Poor cold start after cylinder head change

So my first big engine job so forgive me if I get some terminology wrong. I changed the cylinder head and it's all running again but when starting from cold it needs a bit of feathering on the accelerator to get it going. It's doesn't perform to well after that either, until it gets warmed up and things seem to improve. It's been off the road for a while so I can't really compare to how it was before.

I unplugged the MAF sensor which I read would have showed an improvement after about 12 seconds if there was a problem with that. It didn't make any difference.

The next thing I'm thinking may be a problem is those rocker shaft finger things. I followed the Haynes manual to set them up, which said to get them as close as possible, tighten them up all the way and then back off half a turn. I'm going to tighten them all up by about an eigth of a turn and turn it over to make sure it's all okay.

Is this a good idea? And can I do all this without having to drain the oil?

Lastly one unrelated question. My temperature guage barely even gets over the bottom line, is it supposed to sit in the middle like most cars would? I read something online that suggested that it's supposed to be like that. Sounds odd to me.

Sounds like you may have more than one problem.
Have you changed the thermostat?
Does the coolant level remain constant and where it should be?
Yes the temp gauge should get to the middle and stay there though it is very un trustworthy and unlikely to warn you in time if you have a real problem.
So you may have an airlock.
You shouldn't have to drain the oil to do that I don't think, although some may come on and gainsay this.
Why did you take the head off and have you changed the injector seals?

The rocker adjusters need to be a full turn, some people do a turn and a half too which also seems to be fine. Half a turn isn't enough, although I doubt that will account for your actual issue. When the cam lobe is visibly at full height fully tighten down the adjuster and then back off 1 / 1.5 turns and tighten up the lock nut. No real need to drain the oil to do this.

I would double check you have the timing correct to start with. I have seen several that run with the timing significantly out where people have used the balance holes instead of the timing slot - which is a square slot not a round one!

Thanks for the replies. I’ll check the rocker adjusters. I’m pretty sure I got the timing right, I did have the proper tools and I didn’t make them myself. Everything fit perfectly.

I’ve ordered a new thermostat and coolant temperature sensor. Whatever that pipe’s called that has the sensor in it felt hot and bendy after running and I’m pretty sure that’s right. I’ll check the coolant levels.

*Edit*
Sorry, forgot to say. I replaced the whole cylinder head as the gasket had gone and I was advised that it would be better to replace everything. I did change the injectors seals. The temperature gauge was like that even before I changed head. There’s been no other signs of overheating even though it’s been driven for hours at a time so I’m thinking it’s just the sensor or gauge that’s faulty.

Before I changed the head it started fine.

I think we have to take it that the head was quite damaged for you to feel the need to change it completely.

Twinnie said:

My temperature guage barely even gets over the bottom line, is it supposed to sit in the middle like most cars would? I read something online that suggested that it's supposed to be like that

Click to expand...

Hi, the gauge should go to quarter at 40*C and stay there untill 70 when it should go to the middle where it stays up to 120 then goes to red(that's quite stupid design IMO) if your ECT(engine coolant temp) sensor is fubar the gauge will not work well and it can cause cold start issues too especially if the FT sensor(in the FPR) is not he best too... a live data session with dedicated tester would be relevant though, that sensor can cause various misbehaviours:

Just to update in case anyone reads this in the future. I’ve ordered a new sensor and thermostat to try and fix this. I checked the instructions I’d used for setting up the fingers and I was wrong in remembering that I’d only turned them half a turn, it was actually a whole turn, so I’ll just leave them be. While trying to figure out why my horn wasn’t working I also found that the 100amp fuse for the glow plugs was grey and looked in bad shape, then it half failed a continuity test so I’ve ordered a replacement.