roule

roule

Active Member
HI,
I 've just put back my Heads (with spark plugs) with a new gasket (Elring composite). When i turn the crank , I need 40 NM torque and even more after first move, and i can hear compressed air coming out almost at the rear of the heads ...
Is it normal ?
Valves leaks ?
video here...
 
If you turn the crank with plugs in and valves closed then air had to go somewhere, you'll get blowby past the rings in each cylinder. If a valve isn't sealing properly then you can get leakage that way
 
I suspect part of the problem is that without any push rods between followers and valves, the valves don't open and close as they are supposed to. As a result, you have "compression" in all 8.
 
kermit_rr said:
If you turn the crank with plugs in and valves closed then air had to go somewhere, you'll get blowby past the rings in each cylinder. If a valve isn't sealing properly then you can get leakage that way
Click to expand...
What upset me is that the air don't seems to go throw the cylinders but only at the rear of the heads as if i had a leak near the water port...and it makes a" bubble sound", dont know how to explain it.
For instance I torqued the heads to 60 NM, not yet to 90 NM.
 
classic kev said:
I suspect part of the problem is that without any push rods between followers and valves, the valves don't open and close as they are supposed to. As a result, you have "compression" in all 8.
Click to expand...
i could try once i put back the pushrods ...
 
So you haven't fully torqued the heads and turning it over "dead ended"
Finish the torque and fit the rest .

You may get lucky. where the sound comes from depends on which of the pistons are on the upward stroke. you didn't turn it far.

J
 
roule said:
What upset me is that the air don't seems to go throw the cylinders but only at the rear of the heads as if i had a leak near the water port...and it makes a" bubble sound", dont know how to explain it.
For instance I torqued the heads to 60 NM, not yet to 90 NM.
Click to expand...
Plugs in, all valves closed, heads not torqued down, why did you try to turn it over? It seems to me to be asking for trouble. Turning it over with the plugs out is OK.
 
I'm dumb o_O
Finished to torque to 90 NM and pull off the plugs...less resistance to turn the cranck of course (less than 25 NM), but still hear air mixed with water (like bubles sound) on the rear side of the heads.
 
roule said:
I'm dumb o_O
Finished to torque to 90 NM and pull off the plugs...less resistance to turn the cranck of course (less than 25 NM), but still hear air mixed with water (like bubles sound) on the rear side of the heads.
Click to expand...
Unless you have filled the block with coolant, how can there be air mixed with water bubbles?
 
roule said:
I did'nt flush the block...but the air shoud not go in the coolant circuit ?
Click to expand...
As you say, the air should not go into the coolant circuit, but if there is no liquid in the block how can the air produce bubbles? How can you be sure that the air is going into the coolant circuit?
I'm no expert on the V8, but to me it was not a good idea to turn the engine over with the plugs in, all valves closed and the heads not torqued down, it's possible I suppose that the gaskets have been displaced.
 
Last edited:
Datatek said:
As you say, the air should not go into the coolant circuit, but if there is no liquid in the block how can the air produce bubbles? How can you be sure that the air is going into the coolant circuit?
I'm no expert on 5he V8, but to me it was not a good idea to turn the engine over with the plugs in, all valves closed and the heads not torqued down, it's possible I suppose that the gaskets have been displaced.
Click to expand...
Instead of bubbles, could it be air being forced past a poorly sealing valve? Pure speculation.. or past the gasket if it's not very tight
 
Datatek said:
Comme tu dis, l'air ne doit pas entrer dans le circuit de refroidissement, mais s'il n'y a pas de liquide dans le bloc comment l'air peut-il produire des bulles ? Comment être sûr que l'air entre dans le circuit de refroidissement ?
Je ne suis pas un expert du V8, mais pour moi, ce n'était pas une bonne idée de faire tourner le moteur avec les bouchons branchés, toutes les soupapes fermées et les culasses non serrées, il est possible, je suppose, que les joints aient été déplacés.
Click to expand...
60 NM ...i dont' think gasket moved. some water again in the block (water holes at the rear of the block) i did not flush after removing the heads...
 
I just hope i d'ont have a gasket leak near the water holes. I go under the engine, oil sump out, and moving the crank... it seems the bubble air sound is near or inside the autogearbox ? may be it's ok and i go paranoiac :vb-gémissement2:
 
You must log in or register to reply here.

Similar threads

roule
Range EFI 3,9 cylinder head diagnostic
Replies
6
Views
1K
roule
roule
T
Land Rover Discovery 1 V8i 3,9 L EFI doesn´t start
2 3
Replies
49
Views
9K
Ratae
R
xDParis64
Hello Again! (SOLVED, Engine replacement)
2 3
Replies
56
Views
3K
xDParis64
xDParis64
xDParis64
Freelander 1 Converting from wasted spark to distributor (or Visa Versa)
Replies
0
Views
391
xDParis64
xDParis64
MrGorsky
P38A 4.6 V8 won't pull, sluggish, otherwise runs fine.
5 6 7
Replies
135
Views
11K
MrGorsky
MrGorsky