1933 ten, valve grind

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GaryCullen
Posts: 28
Joined: Wed Nov 20, 2019 1:34 am

1933 ten, valve grind

Post by GaryCullen » Sun Oct 04, 2020 4:11 am

Hi all,
I am half way though a valve grind on my ten and have discovered pitting on each of the exhaust seats, not to bad but also some pitting on the ex valves. I am awaiting seat grinding tool but the thought comes to me that I wonder if this shows the first stages of seat degradation caused by unleaded fuel use. No lead has been added to NZ fuels for many years.
Compression readings before the pull down showed only about 40 pi’s give of take on each cylinder. Hence the reason to do a valve grind.
My question is should I start using a leaded additive from now on.
I believe that when these engines were made leaded fuels were rare. But I wonder why valve grinds were common place and indeed the procedure is outlined in the owners guides?
Dive appreciated
Gary Cullen
NZ VAR

Cheers

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peter_winney
Posts: 665
Joined: Wed Nov 20, 2019 3:31 pm
Location: BATH

Re: 1933 ten, valve grind

Post by peter_winney » Sun Oct 04, 2020 10:02 am

Gary
Yes valve-grinding was a regular service requirement. My Nov 1933 handbook recommends removing the carbon deposits every 2000 miles and grinding the valves every 4000.

On leaded fuels (petrol containing a small proportion of tetraethyl lead) the handbook says
Provided that the same reasonable attention is given to valves and adjustments as with ordinary petrols there will be no trouble when using these fuels
There are opposing views on whether or not additives are now needed to the fuel for our low-revving side-valve engines. Most tests displaying the dreaded "valve recession" were made on the BMC A Series OHV engine

Peter W
Member since July 1972

GaryCullen
Posts: 28
Joined: Wed Nov 20, 2019 1:34 am

Re: 1933 ten, valve grind

Post by GaryCullen » Mon Oct 05, 2020 5:32 am

Thanks Peter.
My next question is I have a brand new copper head gasket to install and I recall reading some where about being careful which way up it goes.
It is made from two sheets of copper with one side going through the openings and being pressed down on the other side.
Or does it not matter.
If it does I would like to know why and so would some other NZ VAR members here.
Regards
Gary

Rod
Posts: 33
Joined: Sun Nov 24, 2019 9:44 am

Re: 1933 ten, valve grind

Post by Rod » Mon Oct 05, 2020 9:02 am

Hi Gary,
ATDC most likely has a best practice recommendation, and opinions vary, but fyi the general trade rule for fitting this style of gasket was 'smooth' side to the block unless there is a specific recommendation [i.e. the gasket is marked 'top'] . The rationale for this orientation is that, if there is any fretting, the damage caused by the 'rough' side is confined to the cylinder head gasket face and is easily rectified, rather than the alternative of damaging the top deck of the block which is not a trivial matter to repair. Regarding the valve recession issue, we did a bit of research back in the early 80's when alternative fuels [CNG/LPG] were a big thing in NZ and the general consensus was that the absence of lead additives would only be an issue on the exhaust valves/seats of high powered/high duty cycle engines.
Also, to touch on the "valve grinding at 'x' mileages", the explanation I received was that the seatings/valves became pitted by imbedded carbon, which tended to build up in the combustion spaces due to burnt engine oil [which was an unavoidable side effect of the contemporary lubrication technology and imperfect piston ring-cylinder oil control], hence the instructions to decarbonise at regular intervals in an attempt to minimise this issue.

phil_taylor
Posts: 164
Joined: Thu Nov 21, 2019 10:49 am
Location: Hampton Hill, Middlesex

Re: 1933 ten, valve grind

Post by phil_taylor » Mon Oct 05, 2020 5:01 pm

Hi Gary,
I agree with Rod. Smooth side up for the gasket.
From my experience I had to grind the valves in every 2500 miles when using leaded ( before 2000 in UK) but with unleaded they last 25,000 miles - and I only did them then because the crank broke. No seat recession at all and no carbon build-up - much more recession with leaded fuel. I put in a slurp (not measured) of 2 stroke oil with each fill up as an upper cylinder lubricant (and it stops the tank rusting.) I have always used the cheapest petrol and no other additive. Some with prewar Tens have fitted hardened valve seats, lead substitute in the fuel, octane enhancer (or 99 octane petrol), ethanol treatment etc etc. Save your money in my view.
Unfortunately our Club slavishly follows the existing research which, as Peter says, was not based on our low compression, low revving sidevalve engines. Happy motoring,
Phil

6350_William_French
Posts: 78
Joined: Wed Nov 20, 2019 10:27 am

Re: 1933 ten, valve grind

Post by 6350_William_French » Mon Oct 05, 2020 7:11 pm

Hi All
I am confused is it smooth side up, or smooth side down.
from Bill French

phil_taylor
Posts: 164
Joined: Thu Nov 21, 2019 10:49 am
Location: Hampton Hill, Middlesex

Re: 1933 ten, valve grind

Post by phil_taylor » Mon Oct 05, 2020 9:02 pm

Hi Bill,
Absolutely right. I am opposite to Rod, my fault. Went to garage and looked at my stock - all marked 'top' on the smooth side.
Sorry everyone,
Phil

Rod
Posts: 33
Joined: Sun Nov 24, 2019 9:44 am

Re: 1933 ten, valve grind

Post by Rod » Tue Oct 06, 2020 1:14 am

So there you go guys, the gaskets Phil has do have a specific orientation which in this case happens to be the reverse of the 'normal' practice the old geezers who taught me subscribed to :D . I suspect that it doesn't really matter so long as the obvious factors of water passages lining up etc are considered.

bob_allison
Posts: 240
Joined: Wed Nov 27, 2019 3:20 pm

Re: 1933 ten, valve grind

Post by bob_allison » Tue Oct 06, 2020 10:41 pm

Because people disagree , and because there is no obvious answer , then it likely does not matter much .

GaryCullen
Posts: 28
Joined: Wed Nov 20, 2019 1:34 am

Re: 1933 ten, valve grind

Post by GaryCullen » Wed Oct 07, 2020 11:28 pm

Thanks for all your thoughts and advice people.
I think I will put mine smooth side down so the "rough side" is in contact with the head.

Next question is does anyone use or recommend a sealant or just grease be applied to both sides of the gasket before fitting ?
cheers
Gary

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