grizly
Well-Known Member
oh hell , need some expertise..
i suspect valve spring weakness is causing the lack of power .
But i am usually wrong at times..
I have a DU 4U ,it was going great except it threw a fan belt ,by the time i noticed dam thing was boiling ..Then i also noticed the inlet manifold bolts had unscrewed and the thing was sucking dust and all..
Any how that is fixed now and i plus have orderd a new thermostat .Like i said it started well before ,the next day it was difficult to start .It is now difficult to start and is down on power.
I put my hand over the exhaust pipe when i crank it and it sucks and then blows..so i suspected a burnt valve obviously.
I pulled the head but the valves seem ok,even with diesel poured into the throats of the valves they dont really leak.But i can easily, or quite easily rock the valve springs across their base with my fingers ,with a little effort it isnt really hard ?? they seem too loose to me .Shouldnt they have a high seating pressure ?i think there is something wrong right there.
I also suspected a tight valve but i am really just guessing now as i should have checked that before i pulled the head.The head gasket seems fine,there is no coolant in the sump and it doesnt blow and oil out the exhaust ..
post edit..i just realised that i may have had to decompression lever on when i had my hand over the exhaust manifold,which would make it suck air ?
An help appreciated..
Thanks
i suspect valve spring weakness is causing the lack of power .
But i am usually wrong at times..
I have a DU 4U ,it was going great except it threw a fan belt ,by the time i noticed dam thing was boiling ..Then i also noticed the inlet manifold bolts had unscrewed and the thing was sucking dust and all..
Any how that is fixed now and i plus have orderd a new thermostat .Like i said it started well before ,the next day it was difficult to start .It is now difficult to start and is down on power.
I put my hand over the exhaust pipe when i crank it and it sucks and then blows..so i suspected a burnt valve obviously.
I pulled the head but the valves seem ok,even with diesel poured into the throats of the valves they dont really leak.But i can easily, or quite easily rock the valve springs across their base with my fingers ,with a little effort it isnt really hard ?? they seem too loose to me .Shouldnt they have a high seating pressure ?i think there is something wrong right there.
I also suspected a tight valve but i am really just guessing now as i should have checked that before i pulled the head.The head gasket seems fine,there is no coolant in the sump and it doesnt blow and oil out the exhaust ..
post edit..i just realised that i may have had to decompression lever on when i had my hand over the exhaust manifold,which would make it suck air ?
An help appreciated..
Thanks
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