Some advice on engine rebuild

[buzzer]

Having now rebuild the gearbox, I am now working on the engine and just after a bit of advice on rebuilding.
The engine, big valve twin cam. internals look in good condition with no perceived wear, with  -.010 journals and +.020bores .
The head is mucky but looks ok. But as I have it all apart the decision on what is the best thing to do with it.
Bottom end,. New shells, was thinking of upgrading the big end bolts to ARP bolts. And balanced

Top end was thinking of getting done professionally,  do I get the head lead free converted and what about gas flowing. Company I was thinking of was Vulcan engineering or lakeside here in the UK.
Comments and advice welcome

Dave

[blasterdad]

I would think your engine builder should be able to give give you a good baseline as to what should be done given it's intended purpose...ie, stock, street, race, ect. New valves & seats for sure.
 

[BDA]

Do you have a Weber head? (I don't remember if the big valve head only used Strombergs)

If you have a Stromberg head, it can be converted to use Webers. One benefit of the conversion is that it can be ported much better. I would assume somebody on your side of the pond could do it. It would not be cheap and only you know if that would fit in your budget.

If you're getting the head ported, I would certainly balance the crank, rods, and pistons. I think there are already steel valve seats so I don't think anything special needs to be done to use unleaded fuel. We haven't had lead in gasoline for a LONG time.

If you don't have one already, I would definitely get a cassette water pump before I worried about any go fast mods!

You might want to consider "warmer" cams. It all depends on what you're going to do with it and how much you want to spend.

Don't forget to tell us your plans so we could generate the proper shade of green envy!

[EuropaTC]

Hi Dave,

I guess it depends on what you are going to do with the car. If it's for some type of competition or track day fun then you'll probably want to change most of what's been mentioned, cams, ignition, gas flow, balance, etc.

If it's a road car then personally I'd just treat it to an overhaul because with a BV engine you've already got the best standard spec.  Bottom end, new shells and balance if it's something easily done although as I only ever use my cars on the road I've just rebuilt "as was".  Assuming the bores and pistons are within spec I'd probably also replace the piston rings. No great driving force behind that thought other than it's easy to do when it's in bits. And a new oil pump of course.

The cylinder head I would certainly rebuild with new guides and seats using modern materials. It seems fuels are changing composition more regularly these days and I'd like as much leeway as possible with materials designed for modern conditions.  Cams I'd leave alone for now unless you're prepared to do the dellortos as well.  Ignition would be electronic, probably with a new distributor although if yours isn't too worn then I'd use a conversion kit for now.

Where to go ? Personally I think I'd talk to people like QED because they've been around for a long time with these engines and at one time were the "go to" people for cylinder heads. Also Tony Thompson because although he's mainly Elans he does have lots of racing experience if you intend heading for even a mildly tuned engine.

http://qedmotorsport.co.uk/qed-shop/lotus-twin-cam

http://shop.tonythompsonracing.co.uk/engine-ancillaries--plugs-14-c.asp

It can be an expensive job rebuilding a TC these days. When I was picking up those links I had a quick browse through some prices and now I understand why people fit Zetecs !

Brian

[4129R]

Lead free fuels burn hotter than leaded, so the valve seats burn out quicker, unless they have been changed.

Balancing is only really required if you are revving the car to high RPM.

If you are only using 6000-6500 infrequently, I would not bother with balancing.

If you gas flow the head, you will have to re-jet the Weber/Dellorto carbs to get the new power output.

[EuropatcSPECIAL]

Good evening Dave
                                I have just had my Elan BV engine rebuilt. I ended up with a company in Northallerton N Yorkshire
https://www.google.co.uk/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0CCUQFjAA&url=http%3A%2F%2Fwww.amacengineering.co.uk%2F&ei=DdsFVdfZM8v7UJrCgYgE&usg=AFQjCNGakX25izd2lXiUUfoALD9exOUtlA&sig2=dEUYbYiyGlJD7rqdYNz_Nw
They did a cracking job. Its a father son and an apprentice. I took the car one Sunday to leave it with them. They do Aston, Jag everything. I don't recommend people or services easily but these are top chappies and a fantastic price.
good luck
Stuart

[TCS4605R]

Dave,

One modification I did was an electric feel pump.  Mounted it on the vertical piece of engine bay fiberglass in front of the right rear wheel.  Could send you photos if you desire.  I also cut the lay shaft that drives the distributor and mechanical fuel pump - cut it to the rear of the middle bearing - little less rotating mass.  The shortened lay shaft will now only drive the distributor.  Remember to insert the old rear layshaft bearing 90 degrees out to block off the oil gallery to bearing #3.  You will also need a blanking plate to cover the old mechanical fuel pump hole in the side of the block.  I never did like the mechanical fuel pump - any leaks can drip down on the starter and possibly start a fire on startup.  I also used braided fuel lines and aero quip fittings for more fire protection.  I installed a Luminition ignition system - gives more accurate timing and does away with points and condenser.  You can also get an adjustable rev limiter module for the Luminition system.

Tom Berkeley
74 TCS - 4605 R

[buzzer]

Guys.
Thanks for the advice, have a lot to think about. The car was raced in the 70's sadly As a production racer, but the engine I have is not the original one. My plan is to restore it to the same spec as a production racer get its passport but mainly use it on the road. Plan to dabble in racing a bit but not too seriously. On the tuning front my plan was to basically keep it standard with minor tweaks.
The car has dellortos fitted as it should for a UK special.
I'll get the head professionally rebuild with new seats, valves and guides. Still thinking about gas flowing and cams.  Nothing too hairy anyhow as even with ARP bolts and std crank need to keep the revs below 7k (I think,  based on my experience with the 711 block, but will check). On balancing its is always worth while, I had my 711 block cross flow balanced and wow did it make it feel much much smoother.  Probably fit lightened flywheel as well.
So so far it's
Head, new guides, valves and hardened seats
Bottom end, check crank for trueness and dimensions. New top spec shells, ARP. Big end bolts, lightweight flywheel, balance
New oil pump
new rings , probably
Cams.  Do some more thinking and advice.
Will do the engine assembly myself

Dave