Jump to content

350 Dead?

Snowman420

Recommended Posts

Snowman420 New Member

Snowman420

Posted
Posted

:D Hi, I have a 1980 chev truck with some engine problems. I had the engine rebuilt 1 1/2 years ago. It worked great until 3 weeks ago. I was travelling on the highway, pressed the gas to pas a car, and Bang! I heard a loud pop through the carb. The engine ran rough after that and my vacuum guage fluctuated wildly like I had a dead cylinder. I removed the valve covers and found a bent pushrod on the intake valve of #8. Replaced it and the engine was fine for 3 or 4 days. Then it bent another intake pushrod (Cylinder #3). Both times the intake pushrod was bent and the exhaust valve for that cylinder was hardly moving. #8 is fine now. I replaced all the pushrods and set the valves 1/2 turn from zero and gave the engine a complete tune up. I thought my rocker nuts were backing off but I have poly locks on the rocker studs and they're staying tight. I even rebuilt the distributor (I thought my timing was advancing too quick or sticking). Again, the engine ran fine for 3 or 4 days. Then, on my way to work I was on the highway again, pressed the gas and pop, pop, pop. After that, same thing. Fluctuating vacuum and rough at low rpm's but seems to get better if I get the rpm' up a little (Vacuum smoothens up too). Seems to run better when cold too. I'm thinking of replacing all the lifters but I don't hear the ticking usually associated with dead lifters. I just wondering if I'm missing something stupid. I don't want to spend $$ on lifters and have the same thing happen again. Cam looks good and the valves open all the way after every time i fix it. Any help would be greatly aprreciated. Oh yeah, one final thing, the compression is 180 psi across the board.

 

Heres the specs on my engine for reference:

 

-Chevy 350 4 bolt 14010207 block 0.030 over with stock crank and rods.

-9:1 pistons

-Comp Cams xe262h Cam

-Lunati performance Hydraulic lifters (Might be the problem)

-Clevite hardened pushrods

-GM Camel hump 3917291 heads with 3/8 screw in studs

-Comp Cams magnum roller tip rockers 1.52 ratio

-Stainless 2.02/1.60 valves

-Stock Distributor with a Moroso Advance curve kit

 

Thanks,

Kev

Archived

This topic is now archived and is closed to further replies.

Go to topic listing

  • Recently Browsing   0 members

    • No registered users viewing this page.

  • Forum Statistics

    250.6k
    Total Topics
    2.7m
    Total Posts

  • Member Statistics

    343,007
    Total Members
    8,960
    Most Online
    Brendan C
    Newest Member
    Brendan C
    Joined

  • Who's Online   5 Members, 1 Anonymous, 1,163 Guests (See full list)

  • Latest Articles

  • Posts

    • richard wysong
      Electrical Problem - solved

      By richard wysong · Posted

      Thanks for posting, I'm sure it will help someone
    • Brendan C
      2026 6.6 L5P oil cooler leaking oil at 4,000 miles

      By Brendan C · Posted

      New to diesel trucks. I happened to find my oil cooler leaking oil externally with only 4,000 miles on the truck. I didn’t realize this was an issue until I started researching it. Dealer is going to replace it under warranty but I’m wondering if there’s anything GM is working on to fix this issue. I’ve heard the oil filter used is the same as they use on their V6 motors and that’s what is causing the problems. Should I switch to a bigger filter or keep using the OEM recommended? 
    • Vu1can
      Seems to be Missing a lot of Updates

      By Vu1can · Posted

      So, GMCustomerService:  Judging by the Update History pictured above, is this truck missing any updates that it actually needs. If it's just for the infotainment system, the radio is working fine and no trouble with SeriusXM. and Android Auto is working fine wirelessly with my phone. Some months ago, an update notice was sent to my truck. I approved the update and it finished saying that the update was successful, but it seems that whatever that update was, it didn't actually get installed - at least not if I'm to go by the Update History shown above.   So, again, are there any updates that this truck really should have? I've checked with my dealer but they're reluctant or commit to anything and if I want them to check, they require a $200.00 fee just to check it out and then I'd have to pay for the actual update(s).    Ignorance is bliss, and if none of the updates goes to fixing any mechanical discrepancies, I'll just leave things as is.  
    • CNH-320
      Electrical Problem - solved

      By CNH-320 · Posted

      Hey everyone, I recently had an issue with my 07 2500HD GMT900. My DRL’s stay on at all times. Right front turn and right mirror turn signal indicator stay on solid at all times. By “at all times” I mean the only way to make them go off is disconnecting the battery. I tore the headlight assemblies out, tried disconnecting the harnesses to eliminate bad wiring at the harness, I unplugged the headlight switch, no change and the mirror turn signal still stayed on. My first thoughts were : Bad bulb and/or socket somewhere, under hood fuse panel bad, bcm bad, tail light or trailer wiring problem, or some random short to power in the harness.  Possibly a bad ground but unlikely. I had a big clue in the fuse panel, it had a burnt smell. I started pulling every fuse that had to do with DRL or right turn/park lamp. Nothing made the right directional turn off but pulling the DRL2 fuse made the DRL’s go out.  After studying wiring diagrams, I found that both problems had that fuse panel in common, the bcm also controls both problems but knowing the fuse panel had a burnt smell I removed and disassembled the fuse panel and found a little corrosion on the printed circuit board.  I ordered a new fuse panel from Amazon for like $260. When it arrived I installed it, and put everything back together, the problem was fixed. I figured the fuse panel needed to be replaced anyway so that was a logical place to start. Hopefully this story helps someone in the future. Regretfully I didn’t scan for codes before I did everything.
    • 2022LtTbZ71
      Service 4wd, ESC light, traction control light on, Service charging system (vehicle may stall)

      By 2022LtTbZ71 · Posted

      That stinks. I’m sitting on the side of the road right now with the same issue. Never had an issue before taking it in for the ground strap recall. Now I’m outside of warranty and they’ll probably want $200 just to diagnose what they already “fixed”. 

  • GM-Trucks.com Clubs

  • Popular Contributors

×
×
  • Create New...