m20 b25 head gasket replacement . should i replace piston rings while im there?

[flybynite]

Yes it all depends on whether the bolt is actually loose or you felt a slight give on tightening due to rough threads.

In an alloy block it is usually the sign of stripped threads but very unusual in an iron block but would not the first bad head bolt

Set the torque wrench to 30 and see if you can reach that torque. (make sure you don't pull past the click) If you have pulled a thread it won't achieve that and it will spin.

[Gaffasgaff]

It depends on your definition of loose. I would say as long as it still took force to tighten and it didnt make any nasty noises it should be okay. I recall mine taking quite a lot of force on the last sequence.

One option is to buy a single head bolt from bmw as they can be replaced singularly, and have a look what's going on if it worries you.

It started off tight but then become easier to turn 3/4 of a way . I was using a 1/2 breaker bar . Was confused as that was the only bolt that done that and all the other 13 was fine .

[Gaffasgaff]

Yes it all depends on whether the bolt is actually loose or you felt a slight give on tightening due to rough threads.

In an alloy block it is usually the sign of stripped threads but very unusual in an iron block but would not the first bad head bolt

Set the torque wrench to 30 and see if you can reach that torque. (make sure you don't pull past the click) If you have pulled a thread it won't achieve that and it will spin.

I will give that a go tomorrow . Fingers crossed it's nothing serious .

[Gaffasgaff]

Yes it all depends on whether the bolt is actually loose or you felt a slight give on tightening due to rough threads.

In an alloy block it is usually the sign of stripped threads but very unusual in an iron block but would not the first bad head bolt

Set the torque wrench to 30 and see if you can reach that torque. (make sure you don't pull past the click) If you have pulled a thread it won't achieve that and it will spin.

Ok so I got round checking the bolt with my torque wrench set to 30NM . Non of the head bolts moved . All felt tight .
Just waiting on some parts to arrive new HT leads and spark plugs fuel filter oil filter . Coolant recommended by tha881.
I'm looking at buying the oil from halfords
10w 40 semi . Should this be ok ? Should have it up and running on the week end

[tha881]

Oem HT leads rarely fail, they can be checked by doing a simple multimeter test.

Halfords oil will be absolutley fine, I use mobil 10w40 because I did away with my oil cooler and like to think it offers a bit better protection, but in reality it's probably the same.

Good news about the bolts. It will be a good feeling when you get to fire it up again. One tip with the coolant is fill some of the hoses around the thermostat before connecting them, if you just pour it in the tank it will never bleed. You need to fill it with approx 10 litres in total.

[Gaffasgaff]

Oem HT leads rarely fail, they can be checked by doing a simple multimeter test.

Halfords oil will be absolutley fine, I use mobil 10w40 because I did away with my oil cooler and like to think it offers a bit better protection, but in reality it's probably the same.

Good news about the bolts. It will be a good feeling when you get to fire it up again. One tip with the coolant is fill some of the hoses around the thermostat before connecting them, if you just pour it in the tank it will never bleed. You need to fill it with approx 10 litres in total.

Ahhh ok . HT leads was originally bought from Ebay. They didn't run inside the plastic track . Just looked a bit tacky . So I bought some from euro BBT ones they are OEM I think . I seriously cannot wait to get it running after the service . Just miss not been able to drive it . Been standing for some time now . Kids have taken over my life .
I will fill all the hose's up before filling the tank . I may just fit a new thermostat as it isn't expensive . Might as well do it now before later finding out Its no good .

[Brianmoooore]

Yes it all depends on whether the bolt is actually loose or you felt a slight give on tightening due to rough threads.

In an alloy block it is usually the sign of stripped threads but very unusual in an iron block but would not the first bad head bolt

Set the torque wrench to 30 and see if you can reach that torque. (make sure you don't pull past the click) If you have pulled a thread it won't achieve that and it will spin.

Ok so I got round checking the bolt with my torque wrench set to 30NM . Non of the head bolts moved . All felt tight .
Just waiting on some parts to arrive new HT leads and spark plugs fuel filter oil filter . Coolant recommended by tha881.
I'm looking at buying the oil from halfords
10w 40 semi . Should this be ok ? Should have it up and running on the week end

Bolt may break or strip its thread if accidentally given an extra 90 degrees turn while torqueing up, or will not be tight enough if one of the 90 degree turns is missed. To eliminate the possibility of this mistake, it's a good idea to put a mark on each bolt head with a permanent marker after the initial tightening with the torque wrench. You can then easily see when they've all been given the first 90 degree turn, and then the second.

[Gaffasgaff]

Yes it all depends on whether the bolt is actually loose or you felt a slight give on tightening due to rough threads.

In an alloy block it is usually the sign of stripped threads but very unusual in an iron block but would not the first bad head bolt

Set the torque wrench to 30 and see if you can reach that torque. (make sure you don't pull past the click) If you have pulled a thread it won't achieve that and it will spin.

Ok so I got round checking the bolt with my torque wrench set to 30NM . Non of the head bolts moved . All felt tight .
Just waiting on some parts to arrive new HT leads and spark plugs fuel filter oil filter . Coolant recommended by tha881.
I'm looking at buying the oil from halfords
10w 40 semi . Should this be ok ? Should have it up and running on the week end

Bolt may break or strip its thread if accidentally given an extra 90 degrees turn while torqueing up, or will not be tight enough if one of the 90 degree turns is missed. To eliminate the possibility of this mistake, it's a good idea to put a mark on each bolt head with a permanent marker after the initial tightening with the torque wrench. You can then easily see when they've all been given the first 90 degree turn, and then the second.

Hello brian . I made sure I did this . I followed the pattern of tightness and marked each bolt with a paint pen so that I know which bolts I had done . It was just bolt number 6 was tight and then became easy to turn as if the bolt had streched . I had 1/4 of a turn left to go . I had completed the process . Only thing I noticed was that in the haynes it does not mention after first 90 degree waiting 15mins before going round again . I only saw this on the wiki after I had finished installing the head .

[flybynite]

Only thing I noticed was that in the haynes it does not mention after first 90 degree waiting 15mins before going round again . I only saw this on the wiki after I had finished installing the head .

There are quite a few different permutations for head tightening, most have a wait 1st stage to 2nd then 3rd when up to temperature, but both Haynes and Bentley say this is not necessary on torx head bolts (which you have). Not sure the wiki is correct in that respect.

Had to look again myself because I have only really worked on a 323i with hex head bolts which is a completely different kettle of fish

[Gaffasgaff]

Only thing I noticed was that in the haynes it does not mention after first 90 degree waiting 15mins before going round again . I only saw this on the wiki after I had finished installing the head .

There are quite a few different permutations for head tightening, most have a wait 1st stage to 2nd then 3rd when up to temperature, but both Haynes and Bentley say this is not necessary on torx head bolts (which you have). Not sure the wiki is correct in that respect.

Had to look again myself because I have only really worked on a 323i with hex head bolts which is a completely different kettle of fish

So considering I checked it at 30NM and it felt tight would I be ok ? Or should i remove the bolt and replace it . Just worried about snapping a bolt in the block and stripping it all back down again .

[flybynite]

So considering I checked it at 30NM and it felt tight would I be ok ? Or should i remove the bolt and replace it . Just worried about snapping a bolt in the block and stripping it all back down again .

30nm should be enough to move a stripped thread without messing with the torque and stretch you set. Both Haynes and Bentley say you can tighten these cold with no waiting so I would say you did it correctly..

If you are sure you did the sequence correctly my gut feeling is it should be OK.

I think you just felt the 'give' of a stretch bolt (probably doing the 90 degree turn a bit quicker towards the end which can make the bolt 'give' a bit if you don't do the turn slow and progressively) but as above you can always replace the one bolt for peace of mind. It is a difficult call when you are not the one on the wrench.

[Gaffasgaff]

So considering I checked it at 30NM and it felt tight would I be ok ? Or should i remove the bolt and replace it . Just worried about snapping a bolt in the block and stripping it all back down again .

30nm should be enough to move a stripped thread without messing with the torque and stretch you set. Both Haynes and Bentley say you can tighten these cold with no waiting so I would say you did it correctly..

If you are sure you did the sequence correctly my gut feeling is it should be OK.

I think you just felt the 'give' of a stretch bolt (probably doing the 90 degree turn a bit quicker towards the end which can make the bolt 'give' a bit if you don't do the turn slow and progressively) but as above you can always replace the one bolt for peace of mind. It is a difficult call when you are not the one on the wrench.

I know what u mean . I think I'm gonna chance it .it all seemed ok today . Cheers for your input . Really appreciate it . Hopfully she will be up and running very soon . I will do a compression test before I fire her up properly . .

[Gaffasgaff]

Update .
So I have been losing a bit of sleep over that 1 cylinder bolt. Nightmares of it breaking and rattling around in the valve train . . So I have now decided to just replace it . I contacted bmw sytner and the cylinder head bolt is on a 4 week back order . So I decided to contact the seller and explain my concern . He was very helpful . He contacted the elring supplier and got back to me today . They are sending me a complete new set of head bolts .

[Brianmoooore]

Just change the suspect one. No point in changing the others and risking the gasket.
Even if the suspect one did break, which I very much doubt would happen, it wouldn't break right under the head like the old hex. ones did, so it would remain in its hole and wouldn't 'rattle about'.

[Gaffasgaff]

Just change the suspect one. No point in changing the others and risking the gasket.
Even if the suspect one did break, which I very much doubt would happen, it wouldn't break right under the head like the old hex. ones did, so it would remain in its hole and wouldn't 'rattle about'.

Cheers Brian . Will do that . I have spent quite a lot on it now I just don't want it all being a waste of time because of something so silly as one bolt not being tight enough

[Gaffasgaff]

Update . Everything is all back on and car is now up and running. I have put some flush into the coolant system to flush out what ever was left of the water less coolant ( thermostats out) . I noticed that the coolant in the expansion bottle was starting to overflow.
I then checked all the coolant hoses and the small return pipe was not getting hot at all . I decided to remove the pipe from the rad and blow through it with the coolant cap removed . The return pipe was totally blocked. I then removed the pipe from the expansion bottle and a load of sludge came out . The bottle was also blocked . After clearing the bottle with a airline all is now working correctly heat coming from the vents . I noticed the temperature gauge would not go past 1/4 . Is this normal .I have fitted new plugs new HT leads . Done a oil and filter service new air filter . When idle the car is fine . But when I hold the revs at 1500 2000 rpm there's a very slight judder whilst I have my hand on the intake manifold it's quite noticeable. Cant feel is much when in the car . It did this before the head gasket change also . I'm going to replace the fuel filter as it hasn't been done since I rebuilt ths car in 2010 also filling it with fresh fuel . Temp sensor was replace a few years ago.

[Brianmoooore]

Well done! A blocked vent pipe from a M20 radiator is far from uncommon and the needle on the temp gauge is exactly where it should be.
I'd be more worried about the needle on the fuel gauge.

[Gaffasgaff]

Well done! A blocked vent pipe from a M20 radiator is far from uncommon and the needle on the temp gauge is exactly where it should be.
I'd be more worried about the needle on the fuel gauge.

Cheers Brian . Yes I will fill it with fuel tomorrow . And see how she runs. Hopefully should feel silky smooth .
When I asked the guy at the machine shop if he had adjusted my tappets he was like yes of course. When the head went on I decided I best check to make sure . All the tappets had no tolerance at all . So I had to redo them . Just saying never hurts to double check everything .

Thanks for all your help guys I really appreciate it .

[minesapint]

That’s been a great post, some interesting stuff & plenty of Zone participation. Well done & thanks.
Good luck with your car, have tons of fun in her.

[Gaffasgaff]

That’s been a great post, some interesting stuff & plenty of Zone participation. Well done & thanks.
Good luck with your car, have tons of fun in her.

Cheers. will be using her this weekend all being well weather wise