info-- help--building lotus twin cam

[marjon]

I have a friends lotus twin cam in bits,I would like to have a crack at rebuilding it,gonna use the parts that are there no upgraded extras,have rebuilt many 1600s, the thing is its January and I got bugger all to do,so to keep my sanity this I hope will help,any how any observations? guidance? suggestions? tips? Go ahead weigh in

[steiny142]

if you can somehow find a copy, google, amazon, the Miles Wilkins book, Lotus twin-cam engine, is pretty much the bible used by lotus owners

[tstrong]

Surprised more people haven't chimed in. If your talking a basic "stock" rebuild the TC is pretty simple and straight forward. Bottom end is just like your Kent, cam timing is just a matter of aligning the proper cam sprocket marks, valve lash is set with shims which is simple but requires either an assortment of shims or a surface grinder to get what you need. About the only unique thing to watch for is cam follower (bucket) to bore clearance. If this is excessive the remedy is either bore and sleeve back to stock diameter, or bore and use oversize followers from cosworth, Alfa, etc. This is definitely a job for a lotus specialist. So as long as follower bores are good the rebuild is no problem. As mentioned above the Wilkins book is a great reference.
If you are looking to race prep a TC that is a whole different story with many mandatory (and proprietary) mods and tricks required to make power and make them last. Definitely not a DIY project.

[teamwisconsin]

I would opt for the cartridge water pump assembly. Not cheap, but makes a repair or replacement of the water pump into an afternoon job instead of a complete engine teardown to get the front cover off. And if you've already got the thing torn down its no trouble to install it now.

[tstrong]

Great point Ethan. The cartridge pump mod is more than worth the money.

[stonebridge20]

Sanity and Lotus should not ever be used in the same sentence.

[gcoffin]

Deep in the back of my mind I believe that stock Pistons and rings resulted in cracked piston skirts.....I sent the head to Ivey for cleaning, assembly and a tiny bit of porting and polishing at a very reasonable price. Other than that normal balancing and assembly. Also a pertonix as the distributor is pretty much buried

[DanW]

Deep in the back of my mind I believe that stock Pistons and rings resulted in cracked piston skirts.....I sent the head to Ivey for cleaning, assembly and a tiny bit of porting and polishing at a very reasonable price. Other than that normal balancing and assembly. Also a pertonix as the distributor is pretty much buried

I have had good life from the replacement pressure cast Hepolites in my twincam. After about 30+ years and 80,000 miles it still runs fine with just ring replacement. The ring lands were nearing their limit for taper. CP and JE both make some very nice replacement piston sets in forged aluminum.

+1 on the cartridge water pump kit from Dave Bean. I have had mine for more than 8 years without problem. The original front covers were poor castings at best. There is no way to economically restore the water pump bearing fits. The cover/backplate assembly warp from time and handfisted mechanics.

Dan