Jump to content

Fumes in engine bay


Recommended Posts

My engine was rebuilt in 2006 and then sat waiting to be fitted into my car while I got around to putting everything back together, so the engine hasn't been run for any length of time since.

I've been moving the car between the garage and the drive and each time had problems with cold starting, resulting in having to crank over the engine for about 4 or 5 attempts before I got very rough idling. The exhaust was spewing out a thick oily smelling smoke while on idle. At the weekend I adjusted the butterflys on the throttle bodies and lo and behold the old gal started on first turn of the key with very little choke, ticking over at about 1100 rpm. The exhaust smoke was gone completely and all seemed well, other than the high tick-over.

I got my timing strobe out and found the timing was quite a bit advanced, so started to retard it. The revs increased to about 1500 rpm and after five minutes I got fumes from within the engine bay (I thought this was steam initially, so shut the engine off and checked the temperature gauge, which had only just started to move). I put my hand on the radiator and it was still cold as well. I've not lost any water from this, although I've noticed a bit of mayo on the radiator cap. The smell in the engine bay (and all over my clothes, much to the annoyance of SWMBO) was very similar to the smell from the exhaust before I closed the butterflies.

I'll leave going back to revisit the timing and revs issue for another weekend, but just wondered if there's anything I should be worried about, or looking into further before I start her up again?

Also, on the air flow adjustment screw, does it screw in for more air, or screw out? It's currently screwed all the way in.

Thanks,

Steve

Link to post
Share on other sites

Steve,

I guess from your post you have an injected Pi. When the butterflies are adjusted it is typical that the engine will stall from lack of air with the large air admittance screw fully in.

The engine will be getting air from somewhere to keep running and unless you have fitted a screw in the stops to keep the butterflies open a little then you will have an air leak somewhere.

If all was well then there are a number of places that can leak but as you mention a smell I would firstly look at the inlet / exhaust manifold. If that is leaking you would also be getting the exhaust fumes in the engine bay. Did you fit a Payen manifold gasket such as this?  https://www.ebay.co.uk/itm/TRIUMPH-TR6-2-5-Manifold-Gasket-Inlet-Exhaust-72-to-74-CF1-Payen-Quality-New/233164433299?fits=Model%3ATR+6&epid=1843356634&hash=item3649aee793:g:pm0AAOSwkR9ch40H 

 I find my TR6 Pi will tick over on two cylinders with an air leak / bad-adjustment the remaining four cylinders running extremely rich (and smelly).

TR6 butterflies are an absolute pain to set correctly and there are several different throttle shafts and adjusters available which all make the task easier than the originals.

I am surprised that with the engine running for five minutes the radiator is still cold, mine is rather warm after five minutes.

 

Alan

Edited by barkerwilliams
Spelling - must try harder!
Link to post
Share on other sites
5 minutes ago, barkerwilliams said:

Thanks for this Alan. The mechanic I had doing my rebuild transpires didn't do exactly as I was expecting and carried out some work that required removing before other jobs could be done. I thought this gasket was fitted, but have noticed that gasket is in the box of spare parts (although I'm not sure if I gave him two in the first place - don't ask, but I did duplicate some purchases!!). Am I right in thinking these fit a certain way as well?

There's no screw stops, and the butterflies snap to at the minute, so I suspect you're right there's an air leak from somewhere. I think, to be on the safe side I'll strip down the manifolds and check there's a gasket there in the first instance.

Link to post
Share on other sites

Hi Steve,

You should be able to see/feel the gasket as it is quitte thick.

If there is one, first retighten the nuts holding the TB’s and exhaust manifold, both below and above the TB’s.

If you retard ignition, the revs will go up at idle, that is my experience too.

Have you checked for leakages from the usual places? Rubber tubes between TB’s, brake servo, MU hose?

Are you sure all 3 TB’s are really fully closed when throttle is “loose”?

Opening the air idle valve will increase RPM.

Regards,

Waldi

Link to post
Share on other sites

Steve,

You ask if the gasket fits a certain way around, I would like to answer that question a slightly different way by not answering directly.

The more I see of classic cars the more I see parts that do not fit, as in do not fit at all. Parts that are a close approximation but to all practical purposes are rubbish. The number of times I buy a new item then end up refitting the old item as the new one is a worse fit /poorer quality. arrrgh.

So now I do not just fit gaskets (or any thing else), I firstly offer the gasket up and check for alignment between the gasket and the metalwork on both faces, it is surprising how often there are discrepancies.

So my advice is every time you pick up a gasket - check in every orientation you could fit it, it's a good habit to develop. Don't rely on what a man said on a forum.

 

Alan

 

Link to post
Share on other sites
5 hours ago, Waldi said:

You should be able to see/feel the gasket as it is quitte thick.

Thanks Waldi. I've got a few photos of the intake manifold from the top and the side and it looks to me like there's a gasket there.

side of manifolds.jpg

top of manifolds 2.jpg

top of manifolds.jpg

Link to post
Share on other sites
5 hours ago, barkerwilliams said:

So my advice is every time you pick up a gasket - check in every orientation you could fit it, it's a good habit to develop. Don't rely on what a man said on a forum.

 

Good advice all round Alan

Link to post
Share on other sites

I've also seen some residue as shown on the photo. I wonder if this is what was dropping down onto the exhaust manifold and causing the smoke I was getting. The next question is what is this likely to be, water? fuel? oil?

I wiped my finger on the area, and it doesn't have any particular smell to it but feels a bit "greasy"

residue.jpg

Link to post
Share on other sites

I'm in the same boat Steve, Air seems to get in from everywhere, my butterflies are still an issue but I have managed to get the air bleed screw open and now idling at around 800. Waiting on a air flow meter. 

I had air being pulled in from brake servo take off, butterflies obviously, I've even changed the o rings on the plastic manifold sleeves the injectors fit in, nice fit now. I had air being sucked in via the tubes that connect the manifolds, new tube that was expanding when hot. 

I found with engine running if you put the palm of your hand over the manifold port if leaking it will cause a vacuum. 

I've had to wash my cloths several times over the last week also:). 

Good Luck Mark

Edited by Mark69
Link to post
Share on other sites

Hi Steve,

yes, there is a gasket.

most likely source of oil is the rocker cover  (if it is oil leakage). Burning oil will give blue smoke, not black, and smell different from unburnt fuel, which is black.

clean the engine thoroughly, this makes detection of leaks easier.

have you checked the 6 butter flies when idling with a flow meter? This will reveal if they are all closed. You should see low and more or less the same readings.

Can you turn the rubber connecting tubes easy, i.e.are they loose? This would give air leakage.

Good luck, you will find it.

Waldi

Link to post
Share on other sites
11 minutes ago, Waldi said:

have you checked the 6 butter flies when idling with a flow meter?

Can you turn the rubber connecting tubes easy, i.e.are they loose?

Hi Waldi

I haven'tused a flow meter yet, and the rubbers aren't a tight fit so are probably letting air in

 

Link to post
Share on other sites

Hi Steve,

to replace the rubbers you will have to remove the TB’s.

I would first install jubilee clips on them (open them, bend open, then wrap around the hose and tighten), it may be enough. 

If not, I would then check the butterfly flows.

Waldi

Link to post
Share on other sites
14 hours ago, Mike C said:

Have you checked your idle vacuum? I know my engine must have 10  inches Hg at idle , been this for decades, any less and I've got a leak.

Mike, I've not checked yet. As soon as I saw what I thought was either steam or smoke I panicked and decided to consult the oracles on here for advice. I was expecting the worst but I'm now more hopeful of a not-too-expensive solution

5 hours ago, Waldi said:

I would first install jubilee clips on them (open them, bend open, then wrap around the hose and tighten), it may be enough.

I like you're thinking Waldi. I'm going to strip down the air plenum chamber and have a closer look at the TB throttle bodies. I'm pretty sure I've got new rubber pipes to replace the ones fitted so I've got a couple of options. I just need a few hours to look at this now, which might be a couple of weekends away

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.