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Oil and fuel consumption issues

3K views 27 replies 7 participants last post by  Ralf S. 
#1 ·
Some advice please guys. I'm driving a 2.0 JTS Spider with 65k on the clock. I'm getting 300 miles max to a full tank (mixed driving). Topped up with a full litre of 10w 60 just 750 miles after an oil change (again, 10w 60). Exhaust tip becomes black after cleaning (oil?!).

Engine sounds fine, no strange noises, accelerates fine etc. Only annoying thing is lack of drivability at low speeds (separate thread made about that one).

Any opinions on whether this sounds normal? Concerned by the oil usage, but does it justify getting the engine stripped at BIG cost? - NOTE engine was rebuilt following a cambelt failure just a few a months ago, prior to my ownership.

Thanks all
 
#2 ·
MPG sounds reasonable but not sure about the oil consumption. My 98k 97 TS does not seem to burn any oil.

However don't take mine as gospel, not had it too long and she is covered for Winter currently.
 
#3 ·
Sounds like you can have a problem in a bore (scratch, worn rings) or the valve guides letting oil through that way.

When I had mine rebuilt after 82K and a cambelt failure, their was a fine scratch on one bore. A glaze bust polished the scratch out and new rings means I use very little oil now.
 
#4 ·
Thanks guys. Gazza82, sounds feasible but too late for me now the engine is back together. Guessing it would involve starting again to find a small (but important) fault like that - meaning mega bucks at the garage. My indy has quoted me 1k+ to strip the engine, with no guarntee of finding anything. Do I continue driving as-is, or am I asking for trouble?
 
#5 ·
If it's burning that much oil then there's something serious amiss.. but having said that, if you keep filling it up with oil it'll keep running for the time-being.

You don't need to strip the engine just yet.. you need to work out what the problem is.... but if the beast had a cam-belt failure and a rebuild then that's an obvious contender as the culprit.

First of all have a compression test done on each cylinder so you can see which cylinder (if any) are running at low compression. If the rings or the bore were damaged in one or more cylinders, then it'll show up here.

---> When the did the rebuild, do you know if they fitted new rings? They could have cocked it up.. fitting oil scraper ring in upside down for instance. That's a relatively easy fix.

Do you know if they touched the valves at all? Again, they may have not touched the head at all if no valves were damaged, or they may have taken all the cams and valves out and re-ground the seats etc. and fitted new parts.

I'd guess the valves were clobbered but "looked okay" so stayed in there because most people don't like taking valves out if they look okay. It's easier/cheaper to be lazy and leave them in there. But if the valves are marginally bent they will be straining the valve stem seals so oil will be dribbling down the valve stems.

--> Look at the plugs in each cylinder. Any cylinder getting oil dribbling into it will leave oily or black plugs compared to the others.

Of course, if your rings/bore and valves check out okay, it could be a good old fashioned valve stem seal failure (coincidental) or the beast may have a leak from the oilways into one of the bores (head gasket) but these are less likely given the engine's recent history.

Forget all about the rough running for the moment... that's certainly just a side effect of the beast burning all that oil instead of petrol.


Ralf S.
 
#6 ·
It could be that the impact of the pistons against the valves has caused the piston rings to be pinched in their grooves, preventing them sitting against the bore correctly.

This can cause high oil consumption and low compression if they are not sealing correctly.

I bet the garage that did the rebuild didn't bother to check this... Most garages will rebuild the top end and leave the bottom alone, although they should really have done the big end shells.
 
#7 ·
Thanks for the words of wisdom Ralf. I do have paperwork for the new parts that were fitted - I know the list included valves; when I get home tonight I'll check it and let you know everything they (supposedly) fitted. My indy hasn't suggested a compression test (unless this has already been done when I took it in for a look over), is that a relatively cheap test to carry out?

Symon, I'm pretty sure big end work wasn't mentioned on the paperwork I have, again I'll see tonight. the garage that did the repair wasn't an Alfa specialist so it wouldn't surprise me at all if they didn't check.
 
#8 ·
Some advice please guys. I'm driving a 2.0 JTS Spider with 65k on the clock. I'm getting 300 miles max to a full tank (mixed driving). Topped up with a full litre of 10w 60 just 750 miles after an oil change (again, 10w 60).
I get about 400 miles per full tank, and I am seldom overtaken. I actually keep a spreadsheet to calculate mpg and have achieved an average of 33.4 mpg over the last 8,700 miles since I bought the car, 62K now on the clock.

My current JTS uses very little oil but my previous car a 156 2.0 Twin Spark (basically the same bottom end of the engine) used about a litre of 10W60 per 500 miles when I bought it at 71K, and about a litre per 150 miles when we were parted at 114K (and still not smoking!). I bought the car from a friend and know that the engine had never suffered any damage. Due to the expense involved, if your Spider were my car I would not go for an engine rebuild, just source some cheapish 10W60, my last lot was from 'oilman' @ £128 for 20 litres (£6.40/l) delivered.
 
#9 ·
My current JTS uses very little oil but my previous car a 156 2.0 Twin Spark (basically the same bottom end of the engine) used about a litre of 10W60 per 500 miles when I bought it at 71K, and about a litre per 150 miles when we were parted at 114K (and still not smoking!). I bought the car from a friend and know that the engine had never suffered any damage. Due to the expense involved, if your Spider were my car I would not go for an engine rebuild, just source some cheapish 10W60, my last lot was from 'oilman' @ £128 for 20 litres (£6.40/l) delivered.
Well I certainly can't imagine ever seeing 400 miles at this rate. I only drive the car at weekends though, in the last 2 weeks I've probably driven less than 75 miles - so I'm hoping I can continue to enjoy the car with regular oil top-ups for a while yet, without engine work. Bought some 10w 60 from Opie yesterday as it happens.
 
#10 ·
Ok guys here is a list of the parts that were replaced according to paperwork I have:

1 Cyl head re face-car
16 Valve seat re face-car
16 New valves
8 New valve guides
1 Strip lifters colapse
1 Strip clean rebuild head
1 head set
1 Head bolts

The above were supplied by a separate company, and on the paperwork from the garage that carried out the work, they state new timing belt kit, water pump, gaskets and 'word-I-can't-make-out head bolts' (could be 'some' head bolts?).

So no mention of big end shells or the like...
 
#11 · (Edited)
Was this at an Alfa specialist?

It is a bit of a worry that the big end shells were not done.

The driveability issue could be caused by incorrect cam timing. (Not used correct cam-locks)
 
#12 ·
No it wasn't a specialist, it was a garage in Leicester called West End Motors (not heard/used them myself). Is there a high possibility that there has been damage to the big end shells do you think? My dilemna really is do I fork out over 1k to have the engine stipped and checked? Seems crazy money.
 
#13 ·
The way I see it, you have three choices:

1) full engine rebuild by an Alfa specialist. Expensive, but will be sorted.

2) do nothing, keep driving it, keep putting in oil. May be worth just doing the big end bearings to be on the safe side, this is normally only a couple of hundred quid or so at a garage.

3) Sell it

We can't really advise the best course of action, 1) is ideal but expensive, 2) is cheap but potentially risky, 3) gets you out of the car but you'll probably lose money selling it this time of year.
 
#14 ·
2) do nothing, keep driving it, keep putting in oil. May be worth just doing the big end bearings to be on the safe side, this is normally only a couple of hundred quid or so at a garage.
Thanks for the advise. I suppose with this option, whatever is causing the engine to burn oil won't necessarily be sorted, but the engine is less likely to 'fail' - ie go with a bang if you get my drift? What prices should I be realistically looking at for a strip/rebuild?
 
#16 ·
The beast has had quite a comprehensive head refurbishment by the sound of it... all 16 valves replaced and all of them re-seated... We like. :thumbs:

I'd have a look at the big ends to see if they're scored/flattened... it's not too horrific just to replace those if there's any doubt at all about them... and it sounds like there is. These engines do tend to wreck the shells when the cam-belt fails, so it's worth assuming they need replacing unless it turns out they were done and just not recorded, or look absolutely immaculate.

That would just leave the rings to worry about really.. but if the compression test checks out then it's maybe worth a punt to assume they're okay for the time-being.


Unless I've missed something, there's only been 8 new valve-guide oil seals fitted.. which is a bit unusual. It would be extremely bizarre if they did all that work and then re-used some of the old oil seals... but anything's possible. We need to investigate what happened there. It could be that they just had 8 seals... but seals don't like to be re-used (if that really is what they did..?).

Ralf S.
 
#18 ·
The beast has had quite a comprehensive head refurbishment by the sound of it... all 16 valves replaced and all of them re-seated... We like. :thumbs:

I'd have a look at the big ends to see if they're scored/flattened... it's not too horrific just to replace those if there's any doubt at all about them... and it sounds like there is. These engines do tend to wreck the shells when the cam-belt fails, so it's worth assuming they need replacing unless it turns out they were done and just not recorded, or look absolutely immaculate.

That would just leave the rings to worry about really.. but if the compression test checks out then it's maybe worth a punt to assume they're okay for the time-being.
Would knackered big ends be causing the high oil consumption? Or more like they probably need replacing regardless of that… and the piston rings are likely to be the culprit with regards the oil usage? All speculative of course..
 
#17 ·
The guides are separate to the seals. The head gasket set comes with a full set of 16 seals, the guides are separate, they are part of the head but they can be knocked out and replaced if they are damaged when the belt snaps. It's pretty typical for only 3 or 4 guides to be needed.
 
#21 ·
Yes.. the only oil-consumption related parts are the rings and the valve guide oil seals. I misread above... guides and seals.. must be going sydlexic.. :D It sounds like the top end is pretty much all new, so probablilty shifts to the rings.

If you're going to do the big end, you're not far off from taking the crank, rods and pistons out to fit new rings.


Ralf S.
 
#22 ·
Gotta take the gearbox off to get the crank out - might as well take the whole lump out. You can change rings by taking off the sump & head tho and knocking them out the top with the engine, gearbox & crank still in situ. Its an effort though, and its still 'arthur job'. Better off doing everything IMO.
 
#23 ·
Could be the inlet manifold gasket causing the high consumption..

If the bit that seals the oilway for the variator is leaking it will chuck oil into the manifold and it will get sucked into the engine and burnt.
 
#25 ·
Thanks for all the comments everyone, I have an update for you. Basically I had the engine looked at and the piston rings have had it as some of you suggested. Compression was way down on at least 2 of the cylinders. So it's at the garage now having plenty of hours thrown at it to get the engine sorted properly once and for all. Not the best time of year for this to happen :(
 
#26 ·
Hmm.. that's a pity.. but at least the motor will be effectively all new... and the extra compression will give you a fair bit extra poke too.. so it'll be worth it as the pain to the wallet subsides.. :)

Run the beast in for 150 (?) miles or so, so that the new rings get the best start in life..


Ralf S.
 
#27 ·
Right, I have the Spider back! At long last! Basically the engine has had a comprehensive rebuild after discovering the knackered piston rings. The strip-down revealed a few other issues so pretty much everything has been replaced or at least properly checked…Now I need to drive her in gently but it already feels much better. Work was carried out at my usual indy AFH1 in Mansfield - it's taken a while with xmas in the way etc, but I'm very pleased with the thorough work and great service, cheers guys. Now to enjoy the Spider again - definitely worth the expense (I think?)! :lol:
 
#28 ·
If it's had so much heart surgery, it may be worth giving the beast some new oil and a filter after a few hundred miles, just to flush out any bits and pieces that have found their way into the motor. Essentially it's more or less a new engine really.. :thumbs:


Ralf S.
 
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