Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

blown ring and solutions?

Discussion in 'The Garage' started by blazinfast, Mar 4, 2007.

  1. blazinfast

    blazinfast Registered Member

    Joined:
    Mar 4, 2007
    Posts:
    7
    Likes Received:
    0
    Location:
    Blue Ridge, GA
    im a "young'n" so dont verbally beat me just yet.

    i have a 85 k5 that i think the rings have gone out on and since i will have to take the motor out to fix that anyway i was going to bore it out and try to get more power out of my engine. what would be a good course for me as an 18 year old to take with this engine?

    "take it to the shop" isnt an option, dont have the money
    only the machining would be done there

    and its a 350, if you guys need more details let me know and ill try my best

    :k5:
     
  2. blazinfast

    blazinfast Registered Member

    Joined:
    Mar 4, 2007
    Posts:
    7
    Likes Received:
    0
    Location:
    Blue Ridge, GA
    is there another place this post should be?

    or is it slow like this usually?
     
  3. readymix

    readymix 3/4 ton status

    Joined:
    May 30, 2004
    Posts:
    6,706
    Likes Received:
    26
    Location:
    Murrieta, California
    You only waited 28 minutes....


    Have you done a compression test?
    Leakdown?

    It could be as simple as a valve issue.
     
  4. Pvt. Maggot

    Pvt. Maggot 1/2 ton status

    Joined:
    Sep 27, 2005
    Posts:
    559
    Likes Received:
    0
    Location:
    Brownsville PA
    You can pickup a 383 kit for about 800 bucks, I'd say go that route..get a manual and tear it down, make sure you bag and mark where everything came from. now go get some wrenching done.
     
  5. K5dreamer

    K5dreamer 1/2 ton status

    Joined:
    Mar 14, 2005
    Posts:
    3,084
    Likes Received:
    1
    Location:
    Alexandria, Va
    first thing is first, go to sears, napa, whatever, and get yourself a compression tester. Its a very easy test to do, especially on these trucks because the engine bay is so big. all you do is pull out the spark plugs and screw the compression tester into the hole, then crank the engine over a few times on each cylender to get a reading. they should be around 120-150psi and all very close to each other. if you get a random flyer thats at say, 80 psi, youve got a blown piston ring.

    if youve never done any serious work like this, pulling and rebuilding the engine by yourself is a big step. do the compression test and make sure its actually nesseary.

    just for fun, what makes you think the rings are blown???
     
  6. readymix

    readymix 3/4 ton status

    Joined:
    May 30, 2004
    Posts:
    6,706
    Likes Received:
    26
    Location:
    Murrieta, California
    K5dreamer, A reading of 80psi does not autimaticaly mean a blown ring. Could be a valve or gasket issue too.......

    Leakdown test is also needed to properly diagnose.
     
  7. vortec

    vortec 1/2 ton status

    Joined:
    Jul 22, 2004
    Posts:
    1,472
    Likes Received:
    0
    Location:
    fort worth, texas
    find a wrecked gmt400 on ebay or junkyard and yank the engine with all its goodies attached. engine building is fun, but it's not always practical.
     
  8. W7NB

    W7NB 1/2 ton status

    Joined:
    Nov 9, 2006
    Posts:
    716
    Likes Received:
    0
    Location:
    Springtucky, OR
    Boring an engine makes very little difference in power. You main gain a few cubic inches but compared to the original 350 inch displacement it's less then 2% for a .30 over. Boring is done to clean and true the cylinder walls for the new piston and rings.

    The 383 is a great idea. I ran one in a jeep and plan to build a TPI 377 or 383 this summer for my blazer. The 383 is a 350 with the longer stroke of a small block 400 crankshaft, but uses the smaller bore of a 350 which avoids the heat/cracking problems the 400's had. Just to give you an Idea the only difference between a 377 and 383 is the bore - a 350 bored .30 over with a 400 crank is a 377 and bored .60 over is a 383. Thats all you gain - a whole 6 cubic inches, and the block is finished after that build, although some people will bore them beyond .60 over.

    Building an engine requires a fair number of tools, measuring equipment and expertise. I have seen several people decide they would just "Build it myself" rather then pay for a shop to do it. By the time you by the tools, engine stand, books etc, pay to have the block cleaned and machined, have the heads done, and pick up all the parts you will need to do the build you will find that you spent very near the cost of a decent longblock from a reputable builder. And thats IF you block is rebuildable. And IF you don't mess up somthing critical and have to tear the motor down again.

    The only time I find it worthwhile to build a motor myself is if I want to keep the vehicle original with matching #'s or if I want somthing non-stock and have to build it myself. On the other hand there is the pride in building it yourself.

    Answer some questions for us. Why do you think it's got bad rings? Blowby could be a PCV valve issue. Is it burning oil? Noises? Some more info to work with would help.
     
  9. blazinfast

    blazinfast Registered Member

    Joined:
    Mar 4, 2007
    Posts:
    7
    Likes Received:
    0
    Location:
    Blue Ridge, GA
    well i think it is a blown ring because when it cranks up, it smokes like crazy out of both sides and the after its warm it lessens alot on one side. it still smokes like crazy from the right side though. it goes kinda away when driving, but i just assumed that was because im going too fast for smoke to collect and be visible.


    it could also be a blown head gasket. im hoping that it is this

    in any case i will pull the heads off and have them ported and maybe get a bout .005 shaved off the bottom to increase compression
     
  10. 76zimmer

    76zimmer Flyin Rat Premium Member GMOTM Winner

    Joined:
    Nov 14, 2005
    Posts:
    23,030
    Likes Received:
    1,347
    Location:
    Kzoo, Mi
    Slow down a little here, do you want to cure this problem, or are you looking for a new engine.....you seem to want to jump into this with all 4 feet.
     
  11. 1977k5

    1977k5 3/4 ton status Vendor

    Joined:
    May 26, 2003
    Posts:
    9,992
    Likes Received:
    130
    4.030*4.030*(pi/4)*3.75*8 = 382.66 cubic inches

    4.000*4.000*(pi/4)*3.75*8 = 376.98 cubic inches

    A 377 is a stroker with the stock 4.000" bore, a 383 is .030" over.
     
  12. W7NB

    W7NB 1/2 ton status

    Joined:
    Nov 9, 2006
    Posts:
    716
    Likes Received:
    0
    Location:
    Springtucky, OR
    Yeah, bad math on my part. Still, what will 5.66 cubic inches yield in horsepower on a 35+ cubic inch motor?

    76 zimmer just wants a bragging motor. Never mind the one he has might be fixable.
     
  13. blazinfast

    blazinfast Registered Member

    Joined:
    Mar 4, 2007
    Posts:
    7
    Likes Received:
    0
    Location:
    Blue Ridge, GA
    well i think i might just shave the heads alittle and get them ported and get some quick power

    been researching and it seems like the way to go
     
  14. W7NB

    W7NB 1/2 ton status

    Joined:
    Nov 9, 2006
    Posts:
    716
    Likes Received:
    0
    Location:
    Springtucky, OR
    Shaving the heads increases compression which will increase power, but if you shave too much you will have to burn priemium to prevent knocking.

    Also, porting will help airflow, but mainly at higher RPM. Figure out where you want your powerband to be before you decide how you want the motor built.
     
  15. blazinzuk

    blazinzuk Buzzbox voodoo Premium Member GMOTM Winner

    Joined:
    Dec 20, 2002
    Posts:
    17,412
    Likes Received:
    3,799
    Location:
    Afton / Star Valley Wyoming
    Depends on your budget but if i was going to try for cheap power (a realitive term) I would get a basic rebuild kit for the 350 and spend money on vortec heads. There is only so much power you can build with stock heads. Engines have to breath. Look at the engine as a system. If you do that you will come out with a much better engine. You will probably need an aftermarket cam and aftermarket intake, a decent ignition, make sure your carb is in good working order, a set of headers and a good exhaust. These along with vortec heads will give you a surprising amount of power.

    Anyone can rebuild a small block Chevy. The first motor I rebuilt I got a cheap torque wrench, some plastigage, some feeler gauges and I think that was about it. Obviously you will need basic handtools. Buy a book and read the whole thing before you start. A book will educate you about the machining process too so you know what you need.
     
  16. blazinfast

    blazinfast Registered Member

    Joined:
    Mar 4, 2007
    Posts:
    7
    Likes Received:
    0
    Location:
    Blue Ridge, GA
    well i know all the basics of an anegine and ive rebuilt little stuff like lawnmowers and the top end of my volkswagon, but i pulled the heads off and heres what i found:

    the exhaust manifolds only had a gasket on one side

    the gasket on the right head was destroyed

    the pistons and rings are in amazing shape

    found out i have an aftermarket intake, edelbrock

    also i have a busted ball joint, which doesnt relate to the heads but it was good to find

    thats about it, the heads are at the machine shop now, will keep you guys posted,
     

Share This Page