Huge engine oil consumption

[flatfloor 3.8]

To flatfloor: I could see it was glazed because I could still see the original honing cross hatch on the cylinder walls - something that should be worn off at the mileage the engine had run. To deglaze the cylinder walls you need to remove the pistons, which can be done with the engine in the car. You need to remove the head and oil pan. I used a ball hone for the deglazing and a new set of rings.

Hi, I have now removed my pistons ready for de-glazing. Where did you buy your ball hone? Do you still have it ? Would you sell it or hire it out to me for a week ? Thank you Bill White.

[mtnjag]

I know this is a old thread but I am having a similar problem on a 3.8 with about 4000miles on the eng. Not smoking,surprisingly, but getting 200miles to the quart and can’t get rid of pinging when all warmed up and giving very moderate throttle at 2000-3500 rpm. No pinging at low rpm 1500-2000 when flooring it in 3rd or 4th. Thinking it’s the oil consumption lowering octane of gas way down. Timing down to 6degrees. Compression ~170 on all on a 9:1 engine, leakdown below 5%. Clean ring around pistons I am told indicates excessive oil consumption which seems clear.

I am thinking oil ring should be broken in by now.

Any comments and how did the honing and re-ring work out?
Any idea of shop time for this.

Thanks

[PeterCrespin]

Do hou know if your engine uses a chrome top ring?

Have you red-lined your engine? If so, how often and what mileage did you first do it?

Have you calibrated the dipstick ?

Do you know whether it keeps on using oil heavily after the first litre or so has disappeared?

[mtnjag]

First rebuild on orig eng. Not relined, min oversized. Rings as supplied on AE pistons, don’t believe it was chrome.
Have not calibrated stick but was running to top of crosshatch. Drained it down to bottom of crosshatch and it continues to use at about 200/quart, so yes it continues to use heavily after 1-2quarts are gone. It is an E stick. Initial break in on dyno.
Sorry for late reply, in central Calif and power shut down along with my internet.

[PeterCrespin]

Good luck with the power and fire risk...

I asked if you’d red-lined, not re-lined the engine. By your answer I’m guessing not. My query abkut ring type was related. In my motorbike engine days, chrome top rings came with a waxy red coating that was in effect jeweller’s rouge, to help the hard metal bed in against a freshly-honed cylinder. If neglected, running-in/breaking-in a chrome-ringed engine (and others) causes poor sealing and high consumption.

The cure is to work the engine hard and if you are lucky it’s not too late.

Hopefully, you haven’t used synthetic oil. If you have, transfer it to another engine, if cleanish. Fill with cheap mineral oil or break-in oil if you can find it. Drive briskly for about 10 miles or until the block is fully warm - which takes much longer than the coolant warming up.

If you’ve never taken the engine to the red line you need to start doing so, initially as brief bursts at full throttle in the lowest gears and then holding throttle open for longer periods until speeds become risky. Let engine temp drop with a minute or two of gentlre running between bursts and don’t be surprised if the temp gauge hardly reacts, as the heat will be unusually local at the friction faces of rings and bore. Rings exert only light rubbing pressure due to their ‘springy’ construction and the real pressure comes from combustion gases getting behind the ring, which in turn happens most forcibly at wide open throttle.

If you didn’t gradually and deliberately give the engine progressively more work, often beyond how you intend to drive the car, the chrome ring never conforms and the bore surface is nicroscopically ‘smeared’ flat at the high grain tips, instead of ‘chewed’ flat by cutting/ wearing some of the machine marks smoother. This affects sealing, lubrication pockets etc. and synthetic oil slows down or even partially prevents good break in.

At your mileage it may be too late and re-ring and hone may be required, but you have nothing to lose by caning it and seeing what happens. Provided your tach isn’t reading low and the engine is sound, you should be fine. Please report back. There is nothing magical about the red line, it’s just a case of working the engine hard.

[mtnjag]

Thanks, another day or two and winds should subside with power coming back on.
Sorry, reading on my phone, kinda small .
No, haven’t red lined eng, perhaps 5k a few times. Spirited driving but usually shifting about 4500.
Ran breakin oil then to the old Kendall oil with high ZDDP. Continuing with similar.
I’ll switch to Break In oil which is available and give it a go. Was thinking this would be worth a shot before a hone job, going back to an aggressive breakin procedure with the breakin oil is a one two punch I hadn’t considered.
Thanks for advice, I’ll report back.

[PeterCrespin]

Hmmm, if you’re a spirited driver snd usually shift around 4500 it may not work, but you’ve given it your best shot. Bruce Harless, a 3.8 owner and personal friend on Jag-lovers, had his engine rebuilt by a pro but got bad advice on break-in. He did abiut the same miles and was losing oil heavily. His ‘high’ revs were 3000-3500 but everything came into line when be drove it harder for a couple of weekends. 4500 is reasonable, if not the ideal.

[mtnjag]

We shall see. Gotta replace an alternator and then out to the coast.

[Mark Gordon]

Hmmm, if you’re a spirited driver snd usually shift around 4500 it may not work, but you’ve given it your best shot. Bruce Harless, a 3.8 owner and personal friend on Jag-lovers, had his engine rebuilt by a pro but got bad advice on break-in. He did abiut the same miles and was losing oil heavily. His ‘high’ revs were 3000-3500 but everything came into line when be drove it harder for a couple of weekends. 4500 is reasonable, if not the ideal.

I followed Pete's advice when I broke in my rebuilt engine in 2012. Over 20,000 miles later, it uses about 1 qt. every 1000 miles, but most of that is leaks. What I don't understand is why, back in the 60's and 70's, and probably before, the advice was to drive gently for the first 1000 or so miles with no hard acceleration regardless of engine rpm's. I understand that modern engines have much tighter tolerances and don't need that break in period, but surely Chevy and Ford engines of 50 years ago weren't much different from XK's in terms of tolerances and materials, so why would there be a different break in regimen?

[mtnjag]

Oils have improved since then, maybe that has something to do with it?

[mtnjag]

Finally got the alternator back and in and did the oil change to break-in oil.

Drained, changed filter, added 9 quarts of oil per manual and Dipstick oil level is about 1/4 up the crosshatch from bottom of crosshatch.

So to top of crosshatch would be almost 2 quarts overfill, which is where I have been filling it.

Now for the fun part, drive it hard and see if oil consumption comes around.

[Tom W]

If your dipstick is accurate, then filling to the top of the hatching is not actually over filling. Anywhere on the hatching is “the right amount”. There is a tolerance on the correct amount of oil, and the figure from the workshop manual should put you somewhere in the middle of that value. This is just to make the car easier to look after, e.g. it can go down a bit without doing any harm (important when engines used to use oil) and when topping up, it doesn’t need to me mm perfect.

Have fun testing, hopefully filling slightly lower cures your oil consumption.

[mtnjag]

Well, finally finished the secondary breakin drives. Worked it hard as discussed for 1000 miles. Looks like I have improved to about 500 miles per quart when measured with incremental additions of oil so I could monitor progress.

So a good improvement over 200 miles/ qt if not as high as I’d like it to be. Planning on changing the oil/ filter today and get a real world result. Perhaps the cylinder glaze has been broken and some continued improvement will occur. Also going to see if I can address some leaks that have some sort of an effect.

Thanks for the help. I’ll report a “final” result. Looks like rain is finally here so it may take a while.

[PeterCrespin]

Well done. Happy for you managing to stay out of jail whilst driving an E-type hard.

There is nothing magic about 1000 miles so there ay be ore to come - especially as it had the oil consumption of an under-driven car. That can mean that the improvement may never quite match a harder driven chrome ring engine. Just fitted my rods and chrome ring pistons today, so have it all to do myself.

[mtnjag]

Yes, very happy about that myself. Had to keep an eye on the rear view, tach, and road making for a busy drive. Fortunately traffic moves at 75- to 90mph in that area of Hwy 1 so I didn’t stand out to much. Damn Camry passed me at 110mph!

Have fun with your break in.

[Geoff Allam]

Is it necessary to drive at high speed while breaking in? Would driving in second or third gear at high rpm achieve the same result or is there a benefit With the engine having to work harder in high gear to achieve the same rpm?

[mtnjag]

Well, third gear at high rpm runs is a rather high speed condition, especially with a shift to forth. Back off, take a nice off ramp, and give it another go. Results in not constant high speed but significant speed peaks with a little cruising at speed for the fun of it. That’s what I did anyway. Hope it was appropriate if not entirely within speed limit postings.

[mtnjag]

So finally an update. Ran into some delays as along with an oil change from the break-in oil back to the normal oil I had been running (Pengrade-1 20/50 a high ZDDP oil) I decided take care of a few projects on the car that had been accumulating before driving it to discover the result.

First, I believe I had some success with the retro breakin. Have now put 400 miles on the eng since the oil change, added a 1/2qt to bring it back to starting location on the stick. That would be 800miles/qt which, when compared to my starting at about 200miles/qt, is fantastic. Also plugs are dry, light tan to grey, no smoke, and rather than a clean ring abound the piston top it has carbonized. Hope the rings continue to bed in with improving results. Thanks for all the help on this matter.

While up for the oil change I installed the Cool Cats radiator fan in place of my adapted Camaro 30amp draw fan, had to make some changes to my new 10si alternator mod, changed coolant, replaced tie rod end boots, discovered my brake problems and did the brakes which I worked out in another post with help here, discovered a stub axle hub seal leak on one side, and what I think/hope is a rear pan seal leak (hopefully NOT a crank seal leak!). I'll be researching the pan seal in other posts I have seen and just put it back up on stands for that little project. After that I need my buddies rack for the hub seal.

Again, thank you for the help.