New Engine Smoking

Discussion in 'Street/strip 400/430/455' started by Rockable, Nov 24, 2021 at 12:32 PM.

  1. Rockable

    Rockable Well-Known Member

    1124211132a.jpg 1124211132.jpg So, I fired up the new 74 455 build that Dave and I carefully assembled. I ran in the cam last week and did not notice any smoking. This week I've chased leaks. I got most all of them stopped but now I have a weird smoking problem.

    I observed and smelled oil smoke yesterday while running the engine and again this morning. I also saw oil dripping from #6 EXHAUST manifold! (There is no gasket, as Dave milled my exhaust manifold.)

    I checked the PCV line and there is no sign of oil in it. I ran a compression check and all cylinders blew 170 psi + or - 5. All valves have seals on them, so its not leaking down the stems. The plugs on 6 and 7 are oil fouled and 8 has some fouling.

    Every wear part in this engine is new. Where could the oil be coming from? I'm stumped.
  2. Jim Weise

    Jim Weise EFI/DIS 482

    Make sure your not seeing bolt lube from the head bolts, melting out and running down the engine, burning on the manifolds. Depending on what was used to lube the bolts, this could be the issue. I use CMD 3, which is the best lube there is for torquing, but the downside is that it melts at about 150 degrees, and then runs down the head.. I usually clean all this up in post production, but occasionally I get a phone call from a customer, concerned that their head bolts seem to be leaking oil.

    Good luck

    69GS430/TKX likes this.
  3. Rockable

    Rockable Well-Known Member

    No, Jim. This is oil inside the combustion chamber. Look at the pictures of the plugs.
  4. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Make sure the drain back holes in the heads are clear. If oil sits up in the head, it will get sucked down the guides and burn in the combustion chamber.
    chrisg and 69GS430/TKX like this.
  5. Bens99gtp

    Bens99gtp Well-Known Member

    Could be a ring much run time is on it.......compression test is ok , I'd rather see a cylinder leak down test, much more useful information, but I do normally run both

    It is possible to have a good cranking psi and a high % of leak.

    I had a motor once that would stay sealed right till the last little bit of piston the top half inch.....the bores were bell mouthed up cranked good, and tested good on leakage depending where you were in the stroke......
  6. Jim Weise

    Jim Weise EFI/DIS 482

    Sorry.. missed the plug pics... they weren't there when I replied. Or I would have said...

    That looks exactly like an engine that has not fully seated the rings yet. Depending on what type of ring you used, it may take up to 1000 miles t0 fully seat them. The compression rings will not start to seat, until compression pressure is applied to them. Compression pressure is directly linked to percentage of throttle opening.

    It takes 3-4 WOT pulls on the dyno, to seat the rings I use, which are the plasma moly faced pieces for most engines. Careful attention is paid to proper cylinder wall finish, as well as specific procedures and lubricants are used during assembly, to make sure the rings break in as fast as possible.

    I built a motor for the shop truck once, 455 Buick, we just used a cheepy set of $60 cast rings, and did not dyno it.. that thing used oil for the first 3 oil change intervals (3K miles) and then after that, it stopped, and did not burn a drop until I yanked it out of the rusty body some 10 years later.

    So don't worry about it yet, go out and drive it hard..

  7. Rockable

    Rockable Well-Known Member

    I think you are right, Jim. That is the only logical thing it could be. The engine has not had any loading on it yet. Wish me luck!
  8. qak

    qak Well-Known Member

    My opinion, try not to stress over it just yet. Just follow jims advice, get it up to temp grab a couple on ramps and give it hell itll break in soon enough.
  9. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Get that car out on the road with the proper oil. Go to the 5:30 mark, and they talk about how to break in rings.

    Rockable likes this.
  10. Mark Demko

    Mark Demko Well-Known Member

    I used WD 40 on my rings and walls on my current build.
    Yes, go out and run 'er hard, take it up to 80 mph, then back off the gas (foot off pedal) till about 55/60 mph, then floor it again, foot of pedal again, repeat 3 or 4 times, DO NOT BABY IT!
    qak likes this.
  11. sean Buick 76

    sean Buick 76 Buick Nut Staff Member

    The best break on I ever did was a fresh engine and I took it on a 600 mile road trip as soon as the cam was broken in. Engine worked flawlessly for years and years!
    qak likes this.
  12. 70skylark350

    70skylark350 Well-Known Member

    Agreed. As soon as I broke in my cam I hopped on the highway and beat the snot out of her.
    Mark Demko and qak like this.
  13. Super Bald Menace

    Super Bald Menace Well-Known Member

    So I'm curious why this isn't an issue with new cars.
    Mark Demko and PGSS like this.
  14. PGSS

    PGSS Well-Known Member

    New cars from back in the day? or all new cars?
    I curious also and have only seen new cars on videos from the 60's and 70's go on the rollers at the end of the assembly line for a couple minutes. Saw in in person one time when I went to the GM Framingham plant in MA on a tour in 1980 or 1981.

    My brother inlaw's Father bought a new 2015 or something close ZO6 Corvette and it had a governor that limit the rpms till a certain number of miles were put on the motor.
    Not sure if it was the same thing though as far as seating the rings and cam lobes
    Last edited: Nov 26, 2021 at 11:04 AM
  15. Rockable

    Rockable Well-Known Member

    Thanks, guys. Once I get the car roadworthy, i.e. all front end, glass, etc. installed, I will break her in on the road.
  16. Mark Demko

    Mark Demko Well-Known Member

    I’m gonna go out on a limb here and say the factory doesn’t flood the rings and cylinders with engine oil like a lot of people do when rebuilding. I stopped that practice on my last build and use WD 40, Total Seal even recommends this practice and it makes sense, engine oil being thick, the rings just kinda glide over the walls, WD 40, being like water, lubes enough till oil splash takes over, it lets the rings rub on the walls to seat or wear in
    qak, PGSS, chrisg and 1 other person like this.
  17. qak

    qak Well-Known Member

    I did wd40 also on the 455 my son and I built and basically just broke in, no smoke beyond typical break in smoke and none now with no oil loss. Now I just have to decide which oil to go with, I used 30w brad penn break in oil so far. After a super hot soak and drive on the highway at 70 mph back to an idle is about 15 and a little over 60 revving it up, I might give the pressure adjuster from TA Performance another quarter turn or maybe just run 10w40

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