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I need to know if my pistons have gone!


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First things first ive done a compression test and all four cylinders were 160psi bang on witch ive been told pretty much rules out the piston ring's! My car is burning a small amount of oil witch I believe to be my valve seals and ive got it booked in with TD to sort that out! But with my oil cap off it smokes can this be the issue with valve seals or piston related? Also my breather smokes intermittently, I'm just concerned about it being more than im expecting as I don't really have a spare 2k at the moment!

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I went for a long drive as ive only been covering 4 miles a day to and from work witch didn't give it enough time for it to warm up(easy driving) so a couple of nights back I let it sit for 20 minutes and went for a long drive for about an hour and at first I drove it normal changing gears at 3000rpm ect then I decided to give it some beans to witch there was no smoking or oil burning I'm a bit confused I posted a video to double check and it doesn't seem to be smoking! would this be because it's had longer to warm up pistons expanding ect what's your thoughts on this? Ive got it booked in at TD but now im thinking I've been worrying about nothing! Compression results were good.

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If compression good then i would be thinking maybe some oil went though system when cold.

What oil do you use??

Try a service and keep a eye on it

Try 5w40 or 10w40

Would defo use 5w40 for these warmer months

Would check your breathers also i dont have much exp with these engines but i know a bit on turbo engines

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If compression good then i would be thinking maybe some oil went though system when cold.

What oil do you use??

Try a service and keep a eye on it

Try 5w40 or 10w40

Would defo use 5w40 for these warmer months

Would check your breathers also i dont have much exp with these engines but i know a bit on turbo engines

im using 5w30 full synthetic, my thoughts exactly with maybe going through the system when it's cold, although i'm still learning so it's good to get others views as I can be paranoid into thinking the worst! I'm going to change the oil to 10w40 and go from there thanks for the reassurance :)
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Yeah i would change to the 10/40 see how it goes.

Could be stem seals or turbo causing the smoke if compression fine

To confirm rings ok you could do a leak down test sure a garage locally can do one at ok cost.

Yeah i am still learning also on these engines but the basics are the same across all engines.

I have read theres a valve on rocker part of breather system that could fail you might of cleared that out with a long hard drive.

Turbo engines do need a beating every now and then

Edited by amatthews45
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Doing little mileage on a forged engine isn't a good idea really as you've already said the pistons don't get time to get up to operating temperature to close the gap on the cylinders which is much wider on forged pistons than stock cast pistons.



What pistons is it your using by the way?


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Doing little mileage on a forged engine isn't a good idea really as you've already said the pistons don't get time to get up to operating temperature to close the gap on the cylinders which is much wider on forged pistons than stock cast pistons.

 

What pistons is it your using by the way?

ross racing 74.5! I'm going to let it sit until its up to temperature the only thing is I start at 6:30 so I'm going to go up the road a sit in a country lane and let it warm up else the neighbours won't be pleased or get a cheap car for work!
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Ah yes Ross use one of the largest piston-cylinder wall clearences, would explain why you get a fair amount of crankcase pressure.


Do you have an oil temp gauge by any chance? If so whats the maximum it reaches on your 4 mile journey?



Would deffinately recommend getting another car or let it warm up fully before driving, the excess blow by will be hurting your oil on short journeys for sure, keep on top of your oil changes :)


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If compression good then i would be thinking maybe some oil went though system when cold.

What oil do you use??

Try a service and keep a eye on it

Try 5w40 or 10w40

Would defo use 5w40 for these warmer months

Would check your breathers also i dont have much exp with these engines but i know a bit on turbo engines

You would want to be using something like a 10w40 in the warmer weather.

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Ah yes Ross use one of the largest piston-cylinder wall clearences, would explain why you get a fair amount of crankcase pressure.

Do you have an oil temp gauge by any chance? If so whats the maximum it reaches on your 4 mile journey?

 

Would deffinately recommend getting another car or let it warm up fully before driving, the excess blow by will be hurting your oil on short journeys for sure, keep on top of your oil changes :)

I have a oil temp gauge it gets to 50-55° full temp I'd say is 70° with you saying that with regards to the pistons would that be the reason for burning a little oil? I'll save some money for a second car and till then warm mine to max temp, thanks for the advice and information adam :)
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50-55 degrees is a bit low mate. 75ish would be ideal.

Are you losing any oil on the dipstick?

Because the pistons aren't expanding to what their operating conditions the oil control ring won't be scraping the oil off the cylinder walls, giving it a chance to burn.

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I have been losing a little oil yeh! But when I ran it up to temp it seems to be fine with no loss of oil! The problem was until I decided to take for a good long drive I hadn't been driving it far as I was worried about causing damage ect but I guess now I know it's fine I'll be driving it more distance.

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Yes mate it will be fine for long distance, its quite the opposite actually with forged engines, they don't like short distances,. unless you use pistons with high silicone content that run piston-bore clearances of 0.0015-0.025 or cast pistons which don't expand as much :thumbsup:



Word of warning though pistons with high silicone content become more brittle and are more susceptible to damage through knock.


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Yes mate it will be fine for long distance, its quite the opposite actually with forged engines, they don't like short distances,. unless you use pistons with high silicone content that run piston-bore clearances of 0.0015-0.025 or cast pistons which don't expand as much :thumbsup:

 

Word of warning though pistons with high silicone content become more brittle and are more susceptible to damage through knock.

you certainly know you stuff mate, again thanks for the info and reassurance I know who to contact with anything engine related in the future :lol:
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