i took a look at a 80 gmc 1/2 trailer special decent truck smokes on start then goes away. And after i went for a drive the guy said it smoke by the motor because it needs valve cover gaskets? would that make it smoke a bit? also he said tranny acts like it wants to shift into overdrive at 30 when your putting along he said it was a selanoid under the hood? any help?? also i could get the truck for 1200
truck smokes?
- Thread starter wardog76
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MotoArts
Well-Known Member
Smoke out the pipes? Worn valve guides most likely, not leaky gaskets.
Requires machine shop to install. You can add "umbrella seals" to the valve stems (Chevy uses useless O-rings that do nothing) that will keep most of the oil from splashing on the stems and running down in the guides. The seals are only a couple of bucks at the local parts store, and take an afternoon to install if you're mechanically handy. It's not a bad thing, there's 15 zillion engines out there with bad guides just like it.
Tranny, on the other hand, I'd be more leery of. If it's the original 700R4, they are not electronically shifted. The only thing electronic is the torque converter lockup, but that's not the problem.
Most likely the throttle valve (called "TV") cable is either misadjusted, or the trans is suffering the effects from misadjustment. The cable goes from the carb to the trans and regulates the trans fluid pressure in the valve body, basically telling the trans when to shift. If it is not adjusted properly, major trans damage can occur.
It is very easy to check and adjust. Do a google search on "adjusting tv cable".
Neither problem sounds like a deal breaker to me, even though the early 700R4's were a POS. I have had several "beater" Chevies like that one, and have a '93 WT with a 4.3 V6/auto overdrive now. Love the truck; easy to work on, plentiful parts available cheap and smokes enough to block out the sun when it starts up (same problem). And I'm a Ford guy.
Requires machine shop to install. You can add "umbrella seals" to the valve stems (Chevy uses useless O-rings that do nothing) that will keep most of the oil from splashing on the stems and running down in the guides. The seals are only a couple of bucks at the local parts store, and take an afternoon to install if you're mechanically handy. It's not a bad thing, there's 15 zillion engines out there with bad guides just like it.
Tranny, on the other hand, I'd be more leery of. If it's the original 700R4, they are not electronically shifted. The only thing electronic is the torque converter lockup, but that's not the problem.
Most likely the throttle valve (called "TV") cable is either misadjusted, or the trans is suffering the effects from misadjustment. The cable goes from the carb to the trans and regulates the trans fluid pressure in the valve body, basically telling the trans when to shift. If it is not adjusted properly, major trans damage can occur.
It is very easy to check and adjust. Do a google search on "adjusting tv cable".
Neither problem sounds like a deal breaker to me, even though the early 700R4's were a POS. I have had several "beater" Chevies like that one, and have a '93 WT with a 4.3 V6/auto overdrive now. Love the truck; easy to work on, plentiful parts available cheap and smokes enough to block out the sun when it starts up (same problem). And I'm a Ford guy.
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1998yamahawarrior
Well-Known Member
If the valve cover gaskets are leaking you should be able to tell as they would have a very good oiling residue around the covers. From the pipes could be valve seals to piston rings, its just hard to tell since you dont know how its been treated through its life.
MotoArts
Well-Known Member
Probably.
Or less likely, either the PCV hose isn't hooked up right or dried out intake manifold-to-block end rail seals, which are/should be replaced by RTV sealant.
All those old Chevys leak like that if they have not had the gaskets changed. The rocker covers are cheesy thin stamped steel and deform easily around the bolt holes. Those bolts always work loose, and ham fisted wrench monkeys always overtighten them. The oil pan is probably in the same condition too, leaky and deformed.
Replace the rocker cover gaskets with good modern rubber style, not cheapo cork ones. Most times you can hammer the warps out with a body dolley, or just replace the rocker covers with a set of aluminum ones.
Again, it's a cheap simple fix.
Or less likely, either the PCV hose isn't hooked up right or dried out intake manifold-to-block end rail seals, which are/should be replaced by RTV sealant.
All those old Chevys leak like that if they have not had the gaskets changed. The rocker covers are cheesy thin stamped steel and deform easily around the bolt holes. Those bolts always work loose, and ham fisted wrench monkeys always overtighten them. The oil pan is probably in the same condition too, leaky and deformed.
Replace the rocker cover gaskets with good modern rubber style, not cheapo cork ones. Most times you can hammer the warps out with a body dolley, or just replace the rocker covers with a set of aluminum ones.
Again, it's a cheap simple fix.
ok well the guy that has it is the 2nd owner and has only had it a month. The first owner bought new apperently and was a college professor the guy now is hurting for money he needs a house. So my only big issue is the tranny at them moment he said he took it to a tranny guy and said that selanoid is probably going bad. it ran good only other thing is the exhaust manifold has a leak he said the gasket is out and he just rather hear a tick then possibly break a bolt out in the block changing them
1998yamahawarrior
Well-Known Member
Make sure the oils topped off and you should be good. You could also stop half way back just to check it and add if necessary.
