i just took a compression reading ..

[xpress]

i took all the plugs off and with my foot to the floor i cranked and took four readings on each cylinder and took the best of each, resetting the compression tester before each new cylinder ..

from the cylinder nearest to the radiator and in sequence towards the dashboard ..

1. 185
2. 180
3. 175
4. 161

how do these sound and why would the fourth one be a bit lower?

new champion plugs, the copper ones, *this guy was telling me about pinpoint platinum electrode, start in -30 plugs, EY plugs? they sound quite good), new distributor cap, idle sounds smoother and more even already.just need new leads now).

ps the gap was a bit large on the old plugs, and they were a bit black and sooty. i think the previous owner ran rich to guard against valve seat recession with unleaded, i plan to tweak the mix back and not worry about the head, i figure running too rich would do more damage long term, to my pocket and the engine than a new head!)

i am feeling a bit better about going ahead with the welding now.

[bmcecosse]

Well - the 4th one is a bit down - but maybe your battery had lost a bit of charge by then, and the oil pressure could have come up - loading the starter more = lower cranking speed. Ideally - with the engine hot and battery fully charged - take another set of readings - this time starting at # 4 and working to #1. Let us know how it goes! But these comps are v good - just that 4th one a wee bit lower - but still 'good' . Nothing serious there.

[xpress]

ah, they seemed pretty good and the engine pulls well. ah that's grand news. getting closer to getting her sorted now! thanks bmc. i think the plugs might have been sooty because the electrodes were worn down and poor spark. going to replace the leads next and keep the old as spares!

[MarkyB]

While you are under the bonnet, check that tappet gaps, unless you've done them quite recently.

[xpress]

ah ok yes i thought the valve might not be gapped enough at the back cylinder. thanks marky. could you briefly talk me through what to do, do i have to take the head off, do i need to torque it back up or can i just seat them in like wheel bolts opposite each other and torque them back up by feel? just going to check the haynes. marky, if you're near, come and spin by and say hello. would be good to see you!

[MarkyB]

Sorry, got lots to do this weekend.
Haynes should be a good enough guide.
Only the rocker cover needs to come off.
Unless the head gasket has been replaced recently you shouldn't need to torque the head down, but it wont do any harm to check either.

When number one valve (nearest to rad) is down, check number eight (furthest from rad)
Use the starting handle to turn the engine until another one goes down then check the one that makes 9.
7 and 2 ,6 and 3 etc.

[xpress]

not this weekend, anytime if you're passing by!

cheers for the tips, i should be able to do that.