S3 Airbox Question

[Mazzini]

My old '66 S3 had an early airbox, it was rounded, like the type used on MK 1 Lotus Cortinas, I think the design was common to S1 and S2 Elans as well.

I've noticed a couple of late '67/68 S3 Elans with a later type airbox, it's more squared off and angular. I think it was the same sort used on Sprints.

I believe the angular style box is correct for the late S3's, does anybody know if they were introduced with the Mk 2 six bolt crank engines?

From memory I think the six bolt crank engines were introduced right at the end of S3 production? I'm sure somebody will correct me if I'm out.

[Elanintheforest]

The six bolt crank came out at engine #7800, which after a long debate with Tim Mees, we reckoned on May / June '67 for the change....there will of course be earlier 6 bolt and later 4 bolt ones!

My S3 has the rounded airbox and the 6 bolt crank, and is dated from June 67 with engine #7988. It also has the metal tube breather rather than the breather that goes into the airbox, although the airbox does have the input stub which has been blanked off. It looks like that change happened right at the end of S3 production, maybe the beginning of S4. However, that is probably different for the Federal Elans which may have had a more stringent 'clean air' requirement. Certainly Lotus Cortinas had the breather venting into the airbox in 1965!

Mark

[nhhiker]

My 1967 S3 SS 36-7502 had the later weber airbox. (I cannot remember the motor #). The car was built in Aug of '67. S4 dash with S1-3 crash pad! With Lotus, you will never the change over date/ car.

Bill

[billwill]

My S3 originally had the rounded air box and on the head an oil vent tube, which was a pipe to drip on the road.

I had my car renovated by Vegantune in Spalding in 1982-83 and they changed it for the squared air box with the head oil vent piped across into the air box.

[Mazzini]

Thanks for all of the replies. I think it's perhaps a little early to see a trend forming. I'm discovering more about the late S3's by the day. Thanks again.