Oil burner... solutions?

[Ben Hutchings]

Hi, my engine is going to machineshop soon for some work following a thrust washer 'incident'. It was quite an oil burner previously so that needs some attention too. I've not and block work done on an engine before so bear with me, I'd like to know what the options are, and please excuse any stupidity in the next few paragraphs!

Oh.. stats: 1998cc (6 obviously).

So.. is it correct that I have several options:
1) over-bore & larger pistons.
2) hone, larger rings & same pistons.
3) sleeve, same rings & same pistons.

Is that utter rubbish I've just typed there? All comments, crazy suggestions, rants, advice and cautionary tales will be assimilated.
(last time I asked a question this open, someone suggested I "put a turbo on it"... *sigh*)

Thanks!

[Deleted User]

My Vit, 88,0000 miles, just had a hone and new rings but it will depend on how much wear you have in the bores. Honing will only take out a few thou.

[Nick Jones]

Depends entirely on what proper measurement of the bores and pistons finds, but unless the bores are really quite good you will be needing a rebore, hone and new pistons and rings.  These engines die slow, so once they start showing signs of wear they are usually pretty well worn.  You may be needing another block due to the thrust washer issues anyway......

Worn valve guides can also lead to oil burning, although not usually in large amounts unless you have an external oil feed pipe to the rockers.

Nick

[GT6 M]

[quote=Hutch]

So.. is it correct that I have several options:
1) over-bore & larger pistons.
2) hone, larger rings & same pistons.
3) sleeve, same rings & same pistons.

Hutch,  it all depends on how bad it is when it measured up
but if its n too bad, then just rings may doo, with a hone,

you can also fit OS rings, but you may  have to fit a shim to the piston ring backs, to stop the rings frae flapping back and forth too much,in a standard size piston. but best to measure up when done .  most likely the ring grooves will be worn on an engine so old,!!
so new pistons will be needed in the fust spot.


if you sleeve, you may well find pistons are too worn in the first spot to gaa back in, so new pistons as well,=moer expense.

so best bet maybe just a rebore,and a set of pistons [if its too worn ] this may be cheaper.

Try the ..total seal rings.., theres no gap as such,so hold compressions better,

Marcus

[Deleted User]

Cheap option, get another engine. There's a Vit engine on fleabay at the mo.


http://cgi.ebay.co.uk/Triumph-Vitesse-2-litre-Mk-2-engine-/220679895860?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item33618bfb34#ht_500wt_1154

[James]

Ask the machine shop when you get there - for all you know the block is knackered, so don't buy anything yet.

I expect rebore, pistons and rings?

[AlanChatterton]

The 6 cylinder engines rarely need boring.

Try not to unless you really have to, as the pistons available are crap quality, better to stick with the originals.

Get new rings, glaze bust the bores and refit with new rings and bearings.

My old yellow estate was a burner, had 160k on the clock. Took the engine apart, glaze busted the bores and fitted new rings and one NOS piston. Then did the 2008 RBRR, used less than a pint for 2300 miles.

Have a look at my blog (link below) and you need to get to engine rebuilt which was Sept/Oct 2008 and you'll see what I did and how.

Even the epic oil consumption on the old Torry Canyon on the 2010 RBRR will get cured the same way.

Don't bore and put in oversize reman pistons unless there are HUGE scores down the bores, but I bet there won't be!

[James]

Ben's engine is already a rebuilt screamer so is likely to have rebore, different pistons etc

[Deleted User]

Hutch wrote:

It was quite an oil burner previously so that needs some attention too.

Forgot to ask the obvious…

Smoking on the overrun~lift off throttle? - (Worn guides)

Smoking when you rev it? - (Worn bores/rings)

[Royboy66]

Ben,

judging be the other 'old skool' mods you found on the top end, I reckon there are going to be some down the bottom too. ;)

10cr2011, Team sauna reunion!?  ;) 8)

[bodders1]

AlanChatterton wrote:

Even the epic oil consumption on the old Torry Canyon on the 2010 RBRR will get cured the same way.

If you want any of your oil back, you can wipe it off my front bumper :-)

[AlanChatterton]

bodders1 wrote:

If you want any of your oil back, you can wipe it off my front bumper :-)

My gift, to you............. keep it.

See, my generosity knows no bounds................. ;)

[TedTaylor]

Up to a point Alan is correct because modern oils are so efficient that the sort of wear that we used to experience in the 50's and 60's and requiring engine rebuilds are very much in the past.  However there are a few points to note.

Hutch's comments about when smoke is produced are a good indication as to whether you need a full strip down, or whether just a refurb of the head is needed (a valve guide or seal problem).  You don't want to do a full engine rebuild if you only have a cylinder head problem.

If you strip the engine have a good look at the pistons because this will give you a good idea what work needs to be done:  
Do they show signs of burnt oil, especially between and/or below the piston rings which indicates worn rings.  
Are the rings free in their grooves as they should be, or are they sticking or seized?  
All these points will also indicate a likelihood of worn pistons which need to be replaced though it is worth carefully scraping out any carbon that is present in the grooves with a broken ring and carefully checking for side wear.  If there is more than 2 or 3 thou clearance between the ring and the side of the groove the excessive clearance can cause a pumping action drawing oil from below the piston to the combustion chamber.  Correction could be possible with new rings but often it indicates a worn piston which needs machining to take wider rings - or scrapping.
Check for scored pistons but don't confuse polished patches on the thrust side of the pistons as indications of wear because they usually indicate nicely bedded in pistons.
Check the ring gap in the top or middle (unworn) parts of the bore.  Factory dimensions are 8 to 13 thou for all rings on a 2000, (PI are different).  This is more a check on wear because rings are comparatively cheap and should be replaced in a rebuild as a matter of course.  If bought for a specific car or bore size they should come ready gapped but it is worth checking them before fitting to the pistons.
It is important to break the glaze on the bore when fitting new rings. Either with a proper glaze removing tool, rubbing with 240 or 400 grit wet and dry (not emery paper), or get a machine shop to do it for you.

Bore wear (the step just below the top of the bore between the unworn couple of millimeters and the worn part below it) should not as a rule of thumb exceed 7 thou.  A rough check is to place a piston ring in the cleaned unworn part at the top of the bore and measure the gap.  Then slide the ring into the worn bit and remeasure the gap.  Divide the difference by 3 and it should not be greater than about 7 (thou).  You could measure the bores and the pistons yourself but it requires specialist tools and a bit of experience to interpret things.

Further than this to be be honest it is best to take your stripped block to an engine machining workshop (don't get them to strip it because they will charge you) and get them to take appropriate measurements. Then discuss the work to be done ..... and the cost.  Or have a chat with some of the members from the local group as to what work needs to be done.

This is an extremely brief set of pointers and there is much that I have not mentioned (or may have not explained properly in my aim for brevity) - best thing is to buy a book on the subject, or see if there is a clean readable  ;D in the local library.  You may even find something on the web.

Ted

[Slimboyfat]

Pretty much agree with all the above.

If you are sure the engine has done less than 100,000 miles it's unlikely to need a re bore, a hone and a set of rings should do it.

More than a 100,000 miles and it's more than likely going to need a bore and new pistons.

Piston quality from the majority of manufacturers today is absolutely superb. There was one notable exception in the 1980's but hopefully they were all sold off long ago.

We use County pistons, they have been without exception a joy to use. The American Grants rings with them are brilliant as well. Can't fault them, and would have no hesitation in recommending them.