Piston / combustion chamber damage

[UAB807F]

Hi, I've been lurking around here for a few years but this is my first post so please be gentle!

Another "welcome to the Forum" Paul.

If it's any consolation I'd do exactly what you're proposing to do as regards the engine work.

True, the marks on the cylinder head are unlikely to cause any major problems in the engine running but there has been a serious thump adjacent to a valve seat and I would be concerned if there had been any damage to either the seat (cracked in the bore ?) or how well it's held in place. The welding itself is very simple and I can't see it taking more than 10 minutes at most. The machining costs will be the biggest portion of the bill, but having the head rebuilt & skimmed will, as you say, sort that problem out for probably as long as you want to drive the car.

Like Rohan I'd also replace the piston and probably also crack test the con rod/caps. The latter is unlikely to have any damage but I'd feel pretty silly if I rebuilt it and it fell apart 1000 miles later.

Brian

[ricarbo]

Paul, i think you are right to have a good look at things at the stage you are. Your time and a gasket set.
When i bought mine at about 50,000 miles, it all seemed ok, but i stripped down the engine anyway, with the intention of changing the shell bearings and generally assessing condition. I was very glad i did, because i found one piston had split from gudgeon pin to skirt. I was able to put it back together with not that many new parts and have the confidence that it was all sound.
I wouldn't feel happy if i hadn't checked. After several owners have had the thing, you have little idea of what has happened in the past, or what horrors could be lurking beneath. As Rohan pointed out, you could have a damaged con rod. Far better to have it checked for straightness etc and replace it if necessary than have it break.
regards
richard

[PaulFinch]

Many thanks for the welcomes and to everyone that has taken the time to comment on this.

Simon, cheers for your detailed reply - I won't go into as much detail in my response, but yes, I have had several quotes which make your ?2K estimate look quite optimistic. They range from ?2.5K - ?5K for a complete rebuild (including new pistons) depending on what specification I want. The higher priced options also include running in / set up on a dyno. This is eye watering, but I knew this would be the case and wouldn't have got involved in Lotus' (Loti?!) if I wanted something cheap

Of the five engine builders / machine shops I have contacted regarding the engine damage (either in person or via emailed photographs) three have said they would weld it up, and two would probably just leave it (after, as you suggested, "polishing its tits off") but would make a decision upon further strip down and inspection.

Your offer of help with regards a single, original piston is intriguing and gratefully received. If I choose to go down this route I will bear it in mind.

'Box is being stripped this week and will know more about what's happening with that next weekend.

That's pretty much where I am now - searching for ?3K down the back of the sofa. Having rebuilt engines in the past (lowly A series and the odd Peugeot Mi16) I know I could probably do a lot of the dismantling and assembly work myself but in this case my gut is telling me to leave it the pros. Daft, maybe, but just the way I'm feeling about this particular situation.

Ah, looks like I went into a bit of detail after all .

Thanks again

Paul

[kstrutt11]

As long as you are keeping it standard, Building the engine up is pretty straight forward, the bottom end is a Cortina after all I wouldn't dismiss it just because it is a lotus.

[AHM]

Paul,

If you have rebuilt another engine then you can do this one - nothing special and the contentious issue seems to be what colour to paint the sump.

Having gone both routes (there isn't a cheap one). My advice would be to strip the engine yourself. Then you can decide what needs doing Give the head to a shop to sort. Do the rebuild yourself, and spend the money saved on balancing.

Simon