Help, I broke my truck!!!

[73_K5_girlie]

Here's the deal... I have a 73 K5 Blazer with the original but rebuilt 350 in it. It has run great since i got it, it uses a lot of oil, but i don't ever see any under the truck so i guess it's not leaking. I check the oil everytime i put gas in the truck so it stays full. Yesterday on my way home from work from the time I started it to go home it sounded awful funny, just a little louder than normal. As i got up to speed on the main road about 45 mph, the RPM's are way high, around 4000 and it starts to get really loud. When i would let off the gas pedal it would quiet right down and slow significantly, like it was struggling to maintain 45 mph. I pulled over into a parking lot, turned the truck off, and went to check the oil again, bout a quart low, but not too bad. I went to crank it back up and it acted like it wanted to turn over but couldn't, just kinda growled, i pumped the gas a couple times and it fired up, but as soon as i took my foot off the gas it died again... I tried to crank it again and it madew a squeeling noise very loud as it tried to crank so i shut it back down. I walked down to the gas station got a quart of oil and put it in, by that time the man that works in the apartment complex i had pulled over into had gotten the truck to start... but it was knocking... bad. I limped it the mile and a half home really slow and it knocked the whole way. I have a friend coming over tomorrow to look at it, but i was just wondering if from what i've told you if you guys have any idea what could have happened. Thanks guys

[plumbcut]

I would say either a rocker arm nut came loose or a lifter or cam lobe took a puke. If it was the lower end knocking it really wouldnt affect the way it ran. As for the oil being low, the truck doesnt know the difference between a quart over fill and a quart underfill. It had plenty of oil if it was just a quart low.

pc

[1972C10]

Might have been a cheap Rebuilt Like a blaines motor

Alot of the places that sell longblocks for 450 use cheapest parts available and regrind cams ive even seen used oil pumps

If it was using oil that indicates a problem

Its possible that it was a regrind cam it and Went south. the grind cams seem to go flat quicker something about not being heat treated as well after regrind.

And if your turning 4000 at 45 mph something is wrong either its in 2nd gear or you have extremly low gears Ive Got 3.73s and it only does 3000 at 70 and more than likley has smaller tires than your truck.

[Russell]

Hmm, sounds like you are getting a new top end

Might want to re-ring it as well. There is a chance that, like the others mentioned, someone didn't know what they were doing when rebuilding it...

A rebuilt motor shouldn't burn any oil at all... Go ahead and either get a good used motor, or spend a couple hundred bucks on this one to put a new oil pump, new cam, new lifters, new rings, and a gasket set for the motor and rebuild it yourself. Oh yeah, also probally want to get new bearings if motor ate the cam, there will be a bunch of metal in the oil, which is never a good thing...

[1972C10]

Its not really a good idea to take one junk rebuild motor take it apart and rebuild it No telling what kinda crap could have been done to it . Ive seen some blaines engines thats a local cheap rebuilder ,, With mis matched rods 0.30 0.40 cranks mismatched heads different cc even. And sloppy cylinder bores that can cause oil use.

Im not sayin your motor is like that but it could be.