blue smoke on start up
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Professional
Joined: Dec 2009
Posts: 118
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From: Arkansas
blue smoke on start up
my 84 ram's 318 has started to smoke when i first start it, i figured it is something in the vavles... right?
if i were to replace all of the seals and in the heads what would i need to look for?
if i were to replace all of the seals and in the heads what would i need to look for?
Record Breaker
Joined: Mar 2006
Posts: 2,165
Likes: 2
From: Alberta
1. Piston rings
2. Valve seats valve guide's
if compression test checks out, you can rule out the rings.
valves move up in down in a guide built into the head, over time the valves can wear down and not set properly due to carbon build up.
replacing the selas with out removing the heads can be done, but you need a compressed air source into the spark plug hole, piston has to be TDC to keep the valves drom droping when you remove the nut holding the valve spring.
Popping off the valve covers will show if the seals are dry and worn out.
a little puff out the tail pipe is farly common on a 16 year old engine, as long as your not burning blue going down the road, your ok.
2. Valve seats valve guide's
if compression test checks out, you can rule out the rings.
valves move up in down in a guide built into the head, over time the valves can wear down and not set properly due to carbon build up.
replacing the selas with out removing the heads can be done, but you need a compressed air source into the spark plug hole, piston has to be TDC to keep the valves drom droping when you remove the nut holding the valve spring.
Popping off the valve covers will show if the seals are dry and worn out.
a little puff out the tail pipe is farly common on a 16 year old engine, as long as your not burning blue going down the road, your ok.
Champion
Joined: Mar 2009
Posts: 2,639
Likes: 4
From: Bent Mountain Va
If you do a compression check, which I also would recommend, here is an additional check that will help with your diagnoses. After you get your pressure reading pull the gauge and squirt a tablespoon or so of oil in the spark plug hole and reinsert the gauge. Take another pressure reading and note the difference. The oil will help seal the rings and tell you if the problem is rings or valves.
Hall Of Fame
Joined: Jul 2006
Posts: 12,204
Likes: 10
From: Gainesville, Ga.
another trick for replacing valve seals without removing the heads is to use soft cotton string in the cylinder.
remove plugs and valve covers. one cylinder at a time - rotate piston down, feed a piece of string into the cylinder through the spark plug hole. rotate piston up until it stops, and let it compress the string. rotate piston back and forth several times to let the string settle out. remove valve keepers, spring, and replace seal. reinstall spring.
the good thing about this is there is no risk of air pressure loss, etc while you have the valve loose.
personally, i wouldn't worry about a little bit of smoke at startup.
remove plugs and valve covers. one cylinder at a time - rotate piston down, feed a piece of string into the cylinder through the spark plug hole. rotate piston up until it stops, and let it compress the string. rotate piston back and forth several times to let the string settle out. remove valve keepers, spring, and replace seal. reinstall spring.
the good thing about this is there is no risk of air pressure loss, etc while you have the valve loose.
personally, i wouldn't worry about a little bit of smoke at startup.
Thread Starter
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Professional
Joined: Dec 2009
Posts: 118
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From: Arkansas
the smoke is only at start up but it is burning a bit of oil. there shouldn't be much if any carbon in there because i have recently done a couple of the seafoam treatments. this engine is 26 years old but it only has 101k miles on it. how much air pressure is needed to hold the valves up?
Legend
Joined: Jun 2009
Posts: 8,025
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From: orangeville ontario
http://www.youtube.com/watch?v=vRAV5...eature=related
Last edited by crazzywolfie; May 2, 2010 at 08:31 PM.