Results 1 to 28 of 28

Thread: should I be worried? rebuilt motor burning oil

  1. #1
    VCVC Member Dan Wilson's Avatar
    Join Date
    Feb 2002
    Location
    Santa Rosa
    Posts
    2,467
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Question should I be worried? rebuilt motor burning oil

    Okay, here is the story. I found a rebuilt 230 standard bore engine and to the best of my knowledge it showed all the signs one would look in a rebuild without 'papers'. I have driven it about 130 miles. At 100 miles I checked the oil and noticed it was down 3/4 of a quart. I am running 10-30 which is what the manual calls for. The engine has tons of power but burns oil and doesn't seem to be in any hurry to break in if indeed it is a break in issue. The oil pressure is between 25-35 depending on rpm. I don't remember this the last time I had a rebuilt 230/250 but then again that was almost 30 years ago. Should I be concerned? Is the oil pressure okay? Should I be running a different viscosity? Is it possible the valve seals are bad or what? Should I do a compression test or will this tell me anything? Thanks for any advice!

  2. #2
    Administrator smiley's Avatar
    Join Date
    Apr 2000
    Location
    New Orleans, LA
    Posts
    6,162
    Mentioned
    12 Post(s)
    Tagged
    1 Thread(s)
    I've never run that viscosity before. I've always run 20W-50, but it's getting hard to find now. If you aren't seeing a leak or smoke, my amateur guess is perhaps the viscosity.
    1966 Chevy Display, "Southern Belle"
    1968 Chevy, "Blue Overdose"

  3. #3
    VCVC Member Dan Wilson's Avatar
    Join Date
    Feb 2002
    Location
    Santa Rosa
    Posts
    2,467
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Thumbs up

    hmm......that's interesting. I'm pretty sure I ran 20-50 in my last 3 vans including the one I had rebuilt in the 80's. I double checked the manual and it does recommend 10-30 and I figured why not go with spec? I need to dump the oil soon as I have been told I should do. I'll try the 20-50 if I can find it lol. Any other suggestions are welcomed! Thanks Smiley.

  4. #4
    VCVC Member digz's Avatar
    Join Date
    Sep 2005
    Location
    six lakes mi
    Posts
    1,732
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Sometimes it depends on what they put in for rings how quick they seal/seat . Used to run 20w non detergent to break in a set for a while then switch over. seemed to work. One time I ran 10-30 from the get -go on a fresh bore with chromoly rings and I can't recall if they ever seated before I sold it, Tried all kinds of Visc' still used oil. Current engine I did the 20w thing and it sealed.
    64 Project,65 Driver,66 Parts sorta

  5. #5
    VCVC Charter Member Vanner68's Avatar
    Join Date
    May 2000
    Location
    Kimball MI USA
    Posts
    13,439
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    How long did this engine sit before you got it?


    Might just be valve stem seals dried out.
    Gregg Groff


    There's no place like 127.0.0.1

    1968 Chevy G20 108 panel Now with 454 power!

    1965 Chevy G10 panel- OHC Pontiac inline 6

  6. #6
    VCVC Member
    Join Date
    Jul 2004
    Location
    Sacramento, Ca, USA
    Posts
    2,835
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)

    Oil Burning

    If you are burning 3/4 of a quart in 100 miles then you should see some blue smoke. Maybe not all the time depending on the cause. I would advise a leak down test and performance test with vacuum gauge installed. Bad valve guides will show as a vibrating needle on the vacuum gauge, blue smoke during continued throttle off deceleration downhill and intermittent blue smoke on startup after sitting a short time. I prefer a leak down tester over a compression test but it takes a little more time. I do not think a change from 10-30 to 20-50 oil is going to change an oil loss problem like you describe. It could be many things from improperly installed rings, poor cylinder finish to bad valves or guides. If it's not leaking it, it's burning it and there's only so many ways that much oil can get in the combustion chamber. Whatever the cause, you may be looking at a complete re-rebuild. Best wishes.
    108VanGuy...
    1969 Chevy Panel, 250 CID, 3 ring 4 Spd. with OD, 2.73 "WedgieVan" Daily Driver
    1967 Chevy Panel, 230 CID, 3 Spd. 3.36 "UtiliVan" 292 TFI coming. Owned since 76
    1964 GMC Panel, 194 CID, 3 Spd. "CrunchoVan"
    1965 GMC HandiBus Custom, 194 CID, 3 Spd. "MilkVan" Seized Engine
    1965 Chevy Panel 350 CID, 3 Spd. "RustoRoof" Runs but wiring bad
    1969 Chevy 108 Display 307 CID THM 350 Power Brakes 3.73 Posi
    1965 Chevy Panel, V8, 3 Spd. "Gold Hills Van" Best body of my 65s
    1965 CamperVan, V8, 3 Spd.

  7. #7
    VCVC Member ExEarlyVanner's Avatar
    Join Date
    Nov 2004
    Location
    Moonachie NJ
    Posts
    1,707
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Dan are you running synthetic oil or regular motor oil .I have heard you need to use regular motor oil for 8 to 10K miles to break in the engine. Synthetic is a no no to breakin an engine

    Ken
    68 90 6cyl three speed

  8. #8
    VCVC Member Dan Wilson's Avatar
    Join Date
    Feb 2002
    Location
    Santa Rosa
    Posts
    2,467
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    response to Vanner68/ExEarlyVanner

    Running regular oil. Not sure how long it sat. When I bought it, the guy said he had it for 6 months but he bought it from a lady whose husband had it rebuilt for a Nova project but then died and it probably sat in that garage but for how long I don't know. How would it take for seals to dry up?




    Quote Originally Posted by ExEarlyVanner View Post
    Dan are you running synthetic oil or regular motor oil .I have heard you need to use regular motor oil for 8 to 10K miles to break in the engine. Synthetic is a no no to breakin an engine

    Ken

  9. #9
    VCVC Charter Member Vanner68's Avatar
    Join Date
    May 2000
    Location
    Kimball MI USA
    Posts
    13,439
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    I've seen the seals dry up in a year if the engine wasn't wrapped.
    Gregg Groff


    There's no place like 127.0.0.1

    1968 Chevy G20 108 panel Now with 454 power!

    1965 Chevy G10 panel- OHC Pontiac inline 6

  10. #10
    VCVC Member Dan Wilson's Avatar
    Join Date
    Feb 2002
    Location
    Santa Rosa
    Posts
    2,467
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Stored in a hot dry garage in the hot and dry foothills of California..................I'm hoping it is seals! I mean this beast just has too much power to be anything else. Updates later...............

  11. #11
    VCVC Charter Member Vanner68's Avatar
    Join Date
    May 2000
    Location
    Kimball MI USA
    Posts
    13,439
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Hot and dry doesn't help seals one bit....
    Gregg Groff


    There's no place like 127.0.0.1

    1968 Chevy G20 108 panel Now with 454 power!

    1965 Chevy G10 panel- OHC Pontiac inline 6

  12. #12
    VCVC Member Wookee's Avatar
    Join Date
    Oct 2002
    Location
    Joppa Maryland U.S.A.
    Posts
    15,769
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)

    Cool

    Valve seals in a GM 6's head are brass.....Unless the machine shop used the Ford style unbrella style rubber seals
    Just because the engine has plenty of power does not mean the oil rings are installed and working correctly.
    I have had a couple of 6"s that had self changing oil systems in them. Pour oil in the top and it comes oil the bottom,Via bad gaskets and worn out rings.

    Did you get any paper work with the alleged rebuilt engine you bought ?
    Maybe be a recite from the machine shop who did some or all of the rebuild work ?

    How many miles have you put on this engine since it was installed ?
    Its a "van thing". A life style you have to live to understand!!!!

  13. #13
    VCVC Member Dan Wilson's Avatar
    Join Date
    Feb 2002
    Location
    Santa Rosa
    Posts
    2,467
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Wookee View Post
    Valve seals in a GM 6's head are brass.....Unless the machine shop used the Ford style unbrella style rubber seals
    Just because the engine has plenty of power does not mean the oil rings are installed and working correctly.
    I have had a couple of 6"s that had self changing oil systems in them. Pour oil in the top and it comes oil the bottom,Via bad gaskets and worn out rings.

    Did you get any paper work with the alleged rebuilt engine you bought ?
    Maybe be a recite from the machine shop who did some or all of the rebuild work ?

    How many miles have you put on this engine since it was installed ?
    In answer to your question:

    "Okay, here is the story. I found a rebuilt 230 standard bore engine and to the best of my knowledge it showed all the signs one would look in a rebuild without 'papers'. I have driven it about 130 miles. At 100 miles I checked the oil and noticed it was down 3/4 of a quart. I am running 10-30 which is what the manual calls for. The engine has tons of power but burns oil and doesn't seem to be in any hurry to break in if indeed it is a break in issue. The oil pressure is between 25-35 depending on rpm."

    Wookee, I need to pull the valve cover to see what kind of seals I have. Once I determine that, I can move forward.

  14. #14
    VCVC Charter Member Vanner68's Avatar
    Join Date
    May 2000
    Location
    Kimball MI USA
    Posts
    13,439
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    https://www.youtube.com/watch?v=XkVvZzsa_jk

    Nice video on replacing valve seals
    Gregg Groff


    There's no place like 127.0.0.1

    1968 Chevy G20 108 panel Now with 454 power!

    1965 Chevy G10 panel- OHC Pontiac inline 6

  15. #15
    VCVC Member Wookee's Avatar
    Join Date
    Oct 2002
    Location
    Joppa Maryland U.S.A.
    Posts
    15,769
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)

    Cool

    To do what he did with the head still on the engine you will need to use compressed air to keep the valves from falling down into the combustion chamber..
    You can also turn the engine until the piston in the hole you are working on is all the way to the top of the hole
    The brass valve guides he mentioned also act like a seal.
    The Ford umbrella style valve seals ride on the valve it's self under the valve spring.......
    Its a "van thing". A life style you have to live to understand!!!!

  16. #16
    VCVC Charter Member Vanner68's Avatar
    Join Date
    May 2000
    Location
    Kimball MI USA
    Posts
    13,439
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Them little rubber seals dried out and cracked on my 68's original engine, smoked like a choo choo train.

    Replaced them in the parking lot of my apartment, using nylon rope thru the spark plug hole to hold up the valves.

    Nice thing about engine work on these vans, the van provides it's own dry garage.
    Gregg Groff


    There's no place like 127.0.0.1

    1968 Chevy G20 108 panel Now with 454 power!

    1965 Chevy G10 panel- OHC Pontiac inline 6

  17. #17
    VCVC Member Dan Wilson's Avatar
    Join Date
    Feb 2002
    Location
    Santa Rosa
    Posts
    2,467
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Question UPDATE

    Using my old head from my old engine for practice using a valve spring compressor tool, I pulled #1 valve springs to find NO seals. ? My old engine did not burn oil. So.....I'm a little confused about the seals shown in a video linked to this thread. I'm also confused about a reference to brass seals or guides referred to by Wookee. ?
    I changed out the oil & filter after 135 miles... very dirty. I also changed from 10-30 to 20-50. It's possible I haven't given the engine enough time to break in. I hope that is the case. Here are some pictures of the old head. Maybe someone can school me. #1 would all 230s have seals of some sort? #2 If so, why didn't my old engine burn oil? #3 where would these brass guides be in the picture?
    Click image for larger version. 

Name:	DSCN0500.jpg 
Views:	42 
Size:	85.5 KB 
ID:	23794Click image for larger version. 

Name:	DSCN0495.jpg 
Views:	42 
Size:	79.4 KB 
ID:	23795

  18. #18
    VCVC Member
    Join Date
    Feb 2004
    Location
    santa clara,cal
    Posts
    2,797
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    If your running moly rings you can expect elevated oil usage for approx 2000. Miles.if the rebuilder used something else it could take as long as 10k. GM uses a cast iron that's pretty soft (low tin)...wears faster than say Toyota blocks but breaks in faster. For break in you should be using a high solpher? Oil or additive. A lot of acceleration and slowing down using the engine as a brake (loads the rings against the cyp.walls.) willaid the break-in. Frequent oil/filter changes will rid the motor of trash that gets shook loose.Long periods of idleing are not recommended. Never disassembled a i6 but based on your flics your seals could have just disintegrated w/old age. The bronze parts your looking for are replacement valve guides. As a engine racks up miles the cask iron head "guides" (holes that the valve pokes thru) experience wear which leads to leakage, allowing oil to migrate past the valve/seal. To restore the fit, the holes are drilled oversize and a bronze guide is pressed in.I think its possible that stock I6s came w/o seals. My guess would be that a engine that required a rering had enough miles to require a valve job/bronze guides and seals that would fit over the valve stem and over the cast iron valve boss.The fact that yours doesn't have the seals suggest this was a backyard down n dirty job...or at least warrants further looksee.BTW, valves run around .0003 inch clearance .
    Gluk,Randy

  19. #19
    VCVC Charter Member Vanner68's Avatar
    Join Date
    May 2000
    Location
    Kimball MI USA
    Posts
    13,439
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    My seals crumbled on my 68, the exhaust valve seals were gone completely.

    The bronze valve guides get there lube from the valve stem- the rubber seal really seals only when the valve is fully open. It's more of a restrictor than a seal.

    That said, a head assembled without seals may not show much oil consumption if the valve guides are fresh.

    The biggest factor in a 'rebuilt' engine is who did the rebuild. It is possible for a 'backyard builder' to do a better job than a shop, if they take the time to do everything correctly. However, that is the exception rather than the rule. Often, the builder buys a rebuild kit and just puts all the new parts in, without taking the time to check clearances.

    As an example, my son spun the rod bearings in his slant six Plymouth. I had him drop the pan, and pull the bearing on the 'sloppiest' rod. He mic'd the crank surface, we found that it was on the low end of spec, but still within spec. Ordered standard bearings, installed, and the bottom end is now as quiet as ever. Will it go 100,000 miles? Probably not. But it will get him to work until he can afford a proper rebuild.
    Gregg Groff


    There's no place like 127.0.0.1

    1968 Chevy G20 108 panel Now with 454 power!

    1965 Chevy G10 panel- OHC Pontiac inline 6

  20. #20
    VCVC Member Wookee's Avatar
    Join Date
    Oct 2002
    Location
    Joppa Maryland U.S.A.
    Posts
    15,769
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)

    Cool

    You will not see the valve seals /guides i spoke about until you remove the valves them selves from the heads.

    At the low mileage the engine has the oil should be pretty clean.That's IF the engine was cleaned correctly,internally before the rebuild.
    Unfortunately this is also a step a back yard re builder would have skipped
    The more details you bring up the more it looks like the engine received a 7.99 rebuild.(price of a can or two of engine enamel).
    Not knowing any thing about the shop/mechanic who performed this engines rebuild all you have to go by is the sellers word.

    This is the down side to buying used engines.
    Last edited by Wookee; 10-01-2015 at 12:52 PM.
    Its a "van thing". A life style you have to live to understand!!!!

  21. #21
    VCVC Member Dan Wilson's Avatar
    Join Date
    Feb 2002
    Location
    Santa Rosa
    Posts
    2,467
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Thanks for the useful info, I appreciate it. Just to clarify, the pictures shown are my old factory built engine, not the one in question.




    Quote Originally Posted by fustkarr View Post
    If your running moly rings you can expect elevated oil usage for approx 2000. Miles.if the rebuilder used something else it could take as long as 10k. GM uses a cast iron that's pretty soft (low tin)...wears faster than say Toyota blocks but breaks in faster. For break in you should be using a high solpher? Oil or additive. A lot of acceleration and slowing down using the engine as a brake (loads the rings against the cyp.walls.) willaid the break-in. Frequent oil/filter changes will rid the motor of trash that gets shook loose.Long periods of idleing are not recommended. Never disassembled a i6 but based on your flics your seals could have just disintegrated w/old age. The bronze parts your looking for are replacement valve guides. As a engine racks up miles the cask iron head "guides" (holes that the valve pokes thru) experience wear which leads to leakage, allowing oil to migrate past the valve/seal. To restore the fit, the holes are drilled oversize and a bronze guide is pressed in.I think its possible that stock I6s came w/o seals. My guess would be that a engine that required a rering had enough miles to require a valve job/bronze guides and seals that would fit over the valve stem and over the cast iron valve boss.The fact that yours doesn't have the seals suggest this was a backyard down n dirty job...or at least warrants further looksee.BTW, valves run around .0003 inch clearance .
    Gluk,Randy

  22. #22
    VCVC Member Dan Wilson's Avatar
    Join Date
    Feb 2002
    Location
    Santa Rosa
    Posts
    2,467
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    In defense of my own eyes I did a pretty close inspection of the engine and nothing stood out as a rattle can rebuild. That said, probably best to wait it out put some miles on it before I get too worried. I did learn one thing, it's easy to take valve springs off while the head is off but I would be sweating it if I attempt it on the engine lol.

  23. #23
    VCVC Charter Member Vanner68's Avatar
    Join Date
    May 2000
    Location
    Kimball MI USA
    Posts
    13,439
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    A telltale is whether or not there is crosshatch in the cylinders.

    If the block has had any machine work done, usually the cylinders get honed. A backyard builder generally does not do this, and the rings will take longer to seal, if at all.
    Gregg Groff


    There's no place like 127.0.0.1

    1968 Chevy G20 108 panel Now with 454 power!

    1965 Chevy G10 panel- OHC Pontiac inline 6

  24. #24
    VCVC Member
    Join Date
    Feb 2004
    Location
    santa clara,cal
    Posts
    2,797
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Maybe...maybe, you can rent/borrow a mini camera, remove a sparkplug and take a look inside to see whats goinon. Possibly a builders supply might have them to rent out, or u could buy one {about 150/200}...enough resolution to see crosshatch?
    Gluk, Randy

  25. #25
    VCVC Charter Member Vanner68's Avatar
    Join Date
    May 2000
    Location
    Kimball MI USA
    Posts
    13,439
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    Gregg Groff


    There's no place like 127.0.0.1

    1968 Chevy G20 108 panel Now with 454 power!

    1965 Chevy G10 panel- OHC Pontiac inline 6

  26. #26
    VCVC Member
    Join Date
    Feb 2004
    Location
    santa clara,cal
    Posts
    2,797
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    If you have a indicator and a mag base you can get an idea of whats going on w/the valves/guides by placing the indicator against the valve stem and pressing w/your thumb....003/4 slop means that head wasn't touched {w/springs etc. removed}..W/that same indicator you can place it against the crank bolt and move the crank back/forth and check the end play...too much play means the bearings probably wern't replaced. BTW, all motors look the same from the outside, thats why compression testers/leak down testers & indicators are required. Unless your buying from a trusted source, consider any purchase a gamble or buy w/the express intent of rebuilding.
    Gluk, Randy

  27. #27
    VCVC Member Dan Wilson's Avatar
    Join Date
    Feb 2002
    Location
    Santa Rosa
    Posts
    2,467
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)

    Thumbs up

    Cool tool!, I can also save on my next colonoscopy. Probably TMI.

  28. #28
    VCVC Member TurboVan's Avatar
    Join Date
    Dec 2000
    Location
    Ojai, CA, USA
    Posts
    6,437
    Mentioned
    2 Post(s)
    Tagged
    0 Thread(s)
    I've been thru this with Taco. Only the rubber umbrella-type seals will fit between the springs and those fat original (cast iron) guides.
    If you want something better, like teflon seals (I have no idea what he meant by "brass seals", there is no such thing), you have to have the guides' outside machined smaller so they can press on.
    If the guides are badly worn, or if you want to go whole hog, you can spring for bronzewall guides, that go inside the guides (expensive), they transfer heat better preventing burned valves, and they wear more slowly than iron guides.
    Last edited by TurboVan; 10-02-2015 at 12:16 AM.
    Keep one foot in the gutter, one fist in the gold...

    '65 Panel, with turbocharged 327 (originally 153 four), TH400 (originally 3-speed), and 3.31 '67 Camaro 12 bolt rear (my first car, 1970)
    https://www.youtube.com/playlist?lis...meE_Jf-hgJU2mG

    '69 Sportvan 108 with turbocharged original 250 six and 700R4 (originally Powerglide), 3.73 rear, starred in eight Taco Bell commercials
    https://www.youtube.com/watch?v=kDfPJ3xmwjY


User Tag List

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •