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CP engine oil consumption - what's "normal"?


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apologies if this has been discussed before but my "search" enquiries on this forum has found none on this particular topic.

anyway, my query to you all is this:- what would you expect the average oil consumption to be on a recently completely overhauled engine (i.e. the works), run-in on mineral oil for 1,000 miles on varying road types and loads and having covered a further 2,500 since then. I don't cosset the car but I don't "thrash it" either - hope that makes sense

My UK car retains OE spec throughout e.g. cams/exhaust/fuel system (Bosch fuel pump/unleaded head + PI conversion) etc etc -  it drives very well, good fuel consumption (25-28mpg), no pinking and no plumes of smoke on overrun. there are no obvious leaks - only a very slight drip from the sump plug  after 1 week standing in the garage.

that said I am experiencing an average oil consumption of 1 pint per 500 miles - and I am thinking this is excessive - your views/feedback most grateful before I start a strip down to investigate possible causes.

hope to hear from you soon.

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I bought my car 4 years ago and have not done any work on the engine. It has excellent oil pressure and doesn't blow any smoke. I don't thrash it but I do give it a serious nudge when I can, 4500 rpm or a bit more. Most driving is built up areas, I live 5km from the centre of Sydney, but with a good run a couple of times a month.

The only oil it uses it leaks. I don't top it up between oil changes (a few thousand miles) more than maybe half a litre.

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1 hour ago, sebring said:

apologies if this has been discussed before but my "search" enquiries on this forum has found none on this particular topic.

anyway, my query to you all is this:- what would you expect the average oil consumption to be on a recently completely overhauled engine (i.e. the works), run-in on mineral oil for 1,000 miles on varying road types and loads and having covered a further 2,500 since then. I don't cosset the car but I don't "thrash it" either - hope that makes sense

My UK car retains OE spec throughout e.g. cams/exhaust/fuel system (Bosch fuel pump/unleaded head + PI conversion) etc etc -  it drives very well, good fuel consumption (25-28mpg), no pinking and no plumes of smoke on overrun. there are no obvious leaks - only a very slight drip from the sump plug  after 1 week standing in the garage.

that said I am experiencing an average oil consumption of 1 pint per 500 miles - and I am thinking this is excessive - your views/feedback most grateful before I start a strip down to investigate possible causes.

hope to hear from you soon.

Hi Sebring!

Was it re-bored with new pistons?  or if not and just re-ringed the old pistons. Did you glaze bust the bores? My engine was fully overhauled re- bore, re-ground crank, valves and guides etc. and is using about 1/2 pint per 3K and getting less.

Bruce.

 

 

 

 

 

 

 

 

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1 hour ago, Hawk said:

My engine was fully rebuilt (rebore, new pistons, fast road cam etc.) about 4,000 miles ago and uses absolutely no oil between changes (done at least every year).  

Yes same here, since running in after 2,500 miles so far no apparent oil consumption.

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5 hours ago, sebring said:

that said I am experiencing an average oil consumption of 1 pint per 500 miles - and I am thinking this is excessive - your views/feedback most grateful before I start a strip down to investigate possible causes.

sorry guys, I will use the metric system:

new/overhauled engine: 0ml -  500ml @ 1.000km

used/normal engine: 500ml - 1000ml @ 1.000km (noted in brown bible)

Anything more than 1000ml @ 1.000km should be checked. Causes will vary from worn pistonrings to valveguides etc. etc. 

A pressure los test can give you a hint on the cause.

Jochem

Edited by JochemsTR
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6 hours ago, sebring said:

apologies if this has been discussed before but my "search" enquiries on this forum has found none on this particular topic.

anyway, my query to you all is this:- what would you expect the average oil consumption to be on a recently completely overhauled engine (i.e. the works), run-in on mineral oil for 1,000 miles on varying road types and loads and having covered a further 2,500 since then. I don't cosset the car but I don't "thrash it" either - hope that makes sense

My UK car retains OE spec throughout e.g. cams/exhaust/fuel system (Bosch fuel pump/unleaded head + PI conversion) etc etc -  it drives very well, good fuel consumption (25-28mpg), no pinking and no plumes of smoke on overrun. there are no obvious leaks - only a very slight drip from the sump plug  after 1 week standing in the garage.

that said I am experiencing an average oil consumption of 1 pint per 500 miles - and I am thinking this is excessive - your views/feedback most grateful before I start a strip down to investigate possible causes.

hope to hear from you soon.

Any oil in the plenum?

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thanks for all of you responses and confirming my suspicions - in answer to some of those that asked, the recent rebuild comprised:-

  •  +40 thou overbore (from previous +20);
  • new set of pistons and rings (of German manufacture);
  • conrods + crank crack tested (all OK) - crank journals polished only;
  • new bearings (ACL/ Mahle), seals etc throughout;
  • new oil pump;
  • new cam (billet), valves, springs, rocker shaft and valve guides;
  • new timing gear and chain;
  • plus new other "odds and sods" incl washing out and re-fitting flame trap (which i do annually anyway) - and no, no oil in the plenum;
  • oil used Millers classic 20/50 - now called (for some reason best known only to the ad-men) Pistoneeze - I  used their running in oil as directed for the break in period.

so something wrong somewhere - will investigate - but thanks again for all of your responses

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One pint/500 mi is about  1l/1000 km. I would wait and see how it develops with more miles.

Is casing pressure normal (no oil in plenum so probably ok) is is it blowing out with filler cap removed and hand on opening?
 

No blue smoke?
Waldi

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9 hours ago, sebring said:

 

  • oil used Millers classic 20/50 - now called (for some reason best known only to the ad-men) Pistoneeze - I  used their running in oil as directed for the break in period.

 

Millerss have been known to sell the same oil under different names. Classic 20w50 and Pistoneze 20w50 were the same but when 20w50 was more common the Pistoneze was sold to garages and workshops and the classic to the enthusiast market.

John the then manager of the Leicester depot (before it was closed down) was really hepful and he'd tell you which oils were the same and which of those he was permitted to sell cheaper.

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hi, again, in reply to Jochem - no valves stem seals fitted - the engine builder (a longstanding TR specialist) advised against them as they had experienced problems with them reacting with the ethanol in the petrol (their diagnosis), with some quite nasty results - so I didn't contradict them and let them build the engine as they saw fit based upon their experience.

As I said, no smoke on overrun (i.e. as tested by coasting down a long hill in top gear then "flooring" the throttle at the bottom),  so if there is oil getting past that way it isn't a lot - but I will be taking the head off myself so I can check the tolerances and the check the cylinder bores and therefore their workmanship,  but I will check out the casing pressure beforehand and report back. 

thanks again for all the replies/interest

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We don't need valve stem seals fitted - at least I've never seen any on a standard Triumph engine. Fitting them would imply some other issue surely.

Jerry

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3 hours ago, jerrytr5 said:

We don't need valve stem seals fitted - at least I've never seen any on a standard Triumph engine. Fitting them would imply some other issue surely.

Jerry

Hi Jerry

As I said it depends on what valves and guides are fitted also if they have been reamed correctly sure sign is drops of oil on the paint at the rear of the car.

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