Spitfire high milage engine using oil

[wimpus]

Hi all, 

Some of you may know me from on the CT forum.

Now.. my daily in use spitfire 1500 engine has done nearly 300.000kms/186.000miles.

Pistons  have never been out and head never been off in 42 years.

All crank bearings are replaced (main crank a few times), has a recent duplex timing chain (previous still original).

And new rocker shaft assembly.

 

But since a few months she likes to drink oil.. 😕

Done a compression test (dry and was hot/driven 30min before) all between 175psi and 182 psi.

Oil pressure still 55/60 at 2000rpm.

25/30psi when really hot on idle.

 

1 plug seems to be more oil burning (no3).

Already got a replacement head to put on as i suspect worn valve guides.

Could this be (worn) piston rings to ? (Checked bores with a camera, looks good).

 

Wim

[Pete Lewis]

Hi Wim,  you must be heading for a record with a 1500 to last that long 

whats the engine breathing like  if the tin rocker cover check the gauze inside at the outlet tube is not blocked ,  on the basis the std oil supply to the rockers is pretty limited there is not much that can get down the guides   but do check the breather and hoses etc   is all ok

i take it there is no external rocker feed kit fitted ??

there are no seals on the valves but high oil use is looking like a oil control ring problem 

any blue smoke after overun ??

Pete

[wimpus]

Hi Pete 

56 minutes ago, Pete Lewis said:

Hi Wim,  you must be heading for a record with a 1500 to last that long 

whats the engine breathing like  if the tin rocker cover check the gauze inside at the outlet tube is not blocked ,  on the basis the std oil supply to the rockers is pretty limited there is not much that can get down the guides   but do check the breather and hoses etc   is all ok

i take it there is no external rocker feed kit fitted ??

there are no seals on the valves but high oil use is looking like a oil control ring problem 

any blue smoke after overun ??

Pete

Hi Pete,

Will check that the rocker cover (got another few rocker covers in my spares to keep Fox/Spitfire running).

 

No extra oil feed kit installed  ( those are bad things !) 

 

Blue smoke.. 

Well in september i came back from the finish from the 10Countries Run in the Netherlands and could see some smoke on the motorway.

And pretty black at the rear.

 

Later could see a bit of blue when setting off at traffic lights, but none under driving.

But now cant see anything behind me Exept a not so nice smell, seems many people hate to stand behind ne now.

Even had a few friends driving behind me and could not see anything out of the 'blue'.. no smoke.

Had a few talks with a teacher at the school I work at.

He says inspect & measure the bores, hone it with flexhone and to fit new rings (already bought).

 

And yes i know... this is one of a kind engine !

The one time they build a good one 😂

 

 

[Pete Lewis]

dont be surprised if black and blue can be bore wash from a rich mixture, and that wear rings quite quick,  

i reckon at your mileage a re ring is on the cards but do check the cheap and simples first 

if there is a gauze in the RC you need to prise the retainer to remove the mesh  

if you do just hone and re ring fit a step ring top ring to clear the wear ridge.

pete

[Anglefire]

My 1500 was using a fair bit of oil and I like you assumed it was guides. I decided to whip off the head and get it sorted. The place I took it to said it would be rings. 
i got the heat done anyway and had hardened seats - they did need doing as the seats had regressed- probably because the po had reground the valves. 
I decided to do the rings at the same time and got hold of a set of nos pistons with rings and replaced them just honing the bores.  I has measured them and they were standard size with no obvious issues.  
 

now it’s not burning oil.  😃

[Colin Lindsay]

2 hours ago, Anglefire said:

now it’s not burning oil.  😃

So which was at fault? Guides or rings?

[Anglefire]

5 hours ago, Colin Lindsay said:

So which was at fault? Guides or rings?

The chap who did the head said the guides were fine - so my money is on the rings. Just remembered the pistons were hepolite and came with rings. They happened to be in the boot of the car when I picked up the head and he said they were a bargain at £100! 

[Colin Lindsay]

Thanks Mark. I'm working on one at present, blue smoke from exhaust - so was wondering if I could be lazy and just replace valve guides. Guess not...

[Pete Lewis]

just to  repeat unless there is the dreaded rocker feed fitted flooding the head  there is so little oil in the rocker/valve guide area its unlikely that worn guide will ever be a problem with oil consumption

pete

 

[daverclasper]

1 hour ago, Pete Lewis said:

unlikely that worn guide will ever be a problem with oil consumption

Though could it smoke a little bit at idle and then a bit more when revved up as it clears?. (my car uses a bit of oil, though if I stop after a run, it seems not to smoke at idle, just interested, rather than concerned).

Cheers, Dave

[Pete Lewis]

smoke from oil burning can be for many reasons  breathing,  .worn rings , worn bores, valve guides and contaminated fuel

rich mixtures washing the bores and  oil from overfilled dashpots  , poor quality engine oils  and so on 

Pete