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Lotus Twin Cam
VERTFELIX - 17/10/05 at 04:37 PM

Hello, somebody can it inform me about the assembly of an engine lotus
twin camwood. I mount pistons lotus 1558 diameter 82 in rods unit,
villebrequin and block xflow of 1600cc the top of my pistons is with
+/- 5 mm below the face of support of the cylinder head on the block
It are necessary to plane the block of how much? PS I am French and
for you ecrire I pass through a translator

britishtrident - 17/10/05 at 05:46 PM

I don't know how much you will have to remove from the top of the cylinder block but I would have thought the pistons would have to be about 0.25 mm + or - 0.05mm of the top of the cylinder block.

The thickness of the cylinder head gasket will provide additional clearance. However you will have to work out the compression ratio to ensure you get a reasonable ratio for modern fuels.

You will also need a special spacer plate for between the top of the timing chain case and the cylinder head Burton Power can supply these part nu FL309

https://www.burtonpower.com/default.aspx

I know from 13 years of Elan ownership that the Lotus-Ford Twincam engine is more than a little unreliable -- it would not be my first choice of engine for anything except and original Lotus Elan/Europa/Cortina

[Edited on 17/10/05 by britishtrident]

Lightning - 17/10/05 at 06:44 PM

Dont understand, the twin cam engine did not have the Xflow block

MikeR - 17/10/05 at 06:47 PM

i think he's looking at putting the pre-crossflow 1550cc pistons in a 1600cc crossflow block.

Lightning - 17/10/05 at 06:56 PM

ahh. Care would have to be taken to ensure pistons dont hit the valves. My big valve twin cam did at 120mph. Ouch!!!!

gazza285 - 17/10/05 at 07:00 PM

He is building a Twink engine but using a 1600 Crossflow block. The blocks are different heights with the 711 Crossflow block being 5.75mm taller than the L block.

VERTFELIX
As above the block is 5.75mm taller than the Lotus block. Pistons are available with an increased compression height to suit the taller block or steel conrods can be found as well. I am not sure that the Crossflow block can have 5.75mm skimmed off the top without breaking into the water jacket, as britishtrident said, ask somebody like Burton Power about this. Good luck.

[Edited on 17/10/05 by gazza285]

VERTFELIX - 17/10/05 at 07:18 PM

_ with britishtrident,
I understand that it should submit the report
volumetrique I order my piéces at BURTON POWER I know also for the
spacer of timing-gear case de distribution (know you how much it make
some thickness?) the block 1600 etait easiest to find for me in
Lightning it is an assembly which I would like to make, one with given
me the distribution, the pistons and the cylinder head LOTUS
in MikeR
yes it is that!

gazza285 - 17/10/05 at 07:39 PM

You have the Lotus pistons, distributer and cylinder head.

What I posted before still holds for using Lotus pistons with the Crossflow bottom end, you still need to lose 5.75mm off the block to get the deck height right, unless you use either longer rods or pistons with a higher comp height.

VERTFELIX - 17/10/05 at 08:04 PM

I test poster a photograph (without guarantee of the result!)

VERTFELIX - 17/10/05 at 08:36 PM

Thank you for your answers,
I will get information aupres BURTON POWER
I have just looked at my block, that seems a little right on the level
of the drainage ducts
escusez me for the translations and the
photographs but it there of with some in the gallery,
still thank you,Serge

MikeR - 17/10/05 at 10:53 PM

silly idea.......

keep the block as normal and add a turbo!

Memphis Twin - 17/10/05 at 11:35 PM

You need the Lotus L block or 1500 pre-crossflow block. It makes it so much easier than adapting a 711m

Memphis Twin - 17/10/05 at 11:43 PM

In fact there's one on ebay right now. It's a Cortina 1500Gt 120E block, but is the same height as the L or 125E block (I think).

britishtrident - 18/10/05 at 10:08 AM

The 1500 pre Xflow block is almost the same as the Lotus block -- 1558 Lotus blocks were thick wall blocks selected from 1500 castings.

britishtrident - 18/10/05 at 10:09 AM

quote:
Originally posted by Lightning
ahh. Care would have to be taken to ensure pistons dont hit the valves. My big valve twin cam did at 120mph. Ouch!!!!


Valve clearance always was a problem on these engines but not so much the valve hitting the pistons as the inlet and exhaust hitting each other jamming open then hitting the pistons. The valves are big and heavy so it dosen't take much of an over rev to trash the valves or worse.

Because of this two valve per cylinder hemi-head engines tend to be fragile at high rpm -- I really don't recommend these engines they are fragile and very expensive to rebuild.

britishtrident - 18/10/05 at 10:13 AM

quote:
Originally posted by MikeR
silly idea.......

keep the block as normal and add a turbo!



Although the bottom end is strong it isn't a good engine to turbo charge --- the twi weber dcoe inlet manifold is cast into the head and the hemi head has no squish turbulence hence quite slow combustion.

MikeRJ - 18/10/05 at 01:13 PM

quote:
Originally posted by britishtrident
Although the bottom end is strong it isn't a good engine to turbo charge --- the twi weber dcoe inlet manifold is cast into the head


No problem if you can source a set of the Esprit Dellortos, that were designed for forced induction My sisters bloke is using one on his turbo'd mini.

Syd Bridge - 18/10/05 at 03:26 PM

How high the pistons go depends on the size of your bollocks! And what the engine is destined for.

We run the youngsters mini with 0.25mm ABOVE the block. (Gasket compresses to 1mm) Some go as far up as 0.75mm, but I am not that big in the gonads.

The only way to get up on power with the Locost series 1300cc is to machine the block down to the lowest piston, then turn the other three down to match, then balance the lot.

Same thing with any race engine, depending on the CR you are after.

Now the armchairs will tell me how wrong I am. They'll also be seeing only my/our exhausts!!!

[Edited on 18/10/05 by Syd Bridge]

britishtrident - 18/10/05 at 06:37 PM

quote:
Originally posted by MikeRJ
quote:
Originally posted by britishtrident
Although the bottom end is strong it isn't a good engine to turbo charge --- the twi weber dcoe inlet manifold is cast into the head


No problem if you can source a set of the Esprit Dellortos, that were designed for forced induction My sisters bloke is using one on his turbo'd mini.


But pointless a CVH Turbo or ZVH would give an identical or much better result for 1/10th the cost be much more reliable and be a more compact installation, Twink parts are getting very rare and very expensive to do almost anything to a Twink involves a high level of engine building engineering knowledge and full maching facilities. What would be relatively minor detail on other engines such as not getting the valve guides reamed to precisely the right clearance can make or break a rebuild.

VERTFELIX - 25/10/05 at 07:30 PM

I found, rods of 1600cc diesel Ford escort: they are 5mm longer of distance between centres it does not remain more that to manufacture a frette there to place a ring of 20,6 and to rectify trés little
villebrequin to place bearings with the dimensions origin of the
diesel. Thank you with all those which one answered to me

VERTFELIX - 25/10/05 at 07:33 PM

I forgot to see the photograph of the two rods in photo archive
Serge