1933 ten, valve grind

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GaryCullen
Posts: 30
Joined: Wed Nov 20, 2019 1:34 am

Re: 1933 ten, valve grind

Post by GaryCullen » Sat Nov 21, 2020 7:42 pm

I tried my new exhaust valves (supplied by our local VAR) in each of the existing old guides and cylinders 3 and 4 are definitely worn more than 1 and 2. I have now punched out all the guides and attempted a measurement and I am sure all are worn more than 5 thou. Anyway I have a new set of guides coming so the engine will have new guides all round and new Ex valves. The inlets are all in great shape. The stems measure 0.312. New springs also.
However I think I have found why the engine had no real power driving on the road. To get the guides out I had to remove each tappet to get the springs out. Then I discovered the tops of each tappet where the valve end sits are worn badly. There is a ring of untouched material around the worn area where the feeler gauge would sit when trying to set the gap. So no matter that you think you have the gap correct when the gauge is removed the real gap is a lot more. The depth of the worn area is about 20 thou would be my guess. So valves open later and close earlier. Bad power and bad fuel economy. I have hand lapped each tappet on an oil stone to reface the top. Can’t wait to now get it all back together!
Thanks for all the advice guy’s.
I would include some photos but I can’t figure out how to do on this forum.
Gary
Auckland VAR

6350_William_French
Posts: 82
Joined: Wed Nov 20, 2019 10:27 am

Re: 1933 ten, valve grind

Post by 6350_William_French » Sun Nov 22, 2020 7:56 pm

Hi Gary
The problem you have described is not uncommon. Where the valve stem hammers against the tappet does wear. So when you think you have set a clearance of 6 thou it is infact about 26 thou. Well spotted.
from Bill French

Rod
Posts: 37
Joined: Sun Nov 24, 2019 9:44 am

Re: 1933 ten, valve grind

Post by Rod » Mon Nov 23, 2020 7:31 am

You're keen hand facing them Gary, I have the same issue with my 14 which also made it awkward to accurately detect #1 valve just opening with the regulation clearance when I did the timing chain on the engine recently without removing the cylinder head [sleeping dogs and all that...]
When I do the engine properly I'm going to wimp out and buy the replacement adjusting screws from the ATDC shop.
I am of the understanding that only the members' forum has the facility for posters to submit photos.
Moderators?

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peter_winney
Posts: 734
Joined: Wed Nov 20, 2019 3:31 pm
Location: BATH

Re: 1933 ten, valve grind

Post by peter_winney » Mon Nov 23, 2020 12:58 pm

Rod wrote:
Mon Nov 23, 2020 7:31 am
You're keen hand facing them Gary, I have the same issue with my 14 which also made it awkward to accurately detect #1 valve just opening with the regulation clearance when I did the timing chain on the engine recently without removing the cylinder head [sleeping dogs and all that...]
When I do the engine properly I'm going to wimp out and buy the replacement adjusting screws from the ATDC shop.
I am of the understanding that only the members' forum has the facility for posters to submit photos.
Moderators?
According to ATDC Technical Reprints Vol 2 page 34 the tappet screw face needs to be re-hardened after grinding flat. Tappet screws area available online from ATDC Spares - item 187.

Club members can upload pictures to the forum
Member since July 1972

phil_taylor
Posts: 185
Joined: Thu Nov 21, 2019 10:49 am
Location: Hampton Hill, Middlesex

Re: 1933 ten, valve grind

Post by phil_taylor » Mon Nov 23, 2020 5:56 pm

I agree with Gary,
I just stone off any deep depression in the adjusting screw on rebuilding an engine from scratch. I have seen no wear after the engine has done a further reasonable mileage. Wear occurs after perhaps 100,000 miles? Perhaps I am not yet convinced that the originals were case hardened? Who is likely to do that sort of mileage now? Most cars do not do more than a couple of thousand a year and I can assure you that there will be no wear in many years. Why buy new screws?
Phil

GaryCullen
Posts: 30
Joined: Wed Nov 20, 2019 1:34 am

Re: 1933 ten, valve grind

Post by GaryCullen » Mon Nov 23, 2020 8:53 pm

Thanks for all the replies and advice.
The thought did cross my mind to get the re-faced tappets re-tempered.... however this car will not do huge miles just the odd club run so I think I will let them be.
I did them by hand on an oil stone, coarse side first then fine side last. took about an hour to do all 8.
A local VAR club member here advised he had done it on a pedestal Drill mainly to ensure the surface was flat and dead square to the Tappet thread, holding the Tappet in the chuck and bringing it down onto an oil stone.
Only problem I can see with that is wearing the stone in one place unless you move it for each Tappet. Even doing that you will end up with a less than flat stone. At least by hand the strokes are long and doing a figure of 8 keeps the wear fairly consistent.

I am now waiting for the new Guides to arrive from the UK, since this will take about two weeks it will be a while before I can put them in and rebuild the engine. I will then report back on the outcome! Hopefully some pulling power on the road and at least 45 mph..!
I will also be able to advise how the SU HS2 carb conversion worked out.

regards
Gary

Auckland VAR

bob_allison
Posts: 262
Joined: Wed Nov 27, 2019 3:20 pm

Re: 1933 ten, valve grind

Post by bob_allison » Tue Nov 24, 2020 10:19 am

The tappets would likely be work hardened in way of the valve with the hammering . Is it possible to lift the tappett and tappett block out with the engine in the car ? I forgot to sort mine when I had the engine in bits

GaryCullen
Posts: 30
Joined: Wed Nov 20, 2019 1:34 am

Re: 1933 ten, valve grind

Post by GaryCullen » Tue Nov 24, 2020 8:54 pm

Bob, yes it is fairly easy to wind out the Tappet adjusting bolt. You will need to take out the valves and remove the springs first. Then just loosen the bottom split lock nut and you can finger wind out the tappet bolt.
I haven't taken the Cam Followers out yet but advice is to remove each small hex headed securing bolt that stops the Follower from dropping into the sump if the Cam Shaft is removed first. If the engine is still in the car it is unlikely the Cam Shaft is removed anyway. There is one of these small bolts in each block casting for each Cam Follower accessible through the valve chest area. Cam Followers, at least in my experience on other side valve engines, don't wear very much at all. The most wear will occur at the Cam Shaft contact area at the bottom of the Follower but the engine will have had to clock up some huge miles, or been run for periods with very low oil levels in the sump.

Regards
Gary
Auckland VAR

bob_allison
Posts: 262
Joined: Wed Nov 27, 2019 3:20 pm

Re: 1933 ten, valve grind

Post by bob_allison » Wed Nov 25, 2020 4:04 pm

Thanks for that Gary . Come spring I shall tackle it , before I replace the head .

GaryCullen
Posts: 30
Joined: Wed Nov 20, 2019 1:34 am

Re: 1933 ten, valve grind

Post by GaryCullen » Sun Nov 29, 2020 3:24 am

Bob, in an earlier post I mentioned that I had hand lapped the tappet on an oil stone and decided this would be good enough for the amount of club driving the car will get. But a little niggle formed in my mind so I decided to check how true , or square I had done the job. A local VAR member suggested I do it in a pedestal drill. So I set mine up and checked that the support table was square to a drill held in the chuck.
Then I removed the split lock nuts, mounted the tappet in the chuck and lightly pressed the face down on the oil stone a few times, moving the stone about each time. Stopped, removed the tappet and low and behold the circular refacing marks showed I had indeed ground a slight angle on the face. Then proceeded to do the other 7. I am now glad I did as even a slight say 1 thou imperfection would mean the tappet would not push square on to the valve stem. This would quickly start to wear out the valve guides and may eventually cause some grief to the valve contact seat in the block.

Regards
Gary
Auckland VAR

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