question about a 1988 lotus esprit engine?

[eyefly]

Are these engine interference or non interference?
I’m trying to find a 88-91 Espirt turbo with either a blown engine or blown turbo where is the best place to look?
Thanks
tom

[wedg1e]

You mean do valves and pistons meet when the timing belt snaps? Given that the scenario has probably written-off more Esprits than enthusiastic driving has, I'd say yes.
Also, I gather that the Citroen box is precisely matched to the block such that swapping engines and boxes is a pain in the parts. How much this affects the Renault box (which you should have on a post-88 car) I don't know...

Ian

[Esprit2]

eyefly said:

Are these engine interference or non interference? I’m trying to find a 88-91 Espirt turbo...

Tom,
The Lotus 9XX engines are all interference designs. If the timing belt jumps timing or breaks, it gets very expensive very quickly.

In the USA, the 88 is equipped with the Citroen transaxle and the 89+ uses the Renault.

wedg1e said:

I gather that the Citroen box is precisely matched to the block such that swapping engines and boxes is a pain in the parts. How much this affects the Renault box (which you should have on a post-88 car) I don't know...

The engine and gearbox are not match-machined. Gearboxes can be swapped back and forth interchangeably as far as bolt-up fit to the engine block is concerned.

However, the Citroen and Renault gearboxes have different diameter spigot journals on the input shafts (small journal on the end of the shaft that fits into the pilot/ spigot bearing). The engine crankshafts have different diameter pockets machined into the back ends to accept either a thin-shell needle bearing for the Citroen input shaft, or a much larger pocket for a ball bearing for the Renault input shaft.

An insert is available from Lotus to sleeve the large-pocket Renault crankshaft down to Citroen size (all current Lotus new replacement cranks come with the large pocket and the sleeve is installed for use with other gearboxes).

To use an earlier crank with a Citroen-size spigot bore with a Renault transaxle, the crank will have to be bored-out to 35mm and a snug finger-press fit with the ball bearing. Install the bearing with Loctite.

Any time you have the crank out of a 9XX with the small diameter, thin shell spigot bearing (Citroen-Esprit, Elite, Eclat, Excel, Jensen-Healey), it would be advisable to upgrade it to a ball bearing. JAE sells a bearing that has the same OD as the Renault bearing, but a smaller bore the same size as the input shaft's spigot journal. The bearing bore and the shaft journal are the same size, so the fit is too tight for an easy slip fit during blind assembly. So the input shaft has to be cut down a couple of thousandths for a slip fit and the end chamfered for a nice lead.

Regards,
Tim Engel
Lotus Owners Oftha North
Minnesota, USA

[eyefly]

Thanks Tim. I guess I'll be looking for a 89 or newer than.
tom