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Compression low in 2 cycl, any additives...bad rings?


n boost

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Asking on behalf of my mate whos run around e36 bmw is running low on power but doesnt smoke.

Did a compression test and 2 cyclinders were down to approx 120 psi each while the others had approx 170 psi.

Added a cap full of oil to do a wet test and the compression shot up to 150 and 168 psi for the 2 low cyclinders.

So i assume this is down to bad/worn rings?

 

Question is: He can't afford to fix the problem right now and wanted to know if their are any additives he can add to restore the compression ?

 

He knows this will only be a temp fix but he needs a couple months to get his bonus, when he will put another engine in.

Also if u squirt oil down the cyclinder to raise compression (wet test)....will this make the car smoke afterwards at all?

 

If he added a cap full of oil in each bad cyclinder, how long would the higher compression achieved last?

 

Thanks in advance.

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Yep, sounds like a ring / bore problem.

I've seen various products that say they help to improve cylinder sealing, usually available at Halfrauds but as to whether they actually work...

I have heard, and I shudder as I say this, of people using Jif cream cleaner squirted into the inlet whilst the engine is running to de-glaze the bores if that's the issue, but there's no way in he'll I would try that on anything worth more than £50.

His oil trick will last approximately 0.001 seconds or less when he starts the engine as it will pretty much instantly burn off.

He may find that although down on power, if he takes it steady it might last until he gets his bonus. But these things do tend to get worse exponentially.

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As said above, if its the aluminium block pre march 97 then it'll be the nicoseal coming off the bores and nothing you can do, i almost bought one but luckily spotted the engine hadnt been replaced by BMW so ran off :D

 

Be wary as apparently a lot of the engines were replaced but with the same engine so if your mate does replace it he could be buying the same problem !!

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Thanks for the advice guys, will relay the info on to him.

Car drives ok but is slow on cranking to start it up...........sounds like battery isn't powerful enough, so he doesn't want it to not start 1 day as he needs it for work which is a 60 mile round trip for him.

Will tell him to pop into halfruads to see if they have anything.

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I really wouldn't bother, he may go from needing new rings to a scrap engine which would be much move expensive. Running with a cylinder down is never good as the engine is fundamentally unbalanced.

 

My advise would be to sort a loan out to fix it until his bonus comes through or a cheap run about.

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I really wouldn't bother, he may go from needing new rings to a scrap engine which would be much move expensive. Running with a cylinder down is never good as the engine is fundamentally unbalanced.

 

My advise would be to sort a loan out to fix it until his bonus comes through or a cheap run about.

 

 

If its the nicosealed aluminium block the engine is scrap and cant be fixed.

 

If not then yes running it dragging round 2 cylinders isnt advisable

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