GM Truck Club
THE PREMIER CHEVY TRUCK & SUV FORUM
Founded in 2004 ~ We're the #1 Chevy Truck & SUV Forum.
Silverado & Sierra | Tahoe & Yukon | Suburban & Yukon XL | SUV & CROSSOVER

Seized Motor

Discussion in 'Chevy C/K Truck Forum' started by 08silverado3500hd, Jun 25, 2013.

  1. 08silverado3500hd

    08silverado3500hd New Member

    Joined:
    Apr 29, 2009
    Messages:
    72
    Likes Received:
    0
    Looking for some opinions. 1984 3/4 ton Scottsdale 5.7L, 4 barrel carb, 4 speed manual, heavy duty cam installed when it was only a couple years old. No catalytic converter (3/4 ton didn't have them that year), around 187,000 miles. Truck did a lot of hauling and towing including a 29 ft camper. Had some electrical issues (fuse link replaced next to the firewall) and brake issues. My dad bought it new in 1983, always smoked a little taken to the dealer several times while under warranty and they could adjust to either white or blue smoke but never completely got rid of it. Only used about 1/2 quart of oil between 3,000 mile oil changes. Truck was my daily driver from 1990 till 2000 then switched off between it and my 1990 Silverado 3500 7.4L. I helped take care of this truck from the day my dad brought it home, I learned to drive in it, and it was my graduation present in 1990. As many on here can probably relate it is still my baby. History lesson over - didn't have time to deal with the electrical and brake issues so the truck sat for about a year and a half. Finally decided it was time to put it back on the road, everything was back in working order but it was running real rich. Several weekends I ran it around the farm figuring with the fresh gas it would clear up then one weekend while it was just idling outside the garage for about 10 minutes it just stopped. Oil level was full and oil pressure was running normal before it quit. When it stopped I was standing within 20 feet of the truck and didn't hear any noises it just sounded like you shut the key off. Now you can't turn the motor by hand and it very slowly turns over with the starter and doesn't attempt to fire (the plugs are sparking).

    Now for the opinions - should I have the motor pulled and opened up to see what happened and if feasible to fix it or just go straight for a new motor? Haven't done any research yet so I have no idea how expensive either option would be. Any opinions/suggestions would be appreciated.

    84 truck.jpg
    #1
  2. phoebeisis

    phoebeisis New Member

    Joined:
    Jun 14, 2006
    Messages:
    1,613
    Likes Received:
    9
    Cut open the oil filter-see if you see chunks or flecks of metal-same story when you drain oil-do it in clean container-look for metal flecks
    If you do-maybe pull oil pan-look for obvious problem
    No metal flecks could mean something relatively minor
    Lotta metal flecks means rebuild or replace maybe
    Luck
    Charlie
    #2
  3. K15 Blazer Guy

    K15 Blazer Guy New Member

    Joined:
    May 16, 2012
    Messages:
    388
    Likes Received:
    2
    weird...
    if it was dumping tons of fuel.... maybe it scored the cylinders/walls/rings... gas is a solvent, not a lube.

    either way, a new engine is the way to go. they come with outstanding warranties now. plus, you can message it before you put it in to make sure you get every bit of power you can from it.
    ive already built my replacement engine in my Summit Racing "wish list" on my account.

    just think about going with something smaller, like a 550 CFM carb. and not the factory quadra-jet....
    ill bet you any money though if you pull a head youll see some very sad cly walls lol
    #3
  4. tbplus10

    tbplus10 Moderator

    Joined:
    Mar 14, 2007
    Messages:
    5,405
    Likes Received:
    25
    187,000 miles, just replace it, with that mileage rebuilding could get expensive if you need machine work.
    The ready availability of remanned and crate engines has made rebuilding financially questionable after adding new parts, machining, and man hours.
    The only real issue would be numbers matching.
    #4
  5. runsdeep0826

    runsdeep0826 New Member

    Joined:
    Jun 25, 2013
    Messages:
    8
    Likes Received:
    0
    The only issue with dumping fuel would be drying the cylinders out
    This creating low compression and most likely did cyl wall damage
    Rebuilds are not bad if u do it yourself I've built several SBC engines
    One Vortec with 200k no machine work dropped in eagle assembly
    It goes both ways new or rebuild could equal the same
    The only warranty a rebuild has is how skilled a engine builder u are!

    Jasper crates go about 1400 down here
    #5
  6. phoebeisis

    phoebeisis New Member

    Joined:
    Jun 14, 2006
    Messages:
    1,613
    Likes Received:
    9
    But like TB says-genuine GM Goodwrench rebuilds or new engines are CHEAP-
    $2000 CURBSIDE for his 5.7 I think
    My 1998 5.7 is just $2300 curbside-NEW GOODWRENCH-not a rebuild
    #6
  7. JTWard

    JTWard New Member

    Joined:
    May 29, 2013
    Messages:
    223
    Likes Received:
    0
    If it was running, and oil pressure was OK, then it should still be Ok, Perhaps just a fuel pump? otherwise like phoebeisis & the others, buy a GM Crate Motor, they are about $2K or Edelbroock sells they own engines, ect, . . . with a buck 87 on the motor it is time for a new something new. 200.000 miles on it, you got all the good out of it.
    #7
  8. 08silverado3500hd

    08silverado3500hd New Member

    Joined:
    Apr 29, 2009
    Messages:
    72
    Likes Received:
    0
    Well, the truck is fixed but now I am broke. GM performance engine 5.7L 290 hp, fly wheel, harmonic balancer, clutch fan, new starter, water pump, fuel pump, master cylinder, wheel cylinders, brake pads, calipers, emergency brake cable, all hoses, the list goes on and on. Now I have a leak in one of the gas tanks that I need to find and determine if patchable. Carburetor still needs some fine tuning after I run out the current tank of gas which is a mixture of old and fresh gas. 84 truck2.jpg
    #8
  9. JTWard

    JTWard New Member

    Joined:
    May 29, 2013
    Messages:
    223
    Likes Received:
    0
    Boy, It looks great. Best of luck and I'm sure you'll really enjoy the flood gates of power being flung open.
    #9
  10. tbplus10

    tbplus10 Moderator

    Joined:
    Mar 14, 2007
    Messages:
    5,405
    Likes Received:
    25
    Looks great, now your ready for another 200,000 plus miles of good memories.
    I enjoy seeing older trucks go back on the road vs end up rusting away behind the barn or getting disassembled in a yard.
    #10
  11. phoebeisis

    phoebeisis New Member

    Joined:
    Jun 14, 2006
    Messages:
    1,613
    Likes Received:
    9
    Looks good
    Great it is running again-probably better-much better and stronger-than new
    Weren't the 350's just 160-170 hp back in 1986?
    #11
  12. 08silverado3500hd

    08silverado3500hd New Member

    Joined:
    Apr 29, 2009
    Messages:
    72
    Likes Received:
    0
    1984 - pretty sure the original engine was 165 hp. Feels stronger on take off and on level ground she will cruise at 65 mph barely touching the throttle. Haven't had much time to play with it yet. Seems my shift point from 3rd to 4th is higher now but then again it has been awhile since I had her on a highway so it could just be my imagination. Never had a tachometer in it - maybe a future project if I find one that looks good/fits well in the dash somewhere. Anxious to get through a couple tanks of gas and have the carburetor fine tuned to really find out how she is going to run.
    #12
  13. tbplus10

    tbplus10 Moderator

    Joined:
    Mar 14, 2007
    Messages:
    5,405
    Likes Received:
    25
    Yea it just gained about a 100 ponies over factory, besides better throttle response you might notice better fuel mileage.
    The downside is all these extra ponies in front of an OEM trans can spell trouble.
    I suspect you dont hotrod the truck, but just be ware the trans has some miles on it and may act out for attention in the future.
    #13
  14. JTWard

    JTWard New Member

    Joined:
    May 29, 2013
    Messages:
    223
    Likes Received:
    0
    I was hoping you weren't going to mention that. BY the time I got my 1990 305 running right, my front clutch pack locked up on me. Well I was planning on a complete overhaul sooner or later. Runs fantastic now !
    #14
  15. 08silverado3500hd

    08silverado3500hd New Member

    Joined:
    Apr 29, 2009
    Messages:
    72
    Likes Received:
    0
    No hotrodding but we all have to spin the tires a little every once in a while. Plan to baby her in hopes she will keep going for a long, long time. Maybe some occasional light towing - I will let the 08 Duramax handle the heavy stuff.

    - - - Updated - - -

    I had a new clutch installed between 10,000 and 20,000 miles ago. By being a 4 speed manual hoping the transmission doesn't give me any trouble. Guess time will tell.
    #15

Share This Page