Restoration project and advice needed please

[Scoobymad555]

First post on here and a bit of a long one! ...

Ok so the story so far then! My brother and I have pseudo-inherited my fathers lotus ?lan plus 2s which he owned before I was born some 35years ago now! His health has somewhat failed in recent years and as a result he's pretty much lost interest in virtually everything including the lotus which I can't even remember being started in my lifetime! Some time around twenty years ago he did some work on it with one of his friends which was predominantly around the carbs from memory but when they started it, it only briefly ran and then died (my brother and I were at school at the time unfortunately!). At the time they thought it was debris dragged through into the carbs from the tank that they'd forgotten to drain down and it's been sat ever since. I haven't seen any letters from dvla for it either so I think it's possibly even disappeared off the system!
My brother and I decided to restore it for him in the hope that it may spark some interest for him in something again (very proud man that had a heart attack followed a few years later by a stroke and now struggles with even basic daily tasks - I'm sure any of you can imagine the kick between the legs that was for him).
First challenge was actually getting him to let us touch his (albeit rotten) baby which we eventually succeeded in by persuading him to let us move it to my unit for 'storage' - that in itself took several weeks of persuasion! We had already acquired a spyder chassis by chance at a lotus show we'd taken him to (some haggling presented a deal too good not to do) but after some thinking we decided to try and keep it fully original.
The body is now off and ready to be stripped down for full restoration inside and out and the original chassis has been gone over closely. It is possibly salvageable with a fair amount of welding but we came across an already prepped and ready original rolling chassis on eBay that appeared to be in good condition and ended up buying that (the cost outweighed the time and parts of restoring our one). It's actually from the same year as ours too which is even better! The only gripe with it is the seller has had a different 'rare' diff fitted (not too sure what though) and had cut the rear bars on the chassis to do it - where they've been welded back in the work isn't great so we're planning to cut them out fully and replace them with the ones from our original chassis.
The engine is also out and somewhat seized to say the least. We haven't had the time to strip it ourselves but a mechanic friend was willing to do it for us for a few hundred quid so it's in his workshop in bits at the moment. This is the part where I'm after some advice from anyone that's been patient enough to get this far and is kind enough to help! My brother and I have limited knowledge on these engines (we're mainly into modern jap-scrap, turbos and v8's!) so we're not too sure what our options are here. Received a message from the mechanic this morning saying the engine is basically 'borked'. All the cam shells were down to the minimum wear marks, couple had hot spots and abrasion marks and the main block itself is in a pretty poor state with the pistons from cylinders 1&4 out revealing a lot of rust and 2&3 currently stuck fast. At this stage in a jap we'd either brute force the pistons out and replace them along with re-sleeving the block (or possibly honing and oversized rings) or just replace the engine since it doesn't really matter on a modern-ish car. Obviously we want to try and keep the original engine so that rules out replacement but I'm not sure what our options are here. Have no idea whether it's possible to re-sleeve or whether the block has tolerance to be honed/bored out - it's older than I am! Lol!!!
Any help or guidance would be massively appreciated - would love to get it done and take him to a show in it at some point (he's unfortunately been told he's not allowed to drive any more by the doctors due to attention problems caused by the stroke but we're hoping we'll be able to let him at least have a 'pootle' about on private property somewhere).

Thanks in advance

Ben

[miked]

Hi Ben,

Welcome.

The blocks do get sleeved. They also get bored out. As a start point ask the mechanic guy to clean the piston tops that he has released to see if they are standard or already bored out. They should be marked up with STD, plus 15 or 20 or more.

Where are you?

Mike

[Scoobymad555]

Hi Mike,

Thanks for the welcome and reply!

That's good news to hear! We're looking at it as fairly positive in terms of the what if's at the moment - the head wasn't seized on and at least it wasn't a seized or damaged crank! I'll pop in and see the mechanic tomorrow and probably grab the pistons to clean them up myself to be honest - can assess their condition myself at the same time that way. Out of curiosity, are these engines noted for top end oil starvation? - the hot spots on the cam shaft bearings are bugging me! In fairness the porting on them wasn't particularly well aligned but even then there's a lot of wear for an engine that hasn't done many miles!

I'm based in Hoddesdon mate although the car is tucked away in my unit about quarter of an hour away - fortunately it's large enough for the project! Are you local at all? (Just looked at your profile and that would be a no lol!)

Cheers,

Ben

[Scoobymad555]

Had a quick chat with the mechanic this evening on the phone - he'd already noticed on the two pistons that did come out that they were stamped with std plus 20. Battle re-commences tomorrow with the other two pistons!

[miked]

There are others that are far more experienced than me but generally they are more noted for a lot of oil at the top end and more about getting it back to the sump. As you can see the cams have their own little baths. As far as I know the cam bearing don't seem to have a hard life if the oil system is clean and in order. What about pulling the cam shaft end plugs and washing out the through port and puting a brush in to see what comes out. Sounds like you are going to have a full rebuild anyway and will be having a new oil pump etc and a lot of cleaning. Hope block bores are not stuffed. I think liners are a couple of hundred quid if required. Mike

[rgh0]

Welcome and goodluck with the restoration.

The engine sounds pretty typical of what you find and is rebuildable relatively easily. The block should take another over bore or two as most blocks will go to +40 thou ( i.e. 83.5mm). Its wise to find a place that can do an ultrasonic wall thickness check and offset the boring to maximise and even up the wall thickness.

The rest of the engine is just systematically working though the assemblies cleaning inside and out and then replacing what needs replacing - bearings, seals, water pump, cam followers, springs, valves.cam chain etc and doing what machining is needed for valve seats, head face, crank journals etc.

The valve stem to guide clearances are critical as the engine has no stem seals so you need to check this carefully.and replace the guides if needed. The other key issue to avoid is cutting the valve seats to deep and then ending up with insufficient clearance between the valve stem and cam so the shim needed for setting the clearance is to thin.

If your mechanic friend has not done Lotus twin-cams before buy him the Miles WIlkins book and give him that and the wrokshop manual engine section to read

cheers
Rohan

[weddingcarclive]

Fill your bores with seized pistons with PLUS GAS penetrating oil, leave them for a week whilst tapping daily, lightly with a mallet shaft they will eventually move and you never know there maybe a God and be able to re use them with new rings if you only need to hone the bores, I did this with a complete engine in a 1947 Fordson van which had been stood for 25 years obviously unable to tap the pistons direct with head affixed, just kept standing on starting handle over a week as I passed the van, when it eventually moved kept on until it revolved, poured oil down the bores left the plugs out, put a 12 volt battery on (yes a bit harsh on 6 volt system) the engine nearly leapt out of the chassis (only short bursts), sprayed my face with oil and smiled, plugs back, in new fuel, engine started , choked me to death nearly with smoke. Job done