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Discussion Starter #1
hey guys im just about 2 buy an 86 3/4 ton chev with a 6.2 in it. it only has around 100k and hasnt been on the road in about 4 years but runs good from wat i can hear. just wondering wat i should look out 4 b4 i jump into buying it and how could i improve power out of it on a tight budget?
 

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Pull the radiator cap before starting, start engine and look for bubbles in radiator, bubbles will indicate leaking head gaskets, pretty common. Do a ph test on the antifreeze, test strips are available at auto parts stores, sitting for a long time can cause problems. Examine oil, hopefully it isn't extra filthy, again sitting for a long time can be hard on bearings if the oil had turned acidic. With engine running, remove oil fill cap and note how much blow by comes out. Very little = good tight engine, lots of blowby = worn rings.
 

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could you explain the blowby test thing a bit please? I don't know exactly what blowby is - are you just to see how much smoke comes out?
thanks,
Paul
 

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If a lot of smoke comes out of the oil fill tube, it is because compression is getting past the cylinder rings.
 

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Need to check blowby when the engine is all warmed up...Also look for oil scum in the aircleaner. Its easy enough to wipe away for a sneaky prospective seller but most don't bother. A litttle is OK.
 

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Also look for oil scum in the aircleaner. Its easy enough to wipe away for a sneaky prospective seller but most don't bother. A litttle is OK.
If the truck has a C-code engine, there will be scum in the air cleaner. I know we are dealing with a 3/4 ton here, but mine is a 3/4 ton with the C-code.

Anyway, I would just check the blowby, check for any large bubbles in the antifreeze, check for any signs of a coolant leak, and fire it up. Check carefully around the waterpump and the aluminum casting it mounts to for signs of coolant. When I got my truck, the water pump was frozen up and the front engine cover had a hole in it about the size of your fist. Not too big of a deal to me (I think the parts to fix that little issue were $20), but it is a rather complex involved repair. If it runs good and no coolant leaks, go for it. Don't worry too much if it runs rough on startup. If it smokes on startup you might have to put injectors in down the road.

Good luck!
 

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To increase power,you can rotate the injection pump to the driver side about 2mm or so to advance the timing.You can also try putting on a K&N air filter if you wanted to.Some guys also turn up the pump internally,but i'd recommend a pyrometer to keep an eye on exhaust temperature.The gear drive is something i'd also look into if you decide your going to keep the truck.No more stretched timing chains.
 

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Discussion Starter #8
kool thanks guys, i think i am going to go with it i checked all the stuff you talked about and it all looks great!
 
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