Got a broken down mini.

All the signs pointed to a blown head gasket. But, I just ran a compression test and they were all around 110 at each cylinder.

(Im assuming at pressures around the same value for all cylinders = good. Im unsure if 110 is ok though....)

Assuming that the above is ok....

Can dodgy spark plugs give the same effects as blown gasket ?

Spark is going to all 4 cylinders, fuel is going there. It sounds like it is running on 3, well it is running on. Plugs are coated in a lovely black crust, replacing them 2moro and see if that solves my problem.

But is it possible for compression test to miss a blown gasket ? Can a gasket blow, but still maintain pressure in the chamber ?

Any ideas ?

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No more Minis!......For now.

I reckon you're on the right track by replacing the plugs... I can't think of a scenario where the gasket would be gone without compression dropping AND without water/oil symptoms...

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did I tell you that I won a trophy?

110 is pretty low , may have a cracked head. or could be head gasket. did you have the head retorqued after 1000 km ?

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lookin for another clubby

If your going to do the plugs do new points or re set them. Possibly to close or sticking and replace the condensor at the same time as that would be my suggestion.

steve

110 is on first hit.

Rockets up to 130-140 on 2nd attempt at starting the car.

(car does start, just sounds like a VW)

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No more Minis!......For now.

have you tracked down which cylinder the problem is on?

just pull off each plug lead one at a time while it's running and yoou'll find which one is dodgy, then swap the plug from that cylinder with another one and see if the problem moves with the plug... if it does, clean the plug with a wire brush and see how it goes...

and don't be a wuss with pulling the leads off, grab the lead with your hand and pull, it won't bite you, if you're wussy about it, you'll get bitten for sure

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did I tell you that I won a trophy?

Car isnt at home atm.

Wont have plugs until 2moro arvo. So I will know by 5pm 2moro if its being towed home for me to spend 5 hours working on it.

With a blown gasket, what is the pressure reading on a guage usually ?

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No more Minis!......For now.

ones I've seen, 50 down to 0

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did I tell you that I won a trophy?

ok, cool.

Then I think i can rule out a head gasket....i hope...

Plugs were coated in a black crust, about .25mm think in some spots, really bad shape.

Ill replace plugs, lean it out abit, and up my idle speed and see what happens.

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No more Minis!......For now.

I've had this problem with my plugs a few times.. Very similar to a blown head gasket.. I usually just clean them. But now my mixture is correct and my plugs are the right temp, so it's all fine now.

Maxi what plugs are you running? Sounds like you need a hotter running set. If NGK BP6ES now, try BP5ES.
Many people recommend this for running unleaded, including the Bosch website, and GR.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.