Dismantled an old 602 engine at the weekend, just for the hell of it and to teach myself something new. All went swimmingly. However, I'd just like to pick collective brains to find out what one should look out for when peaking inside an engine case.

The crank seems nice and solid, with no unnecessary play. The valves look OK (although I'll be getting the grinding paste out to them shortly...).

However, one of the cams has a tiny bit of pitting on it. Questions:
- What would have caused the pitting and what does it signify?
- Is there anything I can do to repair this, or should I just replace the camshaft?

Experienced mechanics: what other tell-tale signs of engine wear do you look for inside the engine?

choke the chicken to check for wear in the big ends
take the rear bearing off and look for scuffing or evidence of pickup on the wear face and check the height of the un worn bit where the oil groove runs, or discolouring of the journal
look at the oil pump for scuffing and scoring on the cover plate
look at the amount of brown varnish in the rocker chest
check the rockers have a sort of fig8 wear mark on the rocker face
make sure there is no wear on the rocker shafts
make sure there is no wear ridge on the barrels
check the piston ring grooves for wear
look at the piston skirts for scuffs and wear
check for uneven wear on the cams
check for pitting or grooves on the lobe of the cam
check the annular wear ring on the cam followers

often the case hardening wears out and the metal below is slightly porous and so it looks a different colour and has slight pitting. Slight pitting on the shoulder of the cam is often seen and the cam still goes on for years

Thanks for this, Sean. Judging from your checklist, my engine is in pretty good condition. It had seized at the rings, but now that I've sorted that problem, I think the unit is good for resurrection. A set of new rings should do the job... or maybe I'll splash out on a new barrel and piston set.

Anything else I should watch out for?

On a 602 M28 AK2, what sort of Psi should you get on a compression test (Hot/Cold) and does anyone have an idea as to a sort of minimum acceptable limit ?

around 150 or above on 8.5:1s, 160 or above for 9:1 check that both cylinders are the same sort of reading

Hi Sean,
I usually work on 175 psi for 9.0:1 pistons.
Seen just over 200 psi on race engines in the good old days when a Citroen camshaft was used instead of the Kent cr@p...

ken

Ugh! So 100 Psi is a little bit down then - starts Ok ! At least its the same both sides.

Bobh,
didn't register your (hot/cold) note last time around, but 'hot' and 'wide open throttle' are the standard conditions for a compression test.
If you forget and leave the throttle closed, the reading obtained can be as much as 20 psi lower.

ken

yup thats a bit low, could just be tappets but if there is a lot of oily mess bottom end or an oily airbox then new barrels and pistons in the next 5 years or so

100 Psi was cold with the throttle closed, so perhaps there is hope yet. As an aside, I am running with 6Volt wipers with a 6v headlamp bulb in series - they seem to be OK, so I'm off for a run in the rain - hope they don't burn out on the way.