rebuild

[cadetchris]

probably a daft question,
but would increased fuel and oil consumption, as well as a plume of blue smoke when i accelerate hard, indicate that its time for a cylinder head rebuild?

[ssnjimb]

When you accelerate hard blue smoke. Add rings to your list.

[PSL184]

that its time for a cylinder head rebuild?

Nope - a full engine rebuild

[andrew.searston]

bit more than a head rebuild unfortunatly

[cadetchris]

i believe the word is "nuts" really not what i can be doing with.
if i remember rightly, its possible to replace the rings with the engine still in, by just dropping the sump, removing the con rods and pushing them up through the block (with the head off or course)

[ssnjimb]

Hello Chris

You could try replacing the rings if you want to get a few more miles out of it. Make sure all the breather hoses are unblocked.

Change the oil cap as it is also a breather.

The oil rings could be blocked with gunk.

There is no harm in changing the oil and going from there.

Jamie

[bmcecosse]

Run a compression check on the engine. As suggested above - if you make sure one of the breathers is connected to the intake system - either at the carb or directly to the inlet manifold - it can help with oil consumption and blue smoke. Head rebuild will do nothing useful. Try rings if you wish - but - probably money down the pan.

[ssnjimb]

I have know this to happen before.

Car with oil that is black and dirty. All breathers blocked up. Dirty Air filter. Blocked dirty oil filter.

Jamie

[cadetchris]

ill do a compression check tomorrow morning, as for all the breathers, they are all nice a clear and attached, air filter is new, new oil filter and not that many drips from the bottom of the engine,
what should the compression be?

[ssnjimb]

what engine size is it

[cadetchris]

1098

[ssnjimb]

A range from 130-160 is what you are looking for. i await someone more experianced to correct me

[linearaudio]

A range from 130-160 is what you are looking for. i await someone more experianced to correct me

I reckon he's out playing "trains" tonight

[bmcecosse]

Nah - watching Scalextric! I agree - 130 would be about the minimum for a pretty knackered engine - 160 is ok for an average engine - higher is better!

[ssnjimb]

i nearly got something right

[mike.perry]

The Workshop Manual says 150 psi.

[cadetchris]

ok, today i did a pressure test, and the results where ad follows:

when running, 70psi and when the engine then is stopped, it jumps to 120psi.
so going by either of these two readings, the compression is a little on the low side

[bmcecosse]

I don't understand - when running ?? Compression test is done with all 4 plugs out - engine hot and battery fully charged. Wedge the throttle open slightly - and then put the tester on each plug hole in turn - and crank the engine over on the starter for 3 seconds on each hole. Note the reading - reset the gauge - nd then test the next one. 120 psi is desperately low - if that's done by the above method.

[cadetchris]

i thonk i may of done the test completly wrong then,
so, i get the engine all nice and hot, with the battery fully charged.
plugs out,
throttle slightly open
attach guage to plug hole, crank over engine a few times with starter only
note pressure
reset guage
next pot along.
so if my engine is good, then it SHOULD be over 130psi min, if its shot and needs a rebuild its below 130psi and is then in need of new rings and gaskets and the valves grinding in again.
ill go do it again and report back with my findings

[katy]

when running, 70psi and when the engine then is stopped, it jumps to 120psi.

How exactly did you do this test?