B17 Rebuilt, Burning Oil and Guzzling Gas

ASSISTANCE Stock Engine-Bay Components
1

I recently rebuilt a B17 with 300k km on it. The rebuild included the following:

  • Deck head
  • Bore cylinders to OS
  • OS PR3 pistons and rings
  • Resurface crank
  • Regrind and reseat valves
  • New valve guides
  • New water pump, oil pump, timing belt, and tensioner
  • All new gaskets and seals
  • New main and rod bolts
  • Cleaned injectors
  • Cleaned intake manifold
  • Replace distributor cap, rotor, leak cover
  • Replace PCV valve
  • Replace ignition wires and spark plugs (NGK standard plugs)
  • New K&N drop-in air filter

Only OEM Honda parts were used in the rebuild, unless otherwise stated.

The following italicized section is a chronological account of the events leading up to my current situation. I have included all pertinent information for reference.

[I]After reinstalling the engine, I noticed some blue-grey smoke expelled from the exhaust, but it was a small amount and mostly at startup. The timing was set according to the service manual when the engine was reinstalled (has not been adjusted since). At the time, I figured it was normal for the engine to burn some oil during break-in. The engine was broken in according to the Endyn method. The engine pulled strong during the break-in procedure; however, the blue-grey smoke at startup has persisted. I did not notice any oil consumption at the first two oil changes (250km and 1000km, respectively); however, with less than 1000km on my third oil change the engine consumed 1/3 quart (checked for leaks and found none). I have been using Shell Rotella T 15W30 non-synthetic oil exclusively since reinstalling the engine.

I also monitored fuel consumption and initially fuel conusmption was within the factory specifcations (27 mpg, city); however, it has gradually decreased and is now at 14 mpg, city. I have not noticed any black smoke from the exhaust. FYI, the car has been driven daily in the city. I have been running 94 octane since reinstalling the engine.

There is still blue-grey smoke at startup, and now there is grey smoke constantly being expelled from the exhaust while the car is idling. I’ve been told that there is blue smoke from the exhaust when the engine is under load. I have smelled burning oil occasionally when exiting the car.

I also noticed that the engine felt progressively more sluggish (i.e. not as responsive) after the rebuild, although it was very responsive intially when reinstalled.

I recently compression tested the engine. The results were 240psi across all 4 cylinders. When removing the plugs for the test, I noticed that there was oil on the threads but no carbon build-up on the electrodes aside from regular fuel combustion.

Most recently, I reset my ECU. I noticed an immediate increase in the responsiveness of the engine. I am closely watching my fuel consumption now, although after putting less than 100km on since resetting the ECU I can feel it losing responsiveness already.[/I]

It is apparent that I have at least two problems on my hands: the engine is consuming oil and too much gas. My concerns at the moment are:

[LIST=1]

  • Will continuing to drive the engine in its current state be detrimental to it? (I think Colin's reply in this thread pretty much answers this question...)
  • Is my oil consumption considered normal for an engine that is being broken in?
  • Is burning oil related to fuel consumption? (i.e. Will it throw off the ECU?)
  • Could the higher compression be throwing off the stock P61 ECU, resulting in high fuel consumption?
  • If my timing is off (i.e. it needs to be readjusted), can that cause high fuel consumption?
  • What could be the cause of the burning oil? (e.g. piston rings, valve seals, valve guides...???) [/LIST]

    To all of the members who have rebuilt engines, or B17s specifically, I seek your council. I realize that these two problems may have separate causes. Your advice and suggestions are welcomed and appreciated.

    PS. Sorry if this is should be in the hybrid forum. It’s pretty close to stock so I thought this forum was more appropriate.

    • 2

    Blue smoke on start up suggests leaky valve seals. The reason for this is after shut down oil runs past the valve seals and drip into the combustion chamber causing a “pool” of oil in your combustion chamber. When you start the engine it quickly gets burned up causing the tell tale blue smoke. This can be caused by improper installation of the guide or the seal, or valve guides having too much clearance allowing the valve itself to distort the seal.

    As far as smoke under load, this suggests that your rings did not seat properly. While your compression rings (based on your compression numbers) seated properly, your scraper and oil control rings may not have. Did you use non detergent oil for your break in? Detergent oils can prevent proper ring seating. Running rich can also prevent proper ring seating causing ring washout.

    While burning oil is not a good thing and can cause excessive build up on valves, pistons, combustion chamber, and spark plugs, keeping your oil level full will keep it running for possibly years to come. I would highly recommend if you do not have one to install a mechanical oil pressure gauge.

    I am sorry about your frustration and wish you the best of luck in your troubles. I have been there and it sucks.

    3

    what type of oil was used during break in? how was it broken in?

    4

    Is it possible for the engine to smoke under load due to leaky valve guides/seals?

    According to the Shell website there are some detergents in the oil; however, it is a non-synthetic oil. I have been advised to use this oil for breaking in the engine from multiple sources.

    5

    the Endyn Way seems wrong dont change the oil untill the 1k mark? to me that could cause alot of issues. Ive always done it “Ken Wood’s” way but only used the cheapest brand oil 10w30 oils for break in’s

    something happened in the break in the 15w could have been the cause aswell as the Endyn Way of doing it.

    have you tried changing the oil to a 10w30 to see if that clears up the smoking?

    Have you done a leak down test?

    6

    [QUOTE=thatblkguy;1935851]the Endyn Way seems wrong dont change the oil untill the 1k mark? to me that could cause alot of issues. Ive always done it “Ken Wood’s” way but only used the cheapest brand oil 10w30 oils for break in’s

    something happened in the break in the 15w could have been the cause aswell as the Endyn Way of doing it.[/QUOTE]
    The oil was changed at 250km and 1000km after the reinstall, as I stated in my original post.

    No, but I guess it wouldn’t hurt to try. Should I keep on running non-synthetic or would switching to synthetic at this point be a good idea?

    No, but I have compression tested the engine and it showed 240psi across all cylinders. If there is a leak I don’t think that I’m losing much compression so that would defeat the purpose of a leak down test…

    7

    It’s probably also worth mentioning that on several occasions, notably when the car has been parked over one or several nights, the car has not started immediately (i.e. nothing happens when I turn the ignition, no crank, not sure if there is a spark). In order to get it to start, I have to turn the ignition several times and hold it there for ~5 to ~10 seconds, and then it cranks and starts like normal. The exhaust smells rich (from fuel injection but no spark) but goes away after a few seconds.

    I bring this up after reading this thread. Could it be a bad igniter or coil that’s causing my starting and fuel consumption problems? Although the starter would still crank the motor even if the igniter or coil were malfunctioning, wouldn’t it?

    8

    probably up there somewhere.

    compression test?

    9

    Haven’t posted in a while, thought I’d update the status of my motor.

    The motor has about 7k km on it now since the rebuild, and is still consuming quite a bit of oil (about 1/2 quart every 2500km). I had to smog test it in February, and I barely passed because of high hydrocarbon emissions (probably both oil and fuel in the exhaust given the high consumption of both). I am still running conventional oil (5W30) since I’ve been advised that there’s no real rush to switch to synthetic. Occasionally I still get the blue smoke at startup, and under hard acceleration there is smoke from the exhaust.

    Fuel consumption has settled down a little since I replaced the O2 sensor a couple of months ago (8-10L/100km, 22-27mpg), but I get the occasional tank that’s brutal (18mpg) with no real change in driving pattern.

    As far as performance, I can’t really tell if it is suffering because of the burning oil. Sometimes it accelerates quickly, and other times it feels sluggish. I remember driving it when it was first rebuilt and that was probably the best it ever felt. But then again, it could just be exaggerated in my memory.

    I haven’t compression tested the motor since, but last time I did a couple months back I got good numbers. I still suspect that my valve guides or seals weren’t done properly in my rebuild.

    Any comments?