Author Topic: New Brodak 40 (Read 7781 times)

Motorman · « **on:** September 01, 2016, 09:07:41 PM »

Did the earlier Brodak 40s have a bronze bushed crankcase? I have one from the latest batch and the crank just runs in the aluminum case.

The venturi it came with measures .303" is that as big as the older ones?

MM

Clint Ormosen · « **Reply #1 on:** September 02, 2016, 12:05:21 AM »

Can't answer the bushing question as I haven't disassembled any of my Brodak 40's that far. But the standard venturi size for them is .300.

Massimo Rimoldi · « **Reply #2 on:** September 02, 2016, 12:46:33 AM »

Quote from: Motorman on September 01, 2016, 09:07:41 PM

Did the earlier Brodak 40s have a bronze bushed crankcase? I have one from the latest batch and the crank just runs in the aluminum case.

The venturi it came with measures .303" is that as big as the older ones?

MM

I checked my,
no bronze bearing and .301 venturi

Massimo.

Chris Belcher · « **Reply #3 on:** September 02, 2016, 10:14:03 AM »

My new one does not have a bronze bushing. The venturi in my old one was .309 the new one is .301. I got a .290, .280 and .270 from Jim Lee....I use the .280 in a Gieseke Nobler, plenty of power on RSM 10 x 5 prop and 4.5 ozs 10/22.

Motorman · « **Reply #4 on:** September 02, 2016, 02:21:49 PM »

Thanks guys. Does anyone have an old one they can pop the drive washer off and look for bronze?

Maybe the new one has a high silicon aluminum bushing??

MM

Motorman · « **Reply #5 on:** September 08, 2016, 11:58:28 AM »

Pulled the head off and found quite a bit of binding on the bolts of both engines. I drilled the holes out to #30 and it helped a little. The heads of the bolts are binding on the cooling fins.

The best way would be to use a 1/4" counter bore to open up the space as the factory counter bore is only 6mm. I don't have that tool so, I opted to reduce the diameter of the bolt heads a small amount.

After drilling #30 and turning down the heads it was still binding. Had to break out the dremel tool and grind the cooling fins back in a few places. Now the bolt heads had good clearance but there was still one bolt hole that was so far off I had to use a mouse tail file to oblong the hole a little.

After all that on both engines I put the bolts in just off their seats and the head can jockey back and forth a little which shows no binding. I torqued them down in stages with a crossing pattern and compression feels great. Ready to start break in.

People say 20 one minute runs before the B40 is ready to fly and 40 flights before it's fully broken in but, I'm hoping this will shorten that by reducing the side load on the head bolts.

MM

Steve Helmick · « **Reply #6 on:** September 08, 2016, 04:32:42 PM »

JB might appreciate this info. The manufacturer shouldn't be sending "kit" engines to the USA. I'd expect the holes in the case and head would be in a CNC program, but maybe the spotting drill went TU or something. I'd wonder if turning the head 180* would have changed the fit?,,,,,,

Once the Counterbore is put in, it'd take a really long pilot to do a rework, and that wouldn't be a great solution. Plunging with a 1/4" end mill would be ideal, but like you, I don't have a lot of options since retirement. Or before, for that matter. They didn't appreciate "G-jobs" much where I worked...the bastards!

Steve

Motorman · « **Reply #7 on:** September 08, 2016, 06:30:57 PM »

The counter bore with long pilot could be done in the drill press but I didn't have one. The 1/4" end mill would need a jig to hold the head on the rotary table and then all the alignment work. I didn't feel like setting it up so I grabbed the dremel lol.

I tried doing a 180 with the head (first thing I tried) but had the same result. I think the right rear bolt hole went off the reservation, it's too close to the bore about .010". It's probably not that much of a problem but it's something I could fix so I fixed it.

Also, the fuel discharge holes in the spray bar looked a little small to me so I drilled it straight through with a #57 drill. I left the other engines nva stock so next time out I can compare needle settings with the same prop, fuel, rpm.

MM

Roy DeCamara · « **Reply #8 on:** September 08, 2016, 11:52:06 PM »

The B-40's that I own are all earlier generations and the crankcase is bronze bushed in front and behind the venture. The rods were NOT bushed in the upper or small end.

Lauri Malila · « **Reply #9 on:** September 09, 2016, 09:48:58 AM »

I wouldn't worry about small end bushing if the conrod alloy is good.
Bronze bush is usefull in bottom end because all kinds of dirt goes past it at every intake stroke, and things get embedded more easily in aluminium than bronze.
But the lack of shaft bearing is a bad sign, pure laziness. Unless the bushes are in white metal? L

Motorman · « **Reply #10 on:** September 12, 2016, 10:03:31 PM »

Does anyone run the B40 in a full 4 stroke? I know it was made for the 4-2-4 so, what would it need, a higher compression head?

MM

Steve Hines · « **Reply #11 on:** September 13, 2016, 02:12:30 PM »

I have both, the bronze bushing one does not run well, put different piston and liner and crank, motor will run away. There is something different a out the case. Samantha has been running the same motor for 3 years or more and it still runs great. I looked at the new cases and where the bearing would be is a lot different color. I was thinking it was some type pf coatings or a different aluminum. My brother did not like the fact there was not brass in his, but they run great, and for a.long time

Chris Belcher · « **Reply #12 on:** September 13, 2016, 04:03:18 PM »

I run my Brodak 40 in a sloppy 4 with a RSM 10 x 6 prop launched at 8900 rpm with a .290 venturi. It just breaks at the tops a little and pulls fine. This is on a Gieseke Nobler that weighs 45 ozs on 65' lines (handle to C/L) but I have also run it on the same plane with a TT 11 x 4.5 prop launched at 10,000 rpm and it feels about the same and lap times are equal...5.2 but it is much more of a wet 2 run. NOW...haven't flown in much wind yet and that is where I suspect the 6" prop will present issues with wind up...

Robert Zambelli · « **Reply #13 on:** September 14, 2016, 08:13:22 PM »

I have, in my possession, the oldest Brodak 40 in existence.

It has a bronze front bushing.

I have no idea what plug it has - it's never been out.

Depending on the plane it was on, I've used props from 10-5, 10-6, 11-4 and 11-5. All wooden, all wide blade. Never tried a plastic prop.

Brodak 10/23, 50-50 fuel exclusively.

I've lost count of how many planes it's been on and have no idea how much time it has but it has never been disassembled or modified.

The runs are absolutely perfect.

The best 4-2-4 engine I've ever used.

Bob Z.

Motorman · « **Reply #14 on:** September 14, 2016, 09:37:43 PM »

I ran both my engines today. One with the drilled out spray bar and the stock one. Same prop glow plug and fuel, both turned an APC 9-6 sport prop 12,600 with just a hint of 2 stroke in the note. I checked both needles and they were both out 3 turns which tells me the holes in the stock spray bar are big enough.

MM

Robert Zambelli · « **Reply #15 on:** September 15, 2016, 09:21:01 AM »

I compared the original and new spray bars.
The original had two holes, .032 diameter.
The new ones have two holes, .028 diameter.

I tried the new one in my old Brodak 40 and it ran perfectly.

Bob Z.

Allen Eshleman · « **Reply #16 on:** September 15, 2016, 09:51:53 AM »

Does the new B40 run as good as the older ones?

Robert Zambelli · « **Reply #17 on:** September 15, 2016, 03:00:24 PM »

As far as I know, it does.

I have sold a number of them and gotten very favorable feedback.
I still have some in stock but I think they will be gone soon.

And my old one runs so well, it will go in a plane soon.

Bob Z.

Evgeny Khromov · « **Reply #18 on:** September 20, 2016, 05:44:16 AM »

Hello everybody. Answer on question of new Brodak 40 from the manufacturer. On russian stunt forum.

Quote

Бронзовые втулки для коленчатого вала отсутствуют уже 12 лет. Причин несколько.Так как втулки заливались алюминием при заливке кокиля расплавом они Очень часто оплавлялись-- что приводило к браку.Т.е. имели проблему. Пробовали запрессовывать-проворачивались коренные.Себестоимость двигателя небольшая - прыгнуть по цене и усложнить нельзя. Вот и вспомнили наш жигулевский распредвал и выкинули все втулки. Но так как картера у нас отлиты из сплава системы алюминий+медь+кремний+магний то после ТО картер имеет твердость 120-140 единиц по Бринелю и кристаллы кремния способствуют уменьшению трения. Так что экстренное выбрасывание втулок никоим образом не сказалось на работоспособности и ресурсе двигателя. Кстати убрали попутно проблему наволакивания бвонзы на кол.вал

Gerald Arana · « **Reply #19 on:** September 20, 2016, 09:29:27 AM »

Quote from: Evgeny Khromov on September 20, 2016, 05:44:16 AM

Hello everybody. Answer on question of new Brodak 40 from the manufacturer. On russian stunt forum.

Gee, that's helpful.............

Would you mind putting that in "English" so us poor mortals can read it?

Thank you, Jerry

Robert Zambelli · « **Reply #20 on:** September 20, 2016, 09:36:42 AM »

From "Google Translate"

"Bronze sleeve for crankshaft absent for 12 years. Reasons neskolko.Tak like aluminum sleeves were filled by pouring molten mold they very often resulting in oplavlyalis-- braku.T.e. We had a problem. We tried to embed-crank the engine korennye.Sebestoimost small - to jump on the price and can not complicate. Here and we remembered our Zhiguli camshaft and threw all bushings. But as we crankcase are cast from aluminum alloy system + copper + silicon + magnesium after THEN housing has a hardness of 120-140 Brinell units and silicon crystals help to reduce friction. So emergency ejection sleeves in no way affected the performance and resource engine. Incidentally removed in passing the problem of galling bvonzy on kol.val"

Evgeny Khromov · « **Reply #21 on:** September 20, 2016, 11:14:17 AM »

Quote from: Gerald Arana on September 20, 2016, 09:29:27 AM

Gee, that's helpful.............

Would you mind putting that in "English" so us poor mortals can read it?

Thank you, Jerry

I translated as best he could

Bronze bushings for crankshaft no longer 12 years
for this reasons few
When we did the crankcase. there were many defects with the sleeve. sleeve melted or cranks
the cost of a small engine and
Make for another not, the price does not allow
We remembered the method of automotive and removed the sleeve
as the crankshaft is made of aluminum + copper + silicon + magnesium
That crankshaft has a hardness of 120-140 Brinell and silicon crystals help to reduce friction.
So emergency ejection sleeves in no way affected the performance and resource engine.
Incidentally removed in passing the problem of bronze galling to the crankshaft

Motorman · « **Reply #22 on:** September 20, 2016, 10:31:21 PM »

Ok, so it's some kind of special aluminum bushing, very good.

MM

Steve Helmick · « **Reply #23 on:** September 21, 2016, 04:21:50 PM »

He says the crankshaft is made of aluminum alloy, but means the crankcase. If you wanted to get a bronze bushing installed, that could be done, but it might not be real cheap. Probably would be best to bush a new case, instead of one with a worn (oval) bore. Could ream it up to bushing size and have more hope it would be square to the cylinder bore.

Google Translate isn't Google Good, is it?

Steve

Brett Buck · « **Reply #24 on:** September 21, 2016, 09:09:21 PM »

Quote from: Steve Helmick on September 21, 2016, 04:21:50 PM

He says the crankshaft is made of aluminum alloy, but means the crankcase. If you wanted to get a bronze bushing installed, that could be done, but it might not be real cheap. Probably would be best to bush a new case, instead of one with a worn (oval) bore. Could ream it up to bushing size and have more hope it would be square to the cylinder bore.

Or. as a crazy alternative, assume they know what they are doing, run it as it came, and then evaluate how it works!

Brett

Robert Zambelli · « **Reply #25 on:** September 21, 2016, 09:20:38 PM »

First off, it's neither difficult or expensive to re-bush an engine - I've done many.
Second, regarding the Brodak 40, I have NEVER heard of one wearing out the front bushing. It may have happened but I'm not aware of it.

Bob Z.

Clint Ormosen · « **Reply #26 on:** September 21, 2016, 10:16:33 PM »

I've been running a couple aluminum bushing Brodak 40s for several seasons now and they're still good to go. Not sure why anyone needs to be fiddling with them. They're great as delivered! Proper run-in required, of course.

Motorman · « **Reply #27 on:** September 21, 2016, 10:25:23 PM »

Glad about the bushing report, I can leave that alone. The reason I fiddled with them is at the end of post #5. Plus I think they revoke your motorman card if you ever run an engine completely stock.

MM

EddyR · « **Reply #28 on:** September 22, 2016, 04:33:09 PM »

The Rustler/40 is the same way no bushing and they do not wear out the crankcase. I was startled many years ago when I bought a new crankcase and noticed no bushing.

Ed

Steve Helmick · « **Reply #29 on:** September 24, 2016, 05:29:10 PM »

Quote from: Brett Buck on September 21, 2016, 09:09:21 PM

Or. as a crazy alternative, assume they know what they are doing, run it as it came, and then evaluate how it works!

Brett

I was only pointing out the alternatives, not intending to suggest that it be done. It's well known that the ex-Soviet bloc countries have access to some really good aluminum alloys with high silicon contents that work extremely well for toy airplane engines. I'd run it as-is.

FWIW, Mike the engineer/machinist in England had his first B-40 go wonky on him, and had to fit a bushing. As I recall, there was a problem with the "cast-in-place" OEM bushing coming loose in the case. There is some reference to this problem in the translations above.

I don't know how the bushing would be located in the casting mold, but I did have an OS Max III .35 that had the bushing mislocated (not far enough aft), resulting in the crank dragging on one side of the casting, shaving aluminum off and running it through the engine...not good. That engine also had a huge steel curly chip (from the drilling op.) in the crank bore, but as I'd taken the backplate off to inspect & removed it, that didn't become a problem. It had a short life. I probably should have sent it back to World Engines, but was afraid they'd be PO'd that I took the backplate off.

Steve

Chad Hill · « **Reply #30 on:** September 25, 2016, 04:31:39 PM »

Just curious how the P & L fit has been on the B40. I have several B25s and the fit has ranged from good to mediocre. A spare set I purchased years ago from Brodaks had almost no compression when installed. For some reason it did not come as a matched set. The P & L were sold separately.

Motorman · « **Reply #31 on:** September 25, 2016, 07:54:16 PM »

The two examples I have are fit a little light for AAC but the taper and roundness was very good. This makes them very user friendly. After 5 two minute runs on the bench I started flying with it. No problems at all in the air. It's not hard to start at all but, it doesn't start like an engine with an excellent fit still, it's a good fit. I'm very happy I didn't have to run it 20-40 times to break it in like some have said. At the price point I think I'll get my moneys worth.

I had plenty of laps left over after the PA pattern with 5oz tank and the engine running with very little break. It pulls my Banshee around with authority with an 11-4 on 10% nitro. These new B40's have allot of power, I had to put on less pitch and open the needle to get the speed down. I need a bigger airplane or a smaller venturi.

Chad, I can relate. I have a B25 that flames out from lack of compression and I didn't wear it out, it came that way. I've been wanting to get into sleeve pinching this winter so maybe there's some help. If you want more info check out RayAracing. I have used him several times. It's about $20 but he does an excellent job.

MM

Chad Hill · « **Reply #32 on:** September 29, 2016, 04:13:18 PM »

"Chad, I can relate. I have a B25 that flames out from lack of compression and I didn't wear it out, it came that way. I've been wanting to get into sleeve pinching this winter so maybe there's some help. If you want more info check out RayAracing. I have used him several times. It's about $20 but he does an excellent job.

MM"

-Thanks for the tip about Ray, MM. I think he posts on an RC forum. I have a couple of brand new B25 P&Ls that need fitting. Chad