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smoking ? gun

Discussion in 'Engine' started by chris frizzell, May 29, 2020.

  1. chris frizzell

    chris frizzell
    Z Club Member

    Hi all been out in the 280z today for a run and all looked ok . but on the way back home i mate was following me and he said the car was smoking at low speed . all was ok at 65mph . not noticed it my self will do a compertion test asap . oil presure in the centre just a small raise on the gas . any thorghts chris or is this nornal with a 45 year old car.
     
  2. Bazzateer

    Bazzateer
    Z Club Member

    If it occurs when you close the throttle it's likely to be valve stem seals. If it's on acceleration then may be piston rings. This is assuming it's blue (oil) smoke. If black smoke look at fuelling as it may be running too rich.
     
    jonbills likes this.
  3. chris frizzell

    chris frizzell
    Z Club Member

    Hi Bazzateer . that is my thinking when i got the car the only thing i havent restored is the engine . My mate said it was at low speed in traffic but didnt say what colour . dont think its the rings as i have good compresstion. But the car is running a little rich as iam haveing some starting problems ie flooding . if its the stems i think i will farm the job out later in the year when i get my billet fuel rail thanks for the post hope your car running well .Chris
     
  4. AliK

    AliK
    Z Club Member
    Staff Member Moderator

    Go down a long hill so that you can be in 2nd or 3rd without being on the throttle, at the bottom of the hill, open the throttle, if at that point you get smoke, it’s the valve seals or coming from the head.

    If you’re getting it while on power / accelerating, it’s rings

    Leave to idle for a minute or two, then blip throttle. If smoking then it’s head / valve oil.

    All of this is valid if the smoke is blue.

    If black it’s mix.

    If white, you have water issues.
     
    Paul_S likes this.
  5. chris frizzell

    chris frizzell
    Z Club Member

    thanks Alik . had a look at the 280z this morning removed all the plugs and all is well not oil just nice and light brown . started the car and got him up to temp with no smoking at all . rang my mate up how said it was smoking and he said it was white which i think would indicate water but looks fine . now for the thought out of left field .i have just fitted a z story exhaust and tucked it right up into the trans tunnel but i have a low spot where the z bit goes to the back box . could this be holding some water ? boiling it off at low speed . but i think i will change the stem seal out in the winter as the car was stud for many years and the top of the engine would be a little dry .thanks for the post chris
     
    AliK likes this.
  6. Huw

    Huw
    Z Club Member

    Hi Chris.
    You can get a smoke at part throttle as oil and fumes are drawn from the crank case into the inlet. Check the PCV crank vent valve is not sticking. You can clean it with thinners as it gets all gummy if not changed regularly. It’s under the inlet and the crank breather connects to it. If it’s fine then do the checks Ali suggested.

    Best of luck

    Huw
     
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  7. chris frizzell

    chris frizzell
    Z Club Member

    Cheers Huw will have a look . When i fitted the new z store exhaust i had to move the crank tube and use a different pipe this could be to long and blocking the PVC valve . apart from that the cars driving the best it ever has after fitting a rt diff mount and driving it a little more on the revs . looked at some seals . Is there a preference for brown or black or just go to rockauto ? thanks chris
     
  8. AliK

    AliK
    Z Club Member
    Staff Member Moderator

    Mine went like the clappers but had a huge oil thirst! You’d be surprised how well a nice loose worn engine can go.i

    I will let someone else comment on which seals.

    If you do get a head gasket though, go Felpro. I know a couple of very experienced engine builders who swear by them.
     
  9. chris frizzell

    chris frizzell
    Z Club Member

    cheers Ali not going to do the seals myself as to many tools to buy . i have looked on the web and they can be done without removing the hole head but whats for winter . i dont think is a major problem yet but need further investigation and i will keep an eye on the oil consumpion thanks chris
     
    AliK likes this.
  10. AliK

    AliK
    Z Club Member
    Staff Member Moderator

    As I discovered, oil is way cheaper than a new engine or a full tear down. So if it’s not too bad, you have good compression across all cyls (over 160 but uniform ish) and you can deal with it easily then I’d say enjoy driving your car and carry a quart in the boot just in case ;)
     
    Paul_S likes this.
  11. chris frizzell

    chris frizzell
    Z Club Member

    Hello all just a quick up date on the 280z . after a little tinkering this weekend i did a compression test and the result are good with rates of 162-170 across all 6 cylinder .so may be no oil leak from the rings ,but not sure about the valve stems . the one thing i did notice was my timing was way out must have move by accident. reset the timing and the car starts a lot easier . could the timing cause the smoking ? Chris
     
  12. Bazzateer

    Bazzateer
    Z Club Member

    If the timing was way out you won't have been getting proper combustion so I suppose it's possible it may have created some kind of fumes????
     
  13. Turn & Burn

    Turn & Burn
    Z Club Member

    I’ve got a spare set of Felpro stem seals you can have for a tenner & post, but I think the best to go for a the Ford Viton Seals as fitted to Scorpio / late V6. These fit like a glove are are also low profile if u feel the need to go for a high lift cam.
     
  14. chris frizzell

    chris frizzell
    Z Club Member

    sounds good PM for the total and send your bank details and i will transfer the money . Chris
     
  15. jonbills

    jonbills
    ZClub Administrator
    Staff Member Moderator

    btw, good compression doesn't prove that your oil control rings are fine. Different rings, different jobs.
     
  16. chris frizzell

    chris frizzell
    Z Club Member

    To true but iam not ripping the car apart just yet . no blue smoke just white . if it smokes anymore there will be a new pope st chris of Assisi
     
    jonbills likes this.
  17. AliK

    AliK
    Z Club Member
    Staff Member Moderator

    The timing going out would not help with a full burn as stated already.

    Those compression figures are very acceptable. Did you test them dry or wet? Hot or cold?

    If you squirt a little oil in the spark plug hole and do it again and if the numbers go up significantly, you have ring or bore issues. If not, then they are Ok.

    My dizzy went loose the other month, thankfully they seem to roll the same way round and I think that has something to do with the direction of the oil pump drive shaft rotation - or we were super lucky ! ;)
     
  18. chris frizzell

    chris frizzell
    Z Club Member

    Cold . wet or dry ? think the dizzy not helped just going to drive it until winter when swop out the stem seals . i would like to get another engine and have a play .dont want mega power but may be a rebore and some polish and porting to be honest quit new to car engine rebuilds last one i did was a 1980 mini special 1100 but that was 30 years ago. but since a have restored the 280 iam hooked on spannering . chris
     
    AliK likes this.
  19. Bazzateer

    Bazzateer
    Z Club Member

    Dry is checking compressions without putting a little oil in the plug hole first (if pressure rises with the oil in there then the bores are suspect). With oil is wet, without is dry.
     
    AliK likes this.
  20. chris frizzell

    chris frizzell
    Z Club Member

    done dry . with the number all being over 160 not to panicy about the block . more likely the timing way out but it was white smoke but no contamination anywhere . still think if the exhaust as it drops some water on my drive from the joint . carcars running well so iam just going to drive to through summer .thanks for the post
     
    AliK likes this.

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