leaky head valve tolerance?

g-mack · Aug 29, 2014

right so im about to put on a second hand head, that has been crack tested and skimmed. (according to seller). i have checked with straight edge and it is flat!
im not looking at rebuilding head just want quick turn around as cheap as pos. to get back on the road.
done a quick valve sealing test by pouring water into ports. all perfect except one! and it is only a slight weep.
i know the right thing to do is remove valves, replace seals and lap them in but that means buying valve compressors, seals paste etc etc....
and more time!
what i want to know is if i put this head on as is, will it be OK? will the compression help seal the valve? or will it just run crap and i will have to change take head off again?
cheers

tetsu0san · Sep 2, 2014

Water isn't a good test anyway, petrol would be better as it's thinner.

It's up to you, but if it were me I would lap the valves in. If you ask I am sure someone on here who is near you might lend you the bits you need, or maybe help for beer tokens?

jamesmartin · Sep 2, 2014

from what youve said it will be ok

g-mack · Sep 4, 2014

bloody bollox!! 10 hours to change head, and its running rough as a badgers arse!!!!! sound like its running 3 cylinders. chuffing air out intake is worse!! lots of grey smoke.

g-mack · Sep 5, 2014

have just cracked off injector pipes and no3 makes no difference. so im guessing its losing compression on that cylinder. lots of grey smoke which i think is unburnt fuel, and engine is vibrating all over the place.

tetsu0san · Sep 8, 2014

Swap injectors no2 and no3 around to rule out a faulty injector/pump.

sk sharma · Sep 9, 2014

check for compression pressure of cyl.no.3

g-mack · Sep 9, 2014

tetsu0san said:
Swap injectors no2 and no3 around to rule out a faulty injector/pump.

done, still in same cylinder so im guessing low comp in no3

tetsu0san · Sep 10, 2014

g-mack said:
done, still in same cylinder so im guessing low comp in no3

Thinking about it, it could be a faulty injector pump too. You could try a fuel supply test with the injectors by putting containers on the leak of pipes on each injector and cranking over the engine with the fuel solenoid disconnected so the engine wouldn't start. Basically you should get the same amount of fuel in each container. If not then it is either a fauly pump or injector. As you have swapped out the injectors then it would be a pump issue.

Never tried it before, but I can see how it would indicate issues.

g-mack · Sep 10, 2014

im not convinced its a fueling prob! it was fine until i put unknown head on!
anyhoo ive got the unknown head off again and cylinders full of oil!! ALL the stem seals were pushed to top of spring !! so zero sealing at all!! i know this wouldnt cause a cylinder not to fire but im guessing the valves just are not in great shape. so enough of this ****, ive bought a new AMC head from turners!!!
hope to get it on this week and will report back!

leaky head valve tolerance?

g-mack

Active Member

tetsu0san

Active Member

jamesmartin

Well-Known Member

g-mack

Active Member

g-mack

Active Member

tetsu0san

Active Member

sk sharma

New Member

g-mack

Active Member

tetsu0san

Active Member

g-mack

Active Member

Similar threads