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No Compression On 1,2 & 4. 998 1988


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#1 Dan 998

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Posted 11 January 2020 - 12:53 PM

Hi all, I have a 1988 998 city. Got picked up today! I bought it with an engine issue I suspect head gasket or possible piston and rings.

So, 1&2 have no compression both reading 0 on compression kit. 3 had good compression and 4 has low compression. I don’t have water and oil mix.

It does start but willingly tick over will not drive.

Anyone had this kind of problem before?

Appreciate any help thanks Dan!!

#2 dyshipfakta

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Posted 11 January 2020 - 01:27 PM

Head gasket is my bet

#3 wile e coyote

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Posted 11 January 2020 - 01:30 PM

I'm astonished it will run at all ...it certainly shouldn't with zero comp on 2 cylinders must sound dreadful  - as a quick check take the rocker cover off and with a chunk of wood give all the valve caps a good knock - then check the valve clearances.

If all ok check the torque on the head if that doesn't show an issue it's head off and have a squint....



#4 Dan 998

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Posted 11 January 2020 - 02:04 PM

Thanks guys new to the world of minis!!

Looking forward to getting stuck in.

Yes runs rough only had it on idle, will get to it next weekend!

I will take a look at valves etc before getting the head off just in case!

Dan

#5 DeadSquare

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Posted 11 January 2020 - 02:15 PM

I'd  remove the 1&2 plugs and leave it as it is.

 

You'll get fantastic MPG, Lol.



#6 Rorf

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Posted 11 January 2020 - 03:14 PM

As coyote above says remove rocker cover but also turn engine over to see what happens as each valve goes up and down. Might have shot valve springs or valve guides. Poor some oil into each spark plug and do the compression test again.

 

First port of call is head off.

 

Do you have the mechanical ability to remove and possible strip this engine apart?



#7 Twincam

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Posted 11 January 2020 - 03:30 PM

Has someone started removing the head and not tightened it back down?

I'd pull it off in any case to see what the issue is and go from there.

#8 Homersimpson

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Posted 11 January 2020 - 03:45 PM

It interesting that you have no compression at all on two, when I have had headgaskets fail between cylinders I still got something but not much (around 30psi).

 

The last car I had with none had a badly bent valve.

 

As above I would have the head off and have a look.



#9 Moke Spider

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Posted 11 January 2020 - 06:25 PM

Also check the Tappet Clearances. It might be getting Valve Seat Recession, particularly on the exhausts.



#10 gazza82

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Posted 11 January 2020 - 11:44 PM

I had a 1098 Midget that ran on just 1 & 2 ... not well though. That had 2 burnt exhaust valves ...

#11 Dan 998

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Posted 18 January 2020 - 05:47 PM

Evening all,

Head is off! Found the head gasket gone between 1 & 2.

So will look to put it all back together next weekend once I have a new gasket kit.

Anything else you think I should check while head is off?

Dan

#12 dyshipfakta

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Posted 18 January 2020 - 05:54 PM

Worth cleaning up the head and abit of paste on the valves see how it looks.

#13 Dan 998

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Posted 18 January 2020 - 07:08 PM

Thanks, I’m checking valves now at the kitchen table! (Wife isn’t to happy!)

I have a box for spares from when I bought the car and there is a head gasket kit there. And it’s the same! Only question I have is what way up? One side is black other is metal?!?

Dan

#14 croc7

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Posted 18 January 2020 - 07:48 PM

The head gasket should have the words "TOP" and "FORWARD" embossed on it.  TOP would then be obvious, FORWARD is toward the radiator/fan.  If you can't confirm how it should be installed, buy a good copper one from Mini Spares.  Make sure to give the mating surfaces on the head and block a good clean and might not be a bad idea to check the head and block for flatness using an appropriately sized steel ruler.


Edited by croc7, 19 January 2020 - 04:39 AM.


#15 DeadSquare

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Posted 18 January 2020 - 10:42 PM

There is a little hole in one corner of the gasket for the oil to pass from the block to the head.






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