Lotus Elan

Catastrophe on Elan ownership day one!

PostPost by: Steve G » Sun Feb 28, 2010 6:15 pm

I bought my Elan yesterday morning at about 11:00. It is a 1970 S4 with Big Valve head and twin Webers. I took it straight to Goodwood and watched the racing, went for a great drive and just had an amazing day. Then when driving home from a friend's house at 23:00 the accelerator pedal got stuck down! I had my foot on the brake hard while I was trying to go for the ignition key (in the dark) but it was just running away and I was afraid of running down a Saturday night reveller on Brighton seafront so I did the worst thing imaginable (with hindsight) and dipped the clutch. This is where I found out about the twink's rev limiter being engine failure. There was no visible sign of damage to the block, no oil or water leaks, the engine would just spin freely on the starter indicating a total loss of compression. I joined the AA who recovered me back home. I realised that the stuck pedal was caused by the pedal getting trapped on the Spyder SIPS footwell bar because when I was adjusting the seat earlier in the day I must have put the carpet back over the bar and the clearance between the bottom of the pedal and the bar is minimal. Doh!

I went to bed feeling sick, my wife is away for the weekend and hasn't even seen the car and I've done this, the very day that I finally took ownership of the car I have always dreamed of owning and I've put it out of action. I couldn't even sleep.

I have spent all day with a mechanically minded friend taking the engine apart, I've got the cylinder head off and I can't really see what has failed. I was fully expecting to see bits of timing chain and valves and pistons all over the place but it all looks good. The bottom end seems fine, the pistons are all turning smoothly without noise. It could be the head gasket or bent valves but all I can see from the head gasket is it hasn't been put on very accurately and there is a small amount of trimming that has occurred around the pistons, the aluminium lifted slightly from the gasket around the cylinder next to the timing chain. If it did blow here then the oil must have gone into the timing chest as none has leaked out. It also wouldn't explain the total loss of compression. The valves don't appear to be damaged or bent but it is very hard to tell, they could be out by a couple of thou I suppose.

So, I have a few questions.

Without knowing the exact details and seeing the car, can anyone say what has most likely happened to the engine if it over-revved for a couple of seconds and then cut out to then spin freely on the starter without compression?

Can anyone recommend someone who could come and look at the car in Brighton or that I could take the cylinder head to in the Sussex or even South-East area?

I also need to buy all of the components I need to put the head back together, can anyone recommend the best place to obtain all of the necessary gaskets, head bolts etc?

Does anyone have a link to an online guide for rebuilding a Twin Cam? It is a Big Valve head with 30/70 cams and Weber 40 carbs. I have the very good $150 Brian Buckland manual that the previous owner very kindly gave to me but it says in there that you should get the Lotus Manual for an engine rebuild. I have done a lot of searching on here and other sites but can't find what I need.

I am trying to look on the bright side and I am seeing this as a harsh lesson learned. It could have been so much worse, if the pedal had got stuck in traffic or if someone stepped out in the road. I also think that I hadn't done anything wrong and was pretty unlucky. I was planning to learn as much as I could about the mechanicals of the Elan, just not expecting to be thrown in the deep end quite so quickly! I am going to use the opportunity to give the engine bay a thorough clean and also repaint the cylinder head and cam cover. It will be good to know that everything is in good working order when it all goes back together. I will also be fitting a rev-limiter!

I would greatly appreciate any advice you can offer.

Regards,

Steve.
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PostPost by: curly type 26 » Sun Feb 28, 2010 6:51 pm

Hi Steve. firstly welcome to lotus ownership & sorry to read your tale of woe. Chances are you have simply bent valves they are quite soft & or timing chain jumped but we cant check that now its stripped. I dont know of anyone in your area but Steve at Vulcan engineering in Hanwell Middex will sort you out. Good luck Curly 1964 26Rr :)
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PostPost by: enskr » Sun Feb 28, 2010 7:00 pm

Steve

I'm assuming that the timing chain was still in one piece and properly engaged on the sprockets when you pulled the cam cover off?
If so, my guess is that the timing chain has jumped a tooth or more on the sprockets. This is also likely to have resulted in valve-piston contact, probably bending some valves. You can usually see this by peering down the ports when the valves are closed, with a strong light on the combustion chamber side.
I've done this before (not on a twin cam though) and got away just putting some new valves in - do check the pistons for damage though.

If you need some help, Miles Wilkins (of Fibreglass Services) is in Arundel, about 15 miles west of Brighton down the A27. There can't be many people in the world who know as much about Lotus Twin Cams as Miles does!

Good Luck
Kevin
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PostPost by: Steve G » Sun Feb 28, 2010 7:06 pm

curly type 26 wrote:Hi Steve. firstly welcome to lotus ownership & sorry to read your tale of woe. Chances are you have simply bent valves they are quite soft & or timing chain jumped but we cant check that now its stripped. I dont know of anyone in your area but Steve at Vulcan engineering in Hanwell Middex will sort you out. Good luck Curly 1964 26Rr :)


Thanks. I think it must be the valves as everything else looks straight. I took pictures of everything before and during the head removal so I might be able to see if the markings were out of sync on the cam sprockets to rule that out (or not).

enskr wrote:Steve

I'm assuming that the timing chain was still in one piece and properly engaged on the sprockets when you pulled the cam cover off?
If so, my guess is that the timing chain has jumped a tooth or more on the sprockets. This is also likely to have resulted in valve-piston contact, probably bending some valves. You can usually see this by peering down the ports when the valves are closed, with a strong light on the combustion chamber side.
I've done this before (not on a twin cam though) and got away just putting some new valves in - do check the pistons for damage though.

If you need some help, Miles Wilkins (of Fibreglass Services) is in Arundel, about 15 miles west of Brighton down the A27. There can't be many people in the world who know as much about Lotus Twin Cams as Miles does!

Good Luck
Kevin


The timing chain looked fine and seemed to have the correct tension, it was engaged on the sprockets. I will try what you suggested with the light. We had a bit of trouble trying to rotate the camshafts, is there a standard method for this?

That's great about someone so useful in Arundel, I will contact him now. Many thanks for the advice.
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PostPost by: alaric » Sun Feb 28, 2010 7:13 pm

Steve, sounds like a terrible thing to happen matey. As you say at least you didn't damage anyone else or the shell of the car. The engine can be fixed, whatever you've done to it - given no parts came out the side etc. Almost impossible to diagnose stuff remotely as I'm sure you realise. There is a book specifically about the twink 'The Lotus Twincam' by Miles Wilkins which tells you how to strip the engine without damaging stuff, and what to look for - as suggested above if he's close to you maybe he can help.

There are guys on here that rebuild these engines for fun, so I'm sure one of them will have some reasuring words. My understanding is the crank is what usually goes on overrevving, as the standard one is not bulletproof. I would have thought the failure mode would be interesting though, so hope that's not it. As the revs climb, I bet the standard chain looks more and more like a rubber band under the tensions that it sees, so the pistons will be able to get closer to the valves as the the timing error increases. If you bent all or some of the valves they'll no longer be seated properly. Again, this is probably a relatively easy fix if the pistons look ok. You can check this with the head off using a valve grinding tool and some grind paste - if they aren't seating it'll be obvious. I think that's where I'd start especially as you already have the head off, before taking the engine out and touching the bottom end. See what the experienced guys say though, as you won't be the first to see this symptom.

Hope you get it sorted out soon and get back to enjoying the car.

Re engine builders mine was done by QED. I'm not sure how much they still do now though. Paul Matty is a good dealer to work with. But this forum is certainly the place to get support.

I look forward to hearing of a happy resolution. I was the first to reply when I started writing this - so apologies if there's some repetition.

Sean.
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PostPost by: trw99 » Sun Feb 28, 2010 7:27 pm

Steve

Give Miles Wilkins a call. As others have said, he really does know his Lotus Twin Cams and he will have all the kit needed to fix it on site (or be able to put his hands on it PDQ).

His contact details are:

Fibreglass Services
Progress Garage
Yapton Lane
Walberton
Arundal
BN18 0AS
Tel: 01243 554422
http://www.fibreglassservices.co.uk/index.html

They do not have and will not do e-mail. In fact, you should be aware that Miles is quite a 'character'. Others on here have described him differently (do a search) but he does know what he is doing.

Finally, welcome to Elan ownership and the great adventure has clearly started for you. Stay with it!

Tim
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PostPost by: oldelanman » Sun Feb 28, 2010 7:32 pm

Hi Steve,
Sorry to hear of your bad luck.

There is a Workshop Manual on ebay if you need one.....

http://cgi.ebay.co.uk/Lotus-Elan-Workshop-Manual_W0QQitemZ320480457162

Good luck. Regards,
Roger
S4 DHC
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PostPost by: Steve G » Sun Feb 28, 2010 7:33 pm

Thanks Guys, I was just searching for Miles' phone number so thanks for that info. I am hoping that it is just bent valves, the cam on the engine is pretty wild (a lot of popping and crackling on the overrun and a lumpy idle) so I imagine it had some fun with the overlaps when it did a fleeting impression of a motorbike engine.
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PostPost by: bob_rich » Sun Feb 28, 2010 8:00 pm

Hi sorry 2 here about your bad luck
You asked about info on the twin cam engine and I see Miles Wilkins name was mentioned by a few posts. He wrote an excellent book on the Twin Cam engine and it can still be got at a fair price from Brammer Books in Germany who specialises in Lotus Books www.lotus-books.com is the web link.

Burtons Engineering still do a lot of Twin Cam stuff if you need parts.

HOpe U dont need 2 many!! best of luck

Bob
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PostPost by: Old English White » Sun Feb 28, 2010 8:25 pm

Hi Steve ,
Sorry to read what happend to you . At least nobody get hurt .
I had about the same experiment two weeks ago when the caburators get frozen wide open ... A very long strait , electric pump and master switch saved the situation.
Then , for your engine , the thing is , you ll soon become an expert of the Twinc .
This wasn't necessary to join us .
Welcome aboard .
Christian.
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PostPost by: enskr » Sun Feb 28, 2010 8:39 pm

enskr wrote:The timing chain looked fine and seemed to have the correct tension, it was engaged on the sprockets. I will try what you suggested with the light. We had a bit of trouble trying to rotate the camshafts, is there a standard method for this?


Steve
Just take the camshafts off the head completely, by unbolting the camshaft retaining caps - much easier than trying to wrestle the camshafts between lobes

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PostPost by: bcmc33 » Sun Feb 28, 2010 9:20 pm

trw99 wrote:They do not have and will not do e-mail. In fact, you should be aware that Miles is quite a 'character'. Others on here have described him differently (do a search) but he does know what he is doing.

Best described as:
He Who Should Not Be Argued With
Brian Clarke
(1972 Sprint 5 EFI)

Growing old is mandatory..........Growing up is optional
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PostPost by: neilsjuke » Mon Mar 01, 2010 12:18 am

You may of sheared the flywheel bolts or crank when you tried the starter was the fan belt moving.
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PostPost by: elansprint71 » Mon Mar 01, 2010 8:43 am

neilsjuke wrote:You may of sheared the flywheel bolts or crank when you tried the starter was the fan belt moving.
Neil


My thoughts too, even if the valves are bent there would have been some semblance of compression (imho). Also, if they are bent, they were bent by the pistons, you will not be able to miss the marks in the piston crowns with the head off.


Bugger!
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PostPost by: Steve G » Mon Mar 01, 2010 9:50 am

That's very interesting, I will take the gearbox off tonight and see if the flywheel is damaged. I didn't check to see if the fanbelt was running on the starter. There are some tiny marks on one of the piston crowns but they don't look like they could have been caused by a valve, not when the valve is still in one piece anyway! The bores look to be in exceptional condition, I don't think the engine's done more than 2,000 miles since it was last rebuilt. The head gasket was a mill or two out of position though, so I'm glad I've had the head off as it's only a matter of time before it would fail (it it hasn't already).

I'm going to phone Miles today. Thanks for all your advice and supportive words.
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