1.6 td engine head

[Estdub]

Hello

I removed the engine head to check for possible valve damage but all the valves where straight. Assembled the head with new valve oil seals, lapped the valves and installed to the engine. Now the engine makes a strange sound. There is air blowing from the turbo(from the wrong side )as the pistons move up and down when running. the engine barely runs, does not react to throttle and sounds like a tractor (the really old kind). The engine head parts where installed to the place where they wore taken from. installed a new head gasket and head bolts. what did i miss when doing the engine head?



Ingmar

[82vdub]

Did you get the injector pump out of time (to the cam/crank) by 180 degrees? There's two dowel alignment holes on a lot of injector pump pully's and if you use the wrong one, it will be 180 degrees out of time.

Either that, or does the injector pump need to be advanced to get the engine back to proper timing? Have you tried adjusting the injector pump timing and see what that does?

[Estdub]

the injection pump mark seems to be in place. also tried to change the injection pump angle, but it didnt seem to make much of a difrence. ill try to upload a video soon...

[82vdub]

Is this a mechanical or hydraulic head? Are the valves staying open a little? This would pressurize both the exahust (exhaust valve staying open) and intake (intake valve staying open) system if this happens, and cause really poor running condition. I purchased a remanufactured mechcanical head that someone forgot to adjust the valve shims and 6 of the 8 valves never closed completely. Of course, it wouldn't run very well at all. Compression check?

[Estdub]

its a mechanical head.Before the "rebuild" the head worked and the parts where returned where they where taken from, so the valve adjustment should be correct.... how can i check if the valves are staying open?

[82vdub]

Compression check will tell you if you have low cylinder pressure. If you lapped the valves, then that will move the valve further into it's seat, making the distance between the valve shim to the camshaft lobe have less clearance. You can also check the valve bucket shim spacing according to the Bentley manual. If you mixed up the valve shims to where they were originally installed, this may cause the issue you're having.

[Estdub]

will have to get a bentley manual and see what they say about valve clearance . when disassembling the head i numbered all the parts so not to mix them up.

[Quantum TD]

Yeah, that won't make much difference. If you lapped the valves (as noted above) you need to check the valve shim clearance. I've seen this happen to people many times.

[Estdub]

Checked the shim clearance and only one valve was acceptable, others where really off. What kind of valve shims to install to those valves whit no clearance? I think that 3,0. if thats too big then i lose a little bit of valve lift, but not compression?

________Shim cap___Shim___New shim
Valve 1-----0,6mm--------3,55-----3,35
Valve 2-----No cap--------3,75-----?
Valve 3-----0,4 mm-------3,55-----No
Valve 4-----0,1 mm-------3,70-----3,75
Valve 5 ----No cap--------3,70-----?
Valve 6-----1 mm----------3,60-----3.0
Valve 7 ----No cap--------3,75-----?
Valve 8-----1 mm----------3,75-----3,05


intake valve cold 0,15-0,25
exhaust valve cold 0,35-0,45

[82vdub]

You will need to install a thinner shim for those that don't have enough clearance to the camshaft. Calculating what shim you need to get the valves within spec is somewhat of a guessing game. I would start by taking an inventory of the shims you have, and then purchase many shims that are thinner than what you need, so that you increase the clearances. You may have to purchase several of the same thickness to get this done as you're dealing with 8 valves. Just save the old shims for the next time you need to do this job. You may be able to swap shims from location to location to get other valve clearances within spec and not have to purchase as many shims. However, if you have the money, I'd purchase a bunch of shims and keep them around for this time and every time after this.

you are correct, if the clearance is too much, you will lose valve lift. The one's that are too tight the valve may be open slightly all the time. Even if there's too much clearance, you may not be getting the proper amound of air into the cylinder and causing low compression numbers as well.

On that remanufactured head that I purchased where someone didn't properly set up the valve clearances, I had to bring some shims to a machine shop and tell them how thick I needed them to be machined down to. I couldn't purchase shims thin enough to get the clearances within spec. One has to question how well a reman'd head is when the purchaser has to reman the head, and custom make shims to get things within spec. It's been doing good for 80K though.

[Quantum-man]

Checked the shim clearance and only one valve was acceptable, others where really off. What kind of valve shims to install to those valves whit no clearance? I think that 3,0. if thats too big then i lose a little bit of valve lift, but not compression?

________Shim cap___Shim___New shim
Valve 1-----0,6mm--------3,55-----3,35
Valve 2-----No cap--------3,75-----?
Valve 3-----0,4 mm-------3,55-----No
Valve 4-----0,1 mm-------3,70-----3,75
Valve 5 ----No cap--------3,70-----?
Valve 6-----1 mm----------3,60-----3.0
Valve 7 ----No cap--------3,75-----?
Valve 8-----1 mm----------3,75-----3,05


intake valve cold 0,15-0,25
exhaust valve cold 0,35-0,45

Swap 1 and 2
3 is fine
grind 0.1 off 4 valve stem
grind 0.2 off 5 valve stem
6 needs a 4.2 shim, but using 7's shim improves gap
7 use 6's shim and grind 0.05 off valve stem
8 needs a 4.35 shim Does not exist get a 4.25. Live with it as is.

Doing above is fine . A larger than spec gap won't harm engine/valves. slightly tighter spec on 7 is fine [ 0.15 compared with 0.2] number 6 and 8 have gaps that are too large, but better than too tight. Order the two shims and replace at leisure.

Grinding valve ends is preferable where smaller shims are required, as valves will eventually be replaced, as they wear faster than seats.

[Estdub]

thanks a lot for you all for your help... got the valve shims into place and the caps are bigger than normal, but the engine works and its nice to hear my turbo whistling at idle ...