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  #121  
Old 25-12-20, 14:57
Bob Phillips Bob Phillips is offline
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Here are dimensions for crankshaft bolts. If anyone has a source for 5/16 tapered washers please advise otherwise you may have to modify conventional cap screws or custom machine.
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  #122  
Old 26-12-20, 00:23
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Tony Smith Tony Smith is offline
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There is a company that makes high quality bolts, nuts and studs for performance cars and racing teams, which is also highly sought after by the aftermarket hot rod and muscle car industry:

https://arp-bolts.com/

On page 21 of their catalog (top right of the home page), they list the requirements for custom dimensioned bolts and studs. ARP are NOT hardware priced bolts and fasteners, but they are reasonably priced for the high quality items they are.

https://arpcatalog.com/20/
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  #123  
Old 30-12-20, 21:16
Don Phillips Don Phillips is offline
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Default Possible simple manufactured bolt

A drawing of the bolt Bob had supplied dimensions for and an idea for making one from an ASTM F835 bolt. 120K PSI
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Last edited by Don Phillips; 30-12-20 at 21:22.
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  #124  
Old 04-01-21, 20:40
Bob Phillips Bob Phillips is offline
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Thanks Tony for the link to the ARP catalogue. Do they ever make NICE bolts and fasteners. I will try to get a quote from them on the costs of making some crankshaft bolts of the type we have been discussing. Meanwhile just waiting for some capscrews from Mcmaster-Carr to see if something useable can be put together at home. Will share the results when done.
I wanted to respond to Dan comments on the care and feeding of the C4 engine in his M18(post118). Now Dan has a really beautiful M18 and has had a hand in other high end, high quality restorations as well. When I was contemplating purchasing armour a decade ago he is one of the people I turned to for an opinion about the pros and cons of such an investment. In short, I value his opinion. Dan's M18 feeding regime is more of the champaine and caviar approach than the meat and potatoes, but as an owner operator he knows more about the need to pamper a 75 year old vehicle and its increasingly rare engine, than most people do. Aside from the higher costs of using AV gas and aviation oils I don't see how this could be an issue. In fairness, several years ago when I was anxious to start up and run both C1 and -46 engines I asked a US radial engine builder that I had known for many years, about fuel choices. His recommendation for both was to use the best pump gas you could get. That mean 91-93 octane but NO ALCOHOL.
In my current fleet of gas burning machines I run the regular slop only in a couple of daily drivers. Everything else;jeeps, trucks, lawn mowers, chainsaws, wood splitters, generators and my 4.2 L Jaguar ALL use no lead, high test fuel. I have had absolutely no fuel issues since I switched to high test. With respect to oil, Jaguar forums recommend the very best grade of synthetic oil you can find. So why not the best for your radial? Finally, at some point in the past I also recall Dan's recommendation to get oil tested for metal content from time to time as a way of preventative maintenance. Big rig owners do this all the time to diagnose the condition their engines are in and hopefully head off major problems before they can occur. Sounds like a very reasonable and prudent recommendation to me. So thanks to Dan for his input and first hand experiences in running his M18!

Last edited by Bob Phillips; 04-01-21 at 21:51.
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  #125  
Old 05-01-21, 00:54
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Thanks for the kind words Bob! When the machine is as valuable as they have gotten - I can see no reason to cut corners; saving a few bucks makes no sense in my way of thinking if the risk (however small) is damaging a rare and a hard to replace machine. So far my engine oil analysis is showing no metal being 'made' and it only costs $18 to get the results!!!
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  #126  
Old 06-01-21, 02:01
Bob Phillips Bob Phillips is offline
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And so, here is the prototype crankshaft bolt in grade 5.
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  #127  
Old 07-01-21, 22:42
Bob Phillips Bob Phillips is offline
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So for now, we are locked down for covid 19and it gives me the opportunity to stay home and get a few things done. One thing I have done is start rooting through some old magazines I have collected and I want to share some of the information I found with the forum. From the publication "Warbirds International", May 2000. There is a very interesting article about what kind of oil to use in large, hard working radial engined aircraft used to fight California wild fires. The main point of the article is that the California Dept of Agriculture decided to change the type of oil used in large radials ( like 1500HP Wright 2800s) from single grade 120 weight aviation oils to Phillips 25w-60 multigrade olis ( sorry no family connection!) the maintenance team reported " a decrease of 35-50% in oil consumption and a noticeable decrease in both cylinder head and oil temperature" . They indicated the multigrade oil offered better protection of the master rod bearings than did single weight oil.
With respect to diagnostics on the engines .."the biggest problem indicator had been metal in the oil screen..usually from main bearing failure" Further.." the type of metal found will give a good idea of whats going on in the engine and whether it needs to be pulled for preventive maintenance...if we find aluminium..its either from a scuffing piston or the blower rubbing on the ..case...if its brass or bronze it's most likely from the bushing ..inside the nose case or ..accessory gears..But if its silver, it's either from the master rod bearing or from the cam bearing- the only two engine parts that have silver.." Very useful diagnostic information, though I am not sure that our 975s have any silver bearings in them!
There is a final comment about the fuel used. " We used to use 115-145 octane fuel...(high lead) now, 100 octane low lead aviation fuel..this effectively drops horse power from 1525 to down to 1475.." but mechanics compensate somewhat for this fuel change by changing the spark advance from 25 to 20 degrees..". They claim the toll of damaged engines is typically about 3 per season, but there were no failures the season they started to use multigrade fuels. So fuel and oil quality clearly matter!
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  #128  
Old 15-01-21, 20:49
Bob Phillips Bob Phillips is offline
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Here are some inspiring photos for radial engine fans ! From the book " Making Waves... Navy Women of WW2" Looks like P&W engines.

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  #129  
Old 18-01-21, 16:09
Bob Phillips Bob Phillips is offline
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Just a follow up on the discussion of suitable fuel grades for the 975. I have exchanged emails with retired engine builder and instructor Tom Henderson from down under. Tom owns and operates a beautifully restored C1 that he demonstrates at shows and events from time to time. He has been kind enough to respond in detail to a variety of newbie questions about fuels, oils, compression ratios and ring types and I really appreciate his patience! Tom tells me he is running 92 octane no alcohol fuel in his engine. He thinks this is a good compromise between lower alcohol infused fuels and higher aircraft oriented gas. While the dangers of using too low a grade of fuel in a higher compression engine are well known, there may also be consequences for running too high a grade as well. This may include elevated chamber temps and burnt valves for little gain in performance or economy. He also runs a semi synthetic 20-40 diesel oil which has better anti corrosion additives and detergents to try and offset corrosion in an engine that only runs occasionally. Cylinder temps (#1)! are about 400 degrees which are well within the acceptable range.
Another interesting thing Tom pointed out is that an aircraft engine runs a cam where there is higher cam lift and more overlap of valve opening, a cam which favors higher speed operation and which idles poorly, hence limiting their use in a land vehicle engine. Hmm, I wonder if I could get some -46 cams reground to C1-C4 specs? In this day and age it is unlikely that any of the 975 engines would get the abuse and hours of a vehicle actually involved in conflict. Hopefully with care and routine maintenance, a radial engine should run, for shows and events, for many years without major problems.

Last edited by Bob Phillips; 19-01-21 at 05:03.
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  #130  
Old 18-01-21, 16:51
Bob Phillips Bob Phillips is offline
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Here are the comparisons of a -46 cam on the left and a C1 cam on the right.You can clearly see the difference in the lobes. The closest lobes are for the intake valves and not surprisingly, the -46 has a lot more air/gas valve inlet time!
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  #131  
Old 18-01-21, 22:45
David Herbert David Herbert is online now
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Bob,
I know that C4 and C1 had different superchargers to each other but I thought that the cams were different too ?

David
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  #132  
Old 19-01-21, 01:57
Bob Phillips Bob Phillips is offline
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Good question about the cams, David. I had a quick run through the manuals and here is what I found. The M18 (G163) book lists 3 cams;
-G104-7006836 (CO201932) being standard for C4
-G104-0100293 (CO200742) (C66800) bolted for the C1
( this C1 being replaced/superceded by)
-G104-1531497 (CO242347) rivetted for C1
so it seems to suggest that there were both C1 and C4 cams...BUT
-my interchange book lists cam 201932 as interchangable in both C1 and C4 engines. Then check out the photos below. I just got these today and they show the damaged engine with sheared off bolts (that restarted this thread a couple of weeks ago) going back together with NOS bolts. Look closely and you can see the number on the cam of this C4 engine. It says 202347 which is supposed to be a C1 cam.(This is the cam in my early Sexton book with C1)
Finally, I reread the " Ordnance Development of the Wright-Continental R975 Radial Engine", from the Sherman Site. It makes reference to changing the aircraft cam for ground use. " To obtain the highly variable speeds required in tank operations, the engineers changed the intake and exhaust cams to decrease the valve overlap, to obtain higher torque at lower RPM and to improve idling characteristics...". But there is no mention through the rest of the report (including where changes made to upgrade C1 engines to C4s are listed) about a different cam. the report says that 85 percent of the parts between a C1 and C4 are interchangable.

So, without a 201932 C4 cam to examine, I would conclude that the cams are interchangable between the C1 and C4.

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Last edited by Bob Phillips; 19-01-21 at 02:04.
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  #133  
Old 27-01-21, 19:08
Bob Phillips Bob Phillips is offline
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Default R975 cylinders and a story

As I am stuck at home during the continuing covid days I thought I would write abit about cylinders (mostly C1) and an interesting historical story I uncovered during my research.
Much earlier in these pages I included descriptions and photos of both C1 and C4 cylinders. I also compared them to the -46 cylinder off the helicopter engine. I have been rooting through my trailers looking to put together a few sets of cylinders and I thought I would give you a look at what I found. First, most cylinders are available in either steel bores (usually new black cylinders ) or chrome cylinders ( reconditioned with chrome bore to bring them back out to standard dimensions).They are usually painted primer red. These cylinders are choke bored meaning they have a taper of about.007 being bigger at the bore opening.They are very similar to the original aircraft type cylinders made by the Wright Corporation in the prewar years, but probably don't have the nitride hardening of earlier Wright cylinders.. Both the black and red cylinders have spark plug coolers and cast bosses beside the rocker boxes. The aviation cylinders (photos 3&4) are easily identified by the large size of the spark plug coolers and by the fact that the cast bosses along side the rocker boxes are drilled and threaded to accommodate baffles.
While some 7 cylinder (760) Wright aircraft engines apparently did not use any spark plug coolers, most did. They were a repair item and could be replaced on C1 engines. Note that C4 engines did not use them.
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C4 cylinders were designed to significantly increase cooling. The increased fin area amounted to 50% on the head and 100% more for the barrel. The barrel no longer was machined with fins but instead an aluminum "muff" was slid over the steel barrel and this design was used on many other large radial aircraft engines of the time. At the bottom of the next post are photos of a steel barrel of the C1 style with machined cooling fins, and a much larger radial cylinder from a bomber, with aluminium muff on the cylinder base.

Last edited by Bob Phillips; 27-01-21 at 20:31.
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  #134  
Old 27-01-21, 20:12
Bob Phillips Bob Phillips is offline
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The steel cylinders that I have were manufactured at the Rock Island Arsenal in the early 1950s. They were built as spares for the 50,000 plus engines that had been built in WW2 and were still widely used around the globe.
The chrome cylinders are used cylinders that were reconditioned for the US government (the RIA) probably also in the 1950s. Unlike chrome cylinder repair jobs done today, they have the complete package; so including new valve guides and valve seats. As I checked the remanufacturing details provided on some of the box labels (see below) I discovered an interesting story.
Some of the cylinders were reconditioned by the Van der Horst Corporation. These cylinders were reconditioned by honing the used bores out oversize, and then chroming the bores back to standard size. This technology had been developed through a patented process by a Dutch engineer named Dr Hendrik Van der Horst in 1936. He called his patented process "porous chrome". He improved his chrome plating process again in 1943 and set up a plating company in the USA called Van der Horst Corporation of America ( later United Van der Horst). His challenge had been to create a plating process that was not as hard and smooth as traditional chrome plating. The chrome needed to have the ability to retain oil in it's surface. This was accomplished by chroming the bores in the traditional way but then near the end of the process to reverse the polarity of the electrical charge which attracted the chromium solution onto the bore surface and in so doing, create a series of tiny grooves and furrows which would retain the lubricating oil. The finished bore has a frosted appearance but is still very hard.
While Dr Van der Horst was setting up shop in the USA, that nation entered the war against Germany. At home his son Kuno was in hiding with the wider group of people that included Anne Frank, having refused to swear an oath of allegiance with the German occupiers. His wife Catharina provide refuge to a number of displaced Jewish citizens but ended up having the family home (Alexanderlaan 22, Hilversum) seized by German forces for the use of their officers. After the war the family moved to the US. There is much more to this fascinating story and you can find it by googling.. "More Than A Footnote, The VanderHorsts, Anne Frank and World War 2 Resistance" .
A final word about cylinders. Steel cylinders are easy to work with, the rings are quickly seated and they have minimal oil consumption. They look great and are often the choice of high end collectors and restorers. Chrome cylinders on the other hand, area little more difficult to deal with. It often takes a much longer time to get rings to seat. One old A&P mechanic I know told me he always uses a ball type glaze breaker to encourage ring seating. Chrome cylinders frequently use more oil than steel though some have reported that this is really most apparent during the first few weeks of break in. Most importantly however, may be the much greater resistance that chrome has to rust and corrosion than steel. If you do not run your vehicle on a regular basis or if you have a cold, damp storage facility, steel cylinders may not be your best choice. I have photos of engines I have dismantled that sat for 25 years, and often it would appear at first glance that with a bit of tidying up maybe the chrome could be used again. Not so with the steel cylinders which are usually badly rusted and pitted.

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Last edited by Bob Phillips; 27-01-21 at 20:27.
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  #135  
Old 10-02-21, 12:54
Bob Phillips Bob Phillips is offline
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Default the good old days...

I wish I had bought a few of these...
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  #136  
Old 11-02-21, 02:58
maple_leaf_eh maple_leaf_eh is offline
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Quote:
Originally Posted by Bob Phillips View Post
...

Some of the cylinders were reconditioned by the Van der Horst Corporation. These cylinders were reconditioned by honing the used bores out oversize, and then chroming the bores back to standard size. This technology had been developed through a patented process by a Dutch engineer named Dr Hendrik Van der Horst in 1936. He called his patented process "porous chrome". He improved his chrome plating process again in 1943 and set up a plating company in the USA called Van der Horst Corporation of America ( later United Van der Horst). His challenge had been to create a plating process that was not as hard and smooth as traditional chrome plating. The chrome needed to have the ability to retain oil in it's surface. This was accomplished by chroming the bores in the traditional way but then near the end of the process to reverse the polarity of the electrical charge which attracted the chromium solution onto the bore surface and in so doing, create a series of tiny grooves and furrows which would retain the lubricating oil. The finished bore has a frosted appearance but is still very hard. ...
Funny you mentioned bore diameters and hard chrome plating. My father was an Olympic shooter and had won a Queen's Medal for Champion Shot as a young soldier. He was a big deal for all things shooting. When the FN C1A1 rifles first appeared, he naturally tested as many as he could find in order to get a very competitive rifle as he went after more Queen's Medals. I remember him telling me that the best rifles were the absolutely earliest serial numbers and first batch of barrels. It seems they had been bored with new sharp tooling and were pretty good as barrels went. Then someone realized they needed to be chrome plated, so these barrels had chrome on top of specified dimensions. They were tight! And shot like crazy! He ended up with 5 Queen's Medals, 1 with a No.4 and 4 with FNs.
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  #137  
Old 13-02-21, 15:04
Bob Phillips Bob Phillips is offline
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A very interesting story about chrome rifle bores,thanks for sharing. Its funny but now days most of us associate chromed barrels with chinese rifles like the SKS. I don't know if any of our modern sport rifles manufacturers use chrome bores. My understanding about SKS bores is that they are highly resistant to corrosion.
On a slighly related topic I found a video on the net showing the use of a non electrical conducting "arbor" or " twisted core" with wires twisted along it. It is inserted in a barrel blank and electricity applied and it erodes the bore beside the twisted(spiral) electrodes to create etched rifling in the barrel. AN interesting idea, ever heard of this before?
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  #138  
Old 13-02-21, 16:36
Perry Kitson Perry Kitson is offline
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Quite often standard steel bore cylinders used chromed piston rings, and on the chrome bore cylinders, standard steel rings, no chrome. It takes forever for chrome rings and chromed bores to seat in.
I had a number of interesting conversations with different companies that do the channel chroming on aircraft cylinders regarding the choking of the bore diameter. C4 cylinders were to have .008" to .010" of choke when new, anything less than .004" was NS.
One company in particular said they had done barrels with no choke and up to .010".
Maximum build up of chrome seemed to be .006"(.012" on dia.) for the repairing of used cylinders.

Regarding chromed rifle bores, most competitive shooters now prefer non chromed bores for accuracy. Hard chrome makes cleaning easier, and greatly extends the life of the barrel.

Last edited by Perry Kitson; 13-02-21 at 16:46.
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  #139  
Old 06-02-22, 03:15
Bob Phillips Bob Phillips is offline
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Default piston ring question

I wanted to revive this post to ask for some input from our knowledgable membership pool. I have been hunkered down at home (like many of you) for a long time now, and have been using the time to get some longstanding jobs finished. One job has been to continue to sort through and catalogue my collection of engine parts. One item I have found raises questions so here goes;
I have a bunch of sealed ring packages for the 975 that are described (in one book) as being "tinned". They are light coloured and almost look like they have been spray painted with aluminium paint. The coat seems to wear off or rub off relatively easily. I have attached photos where you can see the cast iron base material beneath the coating. These spots are not corrosion.
Does anyone know anything about tinned rings, application, pros and cons?
Any input appreciated.
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  #140  
Old 06-02-22, 16:02
David Herbert David Herbert is online now
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I can only think that the tinning is for quicker bed in or corrosion resistance in storage. I have never heard of this before in any application so, sorry, not much help.

David
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  #141  
Old 31-10-22, 20:46
Bob Phillips Bob Phillips is offline
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Default chrome vs steel

In various previous posts I have talked about chrome vs steel cylinders. One of the big advantages to chrome is their resistance to corrosion in damp or high moisture environments. I have made mention of an engine I opened up to check for damage ( and found smashed pistons, cylinder case etc) and point out that it was equipped with steel cylinders. (first photo)

you can see that the cylinder bore is badly rusted and even in the best of circumstances a steel bored cylinder will likely need some level of reconditioning to be serviceable again. So now check out the next group of photos. They show an engine, (opened up to ensure no catastrophic damage) with chrome bores. This engine was rebuilt in 1945, has been stored outside under cover in the weather extremes of Canada. You can see there is only the spattered beginnings of rust on the chrome, some of which I wiped off with an oily rag. I seems possible that the pistons may be removed without too much difficulty and may even prove to be reusable in a fresh overhaul.
The downside of chrome (as Perry pointed out in post 138) is the rings take much longer to seat and they typically use more oil. However for a tank owner who doesnt have the advantage of a temperature controlled storage environment or who doesn't start the vehicle regularly, chrome may well be the way to go. Overall, a nice engine considering it has been sitting all these years!
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Last edited by Bob Phillips; 31-10-22 at 21:01.
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