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norried

Active Member

• Feb 7, 2019

• #1

Compression test results.
Ok I've got a bit of a misfire and done a.compression test it's a 2.25 petrol. I'm getting 130,100,120,130. Now I'm hoping it's just a burnt valve that's causing my low.compresion on No2 cylinder. Apart from an endoscope or taking the head off is there any way of telling if it's a head or piston problem?
Also I've had a quote to get the head refurbed so new guides and seats plus a skim and been quoted £300. Does that sound Ok? That was only new exhaust seats as they reckon the inlets don't normally need done.
Thanks.
Norrie

 

Flossie

Well-Known Member

• Feb 7, 2019

• #2

Teaspoon of oil down the plug hole, comp improves? Piston,bore,rings.
No change? Valve, head gasket.
They all seem a little low to me but it's been yonks since I messed with petrol engines so I could be wrong.

 

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Old Seadog

Member

• Feb 7, 2019

• #3

Might be a good chance to bite the bullet, take a firm hold on your wallet and get it converted to unleaded, if you've not already done that.

 

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norried

Active Member

• Feb 8, 2019

• #4

Good idea about the oil. The £300 IS including new seats so not too bad
Norrie

 

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suburban

Well-Known Member

• Feb 8, 2019

• #5

iirc anything less than 120 is supposed to be bad.

guess it depends how good your tester is i.e. how close the readings are to what the pressure is. I just have a cheapo tester so I don't pay too much mind to the actual values but look for one that is significantly different from the others so in your case two and possibly three.

 

tottot

Well-Known Member

• Feb 8, 2019

• #6

I agree with what the others above say,do the oil test.