Engine rebuild project following blown piston

[Paul.P]

The Man is a machanic so i think he knows what he's talking about

There's mechanics, & there's mechanics Monty ?

[Monty]

shame u don`t know a good one then

[paulwatkins]

Paul i have a engine crane here if ya need it, i can drop it over & you can have it for the duration of rebuild. may save ya a few quid on hire..
just let me know.
stevie

Hi Stevie, thanks for the offer. Very generous. Do you mind if I wait on giving you a reply though?
I'll have the cylinder wall looked at first. If they say that the engine needs to come out aswell, I would really appreciate the loan.
If it can stay in though, I wouldn't want to put you out just to put the cylinder head back on. I'll go back to the local hire place.

Thanks again for the advice guys

[Paul.P]

shame u don't know a good one then

Monty, ain't saying i'm right here, just saying what i was led to believe ?, but will make enquires with a GOOD mechanic, who will know. , but pretty sure the aim of honing is to de-glaze the bore, to give new piston & rings something to bed to. What it does is very lightly scratch the surface of the bore, just cant see that it removes anywhere near enough material to cause piston slap. Now i could be wrong, so anyone with with more knowledge on this, please let us know ?

[Enright]

Monty's puttin' up his dukes again!

Paul W - did you really find it necessary to have an engine crane to remove the cylinder head? I would have thought that it was a bit of overkill from past experiences - although I understand that Elans may be more difficult (they usually are)!

[paulwatkins]

Neil, you are right. The cylinder head wasn't particularly heavy, but it is quite an awkward position to lift it out of - you have to lean over quite far. And to be honest, I wasn't quite sure what to expect - not done this kind of thing before. Using the crane did make the job extremely easy and will probably use it to lift the head back in. Dont want to drop it and cause more damage! I got enough on my plate at the moment!

Any recommendations on the engineering company guys?

[Monty]

shame u don't know a good one then

Monty, ain't saying i'm right here, just saying what i was led to believe ?, but will make enquires with a GOOD mechanic, who will know. , but pretty sure the aim of honing is to de-glaze the bore, to give new piston & rings something to bed to. What it does is very lightly scratch the surface of the bore, just cant see that it removes anywhere near enough material to cause piston slap. Now i could be wrong, so anyone with with more knowledge on this, please let us know ?

Paul,

Don`t know why u`r going on about it, u don`t have to explain what honing is to me. I`m only relaying what i was told, Funny enough I seen Dave today at the golden cup at Oulton where he is a machanic in one of the paddocks where there racing a Marcos & Lotus eleven and asked him again, he`s done high number of honing on different types of engine and never had problems but when he did his M100 he got PISTON SLAP!
and if u don`t shut up i`ll Slap u LMAO

Paul.w
I told dave about u`r engine problems and he said if u`r getting new pistons go for the oversize ones and have the cylinders rebored, if u remove the engine yourself it won`t cost to much to have the reboring done. (only passing information on)

[paulwatkins]

Can anyone point me in the right direction for the replacement piston/s - whether they are standard or oversized?

Going to get some advice on the cylinder wall reconditioning.

[delta]

One piston in oversize and the rest in standard will create un-ballance, stress the crank, give extra wear on bearings etc. ect. Don't do it.!!! If you have to go oversize, then do them all.

Think it will be safe only to hone and replace the one piston with a st. size.

But as also others have stated.: Find the course of the problem before you rebuild anything.
Delta

[paulwatkins]

Delta, thanks for the warning. In fact, I was given the same advice by the engineering company I contacted earlier in the week.
The chap advised me to remove all 4 pistons to check the other cylinder walls for any signs of damage. When they are out, he will then visit to see what repair is required.

1. Hone all 4 cylinders, replace the damaged piston with a standard size one and re-use the other 3 (all with new rings)
2. Rebore all 4 cylinders and go for 4 new oversized pistons.

Hopefully not the later for cost!
His guess - from the info i gave him - was that this was a timing problem; pre-deternation which caused the damage to the piston, cylinder wall and the spark plug.

[delta]

His guess - from the info i gave him - was that this was a timing problem; pre-deternation which caused the damage to the piston, cylinder wall and the spark plug.

Don't think so.
If true, you should see the same problem on all 4.

Still think it's a injector problem.
Delta

[Monty]

Hope that it was obvious to do all 4 if u was going down the oversize route

Can u buy a single piston?

Shame there isn`t someone who`s got a stripped/damaged engine who could donate a piston

Still check timing etc but just wondering how do u check for a faulty injector or is it just a case of replacing them?

[paulwatkins]

Well guys, I got the pistons out with no trouble.
See the pic below for the damage to the rear side of the piston - ouch!
The no 2 cylinder was the only one with severe wall damage. No 4 cylinder had some minor scoring - I'll have the engineering company to look at it and see what repair they recommend. See the pics.
No 4 piston had corresponding scoring on it. See pic.

Any comments welcomed!

Monty,
1. It was pretty obvious that you couldnt just oversize 1 piston! But it is good to have it confirmed by you guys! I did a car mechanics course when i was an apprentice (16 years ago) but i'm no expert. Having fun doing this strip-down and rebuild though!
2. You can buy single replacement pistons. SJ Sportscars supply them.
3. I'm going to replace the injectors with new.

[Candles]

That is horrific! Does anyone know if you can just get oversize rings as these and a bit of honing might sort the cylinders out.

About the injectors; did you notice any rough running? When one of mine was sticking, it ran a bit like a 3 cylinder engine.

Could you have ingested anything nasty?

Candles.

[Enright]

Wow, that is quite some trophy you've got there Paul, probably worth having it mounted and framed at the end of your ordeal!

This is also turning into a pretty trail-blazing thread that you've started, and I for one am continuing to watch it with interest. I also must compliment you on the clarity of your pics - your photography skills have improved throughout the project too!

A few questions though if I may:
What did they say about honing the bores - can the job be done with the engine still in the car?
How difficult was it to get the sump off and the pistons out? Did you have to remove the prongeron or the engine?
Have you got any idea of costs yet?

I guess the shopping list consists of:
Hone x 4
Head gasket
Piston (remember you can re-use the gudgeon pin & con rod)
Set of rings
Injector
Oil & filter change
Spark plugs
Big end bearing shells & valve stem seals? (Might as well do them too while it's all out)

Like Candles, I also wonder about the diagnosis so far.
I've not seen this sort of failure before but it just doesn't seem quite right for it to be fuel related to me.
The reason I say that is because I would have thought that the hotter side of the piston would be the exhaust side if anything. And any pre-detonation problems I've seen in the past usually ended up simply melting a hole straight through the middle of the piston. Although I stand to be corrected on that theory, and would be interested to see other examples. Perhaps a search would be worthwhile.
Also, what do the combustion chambers look like in comparison to one another - is there any valve damage?
Go on, get back out to that garage with your camera and flip your head over!!!

[paulwatkins]

Candles,

About the injectors; did you notice any rough running? When one of mine was sticking, it ran a bit like a 3 cylinder engine.

The car was running really rough on its final journey! I've removed the fuel rail and injectors, but from a quick external glance, I cant see anything obvious. See the pic below.

Neil,

What did they say about honing the bores - can the job be done with the engine still in the car?
How difficult was it to get the sump off and the pistons out? Did you have to remove the prongeron or the engine?

The engineers said that honing could be carried out with the block in-situ. Not sure about re-boring though. They said they have a mobile machine shop, but I assume the block will need to come out for that operation. I'll see what they say when they take a look.
Getting the pistons out was straight forward enough (from the stage I was at ie the cylinder head off). Just had to remove the engine underframe and a semi-circular shield that covered the bottom half of the flywheel - this was a little bit fiddly. Then the sump came off easy enough. Release the 2 nuts from the big end and push the piston up through the block.

I've got some costs for the pistons. standard size £42ea +VAT, rings £23ea set +VAT. oversize 0.5mm £36.68 +VAT, rings £23 ea set +VAT.
+delivery.

Estimate for home visit and honing 4 cylinders - £75. Dont know about cost of re-bore if required.

Dont have costs for injectors yet. I already have head gasket set, oil filter, spark plugs etc. I will need a few more gaskets. I've taken most of the bits apart to give them a thorough clean and will need to replace the gaskets when I rebuild. Aswell as some threads which have corroded / or had to be cut off!

Doesnt appear to be any obvious valve damage. See pic.

Appreciate you following this saga guys! Dont feel like i'm tackling this alone!

Photography skills have improved due to the number of pics I've taken to aid the rebuild! That will be a true test! Will it ever start again!

[F1 LOTUS]

My guess is that you lost a piece of the parking slug and it got lodged just above the top ring?

[Candles]

What's a parking slug? Is that like a snail, but without the shell, that always gets the last spot in the car park?

Whatever it is, I thought it looked like something had got in there as well.

Candles.

[stevieshag]

Paul, i think i have got a set of injectors in my shed, are you interested..
steve

[F1 LOTUS]

What's a parking slug? Is that like a snail, but without the shell, that always gets the last spot in the car park?

Whatever it is, I thought it looked like something had got in there as well.

Candles.

It looks like part of the centre electrode insulation and the earth have gone missing in action? Usually there's evidence of this 'dinging-about' on the combustion chamber surfaces and the piston crown? Perhaps a search with a magnet in the sump oil and on the piston itself will find some steel or iron shrapnel?...