Series 1 head on series 2 engine

[Phil Laing]

I have just replaced the head on my series 2 engine with a series 1 head. I also replaced the original series 2 cams. When I adjusted the tappet clearances, I found it strange that I had to make large adjustments to get clearance. The car won't start despite checking both Valve timing and ignition timing. The sound from the engine is the same as if a sparkplug had been removed - a popping sound. Is there a problem with fitting a series 1 head to a series 2 motor or is it possibl;y something to do with different cams and lift or possibly even different valve stem lengths. Please help!!

[P. de R. Leclercq]

Hello.

First question: why the change? If the S1 head is from a normal 1.3 rallye, then it will have smaller valves, and ports, and (without checking the book) perhaps lower compression too.

As I understand it, you have used the S2 camshafts. If so I presume that you timed them for 2.2mm lift at TDC?. If you have used the S1 camshafts then timing is 17/76/65/17 rather than 28/66/66/28. S1 cams are set at 1mm lift at TDC. I am baffled by the large adjustment required; it is a pity that I cannot see the engine! One thought occurs to me. I once was asked to fit S2 camshafts to a S1 engine. I have a feeliing that the head had larger valves; we found that there was no piston to valve clearance at the usual checkpoints (5 deg ATDC for the inlet and 5 deg BTDC for the exhaust).

Bring the engine carefully towards TDC No I overlap. With the engine at 5 deg or so, push down the No 1 inlet valve with a suitable implement; there is normally at least 8mm of clearance; check the exhaust valve too. If you have no clearance then I am afraid it is likely that you have bent valves...

There should be no problem using a S1 head in general on a S2 engine at least I cannot think of one offhand. I did once fit a S2 head to a S1 engine with no problem.

Paul

[Huib]

Paul, note that the 1.3 engine (818.302) without S head the 818.100 camshafts with the 1 mm set up clearance at TDC. The 1.3S (818.303) and 1.3HF (818.342) angines had the 818.342 camshafts with the 2.2 mm clearance.

I would also worry about the sprocket wheels as the rollers of the S1 chains have different diameters from the ones of an S2 chain.

[P. de R. Leclercq]

Yes, Huib, that's correct; obviously I expressed myself badly!

Also I should of course have mentioned the sprockets, pointing out that the S1 cars used roller chain, whist the S2s used Morse or "bush" chain necessitating diferent sprockets as you say.

Paul

[Huib]

Is it possible that you have the ignition 180 degrees out of phase?

With the TDC mark aligned, move the rockers at 1 and 4. If you can move the rockers on 1, the rotor should point to 1.

[Phil Laing]

Thanks for the response guys! Probably a little too technical for me, however all is well and the car is up and running just fine. I had somehow managed to move the vlve timing whilst re-connecting the timing chain and hence valve timing was badly out.

I will refer back to this thread later this year when I start putting my series 1 rallye back together. This car has cams with a lobe diameter of 3.5mm more than standard and the valves are also 3 mm wider. Someone told me this was an HF head but I suspect it is just a head specially prepared by Viglietti some years ago

[P. de R. Leclercq]

Good to hear that the engine is OK.

As for the other head, it must be special. If the valves are 3mm bigger then they will be 39 and 35mm diameter. This is larger than standard 1600 ones.

You may have to relieve the piston crowns for the big valves; check carefully.

Paul

[Heinrich]

HI phil

looks like all the south africans have their heads off.

I was also busy putting mine back on. And after trying to start it yesterday ALSO just getting pops all over. JUST to find that my cam timing was out.