Valve seal or piston rings?
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Joined: Apr 2019
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From: Belgium
Valve seal or piston rings?
Hy,
Got a question about my:
84 Evo 4speed
I have white smoke coming out of the exhaust.
Is there a way to find out what is causing the problem? The valve seal or the piston ring?
Because, if I change the valve seal, and it turns out that it's not the problem, and I change the piston ring, do I have to change the valve seal again?
Thanx in advance.
PS, sorry 4 my bad writing. I am from Belgium.
Got a question about my:
84 Evo 4speed
I have white smoke coming out of the exhaust.
Is there a way to find out what is causing the problem? The valve seal or the piston ring?
Because, if I change the valve seal, and it turns out that it's not the problem, and I change the piston ring, do I have to change the valve seal again?
Thanx in advance.
PS, sorry 4 my bad writing. I am from Belgium.
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Joined: Apr 2019
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From: Belgium
Thanx, it's indeed also smoking when just idling, so I guess I have got the jackpot.
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From: NW AR
Also, if it smokes when you take off from idle, that is frequently valve seals.
How many miles on this motor? Warm the motor up, check the compression. Add a tablespoon (um, een paar milliliter) and check again. If it goes up significantly, compression rings are likely shot.
Given the work involved, once the heads are off for a valve seals, have the jugs honed and fit new rings. Unless things are worn too far, then replace the pistons and go oversize.
How many miles on this motor? Warm the motor up, check the compression. Add a tablespoon (um, een paar milliliter) and check again. If it goes up significantly, compression rings are likely shot.
Given the work involved, once the heads are off for a valve seals, have the jugs honed and fit new rings. Unless things are worn too far, then replace the pistons and go oversize.
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From: South Carolina
If you are going to remove the heads, you might as well pull the cylinders as well.
At the very least you should replace the base gaskets, but in reality an engine that is smoking is a good candidate for a top end overhaul, cylinder re bore, rings, pistons, valve job.
At the very least you should replace the base gaskets, but in reality an engine that is smoking is a good candidate for a top end overhaul, cylinder re bore, rings, pistons, valve job.
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Joined: Apr 2019
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From: Belgium
Also, if it smokes when you take off from idle, that is frequently valve seals.
How many miles on this motor? Warm the motor up, check the compression. Add a tablespoon (um, een paar milliliter) and check again. If it goes up significantly, compression rings are likely shot.
Given the work involved, once the heads are off for a valve seals, have the jugs honed and fit new rings. Unless things are worn too far, then replace the pistons and go oversize.
How many miles on this motor? Warm the motor up, check the compression. Add a tablespoon (um, een paar milliliter) and check again. If it goes up significantly, compression rings are likely shot.
Given the work involved, once the heads are off for a valve seals, have the jugs honed and fit new rings. Unless things are worn too far, then replace the pistons and go oversize.
Also, I have to order the compression test kit, so it will take a few days.
Last edited by Elecglide; Jun 14, 2020 at 02:56 AM.
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From: Bedford UK
Hi ElecGlide and greetings from across the North Sea. My wife and I were supposed to be in Belgium when all the virus interrupted things - we had a few days booked in Ieper. We hope to visit before too long! 
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If it is the valve seal, Can I re-use the upper and lower gaskets of the rocker or do they need to be replaced?
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From: NW AR
An overly rich carb will also produce smoking. Do the plugs look black like soot or black and oily?
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From: Belgium
Yes, sorry, a tablespoon of motor oil. I was thinking on my Nederlands and forgot to type "oil." If compression is low before and goes up to about normal-ish, compression rings are shot. While it is possible to have bad compression rings and not bad oil rings, it is pretty unusual.
An overly rich carb will also produce smoking. Do the plugs look black like soot or black and oily?
An overly rich carb will also produce smoking. Do the plugs look black like soot or black and oily?
I just ordered the compression kit. Hope that it will come in a day of 2.
Do you know if I can re use the upper and lower gasket of the rocker cover?