The perennial cylinder head thread

[The stoker]

There's been a lot of useful info on these pages, which I've used for for my own Series 2A head change.

However, I could really use some advice as I've a few problems:

The original reason for head removal was to fit new piston rings as I had bad compression and lots of brown smoke. Cyl pressures before new rings were:

1. 10.2 bar
2. 10.2 bar
3. 10.3 bar
4. 9.9 bar

Pressures now are:
1. 11 bar
2. 11.5 bar
3. 11.3 bar
4. 10.9 bar

However, I now have copious amounts of white smoke and have had the head back off twice, I think that there is water getting into cylinder 2 as it has a white emulsion in it. I'm thinking I need a head skim, I've run a engineering rule down the head and it does seem very slightly bowed. As the head and block faces are really clean, I'm a bit stuck for inspiration.

Question 1 is - Will a head skim help me - ie, would even the slightest bit of deflection cause a problem (using a composite gasket)

Question 2 is that I also found a lot of oil in the cylinders and although I have new piston rings and my cylinder pressures seem to be quite good now, where is the oil coming from? (could it be crankcase breather or rocker breather which both feed into carb or valve stems?)

One good thing was that when it was running, it didn't misfire or make unpleasant sounds!

Help me Obi-Wan, you're my only hope!

 

[pobby]

it all depends ow much the head is bowed a couple of thou wont make much diffrence.
as for the oil in the cylinders have you rebuilt the head of just cleaned it and refitted it.
when you put the rings in did you mesure the ring gap or hone out the cylinders.
i would surjest a total engine rebuild
pull it out strip it right down, change every gasket and seal hone out the cylinders and fit new rings everything new bearings the lot

 

[Sean]

1. 10.2 bar
2. 10.2 bar
3. 10.3 bar
4. 9.9 bar

Pressures now are:
1. 11 bar
2. 11.5 bar
3. 11.3 bar
4. 10.9 bar

a think you wasted yer time doing the rings - i'd bet it's the valves and seats that needed doing

the sensible and only viable option was to get get the head skimmed while it was off originally - don't make hard work of it

 

[The stoker]

Head skimmed and valves reground and re-furbed.

Head back on

Judgement day tomorrow!

 

[Sean]

Head skimmed and valves reground and re-furbed.

Head back on

Judgement day tomorrow!

how much did that set you back ?

 

[dr pepper]

Yep the compression wasnt bad when you started.
If you are getting oil into the chambers then you would be getting blue smoke not white.
I wonder if the oil got there when you took the head off.

 

[The stoker]

By Sean:

how much did that set you back ?

£140 all in (about £35 for the skim and the rest for refurb work, hardened seats and a broken off stud removed!)

 

[pobby]

they only charged £100 for head rebuild
sounds a bit cheap to me
should be the better part of half a day where ever you go

 

[The stoker]

Well,

Good news:

All seems well, the oil and water left in the engine and exhaust seems to have burnt off, engine sounds good and it's driving nicely.


Bad news:

Just need to set up the carb (weber 34), but I think I have an air leak - it cuts out in idle and when you take your foot off the go pedal, unless you get some choke on.

As I've totally re-fitted the head, carb and manifolds, I suppose the air leak could be anywhere - could I have your top ten possible locations please? or could it be something other than an air leak?

 

[pobby]

dont just guess find it, its not hard

start the engine and get it to run steady even if you have to tweek the throttle a little
spay something like carb cleaner around the inlet manifold gaskets, any vacum pipes, servo if you have 1 basiclly anywhere that air could get in
listen for a change in engine rev when you hear the change you are in the right area then just concentrate smaller points till you find the exact leak
should take 2 min

 

[The stoker]

Found it, on carb to manifold flange o-ring.

New o-ring in place, carb set up, runs like a beauty

Going for a run out tomorrow.