Hi,
I am trying to persuade myself I may not have to do something, but I am not being very convincing.
Just taken the head off our Nissan Bluebird 1.6 SE Hatchback (carb. engine).
It has been laid up for a year after being relayed home with loss of compression on 2 cylinders.
[I thought the 2 centre ones, but more of this later]I had a major struggle getting the head off - some gorilla had tightened various nuts etc. - and have now confirmed that the head gasket has gone big time.
Big time as in nothing between cylinders 1 and 2; large chunk of gasket missing.
Having said that, both the block and head look O.K. although they need cleaning.
Spooky bit - the pistons of cylinders 1 & 2 (blown gasket) look as new and shiny as when first manufactured. No nasty carbon from combustion etc.
Pistons 3 & 4 are covered in carbon deposits - grey to black.
None of the valves look burned, although there was some crud around the valves in 1 & 2.
I am trying to persuade myself that I don't have to strip down the head and replace the valve stem oil seals and regrind the valves.
I have turned over the OHC and looked inside each valve seat as the valve opens and they all look O.K.ish (no obvious nasty pitting etc.) but I can't be sure without taking the valves out.
So my choice now is to clean up the faces and slap a £20 head gasket in, or strip the whole thing down and get £60 full gasket set.
[and no doubt strip/break studs etc. getting inlet and exhaust manifolds off]The thing intriguing me at the moment is why pistons 1 & 2 are so shiny and clean - and does this hint at problems with the head ( I assume water was leaking into the cylinders and 'steam de-coking' them).
So should I just replace the gasket and plan to run the car for 6 months to a year, or just junk it and buy a 'runner'?
Factors to consider:
(1) looking at Autotrader online the car is probably worth less than £400 although one optimistic trade seller wants £899 for a 'G' Reg 1.6LX with
100K on the clock.(2) It will need a new battery, and probably a couple of tyres, to get through the MOT. Until it goes for an MOT there is no knowing what else might need doing, but the cars are (allegedly) generally reliable. So the risk isn't just £20 vs £60 (and possible problems cause by trying to strip down the inlet and exhaust manifolds).
(3) I could buy a 'runner' with a year's MOT for under £500 (although this is obviously a gamble).
So what are the risks of just putting the head back on with a new gasket?
[If I was a garage, this is probably what I would do for a car of this age. However labour costs are just damaged knuckles and a lot of swearing.]TIA
Dave R