Series 3 engine into series2

[alec2824]

My series 2 engine failed due to cracking between the adjacent cylinders - shows up as very fine cracks. I have installed a series 3 engine (to avoid the possibility of another cracked block) and wanted to retain the carbs (HIF 7 with AED). The engine runs but only with the accelerator pedal depressed to give 1500-2000 rpm. The engine dies with no pedal. Looking through the SU manual it suggests that a 1983 onwards engine used two HIF7 carbs with AED and BDH needles. I have ordered new needles from SU. Has anyone done this conversion? Any advice? Thanks. Alec G.

[S2Alan]

I assume you have a 3.4 as all 4.2 series 3 were fuel injected.

[alec2824]

I should have said that the series 2 is a 4.2 with carbs and the series 3 is a 4.2 that came with fuel injection - that I wish to change to carbs!

[mike020150]

The engine swap should be straightforward and any needle differences should be minor whereas being unable to run below 1500 revs sounds more serious and an unlikely result. Have you gone back to basics and done a compression test on the 'new' engine? I'd start there and if the results are OK, I'd move on systematically to look for air leaks, ignition timing etc. Mike.

[alec2824]

We went back to basics - ran the engine at 2000 rpm until everything was well warmed up, then reset the timing to about 6 before top dead centre. We then removed the carbs, changed the needles and set them as per the SU service manual. Then after re-fitting we started it and rebalanced the carbs - quite a performance! It took quite some time. We now have a car that is driveable and performs reasonably well. It does not start first time from cold, but does start and run! I have put fresh 97 octain fuel in and intend to put some miles on prior to tinkering with the AED. We also revisited the timing and adjusted it more accurately. I need to adjust the power steering drive belt as the assist needs to be improved, and the belt appears slack. We are on a good path at the moment.