Engine rebuild project following blown piston

[GeoffSmith]

Good on you Paul. If you need a hand or tools then give me a shout.

Geoff

[paulwatkins]

Jay - the mechanic suspected it was more likely to be the head gasket. I just ust hope that theres no further damage to other components when I delve in....only time will tell.

Geoff, I really appreciate your offer. Thank-you v much.

Paul

[delta]

Hi Paul.
How are things going. Have you found out what's wrong.?.

[paulwatkins]

Hi Delta,
I made a good start on the car at the end of June, but since then, it has either been so hot I haven't been able to get into the garage to continue or I have been busy doing other things. I am at a stage where I am ready to remove the cylinder head now, but I need to hire an engine crane - and I ideally want a cooler day to do it! When that is done, all should be revealed! Fingers still crossed it isn't anything more than the head gasket.

The irony of it all, is that we have just had the hottest July on record, and my convertable two seater sports car is sat in the garage with an injury!

[dermotbell]

Just wondered how you are getting on now the weathers cooled off.

I had a head gasket go....cost me just over £1000. Pat Thomas of kelvendon motors did it. He's very helpful with mechanical advice and the like.

You should know for sure when the head comes off. usually the gasket shows a definitive blow. However there is another piece that occasionall suffers hairline cracks that only show up when the engine is rebuilt and restarted (ie Hot and expanded). Ask Pat for the more technical explanation.

I was pretty sure mine was gasket when it went as i got white smoke and water dripping out of the exhaust, plus there was no oil in the cylinders.

Hope it's going well.

[paulwatkins]

Dermot,
I am hiring the engine crane tomorrow, so if all goes well, the cylinder head should be removed and the extent of the damage revealed.
I have my fingers crossed that it is nothing more than the head gasket, but I suppose, only time will tell.

Hopefully, I should be able to update this post over the weekend with some good news!

[paulwatkins]

Finally got around to hiring the engine crane!

Got the cylinder head off ok. The head gasket was looking worn, but no obvious signs of complete breaks. It had deteriorated in some places though.

No 2 piston doesnt look quite right though. I am hoping someone can comment. It looks as though the edge of the actual piston has worn away, and there is a rough deposit on the bore wall towards the top. You can just make it out in the picture. There is also a picture of no 3 piston for comparison.

I'm no expert, but it doesnt look right to me!

If the piston is u/s, is it an easy enough job to replace one?

All advice, as always, greatly appreciated.

[paulwatkins]

Finally got around to hiring the engine crane!

Got the cylinder head off ok. The head gasket was looking worn, but no obvious signs of complete breaks. It had deteriorated in some places though.

No 2 piston doesnt look quite right though. I am hoping someone can comment. It looks as though the edge of the actual piston has worn away, and there is a rough deposit on the bore wall towards the top. You can just make it out in the picture. There is also a picture of no 3 piston for comparison.

I'm no expert, but it doesnt look right to me!

If the piston is u/s, is it an easy enough job to replace one?

All advice, as always, greatly appreciated.

[Monty]

Yeah have to agree thats not right and obviously why u were getting blue smoke, just hope it hasn`t damaged the cylinder wall. Anyways i`m like u when it comes to the internals i`m sure someone else will give u advice. Have a check of the valves to see if theres any damage.

[Specky]

You’ve burnt that piston out, but not to badly though

Normally it happens at high engine revs when you ragging the nuts of it...

The probs come with damage to bore.. One ovality check required..

Worst case.. rebore.. Oversized piston rings

may be the first 1650cc Élan engine..

TTFN

[Dico]

All advice, as always, greatly appreciated.

I think you need a replacement engine whilst yours is being reconned

[Specky]

All advice, as always, greatly appreciated.

I think you need a replacement engine whilst yours is being reconned

Not as silly as may seem..and most probably cheaper

Project creep...Valve stem seals.. De-coke..Grind those valves..

I know what i'd do..

Quick compression check

Quick boroscope of the internals.. Upstairs and down

You'll be firing on all fours before you know it

TTFN

[F1 LOTUS]

Oops! It looks like the land above the top ring has disappeared Seems like it is on the intake valve side which would be the cooler side? Question is, what caused the the piston to make contact up there? Any tell-tale marks on the cylinder head?
Anyone know what the 'B' designates (oversize???)?

[Enright]

Ooo, that's nasty.

Fixable, but it's a bloody good job you didn't take it to a garage. You'd be crying at the labour cost by now. Well done for tackling it yourself.

You're faced with a few choices now in ascending order of price. Whether to:
1) Go for a replacement of a single piston (which could be a false economy if another goes later. Honing is required)
2) Complete piston set of standard size (if there's no damage to the bore and it can still be honed)
3) Overbore (this includes a complete new piston set and new rings, and I think you'd have to have the engine out to have it machined out to the new size)
4) Replace the engine

I'm more concerned about the marks on the cylinder wall than the damage to the piston. You would need to have that inspected by an engineering company that reconditions engines to see if it's deposits or damage that has penetrated the surface. If it's the latter then it's an overbore.
If it's the former, then I still don't know if the bore can be honed while the engine's still in the car - it's a pretty specialist job and you'd have to ask.
If it can, then in simple terms you're most of the way there already.
You just need to remove the sump and unbolt the big end from around the crankshaft, and the piston will lift straight out the top.
However, I think that the prongeron might get in the way, and I remember reading somewhere about the gearbox end of the sump being difficult to get to. Perhaps someone else like Monty or Dico can advise.

Whatever you decide to do, the most important thing is to nail the fault that caused it in the first place. You want to get your injectors checked out, and possibly the one from the offending piston replaced. It would be a disaster to do the entire job only for it to happen again.

Hope this doesn't come accross as too negative - I'm simply trying to put forwards all of the points for consideration that must be tackled in order for you to get back up and running again.

[paulwatkins]

Thanks for the comments guys.

It looks as though the marks on the cylinder wall are deposits rather than any penetration damage, so a re-bore will be required whatever I decide to do.

Can anybody recommend a good engineering company in the weston-super-mare / bristol area who could look at this for me?

[Enright]

Paul,

I think a rebore will only be needed if the marks ARE penetration damage.
If they are just surface marks then only honing the bore will be required in preparation for a new standard sized piston and rings.

[Monty]

I remember talking to Dave at Peco asking has he done anything to his engine and he said the only thing he did was Honed his cylinders but he gets piston slap and he wish he never did it.

Not clued up on the internals but replacing the with over sized pistons would be the way to go but thats down to money.

If short of dosh, do it u`r self and just replace that piston as long as the cylinder isn`t damaged. That way it won`t cost u to much.

[Paul.P]

I don't think honing the cylinders would of given him piston slap, from what i know honing just roughs up the barrel lining, allowing the new piston & rings to bed in properly, think Dave must of had wear issues ?

[Monty]

I don't think honing the cylinders would of given him piston slap, from what i know honing just roughs up the barrel lining, allowing the new piston & rings to bed in properly, think Dave must of had wear issues ?

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

[stevieshag]

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