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| blowing smoke https://www.ausmini.com/forums/viewtopic.php?f=2&t=24408 |
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| Author: | hbr [ Fri Nov 03, 2006 12:34 pm ] |
| Post subject: | blowing smoke |
When I take off quickly in first, from the lights, I can notice a puff of smoke. Also, when I am running on back pressure, e.g. down a hill, and then I accelerate it blows smoke. Apart from that I can not notice it. What do you think could be the issue? I have been advised it is the rings but not to worry until it gets worse. I'd prefer to fix it rather than be reported, although it is good for tailgaters. I have been searching but not found an obviously related issue. Thanks in advance for your knowledge. |
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| Author: | pristic [ Fri Nov 03, 2006 12:47 pm ] |
| Post subject: | |
Could be the valve stem seals. If you are driving, does it blow smoke constantly or only under load? Does it blow smoke ONLY when you start at the lights and down hill or when cruising? What colour is the smoke? Is it just smoke or does it feel like its missing too? There are other posts about this, one recently, look up smoke rings valve ine the search 
Especially this one: http://www.ausmini.com/forums/viewtopic.php?t=24321&highlight=smoke+rings+valve Cheers, Peter |
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| Author: | GT [ Fri Nov 03, 2006 12:49 pm ] |
| Post subject: | |
yea....from your description it's valve stem seals me thinks. |
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| Author: | hbr [ Fri Nov 03, 2006 1:01 pm ] |
| Post subject: | |
When I back off....then accelerate it blows a cloud then it seems ok. colour is blue. engine runs fine. Plenty of power. |
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| Author: | pristic [ Fri Nov 03, 2006 1:04 pm ] |
| Post subject: | |
hmm, I reckon its the valve stem seals... did you read through the link I sent? Try the last post as advice... Quote: Could be rings, could be valve stem seals. To find out which is which, run the engine about 3000 revs for 15 to 20 seconds, if there is constant blue smoke, it will most likely be rings, if there is no smoke while you are doing this give it a couple of pumps with the accelerator and then if you have smoke, its the valve stem seals. Compression test is the way to go to get accurate diagnosis, this is just a general idea of what you may be up for.
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| Author: | hbr [ Fri Nov 03, 2006 1:40 pm ] |
| Post subject: | |
Yep have read that post. I will try the rev test this evening at work...my neighbours don't appreciate the sweet sound of a large bore mini exhaust... I did a compression test a few months ago (no more than 1000Km's) and had ~150PSI across all 4 cylinders. I'll advise the outcome of the 3k test later tonight. |
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| Author: | pristic [ Fri Nov 03, 2006 2:27 pm ] |
| Post subject: | |
hbr wrote: Yep have read that post.
I will try the rev test this evening at work...my neighbours don't appreciate the sweet sound of a large bore mini exhaust... Remind them they have every right to move  You'll help them pack
You can be noisy until 10pm I believe (depends on area, etc) Im good to my noisy neighbours (they party alot) ... I only snap if they wake the baby... then I let them know it aint on. Peter. |
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| Author: | Mike_Byron [ Fri Nov 03, 2006 3:24 pm ] |
| Post subject: | |
There is a couple of diagnostic characteristics here. Smoke from worn rings will occur at lights, under load and with the application of throttle at the bottom of a hill or a period of trailing throttle. Slight smoke can often be seen at any rev range. Valve guide wear is characterised by smoke at take off or after periods of idle but then clears. The only clear way to accurately test for rings is with a compression test without and with oil in the cylinders. Don't rush into a remedy unless you are rich. It means an engine strip down and costs. Mini almost never allow just a re-ring. The bores almost always wear tapered and require a rebore and oversized pistons - there is $400 just for that !!! |
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| Author: | Morris 1100 [ Fri Nov 03, 2006 3:54 pm ] |
| Post subject: | |
The thing with rings is the compression rings can be Ok but the oil rings can be shagged, this means the compression will be fine on the gauge but it will still blow smoke. My guess is the valve stem seals. The standard seals are crap and will die quickly. |
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| Author: | hbr [ Fri Nov 03, 2006 4:03 pm ] |
| Post subject: | |
I'll try the with/without oil compression test tomorrow...dependent on whether Brisvegas gets the forcast rain. I'm not rushing for a solution...but changing valve stem seals is simpler than a rebore 
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| Author: | Mike_Byron [ Fri Nov 03, 2006 4:23 pm ] |
| Post subject: | |
Yes - it a lot cheaper but I think you will find its valve guides rather than valve stem seals. But .... for about $250 you can have the guides, seals, chemical clean, surface skim and .. best of all ... unleaded exhaust valve seats al the valves reseated. . |
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| Author: | hbr [ Fri Nov 03, 2006 4:36 pm ] |
| Post subject: | |
The current head was rebuilt 2.5 years ago. Less than 7500 Km's ago (A guess as tacho doesn't tell me how many km's I have travelled). Hardened seats were added then. I expect that the guides were replaced then, along with new valves and iskenderian double valve springs. Mind you the head had a crack welded (it only had one crack the previous head had three). The car had buggered twin 1.25's rebuilt the start of this year and 43d4 distributor recently improved to pertronix. Has been tuned and runs better now. could being out of tune, with too much advance have caused the smoking issue? |
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| Author: | Mike_Byron [ Fri Nov 03, 2006 4:51 pm ] |
| Post subject: | |
Ummmm..... probably not caused by poor tuning. There are valve guides and valve guides. Some of the cheaper ones have a very fast wear rate. As a rule of thumb, its prbably better to buy a set of good competition type valve guides such as off a mini metro turbo or maganses bronze type. When you ultimately take the head off - without the valve springs in place, if you can move the valves from side to side in the guides then the guides are worn. It only has to be perceptable movement for the oil smoke to show. I have no doubt the seals have worn - the rubber cup type are infinately better than the "o" ring type, however, worn seals and good guides will not give the smoke that is being described. |
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| Author: | hbr [ Fri Nov 03, 2006 9:58 pm ] |
| Post subject: | |
OK tried the 3k rpm test... unfortunately it was a bit windy so I'll try again with an assistant. I didn't notice any smoke when rpm held at 3k. Although I could notice smoke when I pulsed the accelerator...which from consensus points to valves... More testing tomorrow 
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| Author: | Spaceboy [ Fri Nov 03, 2006 10:30 pm ] |
| Post subject: | |
try a thicker oil
what are you running now? |
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