TVR S1 - fumes...looks like excessive blowby.

[cnprior]

Evening All,
Whilst I am not a regular contributor I am an avid reader during my lunch at work !!
I own a V6, S1 – 112,000 miles – fairly well cared for but could with some more TLC if I had the time.
This evening I went out for a ‘blast’……I noticed the tickover was a bit lumpy and I thought it might be slightly mis-firing…….anyway when pushed she still picked her heels up so I thought I was imagining it !!
Anyway, I progressed on my regular route but didn’t feel that everything was quite altogether there…..I kept thinking that I MUST adjust my valve clearances as I know they need doing as the engine sounds a bit ‘tappety’…….but I just haven’t had the time to do them yet !!
Anyway, at a set of traffic lights I noticed some ‘fumes’ coming from the bonnet……..I thought again, I might be blowing it out of proportion and decided to go the long way home before returning to ‘her indoors’ (I know you all do this so don’t lie !!).
Anyway, just ,moving away from the traffic lights the car felt ever so slightly lumpy……so I gently progressed towards a local roundabout and made a U turn back homebound. When I got home, I pulled the car into the garage and opened the bonnet………the fumes I had seen at the traffic lights were coming thick and fast……my first thoughts were that the exhaust gasket must be leaking….but the fumes seemed to be coming from the oil filler cap.
I attached two videos, the first one shows the fumes (it is difficult to see though) with the oil filler cap in place….but then I took off the oil filler cap as it looked as though the fumes are coming from the filler cap and took another video to show you all.
The blowby, fumes look extreme to me and I was wondering if this could be caused by excessive tappet clearances as they definitely need adjusting…..the other thought I have is the oil breather system…….has anyone cleaned this out and is there a picture which could be sent advising which pipes to clean out?
My other question is whether you think the engine sounds (listen to the video) unhealthy……is this just tappets needing adjusting or something more serious in your expert opinions?
Looking forward to hearing your opinions !!!!!
Regards,
Chris
P.S - I can't upload the video for some reason....can someone give me instructions please?

[v8s4me]

If you up-load the videos to U-Tube and then post the links here we'll be able to see them.

[cnprior]

Thanks !!

Videos now uploaded to:-

http://youtu.be/069jJ8llO8I
http://youtu.be/XnsPn9spSfc

Thanks - Chris

[phillpot]

Sounds pretty dreadful in first video, not so bad in second but fumes not good!

Were oil pressure and water temperature ok?

Lot of that noise could be loose tappets but that wouldn't cause fumes. You could try taking the plugs out, keep them in order and compare colours (plenty of guides on internet) or you could take it to a reputable garage for a compression check and first hand (and hopefully expert) opinion, imho.

[cnprior]

Oil and water were fine, oil level ok.......video 1 & 2 were taken on different devices-iPad and iPhone.
I do have a weeping radiator but this is topped up and checked every week,

[Barkychoc]

Could be a blocked breather hose - I can't remember the breather arrangement and don't have a V6 haynes manual. Don't write the engine off yet.

[S2Mike]

I would start by checking the valve clearances, maybe a valve is stuck open allowing the gases to escape. If only because the job needs doing, and see if one has somehow stuck open become unseated or worst case senario a rocker snapped off leaving the valve flapping loose. So the symptoms may be linked .
Hope it is one of the simpler solutions, good luck.

[greymrj]

The 'beat' of that engine isnt right and you will notice that there are strong pressure pulses in the fumes and these appear to be at half engine speed. The fumes are not just leaking, they are being forced out under pressure. That has to be a compression leak somewhere. Borrow a compression tester (or have it done at a garage) and look for the one cylinder (park plug hole) which is markedly different from the others. When you have found it, then check the valve clearances on that cylinder; if one valve is very different it would indicate a valve failure. If however a piece has broken or burn off a valve (not unknown in these engines when running on unleaded) the clearance may not have been effected but the blowpast on the firing stroke would still force pressure past the valve stem oil seals. Sometimes, if a valve stem oil seal has been 'blown' there will be some evidence visible round the valve spring, look for a dryer area where the blowpast has burn oil or generally one valve which looks in anyway different.
If you find the cylinder with lost compression that side head will have to come off I am afraid. If it is lost compression and not a valve then I am afraid we are looking at the piston or rings on that cylinder.

If a component has failed then I might just be able to help as I have some spare engine parts from an engine with a cracked block that I broke. I am near Preston which isnt really that far away.

[cnprior]

Hello - thanks for the advice so far. I've just being reading about compression tests and what kit I need. Has anyone done one on their V6? Did you disable the fuel injection system? If so how please....is there a fuse number that needs to be disconnected?

If anyone has a step by step guide it would be appreciated.

Many Thanks for your help thus far.

Chris

[phillpot]

cnprior said:

disable the fuel injection system? If so how please....

There is a "multi-plug" on top of the engine, behind the alternator sort of between the rocker cover and plenum. Pull it apart and that will cut power to injectors.
Pull the HT lead off the coil to stop plug leads trying to spark and possibly "zapping" you while your testing.

A very basic test can be done by putting your thumb over each plug hole in turn as someone cranks the engine, if something is seriously wrong you may detect a difference?

Plug colour may lead you to suspect a particular cylinder, or try running engine and pulling off one plug lead in turn if engine is "rougher" that cylinder is working, if "chuffing" stops then that's the one that's passing. Don't leave off for long or you'll flood that cylinder (well insulated pliers are handy).

[Barkychoc]

It's a 2.8 S1 so mechanical injection.
I'd either pull a lead off the fuel pump or take the fuse out if you can figure out the right one.

Do a compression test and go from there.

[greymrj]

The disabling of the fuel injection shouldnt really be necessary before using a compression tester, provided you do not provide a spark source as well! But certainly disconnect a low tension lead to the coil...whatever you do do not rely on disconnecting a high tension lead....these cars have spark attenuators and you can suddenly get a big spark direct from the coil.

[greymrj]

Just wondering how you got on and what the diagnosis was?

[cnprior]

Hello All – I know this post is nearly a year old – but lot’s happened since the original post!
I decided that I needed more room to work on the TVR properly….therefore having saved up for nearly 8 years I finally submitted building plans drafted by me to the council and got refused !.....So had to fork out for a professional architect and eventually got them passed and built a bigger garage !!

Now got the space, so back to the task at hand !
I want to do a compression test on the V6 2.8Litre S1 as suggested below…..I bought a Sealey compression tester, and have an assistant coming tomorrow night to help me – but wanted to write down what I am planning to do for your guidance and input…..bear with me !

Compression Test instructions suggest:-
1) Run up car to normal temperature
2) Stop engine and disconnect ignition system (greyMrJ – suggests removing LT wires…..these are the two going to the coil –right?......I had also thought of removing the HT lead from the coil to the distributor…..to make sure there are no sparks at all – thoughts please?
3) Instructions don’t mention anything about isolating the fuel system (although other web articles do say to do this)……greymrj – suggests don’t bother…….any other thoughts?
4) Remove spark plugs completely
5) Screw in compression tester
6) Remove air filter
7) Compression tester instructions then say “set the throttle plates to the wide open position……..I interpret this as “get an assistant to crank over the engine whilst having his foot flat to the floor” – can someone confirm this is what it means please !
8) Crank engine for 5 strokes – recording values
9) Repeat test
10) Unscrew adaptor and move to the next cylinder
It’s been a long time waiting for the build to be finished and to get the chance to work on my car again – Very Exciting !
Look forward to hearing from you.

Regards,

Chris

[Loach1]

Chris, you seem to have a plan. The only comment I have is that I would disconnect the purple fuel pump relay to avoid a smelly mess.

Good luck, and remember a low number is most likely only a valve clearance problem.

David

[greymrj]

A few more notes may help:

Oily fumes being forced out under pressure is obviously not good news. You have to ask yourself where is the pressure coming from and and where is the oil coming from.

Plugs: When you take the spark plugs out make sure to note which cylinder each came from and look for one which is different in colour. My guess is that one will be darker and wetter than the others. If so that is almost certainly the problem cylinder and that cylinder is burning oil and you will need that head off to determine what is wrong. If you are lucky and find all the valves the same then I would be looking at the breather system and possibly looking inside the rocker boxes to see if there is any strong evidence of a blow back as a result of an exhaust valve failure (in this case the oil vapour is being pressurised by exhaust gasses leaking past the valve into the rocker box).

Compression test; Yes, no problem taking off all the coil leads. I also agree with Loach1 that taking out the fuel pump relay (or disconnecting the pump) will prevent any petrol vapour being produced.

I am not sure I would bother with the air filter on your K Jet system, but I would just use a bit of wire to hold the throttle open.

You are not looking for an absolute pressure reading. What you are looking for is the compression tester to show you which cylinder is different, and I suspect the difference will be quite marked. If one shows as very different then that head will have to come off.

Keep us posted.

[cnprior]

Hello All,

Well - an interesting evening.

Warmed car up to normal temperature. Discnnected ignition and removed spark plugs.

Fitted compression tester and got the following readings:-

Viewed from the front of the vehicle - Left Hand Bank of 3 cylinders:-
Cylinder 1 - 140 PSI
Cylinder 2 - 130 PSI
Cylinder 3 - 135 PSI

Viewed from the front of the vehicle - Right Hand Bank of 3 cylinders:-
Cylinder 4 - 120 PSI
Cylinder 5 - 40 PSI
Cylinder 6 - 95 PSI

So it looks bad for the right hand bank........my next course of action would be to adjust the rockers and see if this had any effect?

If not, then I would remove the right hand head of the engine......

Advice appreciated.......Many Thanks !!

Regards,

Chris

[phillpot]

.......my next course of action would be to adjust the rockers and see if this had any effect?
[/quote]


Optimistic in my opinion!

Unless some one has made a complete "pigs ear" of adjusting the valves!

Valve clearances on a pushrod engine would normally open with wear/use rather than tighten to the point of holding a valve open?

[tvrgit]

phillpot said:

cnprior said:

.......my next course of action would be to adjust the rockers and see if this had any effect?

Optimistic in my opinion!

Unless some one has made a complete "pigs ear" of adjusting the valves!

Valve clearances on a pushrod engine would normally open with wear/use rather than tighten to the point of holding a valve open?

I agree with Phillpot here - it's unlikely to just be valve clearances unless somebody has seriously botched them before.

Those fumes are definitely "pulsing" at engine speed though, and that would suggest that you have "piston blow-by". The only other ways that I could think of, for the rocker cover to be pressurised in pulses like that, would be a crack in the cylinder head from the cylinder to the valve case, or seriously worn exhaust valve guide, although that itself wouldn't affect compressions, unless the valve was also sticking open.

Low compression readings on two adjacent cylinders normally suggests cylinder head gasket, or a crack in the cylinder head.

My next step would be to put a spoonful of oil into each cylinder on that bank, and repeat the tests. The oil would temporarily "seal" any bore scoring or worn rings, so the readings would rise if that was the problem. If the readings don't rise, then you're looking at the top end (cylinder head/valves) as the problem.

You can buy "block testers" that can detect such cracks or head gasket failure, BUT ONLY IF they result in hydrocarbons reaching the cooling system. Not all such cracks do affect the cooling system though, so again, that test isn't necessarily conclusive.

You could also try running the car with that rocker cover removed (you'll have oil splashing everywhere so don't wear your best tux while doing this!) and see if you can spot where any fumes are coming from, concentrating around the cylinders with low readings. Make sure that the valves and rockers are moving to the same "rhythm" and by the same amount on all 3 cylinders. You'll see (and hear) if a valve is sticking open.

You didn't mention the condition of the spark plugs - were they all clean, were they all the same, were any of them black?

(Edited to correct (Phillpot's) formatting!)

Edited by tvrgit on Thursday 17th July 07:57

[phillpot]

tvrgit said:

(Edited to correct (Phillpot's) formatting!)

It was late, but at least we agree!