the Wasp

My Feedback: (1)

sorry, I was suggesting that straight type Manifold (bored out) for that hopped up 180

Jim

Captcrunch44

I turn a 11X7 APC 11500 with my 56 on 15% fuel.

SrTelemaster150

Longer manifold runners increase intake charge velocity and thus produce more torque. Just look at all of the current high output automotive engines.

There would be little benefit of utilizing a short intake manifold with a bore larger than the intake port of the head. With the FA-180 manifold I ported the updraft portion to 12mm and left the runner from the bend to the intake port @ 11mm to promote velocity at the port.

An interesting note is that neither the stock 9.6:1 compression FA-180 nor the 11:1 compression version with the FG-57 piston showed any performance gains with the larger carburetor/ported manifold. Only the improved breathing of the 12.7:1 compression combustion chamber showed a boost in RPM from the induction modifications.

acdii

I use Fox plugs too. Grab them all up whenever I find them at swaps. Have some Merlins too, but can't really say how well they work as I don't remember which engine I have them in. Also have a couple type F, but use those in the OS engines.

the Wasp

My Feedback: (1)

yes I understand, but only if the head porting can handle that amount, never the less a straight manifold will be better than the stock one with a 90% bend, a straight one will allow a faster charge with a shorter length, and with being straight you can easily tailor the length for peak performance,,, just a suggestion anyway

Jim

acdii

Just as long as it doesn't ice up. Had that happen on one of my engines on a very humid day while running it on the stand.

Rudolph Hart

Jim i don't think plugs make a big difference in the narrow range we talk about re fourstroke model engines on nitro.Sorry i can't help build a snowman there the weather here is perfect motorcycle style cool sunshine.When it's 40c plus here it just eats tyres.

Hobbsy

My Feedback: (102)

I made this little short intake for my 1.50, placing the carb about 1.25" from the intake valve. It did nothing, Dan now owns it.

Don't make me cry Pete, it's 36-f here and about to snow.

Captcrunch44

Did you put a breather nippel on the Cam housing?
and dose that help and do you think that should be done on all?

Hobbsy

My Feedback: (102)

Yes sir, that was failed experiment, not one single drop of oil came out of it, I plugged the rear vent, of course but nothing came out the vent that was located where you see the plug. I have since replaced the cam housing with a new one. I don't know where the oil went.

Captcrunch44

I just ask because the new .40 i got has that on the cam gear houseing.

SrTelemaster150

If you plug the back plate and put a check valve (out) on the breather line from the cam housing, oil will migrate to the cam housing as blowby pressure is vented.

Put a check valve (in) in the back plate and a check valve (out) in the cam housing and you will have copious amounts of oil vapor being forced through the rear bearing and into the cam housing.

Testing on my FA-180HC showed no reduction in RPM from turning the crank case into an air compressor as long as the pressure was allowed to bleed off.

If you make some sort of metered bleed off, perhaps with an old spraybar assembly/needle valve, you can use the pressure to pump fuel. W/O the bleed off you would flood the engine & possible blow up the fuel tank if the engine didn't flood out 1st. This is basically what the Saito "pump" system is except they have a screened inlet and an outlet both of which screw directly into the engine case at some location. Although not as tidy, check valves in silicone tubing would accomplish the same thing.


Single cylinder big block "B" engines with the tall cam housing in the case would be much more suited to having the outlet check screwed directly into the case at the cam location.The housing of the "A series does not have much meat to tap threads into and if you utilize the screw in check valve, it can interfere with the cam housing screws.


The 220 Big Bore Carburetor kit has both check valves in the back plate. Note the metering needle valve which is basically a modified spraybar.


This location may be better for forcing oil into the rod big end on the down stroke.

If you purchase a replacement back plate for an FA-180 the breather hole has been relocated from where it was on the older engines and it will have an additional boss for tapping threads to accommodate another check valve. This is probably standard now on "B" series engines.

Hobbsy

My Feedback: (102)

I have two FA .40a's and they vent just fine. I should pull a back plate after a run and see how much residual lube is in there.
Dan I did not try the check valve trick, I'll just leave it as is. For now.

SrTelemaster150

Yeah, it's not worth tearing the top end off, but if you have the engine apart in the future you could give it a try with your old D&T'ed cam housing.

acdii

Sounds like a YS setup to me.

SrTelemaster150

The only reason I concern myself with cam lubrication is the fact that the much leaner running conditions with CDI reduce the amount of oil being introduced when running. I also want to experiment with mixing my own fuel at reduced oil content, maybe as little as 5% when running spark ignition since stable ignition timing will help to prevent detonation.

If I eliminate nitro, A/F ratios will be even leaner meaning less oil being run through the engine. Aside from the big end of the rod, the cam lobes/tappets are probably the next most critical surfaces for lubrication due to the mechanical pressures involved.

SrTelemaster150

YS is using crank case pressure as a 2 X cylinder volume forced induction system. If some sort of check valves are employed, the crankcase becomes an air compressor. YS is employing some sort of in/out valves in the induction circuit. This is employing check valves in the crankcase venting. Both utilize the up and down motion of the piston that is reducing/increasing crankcase volume as the crank revolves.

The YS system is similar to how a 2-stroke breathes but you get 2 X the reciprocating action (4-stroke Vs 2) to double the volume of air pulled into the crankcase and then forced into the combustion chamber. I have toyed with the same type of set-up on a Saito. A revolving disc valve driven by the back end of the crankshaft and inlet outlet ports in the back plate would accomplish that. If I ever get a lathe in my shop, (something on my wish list) I could do something like that. Right now, all of my "machine work" that cant be accomplished with a mill file, Dremel tool or drill press must be farmed out and paid for with $$$ which are in short supply these days.

This is just using positive crank case pressure via check valves to force oil to specific parts of the engine and/or use (metered) positive pressure to pump fuel.

acdii

On the FG-11 I was concerned of lack of oil with 20:1 mix. When I first ran the motor at that ratio during break in I was concerned since I saw very little oil residue in the exhaust when compared to a glow. I also saw no oil on the breather so mixed it 16:1. I can say now that it has time on it, there is plenty of oil @ 20:1. It doesn't take much oil to protect, just a thin film, as long as it gets there.

Hobbsy

My Feedback: (102)

AC, what oil are you using if I may ask, Thanks

This Webra T-4 .87 achieved YS like super charging with one way valves. I,had a T-4 .87 for a long time but it was not super charged. Mine turned a 14x6 at 9,400 like most other .90's.

acdii

I used Lucas 2 stroke oil for break in, Semi Synthetic. https://lucasoil.com/products/2-cycl...ic-2-cycle-oil It's a low ash variety oil that fits what Saito suggests. I inspected the FG-11 when I pulled it off what was left of the firewall and it looks great.

Switched to Amsoil since it is what is used with the DA 100 and DLE 20 & 30.

the Wasp

My Feedback: (1)

check out this 60T burning gas

Jim

the Wasp

My Feedback: (1)

this is something I have been wanting to see tested on a 4 St glow engine, a Carb with an Accelerator Pump

any one try one ??



Jim

Hobbsy

My Feedback: (102)

The mail lady dropped off a very nice Saito 1.30 twin with Dual Plugs, I was late getting home from taking Geri to the Dr. I will have some play time tomorrow morning then off to our youngest daughters house. Busy, Busy. It was well packaged, has good compression.

Hobbsy

My Feedback: (102)

I did take time to take a picture, it some serious compression, I think Clarence Lee said the compression ratio on the 1.30 is 12.98. I'll go look. It'll be a day or two before I can run it, with 7 kids it's a busy time.

jkr_1100

My Feedback: (15)

create a chart of all engines, there weight, and power and then map them out in a chart

you will find the Saito 1.25 has the highest power to weight ratio of any engine.

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