Hi all,
I have been working on this for the last two days and I am just about bonkers with it. I have recently had a head service done on my 4 cyl second gen and replaced the timing and CB chain. I'm having two problems:
1. The valves are hitting on the pistons when you wind her over by hand (if you loosen the head it lifts off) and
2. The timing marks start out lined up bet end up out with each revolution.

I have never had this problem before, any suggestions?

remember one revoloution of the crank is only half a rotation of the cam, so two full revoloutions of the engine will bring the mark back to original position. as i see it you only have two options, either the timing marks position you are using are incorrect or the chain is slipping for some reason. i havent worked on these engines before so im presuming its the same as any sohc 4 cylinder. Re check your marks and confirm you have the correct position.

Hi robssei, I have checked this, that is why I am puzzled!

Ah well , where are you getting timing settings, workshop manual? make sure your at top dead center of the compression stroke on Number 1 piston by checking the rotor in the dizzy is facing #1 point under the cap (if the distributer is correctly inplace and not out either). then remove rocker cover and check that the intake and exhaust valves on #1 cylinder are both closed. oh as well as checking the valves,check the piston is indeed at TDC, you can do this by removing a plug and using a long thin piece of dowell inserted in the plug hole to tell you when you are just at TDC, as it will rise pause for a moment then begin too drop, use this to confirm your crank marks. now im presuming number 1 is left hand side, looking at engine from the front (DRIVERS side) as most are read left to right, but again not 100% on that as ive never worked on a astron 4.

Take the timing cover off and check all the marks on the cogs. Look at the manual pictures and count the number of links between each chain run, on both chains, as shown in the pics. Mark them on your new chains with liquid paper if needed. Get them off your old chains if you don't have the pictures. Check that the dowel in the top cog is engaging properly and that all guides are set up properly. The dowel should engage in the cam, and the distributor drive gear. Check that the no 1 piston is at the top of its stroke, and don't worry about the above comment about the distributor as it runs off the cam and is probably off the engine anyway. Get the cam in the right place and there is no way the pistons can hit the pistons!

Hi guys, done all that. I don't think it actually is moving now, it seems right but the problem is that as soon as you tighten the head it locks. Whilever the head is loose it can turn but it lifts the head when it hits.

Im wondering if they shaved too much off the head when they did the service on it.

Not likely.

It's got me buggered. The timing marks are perfect, when you turn the engine over by hand it is doing everything it should until it gets stuck around 3/4 of the way.

If you've got some calipers, measure the overall height of the head. Other than that, what else was done to the head when it was serviced?

It was cleaned, shaved and had the valve guides and seals replaced. That's it.

I didn't know before this week that the 2.6 was an "interference" engine lol.

Your cam timing is off, there is no other explanation. You need to start from the beginning and recheck the cam chain and timing marks.

Regards, Andrew.

I took it to the mechanic and took 2 days to find out that the head gasket wasn't made properly. The rings around cylinders 2 & 3 were pertruding into the cylinder.