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Discussion Starter #1
i will keep this as short as possible

i have blueish/black smoke at start up only coming from the exhaust.

84 pickup with 150k original miles on everything. head has never been off.

local shop said its the rings and just live with it. Couldnt do a compression test because the threads on the #4 plug hole are fucked. that plug was in for its last time so i knew it needed a head job/helicoil.

pulled the head tonight to have it machined and valve job done next week. i noticed a lot of carbon buildup on the top of the pistons. how normal is this?
i know the easy answer is to just do the rings while the head is off, but that is beyond my knowledge and id rather not spend a grip of cash having a shop do the rings, plus having it towed there.

so pbb.....do i gamble with the rebuilt head or bend over and pay for the ring job? what would you do?
 

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Carbon on the pistons is normal. If you have big chuncks maybe not. but a even coating of it is normal.

Smoke when accerating is rings.

Smoke when letting off the gas, valve seals. Throttle closes, causes high vaccuum, pulls oil from around the vavle seals.

Smoke at start is also valve seals, as the engine sits oil seeps by the seal and pools on the back of the valve and burns off when it starts to run.

You have the head off, spend the time, put new seals on it. Or get a new head a good one runs 350ish a cheap one 150ish.

It can also be a combination of things. You can do a lot of testing with a simple vacuum gauge and understanding of how to read it. you might try watching a few videos online and try it. they are cheap
 

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Discussion Starter #3
Yeah I'm definitely going to have the head rebuilt. Decked, seals, 3 angle valve grind......just didn't know how bad the carbon on the top of the pistons is. Thank you for the response
 

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Did it have a lot of blow by before you took it apart? If it did then you'll be in the same spot when you are finished as you were when you started.
 

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Just cut reliefs into the head to allow coolant into the combustion chambers. That will keep the tops of the pistons clean. :D
 

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Discussion Starter #6
Did it have a lot of blow by before you took it apart? If it did then you'll be in the same spot when you are finished as you were when you started.
It just started about a month ago
 

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So. You got the head off, you gonna put a new chain and guides on it? Pull the pan off and clean the pickup screen. Trust me.
 

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Discussion Starter #8
Did a new chain and guides, all belts and hoses, fuel pump, and water pump 8k miles ago. All still good. I will pull the pan and clean the pickup screen as you suggested though
 

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Did a new chain and guides, all belts and hoses, fuel pump, and water pump 8k miles ago. All still good. I will pull the pan and clean the pickup screen as you suggested though
20 more minutes and you have the pistons out and can do an in-frame overhaul. if the cylinders look good without any scoring and no lip at the op the get a bead hone (usually rented at the local NAPA/CARQUEST/Kragen) and give the cylinders a new crosshatch, change the rings and at least freshen up the lower end. putting a new head on a lower end that has high miles usually ends in the lower end crapping out in a fast way. bearings can be rolled in fairly easily also.

or you could do this and have a new rebuilt engine for $1500. done ready to go. price it out versus having just your head gone through and a gasket set. this place does good work if there's not a good place in Grass Valley: http://gouldsprocylinder.com/
 
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