bottom end issues?

ey up lads hope everyone is well and safe. (Thanks admin for getting me on)

Needs some advise on the pulsar. shes been off road for a while with what im told could be ring failure. I kept feeling like the engine bay was getting too warm even after replacing the rad for a mishimoto and new fans. oil pisses out of the catch can and dip stick. I did a compression test which was 160 on cylinder 1 155 on 2 155 on 4 and 70 on cylinder 4.

My question is whats next. Should I need to have a look at cylinder four through a borescope to check extent of damage. I know that at some point it will have to come apart and bottom end addressed but is there any way of being sure of what to expect. What are the likely scenarios that can come of his. Im not mechanically minded so apologies if I sound daft.  

Im thinking best new set of rings whack new water pump and check oil pump for wear and replace if required. Or if bore damaged a hone or boreout 86.5 or 87 and then maybe upgrade to JE or Toda bottom end. Money is a object so I cant go wild on it. Im thinking a bottom end refresh new gaskets and back up.  Theres no massive rush to get it done asap. Would rather do it in phases.
Its been sat not driven for 7 monthish. Starts up fine but Ive just left it in to stop further damage.
Whats steps would you take??

Tbh I would just get a new recon engine from Bob... Inc head. Swap all ancillaries renew belts etc and just put it in over a weekend or so.

You can fuck around month after month and still get nowhere or you'll get something else going wrong with the bits you haven't done.

not a bad shout. Im intrigued to know what went wrong with it eg over fuelling. Im defo going to have to shout Bob for parts etc.

cracked ringland / damaged bore on cylinder 4
pretty normal on that cylinder due to less cooling potential that end of block & lean fuelling .
No point messing about, take head off to inspect bores .
If your engine likely good and not abused and not had shoddy rebuilds already you be far wiser refreshing it .
Set of CP forged pistons and ACL bearings, cosworth or tomei head gasket, new oil and water pump and that about it on big parts if rest of it measures and checks out good .
54C nothing that fancy and any decent machine shop and engine builder can put them together for basic use .
If you really tight budget and cylinder not been scored and not worn oval you can get away with a cross hatch hone and new rings on good in spec original used pistons .

The most critical thing is a full checkup and tune when done as you can be pretty sure it lean fuelling/ignition timing that helped kill cylinder 4 and if not checked/resolved you ruin the rebuilt engine .

Mr B I had no idea cylinder 4 was chocolate on these. Learn something new everyday. Personally I wouldn't mind the latter and literally hone the bore and new rings (if pistons are saved) but my luck doesn't work like that.

Noticed quite a few pulsars with CP set up. Do they work well in the motor

CP use to be cheap for great spec pistons and the bore clearances work good for road use .
If bores are good enough for a hone you can source some good used original pistons to make up a usable set .
you can get genuine nissan head gasket for £50 and even the current revised cometic gaskets are suitable for light builds if wanting keep prices reasonable .
Condition of your engine once inspected will dictate how it can be done .
Don't cheap out too much and be very selective on machine shops/builders as many do awful sloppy work  .

Hey

So could someone give quick guide to get off inlet manifold and exhaust manifold. what needs to come off in which order - slam panel -turbro- etc etc

going to get these off so a friend can get the head off anc check bores. Going up on axel stands tomorrow.