3.5 9.75:1 Puffing blue smoke

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Prophead
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3.5 9.75:1 Puffing blue smoke

Post by Prophead »

I got the car back on the road a few weeks back after pretty much rebuilding everything except the engine, because I had no reason to mess with it. Anyway, to get my car finished up and to a show I used TripleQX 20/50 Premium mineral oil when I changed the oil (instead of waiting for delivery of my usual VR1 Racing oil), filter changed at same time, and I also flushed with Wynns Engine oil cleaner and topped up with Wynns protection additive. All was fine and engine running great for over 200miles of road use. I then took the car for a track-day (as it is a tack-day car) and again all was fine engine wise until the last couple of laps of a 10 lap stint. I personally didnt notice anything from inside, couldnt see the smoke or notice any change in the engine, but my friends they started to see it puffing blue smoke when I was decelerating for the hairpin (and their pictures confirmed this). I have also had someone follow me on the road and they also confirmed that it is puffing wisps of blue smoke. Naturally I am a bit concerned as it's never done this before.

When it first happened on track it was a hot evening with ambient temp about 25deg and track tremp +40deg. So, the engine was running constantly at 100deg coolant temp, which is high but not excessive. I'm wondering - and hoping - that the puffing blue smoke is down to the new oil just not being up to the task and has broke down, rather than me having physically damaged the engine.

I try to shift gears before 5500rpm when on track (just to try to protect the engine, as its for fun I'm not racing) but occasionally it might be 5700 or 5800, but never over 6000rpm.

I have checked the plugs, none are showing sings of oil burning, which I thought was odd. I do have quite a lot of black sooty deposits around the exhaust tip, and over the back of the car. I had the rocker covers off and turned the engine over to see if there was any obvious physical damage but none found.

My crank breather is open, TVR style tall flame trap with a filter on top, I've noticed since the smoking started that there are a lot more vapors and oil droplets.

Advice and guidance welcomed. Although I've had the car for 2 years I've only driven it for about 1000miles so still getting to know and learn about this engine.

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Re: 3.5 9.75:1 Puffing blue smoke

Post by russell_ram »

Oil smoke on over run (and just as you go back onto throttle) is normally valve guides/valve stem seals. You don't say what your valvetrain is, but if you have the old umbrella washers then they will have (broken up and) fallen off - completely normal for an old RV8 especially if you're running a bit hotter than usual road use.

Does it puff a whiff of smoke on first start from cold?
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Re: 3.5 9.75:1 Puffing blue smoke

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russell_ram wrote:
Tue Jun 26, 2018 6:23 am
You don't say what your valvetrain is, but if you have the old umbrella washers then they will have (broken up and) fallen off - completely normal for an old RV8 especially if you're running a bit hotter than usual road use.

Does it puff a whiff of smoke on first start from cold?
Standard SD1 heads and valve train I believe.

From the research I've done and observation I'm starting to think it is the valve stem oil seals. Not seen smoke on start up yet, but I have to be in the car to start it. It does seem to smoke on hard acceleration and after being off throttle and engine breaking eg downhill to a stop, then clears again after a bit.

Before I dive into it I will get a compression checker and check the compression just to be sure.

If it is valve stem oil seals:-
1. Is it a possible DIY job to replace them?
2. Do I have to remove the heads or is there a method for doing on the car? presumably I would need a particular type of spring compressor to do this.
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Re: 3.5 9.75:1 Puffing blue smoke

Post by DaveEFI »

My experience of worn RV8s is that if you do have piston etc wear, you're likely to get oil leaks through excess blow-by pressurizing the crankcase. So valve stem seals are the most likely. Which won't show up on a compression check.
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Re: 3.5 9.75:1 Puffing blue smoke

Post by sidecar »

Prophead wrote:
Tue Jun 26, 2018 9:15 am
russell_ram wrote:
Tue Jun 26, 2018 6:23 am
You don't say what your valvetrain is, but if you have the old umbrella washers then they will have (broken up and) fallen off - completely normal for an old RV8 especially if you're running a bit hotter than usual road use.

Does it puff a whiff of smoke on first start from cold?
Standard SD1 heads and valve train I believe.

From the research I've done and observation I'm starting to think it is the valve stem oil seals. Not seen smoke on start up yet, but I have to be in the car to start it. It does seem to smoke on hard acceleration and after being off throttle and engine breaking eg downhill to a stop, then clears again after a bit.

Before I dive into it I will get a compression checker and check the compression just to be sure.

If it is valve stem oil seals:-
1. Is it a possible DIY job to replace them?
2. Do I have to remove the heads or is there a method for doing on the car? presumably I would need a particular type of spring compressor to do this.
There are ways of removing the valve springs whilst the heads are still on the block, you can force rope down the spark plug hole then gently turn the engine over to TDC, or you can use compressed air. The thing is I don't think that the standard 'old' valve guides can use any decent form of valve stem oil seal and using the umbrella type of seal is a total waste of time because they are useless.

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Re: 3.5 9.75:1 Puffing blue smoke

Post by Prophead »

DaveEFI wrote:
Tue Jun 26, 2018 9:58 am
My experience of worn RV8s is that if you do have piston etc wear, you're likely to get oil leaks through excess blow-by pressurizing the crankcase. So valve stem seals are the most likely. Which won't show up on a compression check.
Thanks Dave. I think you are probably correct, no oil leaks but then I've not done much mileage either since it started puffing smoke. Was going to do compression check if only to rule it out (and out of curiosity).
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Re: 3.5 9.75:1 Puffing blue smoke

Post by Prophead »

sidecar wrote:
Tue Jun 26, 2018 10:33 am
Prophead wrote:
Tue Jun 26, 2018 9:15 am
russell_ram wrote:
Tue Jun 26, 2018 6:23 am

The thing is I don't think that the standard 'old' valve guides can use any decent form of valve stem oil seal and using the umbrella type of seal is a total waste of time because they are useless.
Would these be what Rimmers refer to as 'tap washer type' seals? From what I can ascertain these SD1 heads (pre 1994) only have a an oil seal on the inlet guide. If these are useless, where does that leave me? Presume then that I would have to have all newer style guides fitted in order to have the better later style oil seals.....I know where this could end up! a full head rebuild / upgrade, no point spending all that time and money if i'm not going to get any more gee gees from it :lol:
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Re: 3.5 9.75:1 Puffing blue smoke

Post by SimpleSimon »

Oil smoke after prolonged over-run closed throttle is no certainty down to worn guides or valve stems seals :| dont forget vacuum is highest here and oil can be vacuumed just as easily past piston rings also especially if the oil control pack as seen better days or choked with carbon
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Re: 3.5 9.75:1 Puffing blue smoke

Post by Prophead »

Think I have now found the primary cause of my smoke issue, looks like the intake valve guide seal has slipped down the guide, it's the old 'washer' style seal. It also happens to be on the cylinder that was slightly down on compression as well. I've had a bore scope in there and naturally there is quite a bit of carbon build up:-
a) could this carbon / oil residue caused the rings to gum up and cause the lower compression result on that cylinder?
b) will this carbon burn off / clear up once the seal is replaced or will I have to take further action?
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Re: 3.5 9.75:1 Puffing blue smoke

Post by Darkspeed »

100C may not be excessive for a modern engine but its way outside the comfort zone for a Rover engine.
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Re: 3.5 9.75:1 Puffing blue smoke

Post by DaveEFI »

On my SD1 EFI, 100C is midway on the dash gauge, which I'd guess means this is normal under certain conditions like slow heavy traffic. However, the EFI coolant sensor which is in a different place to the dash one always reads lower than the dash one. On the open road, something like 90C is the norm, given the 88C thermostat.
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Re: 3.5 9.75:1 Puffing blue smoke

Post by Prophead »

DaveEFI wrote:
Sun Jul 22, 2018 8:25 am
On my SD1 EFI, 100C is midway on the dash gauge, which I'd guess means this is normal under certain conditions like slow heavy traffic. However, the EFI coolant sensor which is in a different place to the dash one always reads lower than the dash one. On the open road, something like 90C is the norm, given the 88C thermostat.
I have very similar figures 85-95C on the open road depending on ambient temperature, and that with running Evans Powercool which I believe tends to have a 'normal' temperature approx 5C above water based coolant. From what i have read from various sources this is a very normal and standard range.
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Re: 3.5 9.75:1 Puffing blue smoke

Post by Prophead »

Update...

I ruled out, for now, the valve stem seals as after careful inspection they are all present.

I managed to get a bore scope into to the cylinders to have a look and number 8 (which had the lower compression test result) had significantly more carbon build up and looked a bit wet with oil around the outside of the piston. The other pistons had carbon build-up but not as much as no8. My hypothesis is that carbon fowling has lead to 'sticky' rings on no8, which has then caused oil vapor to get sucked past when the engine is hot and on overrun (it never smoked at idle or from cold).

Before taking drastic action I have
a) changed the oil back to VR1 racing
b) had the engine hydro carbon cleaned

I've done about a 100miles since with some fairly hard driving, on over-run down hill, hard acclerations after ect and so far no puffs of blue smoke. I've done another compression check and no8 has improved by 8% in relation to the average of the other cylinders putting it within 8% of the best cylinder and 7% of the average. So for now am reasonably happy that the rings aren't broken.
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Re: 3.5 9.75:1 Puffing blue smoke

Post by unstable load »

Prophead wrote:
Fri Jul 27, 2018 8:45 am
Update...
b) had the engine hydro carbon cleaned
What does that involve, please?
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Re: 3.5 9.75:1 Puffing blue smoke

Post by Prophead »

unstable load wrote:
Sat Jul 28, 2018 2:40 am
Prophead wrote:
Fri Jul 27, 2018 8:45 am
Update...
b) had the engine hydro carbon cleaned
What does that involve, please?
have a look at this site, should answer your question
www.enginehydrocarbonclean.co.uk
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