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Re: 1928 Ariel Model C [Re: Magnetoman] #731416
04/09/18 2:12 am
04/09/18 2:12 am
Joined: Nov 2011
Posts: 4,278
U.S.
Magnetoman Offline OP

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All I was able to do in the time I had available today was to make a valve guide drift stop. The next few days won't be any better. I made the brass drift eons ago and it along with the 1.000" inner length of the Al stop will allow me to quickly press the frozen guides into the hot head, leaving the necessary 1" projecting above the top surface.

Attached Files ValveGuide07.jpg
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Re: 1928 Ariel Model C [Re: Magnetoman] #731589
04/11/18 2:23 am
04/11/18 2:23 am
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Posts: 4,278
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Magnetoman Offline OP

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It was time to install the guides so, to make life easier for them, I froze the guides and boiled the head in a pot of water on the barbeque. Cast iron has a low thermal conductivity so even after the water started boiling I let the head simmer for another 15 min to give it plenty of time to come to equilibrium. I then pulled it out of the pot and placed it on a fiberglass insulating blanket and went inside to get the guide and driver from the freezer. The much larger thermal mass of the head meant it would cool off slower than the guide would warm up, which is why I did it in that order. After driving the first guide in I placed the head back in the water for a few minutes before doing the second guide.

Even with the boiled head and the frozen guides the temperature difference was only ~210 oF so the 0.002" interference fits only decreased by ~0.0008" so both guides took some persuasion with a hammer. The 1.000" Al stop I made two days ago earned its keep since it allowed me to quickly pound the guides home before all the temperature difference was lost without having to periodically stop to measure the projection above the head.

I forgot to carefully check the IDs before installing them so I don't know how much the interference fit caused the IDs to shrink. Although the final honing required holding an oddly shaped 12 lb. chuck of cast iron at an inconvenient angle, both guides are now within 0.0001" of the intended values of 0.002" (inlet) and 0.0025" (exhaust).

Before the final honing I checked to see if the new guides were Concentric with the seats. I painted Dykem on the seats and Simichrome on the valves, and then spun the valves for a few sec. with a drill. The photo only shows part of the circumference, but the valves made line contact with the seats all the way around. A line all the way around the valve doesn't mean much, but all the way around the seat means the guide is Concentric. The extra effort to make the guides the way suggested by chaterlea25 was worth it.

Turning to the valve seats, modern engines call for a 0.040"-0.060" width for the inlet and 0.060"-0.080" for the exhaust. Also, modern engines use 3 and 5-angle cutters rather than the single 45-deg. of olden days. But mine isn't a modern engine, and I'm not looking to extract every last fraction of a h.p. from it.

I looked at a few sources and found Phil Irving in 'Tuning for Speed" mentions 3/32" (0.094") as a typical valve seat width (which is approx. the width of the entire edge of the valve), while then discussing the benefits on flow of reducing that to 1/32" (0.031"). This assumes the seat was originally cut at a single angle of 45-deg. However, in a later chapter he says increasing the 1/32" to 0.045"-0.050" has benefits because "it is wide enough to run for some time without undue hammering back." With these numbers floating in my head I lapped the inlet valve with a series of grinding pastes, with 800 grit as the final one, ending up with a seat 0.062" wide. Again, time ran out, so the exhaust seat is yet to be lapped in.

Once the exhaust seat is lapped I can install the springs, then install the head, and a few bolts later the engine will be complete.

Attached Files Guides07.jpgGuides08.jpgGuides09.jpgGuides10.jpg
Re: 1928 Ariel Model C [Re: Magnetoman] #731595
04/11/18 3:39 am
04/11/18 3:39 am
Joined: Feb 2012
Posts: 173
Los Angeles, CA
L
L.A.kevin Offline
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Los Angeles, CA
As always MM, your method of solving a problem is foolproof. I'm going to use that trick of the stop you made next time I rebuild a head. Thanks as always for the gifts of your time and knowledge.

Re: 1928 Ariel Model C [Re: Magnetoman] #731686
04/12/18 5:13 am
04/12/18 5:13 am
Joined: May 2004
Posts: 3,674
Sydney Australia
B
BSA_WM20 Offline
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Sydney Australia
Way way back when Neway were just launching their replacable cutter valve gear, I took the B40 head to get the seats done.
In those days Hazet were the agants for Neway in OZ.
Even with the very soft 6.5:1 compression on the B40GA's the 3 angle seat made a big difference.
So it has been 3 angle heads on everything ever since.
Even the M20 has 3 angle seats and it did go much better after that, however after that also included a new sleeve Piston & rings so i would have been a bit upset if it didn't run substantially better.
The 3 angle seat has not given a spot of bother in the past 10 years (40,000 miles ) which is pretty good for an old side banger.


Bike Beesa
Trevor
Re: 1928 Ariel Model C [Re: Magnetoman] #731702
04/12/18 12:51 pm
04/12/18 12:51 pm
Joined: Aug 2001
Posts: 3,746
argyll. scotland, uk
gavin eisler Offline
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Heres a wee bit of Ariel inspiration for you taken inthe mart , Forfar at the Strathmore Vintage and Veteran Autojumble last Sunday .


Sorry no data on the black side valve , the 350 NH was a belter, met a lot of sound types. Nearly there MM, hing in there.


Attached Files IMG_0507.JPGIMG_0508.JPGIMG_0511.JPGIMG_0512.JPGIMG_0513.JPG
Last edited by gavin eisler; 04/12/18 12:57 pm.

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Re: 1928 Ariel Model C [Re: gavin eisler] #731767
04/13/18 5:13 am
04/13/18 5:13 am
Joined: Nov 2011
Posts: 4,278
U.S.
Magnetoman Offline OP

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Originally Posted by BSA_WM20
the 3 angle seat made a big difference.
I'm just back from a short trip to Los Angeles. I'll look into 3-angle cutters before I declare the head fit for service.

Originally Posted by gavin eisler
Heres a wee bit of Ariel inspiration for you
Thanks for posting those photos. I've come to be very fond of the look of black Ariels. I'm glad I have the OHV version, though.

Originally Posted by gavin eisler
Nearly there MM, hing in there.
"May you live in interesting times" goes the supposed Chinese curse. I'm cursed with having an interesting art-related endeavor vying for attention, which was the purpose of my trip to Los Angeles. Anyway, the additional multitasking as a result may slow the Ariel down a little.

Re: 1928 Ariel Model C [Re: Magnetoman] #731826
04/13/18 9:27 pm
04/13/18 9:27 pm
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Magnetoman Offline OP

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Originally Posted by L.A.kevin
your method of solving a problem ...
Whether right or wrong, there's no doubt my professional background influences the way I approach motorcycle problems.

While waiting 15 minutes for someone to show up who never did I used the time to google performance information on 3-angle valve jobs. Unfortunately, I could find nothing more authoritative than blogs written by machine shops trolling for business and "My engine guy told me..."

I have no trouble believing a 3-angle valve job alone would increase flow and hence h.p. somewhat. But, is the gain 1%, 3%, 5%, ...? Is anyone aware of actual data on this? Not dyno runs after major work, only one piece of which was a 3-angle valve job, was done on an engine. But just the valve job alone.

If I were building a racer any percentage gain would be worthwhile, but for slogging across America even 5% wouldn't be significant. Further, any extra flow in and out of the engine would be accompanied by reduced seat area to conduct heat away from the valves and that might (or might not) be more significant than any marginal h.p. gain.

Re: 1928 Ariel Model C [Re: Magnetoman] #731827
04/13/18 9:46 pm
04/13/18 9:46 pm
Joined: Aug 2001
Posts: 7,298
scotland
triton thrasher Online content
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Originally Posted by Magnetoman
Originally Posted by L.A.kevin
your method of solving a problem ...
Whether right or wrong, there's no doubt my professional background influences the way I approach motorcycle problems.

While waiting 15 minutes for someone to show up who never did I used the time to google performance information on 3-angle valve jobs. Unfortunately, I could find nothing more authoritative than blogs written by machine shops trolling for business and "My engine guy told me..."

I have no trouble believing a 3-angle valve job alone would increase flow and hence h.p. somewhat. But, is the gain 1%, 3%, 5%, ...? Is anyone aware of actual data on this? Not dyno runs after major work, only one piece of which was a 3-angle valve job, was done on an engine. But just the valve job alone.

If I were building a racer any percentage gain would be worthwhile, but for slogging across America even 5% wouldn't be significant. Further, any extra flow in and out of the engine would be accompanied by reduced seat area to conduct heat away from the valves and that might (or might not) be more significant than any marginal h.p. gain.


You should seek out what J Healy has said on the subject, on Britbike.com.

Example:
http://www.britbike.com/forums/ubbthreads.php?ubb=showflat&Number=124562


Amateur Loctite enthusiast.
Re: 1928 Ariel Model C [Re: triton thrasher] #731835
04/13/18 11:35 pm
04/13/18 11:35 pm
Joined: Nov 2011
Posts: 4,278
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Magnetoman Offline OP

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Originally Posted by triton thrasher
You should seek out what J Healy has said on the subject, on Britbike.com.
Thanks for that link. I knew better than to use BritBike's search function when looking here for information, but I used it anyway and didn't find John's posts. But, here's what he said in that link:

One of the best things you can do for a Triumph is a good three angle, single angle for that matter, done with a Serdi, or competitive single point , valve machine.

"What is the valve seat combination that really makes horsepower?"
Bob, except for broad generalizations, you are not going to get anyone to answer that question. You will ge a lot of opinions, but unless you spent hundreds of hours on a flow bench and dyno it is a "wild a** guess."


From the context, John seems to be referring to cutting the seat after installing new guides in an alloy Triumph head, i.e. where the seats are no longer quite Concentric with the guides so they must be cut. Anyway, he doesn't seem to be dismissive of a single angle valve job, but rather emphasizes the importance of a good valve job of any type over a ham-fisted multi-angle valve job.

Thanks to the rigidity of cast iron, coupled with the concentricity of the OD and ID of the guides, as well as the unworn nature of the seats, the Ariel's seats do not need to be cut and so all that my two valves need are lapping. I could cut the seats if there were significant performance to be gained for my Ariel for its intended use so that possibility isn't off the table just yet. But, I need to see actual data in order to decide if it's worthwhile, i.e. for my Ariel for its intended use.

Re: 1928 Ariel Model C [Re: Magnetoman] #731842
04/14/18 1:02 am
04/14/18 1:02 am
Joined: Oct 2001
Posts: 1,123
Sydney, Oz
S
Shane in Oz Offline
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Sydney, Oz
Some more good info from John on this link
It has more to do with the valve contact width and heat transfer than comparing single angle and three angle seat cuts.

Re: 1928 Ariel Model C [Re: Shane in Oz] #731847
04/14/18 1:47 am
04/14/18 1:47 am
Joined: Nov 2011
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Magnetoman Offline OP

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Originally Posted by Shane in Oz
Some more good info from John....
Any info. from John is good info., so thanks for finding that thread. He wrote:
Originally Posted by John Healy
for the average street rider I recommended something more like .080" .
Since my inlet seat is currently 0.062" it seems some more time with grinding paste is in my future for the weekend.

Re: 1928 Ariel Model C [Re: Magnetoman] #731861
04/14/18 8:06 am
04/14/18 8:06 am
Joined: Aug 2001
Posts: 7,298
scotland
triton thrasher Online content
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Originally Posted by Magnetoman
Originally Posted by Shane in Oz
Some more good info from John....
Any info. from John is good info., so thanks for finding that thread. He wrote:
Originally Posted by John Healy
for the average street rider I recommended something more like .080" .
Since my inlet seat is currently 0.062" it seems some more time with grinding paste is in my future for the weekend.



John appeared to be recommending 0.080" exhaust seat width.


Amateur Loctite enthusiast.
Re: 1928 Ariel Model C [Re: Magnetoman] #731862
04/14/18 9:48 am
04/14/18 9:48 am
Joined: Aug 2001
Posts: 3,746
argyll. scotland, uk
gavin eisler Offline
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AFAIK a wide exhaust side is more important for heat transfer , ,on the inlet side a narrower contact is OK because its cooled by the incoming charge and may help sealing because seat pressure is higher.
A big boy told me this years ago then ran away. I believed him.
I think the deal with multi angle seats is to lose the pocket at the CC side if the valve seats are pocketed.


71 Devimead A65 750
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Cagiva Raptor 650
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The poster formerly known as Pod
Re: 1928 Ariel Model C [Re: Magnetoman] #731863
04/14/18 10:43 am
04/14/18 10:43 am
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scotland
triton thrasher Online content
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I heard there’s a fluid dynamics idea that the incoming charge can follow the surface through an angle of 15 degrees, but no more acute than that.

I may even have heard it here.


Amateur Loctite enthusiast.
Re: 1928 Ariel Model C [Re: Magnetoman] #731873
04/14/18 3:22 pm
04/14/18 3:22 pm
Joined: Nov 2011
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Magnetoman Offline OP

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Originally Posted by triton thrasher
John appeared to be recommending 0.080" exhaust seat width.
Originally Posted by gavin eisler
AFAIK a wide exhaust side is more important for heat transfer
Ah, careful re-reading of that thread shows it started out with a question about seats in general and then morphed into specific comments about the exhaust seat. Like flow at a valve seat, the abrupt transition delaminated me when I originally read it...

Originally Posted by triton thrasher
I heard there’s a fluid dynamics idea that the incoming charge can follow the surface through an angle of 15 degrees, but no more acute than that.
Even if that were true, the angle only starts out at 15 degrees with a 3-angle seat, then after only ~0.020" abruptly increases by 30 degrees (to 45 degrees). So, even if there were laminar flow all the way down the several inches of the inlet port until it reached the seat, with a 3-angle seat it would stay laminar for all of another ~0.020" before separating from the wall. It's hard to imagine that laminar flow argument, even if true, would help matters with a 3-angle seat.

I have a SuperFlow flow bench and toyed with the idea of putting the head on it to make it the first 1928 Black Ariel head ever flow tested. But, that diversion would eat up a day that is better spent getting the bike on the road so I'll skip the flow bench.

As I wrote in an earlier post, I have no trouble accepting that a multi-angle valve seat will increase flow somewhat. The question is whether that 'somewhat' is significant enough to make it worthwhile on this Ariel. At the risk of cursing myself on the side of the road at 10,000 ft. when another 0.5 h.p. would have got me over the Continental Divide, it looks like I'll be leaving it with 45-deg. seats.

Re: 1928 Ariel Model C [Re: Magnetoman] #731880
04/14/18 5:02 pm
04/14/18 5:02 pm
Joined: Aug 2001
Posts: 1,944
Greensboro, NC
Alan_nc Offline
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I think you are talking miles per hour as you go over, not if you get over.


Alan
Cleared m out....left only
59 BSA Bantam (Trials)
78 Triumph Bonny (UPS)
02 Suzuki GS500
Re: 1928 Ariel Model C [Re: Magnetoman] #731886
04/14/18 6:02 pm
04/14/18 6:02 pm
Joined: Aug 2001
Posts: 7,298
scotland
triton thrasher Online content
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If you believe you know better, you really should do it your own way.


Amateur Loctite enthusiast.
Re: 1928 Ariel Model C [Re: triton thrasher] #731887
04/14/18 6:18 pm
04/14/18 6:18 pm
Joined: Nov 2011
Posts: 4,278
U.S.
Magnetoman Offline OP

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Originally Posted by triton thrasher
If you believe you know better, you really should do it your own way.
I'm not saying a 3-angle job wouldn't flow better, I'm just uncertain whether it would be "better enough" to make it worthwhile. I'm glad you pointed out that the 0.080" referred to the exhaust seat because as a result I'll leave the intake as-is at 0.062" and turn directly to the exhaust, which I'll make the 0.080" that John suggested.

Re: 1928 Ariel Model C [Re: Magnetoman] #731889
04/14/18 6:33 pm
04/14/18 6:33 pm
Joined: Aug 2001
Posts: 7,298
scotland
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You might enjoy this, on a long flight.

http://tuningforspeed.com/files/Tuning_for_Speed.pdf


Amateur Loctite enthusiast.
Re: 1928 Ariel Model C [Re: Magnetoman] #731896
04/14/18 8:07 pm
04/14/18 8:07 pm
Joined: Nov 2011
Posts: 4,278
U.S.
Magnetoman Offline OP

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Originally Posted by triton thrasher
You might enjoy this, on a long flight.
Thank you very much. I almost never carry a book with me on trips because of the weight and space they take up, so I make do with magazines and newspapers that I abandon on the plane when I'm done with them. Thanks to flash drives having replaced HDDs, battery life is no longer an issue so I have a small selection of technical books on my computer when I need to fill some time on a long flight. Thanks to you, 'Tuning for Speed' is now part of my pdf collection.

p.s. twenty years ago I made what I think is a fairly accurate estimate of how many CDs it would take to hold scans of all English-language motorcycle books ever published. Doubling that result to overestimate the additional space of books published since then, every such motorcycle book ever published would fit in less than 10 GB. Extending this estimate, scanned copies of every English-language motorcycle book and magazine from the US, UK, Australia, NZ, etc. since c1890 easily would fit on a 128 GB flash/"thumb" drive. That would take care of even the longest flights.

Re: 1928 Ariel Model C [Re: Magnetoman] #731902
04/14/18 9:28 pm
04/14/18 9:28 pm
Joined: Feb 2014
Posts: 417
Cork Ireland
C
chaterlea25 Offline
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Cork Ireland
Hi MM,
Lapping with grinding paste is not a good way to "widen" a valve seat
The paste will cut a channel into the valve head eventually resulting in a concave /convex seating
A gentle touch of a seat cutter will save a ton of lapping

John

Re: 1928 Ariel Model C [Re: Magnetoman] #731910
04/14/18 11:07 pm
04/14/18 11:07 pm
Joined: Nov 2011
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U.S.
Magnetoman Offline OP

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Originally Posted by chaterlea25
Lapping with grinding paste is not a good way to "widen" a valve seat
OK, OK, I'll order an appropriate cutter. But damn you for making me do it the right way. And damn me for my inability to live by the credo 'ignorance is bliss'. At breakfast this morning I was re-reading the chapter on head rebuilding in "Sunnen's Complete Cylinder Head and Engine Rebuilding Handbook" by John G. Edwards (Sunnen, 1998). A section entitled 'Distortion Affects Seat Concentricity, Too' caught my eye, where it says:

"Torquing down the head bolts or even tightening the spark plugs can sometimes load the head casting enough to force the seats out of round ... On some heads... exhaust valve seats have been found out-of-round by as much as .006" when the heads are installed! ... on certain engines when the spark plugs are installed and tightened ... distortion in the casting pulls the valve seats out-of-round by as much as 0.004". This kind of distortion can affect both cast iron and aluminum cylinder heads alike. ... BEFORE machining critical dimensions...bolting a torque plate on the cylinder head "

As a result, my time today was spent making a pilot for the guides so I could use my valve seat run out gauge. I already have the torque plate I used for boring and honing the cylinder[*] but I'll have to make a ring to go between it and the head it to simulate the flange at the top of the cylinder. I'll then check how much, if any, distortion there is of the seats when I torque down the head and spark plug, and then cut & lap the seats accordingly.

[*]At least one person scoffed at the idea when I mentioned I planned to make a torque plate to use when boring and honing this old engine. But, my later measurements, discussed in a post quite a while ago, showed there was significant distortion. Although I have no idea if there will be any distortion of the valve seats, I do know that I will be taking the time to make the measurements to find out.

Attached Files ValveSeatRunOut.jpg
Re: 1928 Ariel Model C [Re: Magnetoman] #732014
04/15/18 11:54 pm
04/15/18 11:54 pm
Joined: Nov 2011
Posts: 4,278
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Magnetoman Offline OP

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Thanks to being berated by chaterlea25...
Originally Posted by chaterlea25
Lapping with grinding paste is not a good way to "widen" a valve seat
...a set of Neway cutters is on order, so blame him for the delay this causes in assembling my engine. At this point it's in for a penny in for a cwt, so I also ordered the 30 and 60 degree cutters as well for a 4-angle valve job (the 45 cutter is double-ended with 15 deg. on the other end). I tremble at the prospect of all the additional h.p. this will give the engine.

I was watching a 'Big Bang Theory' rerun last night while looking through catalogs and on-line sites trying to decide which seat cutting system was "best" for removing the necessary ~0.001". Coincidentally, the episode was about Sheldon being frozen into inaction by his inability to decide which of two new gaming systems that had just been introduced was "best." I decided I couldn't let that be me, and ordered the Neway cutters before I found myself still looking through catalogs hours later.

Before ordering I had watched some Youtube videos on using the Neway cutters, many of which unintentionally are examples of how not to do it. For example, one guy rotated the cutter back and forth like he was operating a grinder rather than a cutter. Another guy noticed the seat looked like it wasn't being cut as deep on one side as on the other so he described and showed how when that happens you should lean sideways on the cutter to correct that (nb. it's cutting asymmetrically precisely because it is correcting the fact the seat isn't Concentric with the guide-- leaning sideways distorts the geometry and increases the concentricity; the seat would end up looking like the watches in a Salvador Dali painting.). Anyway, I learned enough to convince me that 1) it's easy to mess things up if you don't know what you're doing and believe everything that's on Youtube, and 2) it's possible to do a nice job with the Neway cutters if you understand what you're doing.

Concentricity is important because lack of it means the head of the valve is bent slightly each time it closes, in turn bending the stem slightly, so after tens of thousands of cycles the head can break off. Depending on who you believe, concentricity needs to be less than 0.001"-0.0015" per inch of valve head, i.e. 0.0018"-0.0026" for the Ariel's 1-3/4" valves. The Sunnen book I referred to in my previous post quotes the 0.001"/inch value so that's my benchmark, i.e. the concentricity needs to be less than 0.0018" for the Ariel's valves to meet that spec.

I made a ring of Al to simulate the spigot on the cylinder. Since it's just as easy to make something like that accurately as not that's what I did, starting from a 4"-dia. rod and matching the dimensions of the Ariel's spigot. I then measured the concentricity, bolted the torque plate in place and measured again, then bolted the spark plug in place and measured again.

I only measured the exhaust seat, which is the one I had lapped prior to chaterlea25 chastising me. But, the results are clear as well as reproducible. The concentricity of the seat in the bare head is no more than ~0.0005" (half a division on the indicator). Basically, it's '0' within the reproducibility of my measurements, as it should be given that I had just lapped the seat to be Concentric. However, with the torque plate bolted on at 20 ft.lbs. it increases to 0.002". Add the spark plug and it increases to 0.0025-0.003". I wanted to simulate whatever torque I apply by hand to a spark plug so I didn't use a torque wrench on it and instead used a 3/8" ratchet.

What this shows is, when the head and spark plug are bolted in place the concentricity of the exhaust seat in this pretty massive chunk of cast iron is increased to be ~50% more than the specification given by Sunnen. Presumably the intake seat shows a similar effect. I'll definitely be making and using torque plates whenever I deal with heads in the future, especially less massive, less rigid ones made of Al. I'll leave everything bolted in place so it will be ready when the Neway cutters arrive.

OK, those of you who silently bet the torque plate would make no difference on the valve seat concentricity, you lost that bet. Pay up.

Attached Files Torqueplate01.jpgTorqueplate02.jpgTorqueplate03.jpg
Last edited by Magnetoman; 04/16/18 6:18 pm. Reason: 'Persistence of Memory'
Re: 1928 Ariel Model C [Re: Magnetoman] #732074
04/16/18 4:50 pm
04/16/18 4:50 pm
Joined: Feb 2014
Posts: 417
Cork Ireland
C
chaterlea25 Offline
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chaterlea25  Offline
BritBike Forum member
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Joined: Feb 2014
Posts: 417
Cork Ireland
Oops blush blush

The distortion of the head is a new one on me clap clap
More work for me as well frown
Can you see any "grooving" on the exhaust valve seat where its been lapped?
Remember to allow for some "stretch" of the valves when setting the initial valve clearances

John

Re: 1928 Ariel Model C [Re: chaterlea25] #732081
04/16/18 5:22 pm
04/16/18 5:22 pm
Joined: Oct 2017
Posts: 53
England
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George Kaplan Offline
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George Kaplan  Offline
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Joined: Oct 2017
Posts: 53
England
Originally Posted by chaterlea25
The distortion of the head is a new one on me clap clap
More work for me as well frown


Hello John, if I am not mistaken you are using a 24J or 24F Harley?

My 20F has a head and cylinder that are one casting rather than a separate head. If yours is the same (and I am pretty sure it is) then I would expect (with no scientific facts to back up my hunch) that the distortion of the valve seats on tightening down the cylinder would be much less than on a bike with a separate head.

However I am only guessing, what do you and MM think?

John

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