Hi folks,
A lot of Spitfires I see advertised now claim to have had an engine rebuild, or gearbox or similar. I'm starting to consider an engine rebuild myself, but
was wondering at what stage is it necessary?
Obviously mechanical failure (thrust washers, camshaft, conrods etc) is a factor, but what sort of signs does the 'old age' engine give you that it would
like a rebuild?
Currently, mine is running fine. It has 52,000 on it and I get between 33 and 37mpg for fuel consumption, but in the recent long (100 - 200 mile) journeys
I've been doing I have noticed it needs a lot of oil. Typically over a 200 mile trip it will use all the oil between the upper and lower marks on the
dipstick. Other than that, the motor is ok - dizzy shaft has no play in it, thrust washers seem to still be there and there's loads of power...
Then there's the gearbox - usually quiet, easy to engage and no problems, but recently have had some squeals from it which I've been told could be a
bearing getting tired.
Your thoughts on any of this would be much appreciated!
David
'78 1500
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Posted By : Adrian Lee, 22-Jan-2004,
08:02pm
Do a compression test David,should let you know.
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Posted By : Ben Ferguson, 22-Jan-2004,
08:20pm
Woah, thats a lot of oil! Are you not getting any smoke anywhere? The mileage seems to be very low for it to be putting so much oil somewhere! My 1300
unit has only just recenty started to show signs of bore wear at 90ish thousand, but even then over a similar distance would use about a third of that
amount of oil. A compression test may show up something there. As for the crank for instance (the only part thats had work done on mine) its dead easy
to whip the sump off n undo a main and big end bearing cap and hav a look. I did this to try and work out why I had no oil pressure, and virtually
non-existant bearings was the reason! There was no clunking before hand to suspect this though.
So yeh, those 2 checks, compression test and sump off would be my first move, before taking the engine out or anything drastic!
Ben
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Posted By : Jason Chinn, 22-Jan-2004,
08:41pm
If it's not dropping it then it's burning it. There are two area of wear that cause these engines burn oil. Valve guides or piston rings. Having
been through what you're describing I would hazard a guess that you've got piston ring wear and/or gummed up rings.
As my car does between 2500 and 3500 miles a year and everythingelse was fine I decided to fix the problem as cheaply as I could. Firstly I thought
it was valve guides - there was no change in engine idel when I took the oil filler cap off and it would puff white smoke after going downhill
using the engine as a break. The car had not done many miles in the years before I got it. I wanted to convert to run on unleaded so it seemed a
convenient time to swap the head for an unleaded on (&163;190 from Canley Classics).
That improved things but it still used oil - I also now had a possible head gasket leak, traced to what I think was a cheap and nasty gasket. So I
decied to have a look at teh bottom end. Head off again and I popped a piston up through the block to have a look - rings a bit gummy, bores very
shiny. So I took a glaze buster to the bores, put new rings in and reassembled with a copper head gasket and she's been sweet ever since, oil
consumption is trivial and the car runs fine (of course it ran fine before but you know what I mean)
Price of the rings and gasket wasn't great, I think the rings were &163;30 and the gasket a tenner - I replaced all the head nuts too as I
managed to strip one very easily and they were cheap to replace - fiver maybe.
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Posted By : William Davies, 23-Jan-2004,
01:23am
Hi David,
Your oil consumption is certainly high, too high to be valve guides so assuming the oil isn't leaking out, it has to be bores/rings. A compression test
might show this, but bear in mind that the compression rings have little to do with oil control, while the oil control rings have little to do with
compression. It's quite common to have excellent compression and still lose bucketloads of oil up the bores.
As regards other signs indicating a required rebuild, I rely on my nose as a good indicator. There is a very familiar smell to a worn engine, but it's
very difficult to explain in words - it just comes from experience. I'm not talking about the smell of the exhaust, I mean that of a warm engine bay
after a decent few miles.
Cheers,
Bill.
http://www.rarebits4clasics.co.uk
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Posted By : Don Cook, 23-Jan-2004, 11:55am
So David, there you were musing on the need to rebuild your engine, knowing that its fine apart from oil consumption. Now you obviously need a complete
engine overhaul, not to mention the gearbox (and nobody has).
My GT6 was just like yours, used a similar amount of oil over a similar distance. I spoke to my friend Nick who also has a GT6 and he said his did the
same thing; he disconnected the 'oil rocker feed kit' and oil consumption was back to normal. A few weeks later my 'rocker feed kit' split its supply
pipe and I disconnected mine also. Result? Normal oil consumption.
I know this points to worn guides but remember our valves are not fitted with small oil seals! Other cars have them why not ours. Rimmers list them for
TRs but as the guides are not grooved I can't see how they remain in one position to do their job. I've raised this on a number of occasions on other
threads but to no avail.
Just remember when you are up to your ears in muck, spanners, engine hoists etc, oh and rain: did you really need to do it, was it worth it?
Don
(but if you do remember to post the results)
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Posted By : Chris Hamblin,
23-Jan-2004, 04:37pm
I have read that you can use Ford Pinto valve stem seals, apparently a tight fit so heat has to be applied to get them on but if there Loctited in
place they work perfectly.
I've justr dug out an old article and the suggestion was made by John Kipping so if this does interest anyone he may be the man to talk to, merged
with Canley Classics now??? I beleive.
Still think that much oils likely to be bore related, I didnt have any rocker feed on my car when I was burning that much, & theres a
difference between 'burns a bit of oil' and the 'fill it up alongside with petrol' scenario which I was under the impression was pretty much the
case.
Chris Hamblin
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Posted By : David Balfour, 23-Jan-2004,
06:42pm
Thanks everybody for all your help!
I'll have to take a look at things next week, but I also need to persuade it to do another 200 miles on Wednesday, so fingers crossed!
It's funny about the oil, because I really don't know where it's going. The plugs are very oil free and look nice, the underbody isn't coated
in it, there really isn't any blue smoke (can't even smell it) and there are no pools of oil in the garage.
What's also curious is that it only loses the oil on the long motorway runs. Say I do 200 miles from Nottingham to Portsmouth; I will need to
add at least 2 litres of oil. However, do 200 miles going to work and back for a week and I won't have to add any. It must be the speed, does
this suggest anything to anybody?
Thanks again,
David
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Posted By : Michael Davis,
23-Jan-2004, 07:24pm
erm, long fast run = hotter oil = thinner oil = escapes easier?
maybe?
just a thought
Mik
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Posted By : Don Cook, 23-Jan-2004,
11:58pm
You know what we really need is a trader, Moss, Rimmer, Canley, Jigsaw etc to 'turn' a groove on a set of valve guides to locate the seals and
see how it goes. So how about it guys?
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Posted By : Jason Chinn,
24-Jan-2004, 08:35am
I can't think no one has tried this so my first assumption is that it's been done and was no good - I'll ask Dave P at Canley, see what he
says.
J
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Posted By : Jason Chinn,
24-Jan-2004, 09:35am
Apparently Chris Witor has done some work on the oil seal conversion for the 6 pot - he may be worth a call if you're interested
www.chriswitor.co.uk gets you to his web site
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Posted By : Don Cook,
26-Jan-2004, 12:22pm
Cheers Jason
I rang Chris Witor (what a nice bloke) and discussed valve stem oil seals. Yes! He sells copper bronze alloy valve guides that are flow
profiled and have an integral height stop. More importantly, they have a 'D' shape groove machined to locate and retain an oil seal!
The guides need to be honed after fitting in the head. These inlet guides are &163;7.93 each. The guide oil seals are
&163;2.05 each.
Chris is sending me a flyer he has so I'll see if it can be scanned for the board.
I've been looking for this conversion for over a year so now I've found it I'd better get on and unlead my head...after the gearbox and
O/D rebuild...
Just remembered that I'm on the Spitfire board and I've been going on about 6 cylinder heads err, err............
Don
