I recently got an '86 F-350 with a 6.9, C6 and early banks turbo (square air box, Banks Sidewinder on it). 79k miles and never rolled over PO says. This is my first diesel so a learning experience, though I have owned several '80-'86 trucks and built plenty of engines and transmissions. I want to figure out what I have, what it needs, make sure it's reliable then swap in a ZF5, 4" lift, and 35" tires. Truck is a daily driver and will tow in the summer.
Engine seems to run good. Smooth all around, starts right up within a second of cranking even below freezing now some mornings. Seems like it needs a lot of pedal to get moving but I understand these old diesels aren't exactly fast. Feels sluggish unless you get into the pump a lot, though it really wakes up once it gets up around 4-5 lbs or more on the gauge. It feels quick when it making boost.
My concern is anything more than 1/4 to 1/3 of the pedal and it blows white/gray smoke. Increases in volume with more pedal and wide open gets darker as expected Not huge plumes but a fair amount. No smoke on cold or warm startup, maybe a brief fairly light puff sometimes which I consider normal. In about 800 miles I've driven it it's only ever missed once and that was immediately after a cold start below freezing. Fired off within 1 second of cranking, stumbled for a second or two then smoothed right out, nothing I'd consider abnormal. Seems to not really smoke much or at all while engine is cold on high idle and advance though I drive it pretty easy until it's up to temp and let it idle a few minutes in the morning before heading out. Exhaust doesn't smell funny to me at idle and no smoke. Overall it seems to run smooth, start easy, and nothing that would make me suspect any major issues aside from the smoke. Gets about 14 MPG highway with 3.55:1 gears and C6 at 65-70, a little less than I expected.
Antifreeze is clean and looks normal, not dropping, doesn't smell funny. Changed oil when I got it a few weeks ago with Rotella and ended up slightly overfilled, now slightly under filled maybe 1/4 below full mark. Didn't leave any spots on ground when I got it, after changing oil it left a small spot overnight a few times then dry since oil level dropped from slightly overfull. Old oil was black but no metal or water. New oil after 900 miles is now dark but not black, no metal no water on dipstick. Engine was mostly cleaned by PO shortly before I saw it so couldn't really tell about leaks and such up front. I now see front main is very slightly seeping, no drips. Valley pan still clean and front still clean. Some oil on drivers side valve cover below CDR valve (goes into drivers side of banks air box over valve cover). Back of engine is a bit oily and cruddy down to the trans. Sprayed off with brake clean particularly around head gasket and where I was able to clean off is not looking oily again in that area.
I know these 6.9 are prone to head gasket failure and that is my biggest concern. It runs well though and no oil/water mix. I think when I do the ZF5 swap it may be worthwhile to just pull the engine and replace gaskets/seals/oil cooler seals/etc., inspect bearings, and paint just to be sure it's all good and take care of basics. Maybe head studs too since it has a turbo and head bolts are a known weak point. I know white/gray smoke could be unburnt diesel from incomplete combustion. No idea on IP or injector age but if 77k miles I'd suspect original. Ordered a diesel compression tester and a timing setup which should arrive next week. Want to do that much at least to be sure of what I have and cover the basics.
Looking for any input as to what I should check or what could cause the white/gray smoke. Like I said it's not plumes but it's lighter colored and starts at lighter throttle than what I'd expect. I've also never had a diesel before so I am not totally up on what's normal and what's not. Should I be concerned? If so what should I be checking or what is suspect?
Engine seems to run good. Smooth all around, starts right up within a second of cranking even below freezing now some mornings. Seems like it needs a lot of pedal to get moving but I understand these old diesels aren't exactly fast. Feels sluggish unless you get into the pump a lot, though it really wakes up once it gets up around 4-5 lbs or more on the gauge. It feels quick when it making boost.
My concern is anything more than 1/4 to 1/3 of the pedal and it blows white/gray smoke. Increases in volume with more pedal and wide open gets darker as expected Not huge plumes but a fair amount. No smoke on cold or warm startup, maybe a brief fairly light puff sometimes which I consider normal. In about 800 miles I've driven it it's only ever missed once and that was immediately after a cold start below freezing. Fired off within 1 second of cranking, stumbled for a second or two then smoothed right out, nothing I'd consider abnormal. Seems to not really smoke much or at all while engine is cold on high idle and advance though I drive it pretty easy until it's up to temp and let it idle a few minutes in the morning before heading out. Exhaust doesn't smell funny to me at idle and no smoke. Overall it seems to run smooth, start easy, and nothing that would make me suspect any major issues aside from the smoke. Gets about 14 MPG highway with 3.55:1 gears and C6 at 65-70, a little less than I expected.
Antifreeze is clean and looks normal, not dropping, doesn't smell funny. Changed oil when I got it a few weeks ago with Rotella and ended up slightly overfilled, now slightly under filled maybe 1/4 below full mark. Didn't leave any spots on ground when I got it, after changing oil it left a small spot overnight a few times then dry since oil level dropped from slightly overfull. Old oil was black but no metal or water. New oil after 900 miles is now dark but not black, no metal no water on dipstick. Engine was mostly cleaned by PO shortly before I saw it so couldn't really tell about leaks and such up front. I now see front main is very slightly seeping, no drips. Valley pan still clean and front still clean. Some oil on drivers side valve cover below CDR valve (goes into drivers side of banks air box over valve cover). Back of engine is a bit oily and cruddy down to the trans. Sprayed off with brake clean particularly around head gasket and where I was able to clean off is not looking oily again in that area.
I know these 6.9 are prone to head gasket failure and that is my biggest concern. It runs well though and no oil/water mix. I think when I do the ZF5 swap it may be worthwhile to just pull the engine and replace gaskets/seals/oil cooler seals/etc., inspect bearings, and paint just to be sure it's all good and take care of basics. Maybe head studs too since it has a turbo and head bolts are a known weak point. I know white/gray smoke could be unburnt diesel from incomplete combustion. No idea on IP or injector age but if 77k miles I'd suspect original. Ordered a diesel compression tester and a timing setup which should arrive next week. Want to do that much at least to be sure of what I have and cover the basics.
Looking for any input as to what I should check or what could cause the white/gray smoke. Like I said it's not plumes but it's lighter colored and starts at lighter throttle than what I'd expect. I've also never had a diesel before so I am not totally up on what's normal and what's not. Should I be concerned? If so what should I be checking or what is suspect?
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