red reading
Active Member
i think so,it is on the corner of the block on the front by the thermostat housing, try doing it up with an allen key when its in as you wont have much room! its there to seal an oil galley btw.
Oil in Exhaust
- Thread starter PulsarLee
- Start date
Cant see you being able to get much torque to clamp / seal an oil gallery? the bolt is only M6 x about 40 i think, how does it seal? does it pull the corner of the head down or something?
red reading
Active Member
if you dont put it in you will have an oil weep/leak on that corner,it works as you say by pulling the head down.
Do you think i will be able to re tapp this bolt hole m8?
will there be enough wall thickness in the block and lug on the head?
thanks,
Lee
hi guys,
ive just got the head off and had to take the inlet mani off too due to the bloody hoses,,,,nightmare!! ive broken the purple coloured sensor that is screwed into the back underside of the plenum...does anyone know what this part is or even have one?
just couldnt see this when i lifted the plennim,,,,
thanks,
lee
ive just got the head off and had to take the inlet mani off too due to the bloody hoses,,,,nightmare!! ive broken the purple coloured sensor that is screwed into the back underside of the plenum...does anyone know what this part is or even have one?
just couldnt see this when i lifted the plennim,,,,
thanks,
lee
okies,
been cleaning the head and block before i start to replace the HG. The old gasket was showing clear signs of blowing on number 4 cylinder (2 water jackets) this will explain the white smoke. I can also see a slightly orange mark on the side of the piston crown adjacent to where the water jackets have been blowing. Is this type of thing normal to see? The piston crown itseld looks in excellent condition and has not been holed.
still wondering why i was getting oil in the cylinder and out of the breathers inti the inlet??
the exhaust ports are wet through with oil which is sticky,black,and,wet.
Also as it was this piston that had only 60 psi compression, could it be a valve seal causing all the pressure in the rocker and into the cylinder?
was going to take number 4 piston out as suggested by Bob but just trying to avoid the extra work if possible.
any thoughts Bob / Anyone.
Cheers,
Lee
been cleaning the head and block before i start to replace the HG. The old gasket was showing clear signs of blowing on number 4 cylinder (2 water jackets) this will explain the white smoke. I can also see a slightly orange mark on the side of the piston crown adjacent to where the water jackets have been blowing. Is this type of thing normal to see? The piston crown itseld looks in excellent condition and has not been holed.
still wondering why i was getting oil in the cylinder and out of the breathers inti the inlet??
the exhaust ports are wet through with oil which is sticky,black,and,wet.
Also as it was this piston that had only 60 psi compression, could it be a valve seal causing all the pressure in the rocker and into the cylinder?
was going to take number 4 piston out as suggested by Bob but just trying to avoid the extra work if possible.
any thoughts Bob / Anyone.
Cheers,
Lee
Hiya Guys,
couple of questions on the rebuild of my R,
Now my head is off and mindful that there is only a problem with number 4 cylinder, but no apparant piston crown damage, can I take the head to a skim / engineering company and have the valve seals, guides and valve seats checked?
Although i have tied the timing chain up and set the timing, I need to rotate the crank to check the bore in number 4, can this be done with the chain in situ on the crank pully.
sorry about all the questions again.
cheers,
Lee
couple of questions on the rebuild of my R,
Now my head is off and mindful that there is only a problem with number 4 cylinder, but no apparant piston crown damage, can I take the head to a skim / engineering company and have the valve seals, guides and valve seats checked?
Although i have tied the timing chain up and set the timing, I need to rotate the crank to check the bore in number 4, can this be done with the chain in situ on the crank pully.
sorry about all the questions again.
cheers,
Lee
red reading
Active Member
As above
Hiya Bob,
Please could you advise, if it is the O Ring seal or valve seal that has gone would this massively affect the compression of number 4 cylinder (40 psi).
Also, as mentioned in my last post, i have set the timing and tied the chain up at TDC.... if i need to remove number 4 piston, can i do this by removing the sump and disconnecting the conrod, re shell etc without turning the crank at all..... or as Red says, if im careful, can i turn the crank a little keeping the chain taught?
Cheers,
Lee
red reading
Active Member
You'l have trouble getting hold of bob he's in grand canaria (or somewhere like)!
Thanks red,
im going to take the head for pressure testing and a vacum test, also to see if it needs a skim although i hopr it wont as it never over heated. as the head is stripped apart from the valves and springs. As the problem is only with number 4 piston, and all the others are spotless and giving consistant 160 psi pressure. Number 4 is wet and oil burned black on the valves. As I still dont know at this point what was the cause of the 40 pis reading on number 4 piston, should the tests on the head identify if there is a problem with a sticking valve, guide or seal and would any of these possibly account for the massive pressure loss in this piston?
any thoughts would be much appreciated.
cheers,
Lee
im going to take the head for pressure testing and a vacum test, also to see if it needs a skim although i hopr it wont as it never over heated. as the head is stripped apart from the valves and springs. As the problem is only with number 4 piston, and all the others are spotless and giving consistant 160 psi pressure. Number 4 is wet and oil burned black on the valves. As I still dont know at this point what was the cause of the 40 pis reading on number 4 piston, should the tests on the head identify if there is a problem with a sticking valve, guide or seal and would any of these possibly account for the massive pressure loss in this piston?
any thoughts would be much appreciated.
cheers,
Lee
P
pulsarboby
Guest
im back now lee
if youve only got 40psi compression on no4 and the ex port is wet with oil then remove the alluminium and metal part of sump then unbolt the conrod on that particular piston and push the piston out to inspect it.
i guarantee you that it has a cracked ringland or broken/seized rings ; ) may also have scored the cylinder so you need to check that very carefully.
assuming the cylinder is ok (ideally check it with a bore dial gauge for ovality) you just need to hone that particular cylinder and youll get away with fitting a s/h piston.
if the cylinder is more than 8thou out of true or has bad scoring then youve got real probs and will either need a replacement engine or a rebuild/rebore on the one you have.
dont just put it back together without checking that bottom end or youll be back to square one
if youve only got 40psi compression on no4 and the ex port is wet with oil then remove the alluminium and metal part of sump then unbolt the conrod on that particular piston and push the piston out to inspect it.
i guarantee you that it has a cracked ringland or broken/seized rings ; ) may also have scored the cylinder so you need to check that very carefully.
assuming the cylinder is ok (ideally check it with a bore dial gauge for ovality) you just need to hone that particular cylinder and youll get away with fitting a s/h piston.
if the cylinder is more than 8thou out of true or has bad scoring then youve got real probs and will either need a replacement engine or a rebuild/rebore on the one you have.
dont just put it back together without checking that bottom end or youll be back to square one
Thanks,Bob,
Hope you had a good holiday. I will take the sump off as suggested. Do you think i should still take the head for pressure testing first - if a valve is sticking, or seal or guide, would this account for a very low pressure of 40 psi too?
Also as i posted above, i set the timing at tdc and tied the chain up, if i remove the sump to pop out number 4 piston, will i need to rotate the crank to do this or to put the shells back in? Im just worried that if i need to do this ill have to totally remove the chain and all the associated bits?
Cheers,
Lee
P
pulsarboby
Guest
by all means get the head leak tested etc but due to the fact that ex port on that cylinder is soaked in oil i would say your problem with low comp lies with the piston/cylinder.
youll need to turn the crank to get the bigend cap undone as it will be at tdc on 1 & 4, just put a spanner on crank pulley bolt and slowly turn it till no 4 is at bottom then undo the 2 14mm nuts then give it a gentle tap on the studs with a blunt object and the cap will come away then simply push the conrod upwards and the piston will pop out with the rod (dont lose the bigend shells or mark them)
dont worry about the chain too much, just hook it up from topside with a bungee strap to underside of bonnet and it will slide through the bungee as you turn the engine, we'll explain the engine timing upon you assembling it
youll need to turn the crank to get the bigend cap undone as it will be at tdc on 1 & 4, just put a spanner on crank pulley bolt and slowly turn it till no 4 is at bottom then undo the 2 14mm nuts then give it a gentle tap on the studs with a blunt object and the cap will come away then simply push the conrod upwards and the piston will pop out with the rod (dont lose the bigend shells or mark them)
dont worry about the chain too much, just hook it up from topside with a bungee strap to underside of bonnet and it will slide through the bungee as you turn the engine, we'll explain the engine timing upon you assembling it
Thanks Bob,
As ive already marked the timing chain and set to tdc... do you think ill be able to turn the crank bolt and feed the chain through my hands leaving it on the crank sproket, then when the piston issue is sorted turn the crank back until no4 is tdc again?
the actual piston crown is very clean btw with no carbon build up or anything... the smoke out of the exhaust was mainly on over run or when accellerating after been throttled off, I was thinking if it had broken a ring or ringland it would have smoked more all the time.
cheers,
Lee
As ive already marked the timing chain and set to tdc... do you think ill be able to turn the crank bolt and feed the chain through my hands leaving it on the crank sproket, then when the piston issue is sorted turn the crank back until no4 is tdc again?
the actual piston crown is very clean btw with no carbon build up or anything... the smoke out of the exhaust was mainly on over run or when accellerating after been throttled off, I was thinking if it had broken a ring or ringland it would have smoked more all the time.
cheers,
Lee
P
pulsarboby
Guest
yes just feed it through your hand as you turn it, then turn it back afterwards.
the smoke side of things is really irrelevant at this stage, as said if the port is soaked in oil then the prob is engine related full stop.
by the piston being clean on top means nothing, if anything it should be lightly coated in carbon deposits so may well be running lean on that particular cylinder.
you wont know anything untill you remove and carefully examine side of piston and the bore itself!
the smoke side of things is really irrelevant at this stage, as said if the port is soaked in oil then the prob is engine related full stop.
by the piston being clean on top means nothing, if anything it should be lightly coated in carbon deposits so may well be running lean on that particular cylinder.
you wont know anything untill you remove and carefully examine side of piston and the bore itself!
P
pulsarboby
Guest
no idea if im honest with you lee lol
a broken ring can score the bore deeply, a cracked ringland would be the best option and less chance of damage to the bore
a broken ring can score the bore deeply, a cracked ringland would be the best option and less chance of damage to the bore
Hi Guys,
Bob was absolutly spot on with his diagnosis. Ive now taken number 4 piston out and immediatly spotted the problem......a badly broken ringland about an inch long also the rings were ralling off in bits about 1" long!!
To my absolute amazement there appears to be virtually no scoring at all and the bore of the cylinder is still mirror like just the same as the other 3 bores bar one minute fidge near the top of the cylinder.
Looks like the blowing has also caused the HG to blow on 2 water jackets and caused slight carbon build up on the 2 exhaust valves too - i intend to re seat the valves and fit a new HG. Bob, Ill PM you re availability of a S/H std piston M8.
Thanks again everyone for all the advice
Lee