19 posts / 0 new
Last post
eric
eric's picture
Offline
Last seen: 1 week 1 day ago
Joined: 17/04/2014
From my last book on caterham, seems to be VS39
Roger King
Roger King's picture
Offline
Last seen: 12 hours 50 min ago
Joined: 17/04/2014
The best springs for a 264 are from the Hart 420R. Unfortunately they are currently made from Unobtanium. Failing that the Isky works well, but MUST be changed regularly to avoid breakage if very high revs are to be used.
greg
Offline
Last seen: Never ago
Joined: 17/04/2014
Anyone any ideas on an Isky Part number? Are they stamped on the spring(s)? Greg, Q 86 NTM (slow Green XFlow)
Petrolhead
Offline
Last seen: Never ago
Joined: 17/04/2014
I ran a 244 and it was very tractable in fact I recon the 254 would probable be ok in a well sorted engine. I'm back
Iamscotticus
Iamscotticus's picture
Offline
Last seen: 6 days 4 hours ago
Joined: 17/10/2018

Bump.

This is still a very good subject: 234 or 244 for a road only seven?  Will see a lot of time averaging 60-75 Mph (96.5-120.7 Kph) and see a lot of sierra box overdrive on tall 13" wheels.

AM95/1246/UC

Roger King
Roger King's picture
Offline
Last seen: 12 hours 50 min ago
Joined: 17/04/2014

Either a 234 or 244 will work well on the road, but only if the rest of the engine is uprated to suit - forged pistons, decent big-end bolts, doweled flywheel, tufftrided crankshaft, properly flowed head, decent dizzy or 3D map (preferable), better valve material (and possibly bigger too), higher compression ratio, uprated rocker shaft, better valve springs, rejetted carbs with different chokes, etc, etc.

The 234 is slightly better at low revs and the 244 gives a bit more top end as you would expect, but both are fine on the road. 3D mapping or injection would be the icing on the cake. Even a 264 can be road drivable when set up properly; my test for road use was "can I sensibly drive it in a multi-story car park?" which may seem a bit odd, but light throttle and low revs are much harder to set up for than outright power. By the way, a 264 will need a lot more engine changes than listed above.

The Caterham Supersprint uses a 234, but they came nowhere near getting the best from it. I used to see around 120bhp from the later ones, but we had at least one super-special engine that achieved just over 150bhp on the same cam.

Iamscotticus
Iamscotticus's picture
Offline
Last seen: 6 days 4 hours ago
Joined: 17/10/2018

Any conrod upgrade?  As long as the pistons are out...

AM95/1246/UC

Roger King
Roger King's picture
Offline
Last seen: 12 hours 50 min ago
Joined: 17/04/2014

You can always use steel rods, but if you're sticking to 7000rpm the standard item is generally fine so long as they are checked for cracking and they are then balanced as a set.

If you polish the flanks of the rods in addition to the above you can normally extend to 7200rpm. See photo.

Please note that the above is given as generalised advice only and may not apply to a specific engine specification.