etc. They should be with me in about 2 weeks time. When they arrive, I'll be able to arrange for the reboring work to be done.

By the way, for those who want to know, the reboring can be done with the engine block in-situ.

[F1 LOTUS]

If you take the bonnet off can you tell me its weight, please?

[Doc Fizzix]

If you take the bonnet off can you tell me its weight, please?

Do you mean the hood (in US slang)?

Very light, I would be supprised if it was over 5 pounds or even 3 pounds but I am just guessing from when mine was off for the engine swap.

[paulwatkins]

If you take the bonnet off can you tell me its weight, please?

Brian, are you being serious?
Running the risk that you were, I've just jumped on the scales with my hood! To the amusement of my missus.

The weight was 7.8kg or 17.2lb.

That doesn't include the hinges, but does include the catch, spring, prop-up rod, screenwash nozzles and pipes and the lotus badge!!

[F1 LOTUS]

I can't believe you actually did this!





Actually I was serious, I figured it would be at least 15lbs, perhaps closer to 25 in spite of how light it feels compared to other hoods? A good carbon version should save about 10 -12lbs, but at a cost of around $800 it's not particularly good value even though it's weight off the front and it's high up
Thanks for doing that