Lotus Elan and Lotus Elan Plus 2 Forums

But you probably love Taboul? and cous-cous

Chancer wrote:But you probably love Taboul? and cous-cous

Aren't they characters in Madame Butterfly?

Perfect emissions from a VW/Audi??? Is that on a chassis dyno or on road !!

I've just removed most stuff from the combustion area with White Spirit on a cloth; engine has done 11,000 miles in last three years and only a bit, around my oily rear cylinder, needs to be chipped off. A bit of wood dowl should do it.

..as Rohan said
" the hard brown deposits on the exhaust valve that continues to build overtime."
are the best tell-tale signs and are harder to remove., I slip them in the lathe and carefully ,free-hand remove the crud.

John

The head cleaned up easily with carb. cleaner and a copper brush.
All the valves have a fair bit of relatively soft black deposits. There is not much evidence of the hard mid brown stuff except on the valve heads.




To me it looks like it was given a decoke at some time in the reasonably recent past, but there is little evidence of it having had new valve seats, which I would have though a first step for a "lead free" converted head. I was also hoping for new valves !



Your opinions please?

Vince

Hard to tell without measuring it up but valves and seats dont look like just 500 miles old.

I would check the valve stem diameter along its length - they wear in barrel shape and the guides they wear in hour glass shape. I would similarly check the followers and their sleeves.

I would also check the depth the valves are seated at by measuring valve length and valve stem top to cam centre line.

Most of these heads have been played with a lot over the years so you need to do a lot of measuring and not assume anything is standard or that standard parts will fit.

cheers
Rohan

I have an idea that lead-free valve seat conversion for the twincam engine is not really required. This is due to the cooler running of the valve seats in alloy, thus, unless you are running something radical in compression and cams, there is little discernable valve seat recession. Closing up valve clearances would soon show it up if it was happening.

More of a problem in iron head classics.

Opinions?

Jeremy

The original Twin Cam seats are fine with unleaded fuels

cheers
Rohan

An aluminium head should be OK mechanically as it has hardened valve seats as standard. (hopefully!)

The issue here is that the P.O. paid a fat wedge for a a lead free converted head and it appears that the only work done was, maybe, a quick decoke!



Presumably the same muppets who made a mess of the water pump installation.

Not to be too pessimistic! But those exhaust seats look a mess, what are the shim sizes? have the valve stems been shortened ( top of collet grove to top of stem ) standard valve = approx. 0.140 inch.
Maybe of some help.
Ron.

Thanks for the posts chaps. Looks like I'm in for a lot of checking and measuring.

The seats might look a mess, but I filled the chambers with paraffin and they showed no sign of leaking which is a plus.