General advice on expected engine life before rebuild required

[MJH2454]

Hi Guys, just looking for a bit of advice and personal experience. My 1300 Spitfire has covered a documented total of 56,000 miles, she came with an extensive history from which she has had 17 oil and filter changes during this time, i.e. oil and filter changes at an average of some 3200 miles. When starting up she has a momentary knock from the bottom end bearings and once running no knocks at all, oil pressure when hot is 25lbs psi and at tickover 10lbs psi. she also doesn't demonstrate any thrust washer wear by the normal methods of observation, doesn't burn oil or exhibit smoky exhaust. Strangely enough doesn't leak oil in any concerning way just a light mist underneath, garage floor is clean, so I'm guessing that's a plus point.

General opinion seems to be that these engines will rattle on for 100,000 miles, should I be thinking of an engine rebuild at this time or just wait until it becomes a more persistent knock, I do about 3500 miles per year in her. 

Thanks

[Colin Lindsay]

9 minutes ago, MJH2454 said:

General opinion seems to be that these engines will rattle on for 100,000 miles, should I be thinking of an engine rebuild at this time or just wait until it becomes a more persistent knock, I do about 3500 miles per year in her. 

Thanks

This is not going to be helpful, but I'm reminded of that old question: how long is a piece of string? Engines are all different, the wear will depend on past maintenance, driving style and even the quality of the component parts. Some can really go on for ever whilst others need work relatively quickly in life. 56,000 miles isn't high mileage, but to be honest it all depends on what it has endured during those miles - high speed driving, motorway driving, lots of acceleration, or a sedate life at moderate speed? Oil changes are a good sign, and if startup is the only knocking noise (Anti-drain filter in use? might help to fit one if it's not already there), if there's no visible smoke on acceleration and the oil consumption is minimal then I'd say leave it alone until it really needs something. Check the valve clearances, maybe the cylinder compression, and watch for signs of head gasket failure, use a quality oil, flush the cooling system and refill with good antifreeze, and without being paranoid keep an ear and eye open for anything out of the ordinary. It may go on for many miles yet.

[dougbgt6]

MJH,

They ALL have the "death rattle" it's a feature! Oil drains back into the sump and has to be sucked up again and squirted around on start up. No end float? Great! No rattle after start up? Great! The purpose of the gauge is to tell you if it's different from yesterday, the actual reading is not important and probably wrong. 

Drive and enjoy, do nothing until you DO have end float and/or noisy big ends.  It ain't broke, don't fix it!

My engine had to be rebuilt at 38k, (knackered by PO's lack of service) and again at 50k (Wife borrowed car, it lost all it's oil, she didn't notice)

Doug

 

[Steve P]

25 psi running is low,at what revs is that,it should be 40-60 at 2-3k revs.

10 at tickover is a little low.

I would always use a good anti drain filter,I use Mann 719/29,you need a thread adapter for these.

More importantly,good quality oil,many opinions on this,personally I use Valvoline VR1 20/50,excellent pressure and high zinc.

I would do a compression test and check the above,then use it and don't worry about rebuilds.

I always spin it over for a few seconds without choke to get the oil going,never had a death rattle on any of mine.

Steve

[Andy Moss]

I used to get a rattle on start up and discovered that it was caused by a crack in the oil pump impeller. After changing the oil pump for a new one it went away. It’s not a tricky job and you may well consider it as an option if the rest of the engine seems to be in good order. 

[Clive]

I would suggest that the quoted figures are indeed low, (assuming the gauge is correct, but quite possible)

The old Haynes manuals suggested changing big end shells every 40K I think, and it could be what your engine requires. At about £25 for a set including a sump gasket, it would be a worthwhile job. Early intervention can mean avoiding a crank grind in the near future.

You need to drain the oil and a day or maore later drop the sump, not difficult but potentially messy. (wear a hat) and inspect the big ends. While in tehre check the oil pump and mains too. You need to see what size they are, never assume anything. 

As to the question is this unreasonable, it all depends on how the car was driven, and you don't say if the engine is original or hs been previously rebuilt. I have managed to "do" a set of bearings and crank in under 5K. 

[Steve P]

I had a 2500 that knocked out no 1 b/e shells in 100 miles after a rebuild,the machine shop had ground it slightly oval.Also skimmed unevenly front to back so that the no 6 piston protruded from the block at the top of stroke,had to scrap it and start again.

S

[Nigel Clark]

As said above, 25psi oil pressure on the move is low. My first step would be to change the oil and filter, using a quality 20W50 classic oil and a reputable brand of oil filter.

As for mileage between rebuilds, I stripped and refreshed the original 2 litre engine in my GT6 after 110,000 miles. It appears to have regular maintenance throughout its life, certainly over the last 35,000 miles in my ownership. Pistons, rings, bearing shells and thrust washers were all somewhat worn. After honing the bores and light polish of the crank journals I reassembled it with new rings, bearing, thrusts and timing chain. I refitted the old oil pump as it measured in tolerance according to the workshop manual. The only major component that had worn beyond being reused was the camshaft, so I replaced that with new followers.

It ran almost like a new engine (since replaced with a 2.5 litre unit).

I would expected the four cylinder engines are driven harder than sixes, so may not last quite as long in normal use, but it gives an idea of what's possible. Your engine probably has tens of thousands more miles left, unless you're unlucky.

Nigel

[Pete Lewis]

i would try another gauge just to check out the readings  25 is low  there is only one triumph spec  which is 40-60 at 2000 rpm

there is no condition like what oil spec or temperature , all can affect readings , so def a good brand of 20/50 needs to be used 

i would remove the pressure relief valve and check and clean its  seating  its not uncommon for these to be open due to debris 

knock on initial start up is as designed   there are many ideas in various filters that may improve drain back

but you wont stop the gallery from emptying its normal  just let her idle for a few seconds  before any throttle 

its been knocking for 50 years  and can drive some mad , dont  let it get you paranoid  

 

Pete

[MJH2454]

3 hours ago, Pete Lewis said:

its been knocking for 50 years  and can drive some mad , dont  let it get you paranoid  

Thanks for all the thoughts guys and in response. I do use a good quality oil with a hi zinc content, Mann oil filters with double anti drain valves and I have had the oil pressure relief valve out and given it a good clean, as you say if it aint broke don't fix it might be the way to go. The original owner covered 46,000 miles until his death in 1991, and was a late 50's aircraft engineer when purchased so I'm assuming it was looked after and not thrashed. The car then disappeared until it resurfaced again in 2005 underwent recommisioning, some minor bodywork and a respray and now 2021 the actual mileage is still only just at 56,000, 4000 of those done by me in my ownership in  the last 18 months.

[Steve P]

Maybe worth seeing what another gauge says if you can lay your hands on one,they don`t call them worry gauges for nothing.

I have the same model one on my Herald and Vitesse,the Smiths full face one,(0-100 psi),the Herald one flies around matching the revs,the Vitesse one slowly builds

and declines to the reading,never figured out why.Both cars use the same oil.

Steve

[Pete Lewis]

its not unusual for pressure or vacuum gauges to be damped by adding a restrictor in the supply  

that would slow needle shift 

on low pressure clues  i would not assume a modern  high spec filter is ok on a low  engine pump spec and  maybe cork it up more than you expect 

many modern spec filters  are for much higher premium pumps   theres plenty of discussion  on here about  this but the filter does need to be matched to pump performance  volume/ pressure  for a known  pressure drop etc 

cheap solution is fit a std filter and check any change

much easier than engine worries 

pete

[chris865]

i had a dolomite 1500 from new which needed crank regrind at just over 100 000 miles and head gasket about 120 000 ran it to 180 000 still not using much oil it had the oil and filter changed every 6000 miles i did drive with care as a young lad i always thought that engine was happier at 60 mph than 70 

[daverclasper]

On 29/12/2021 at 19:26, Pete Lewis said:

many modern spec filters  are for much higher premium pumps   theres plenty of discussion  on here about  this but the filter does need to be matched to pump performance  volume/ pressure  for a known  pressure drop etc 

cheap solution is fit a std filter and check any change

I've just been using the ones recommended on this site Pete, Mann etc. Are these sort of, standard?

[Pete Lewis]

2 hours ago, daverclasper said:

Are these sort of, standard?

not really they are a more modern alternative ,  some use to supress drain back supposed better than a std filter like spin on GFE173

pete