Lust for POWER!

[jCandlish]

Re: Lust for POWER!

The mounts on the O200 (and C90-14) line up with the A- and C- series but they are thicker fore and aft. An O200 will sit about 1/2" farther forward. Don Swords has an STC'd bushing to convert it to the conical mounts that corrects this.



There are 2 basic cases, pre-O200 and post O200. Pre-O200 cases have studs on the center main bearing. Post-O200 cases use through bolts and are a lot stronger, The A-series and C75 and C85 share one crank and one stroke. The C-90 and O200 share a different crank and longer stroke.

If you put C85 pistons on a C90 crank and rods the compression ratio goes [way] up because there is more piston above the wrist pin. With the C85 crank the compression is less because the piston top comes to the same point in the bore [as the C90] but the stroke is shorter.

Thanks John

Excellent information. Is there some technical documentation to be found showing the swept-area geometries for these engines? Also, is it the 90-8 case that has the same mounts as the a-series? And what are the pros/cons between Millenium and TCM cylinder assemblies? I have a parts catalog that calls out 6.3 and 7.0 compression ratio pistons for the o-200. What is the CR with the -85 pistons on the -90/0-200 crank? Do the -85 pistons carry an oil ring on the skirt?

Jeeze, I could go on forever! Where does one find this information? When I get around to inserting tab-A into slot-B I want it to fit.

Thanks again
jCandlish
.

[NY86]

Re: Lust for POWER!

Excellent information. Is there some technical documentation to be found showing the swept-area geometries for these engines?

You mean bore and stroke? I don't have any more detail than that, except the C85 crank/rods/pistons results in roughly the same combustion chamber volume at TDC as the C90 crank/rods/pistons.

Bore is 4.062". Stroke is 3.625" for the 188 cid engines and 3.875" for the 201 CID engines

Also, is it the 90-8 case that has the same mounts as the a-series?

All A-series, C75, C85, and all C90 except C90-14. C90-14 and O-200 have "Lord" mounts.

And what are the pros/cons between Millenium and TCM cylinder assemblies?

Hmmm, a religous question....

Continental has had valve guide issues in the past and went through the "combo of the month" for a while. Until someone convinces me they've got it together, I'd not use them. Superior was bought by Thielert (sp?) and they filed for bankrupcy in a foreign country (Germany) so I'd not use them for now. That leaves ECI who is wading through some sort of production issue, except I'm not sure it affects the small Continental product. That leaves no one...

I have a parts catalog that calls out 6.3 and 7.0 compression ratio pistons for the o-200.

I've not seen that. The 6.3 CR pistons are for the C75 and C85. The 7.0 CR pistons are for the C90 and O200.

What is the CR with the -85 pistons on the -90/0-200 crank?

Roughly 10:1 You need C-90 rods too.

Do the -85 pistons carry an oil ring on the skirt?

No. Moving the wrist pin up for the C90 necessitated moving the oil ring down.

Jeeze, I could go on forever! Where does one find this information?

A lot is in the overhaul manual.

When I get around to inserting tab-A into slot-B I want it to fit.

One thing to watch is the clearance between the rod bolts and the cam shaft if you mix the C90 crank and C85 cam. Also, the oil slinger on the C90 crank requires a mod to early cases.

Oh, yeah, don't mix C85 pistons, a C90 crank and REM37BY plugs...

[astjp2]

Re: Lust for POWER!

http://www.bowersflybaby.com/tech/fenton.htm

http://www.bowersflybaby.com/tech/engines.htm#a-series

These are a great articles on the little continental engines. You can do the 85 piston swap (not legally), it yields about 8.5 CR, but you have to machine a recess for the plugs or you may contact. I know of several guys that have done it and they seem to run the best on 100LL, if you use a -14 case, you get the lord mounts and reduced vibration It does move the engine foreward 5/8" on the short mount. The long mount is about 5 inches longer which will allow for a 90kg baggage area.....

Aircraft Specialties can legally dynamically balance the crank and static balance the rods/pins/rings/pistons. Its well worth the money. If you install an Ercoupe spinner, you can then get the whole shebang dynamically balanced and will probably have the smoothest running 4 cylinder aircraft engine in Europe....

[jCandlish]

Re: Lust for POWER!

You mean bore and stroke? I don't have any more detail than that, except the C85 crank/rods/pistons results in roughly the same combustion chamber volume at TDC as the C90 crank/rods/pistons.

Thanks !

I was hoping to know: Rod length, Piston height & skirt depth from the wrist pin, and the internal cylinder height from c/l.

The lowest I operate is 1700msl, (taxi). In the lowlands I usually cruise at ~3500msl & that keeps me in G airspace. But to the West there are some altitude challenges! A little more compression may just compensate for the altitude.

That and I feel like I'm entitled to get all the value out of the 3SFr/l = $12/gallon 100LL I'm buying.

Once again thanks for the infos. Getting clearer now.

Cheers
jCandlish
.

[wlas]

Re: Lust for POWER!

John,
Have you measured the compression ratio of the C-85 pistons with a 0-200 ? it wouldn't surprise me if it were 10:1, I know it sure props harder and likes avgas better than car gas.

[gcgilpin]

Re: Lust for POWER!

... use the O-300 intake elbows and it looks like a 65 but perfroms like a 90. Tim

Tim:
Do the O300 intake elbows give a performance increase?

[gcgilpin]

Re: Lust for POWER!

Oh, yeah, don't mix C85 pistons, a C90 crank and REM37BY plugs...

Could you expand on this? Do you have first hand experience? How much longer are the electrodes on the REM37BY plugs than say regular cermamic or the REM40 plugs?

[gcgilpin]

Re: Lust for POWER!

... An O200 will sit about 1/2" farther forward. Don Swords has an STC'd bushing to convert it to the conical mounts that corrects this...

I didn't realize Don had an STC specifically for the conical insert bushing?

[astjp2]

Re: Lust for POWER!

Tim:
Do the O300 intake elbows give a performance increase?

I was told by an old timer that O-300's lack of fuel injection bosses yields about 4-5 HP in an O-200. He used to race Reno in F1 and that is one of the popular mods is to cut off and weld in a patch over where the fuel injection bosses used to be. You would have to get a field approval to install them, they were only approve for installation in 1 manual that I saw from the 1950's and continental has several revisions since that do not allow them to be used. You will also have to cut about 1/4" wedge from the end of the pipe for them to fit. Tim

[NY86]

Re: Lust for POWER!

John,
Have you measured the compression ratio of the C-85 pistons with a 0-200 ?

It was calculated. I could be wrong.

There is another thread on the REM37BY plugs. I just threw it in here as a joke... But, yeah, they stick into the combustion chamber a lot more. Along the same lines, if you have to relieve the pistons, maybe that accounts for the lower compression number.

[VictorBravo]

Re: Lust for POWER!

I was told by an old timer that O-300's lack of fuel injection bosses yields about 4-5 HP in an O-200. He used to race Reno in F1 and that is one of the popular mods is to cut off and weld in a patch over where the fuel injection bosses used to be. You would have to get a field approval to install them, they were only approve for installation in 1 manual that I saw from the 1950's and continental has several revisions since that do not allow them to be used. You will also have to cut about 1/4" wedge from the end of the pipe for them to fit. Tim

The better way to do this is to simply weld the patch inside the normal 85 / O-200 elbow and grind it smooth. That way, the local FAA ramp-checker would have to be inside the !($*%^ engine to see it While you're at it, golf-ball the short side radius of the elbows with a Dremel tool, taper the intake runner tubes, turbulate the inboard third of the prop, etc. etc.

That being said, I'd be willing to bet a round of drinks that there ain't no 4-5 HP in those elbows, no way no how. If there was 1 or 2 horsepower, it would have been a lot, but this would have been at 4000+ RPM where there was some flow involved.

In IF-1, our organization's chief "engineer emeritus" calculated the approximate horsepower we all were getting, based on the engine rules and such. The vast majority of the horsepower over 100 was from the RPM increase only... because the HP/RPM curve dropped off rapidly his estimate was that at 4000 RPM we were still only making about 115-118HP.

Other minor modifications like screwing around with the cams (not much allowed), ram air intakes clocked to the prop blades, Total Seal auto racing piston rings, Dykes style rings that only created drag under compression, John's super hot magnetos, and on and on... were adding fractions of a horsepower here and there.

To the best knowledge of the best knowledged, there was nobody making an honest 130 or 135 horsepower. Plenty of people were talking about a lot of power, but it was nonsense.

If you happen to have your intake elbows off, and they happen to be welded up and smoothed out, then you're a little better off than before. But disassembling a flying airplane to get this little benefit is probably not a priority IMHO.

Jcandlish, for whatever my bumble opinion is worth, I believe that your best possible modification for altitude, yielding both a little performance benefit and a larger safety margin, is the vortex generators. They're not particularly attractive, but you can't see them from inside the cockpit.

[jCandlish]

Re: Lust for POWER!

Jcandlish, for whatever my bumble opinion is worth, I believe that your best possible modification for altitude, yielding both a little performance benefit and a larger safety margin, is the vortex generators. They're not particularly attractive, but you can't see them from inside the cockpit.

Hi Bill

I think vortex generators would be insufficent. Here is the chart around Sameden. To the northwest following the river valley Inn, is the village of Sent at 1800m, where my inlaws have a farm and there are landing possibilities, especially in winter.

more POWER please!

[astjp2]

Re: Lust for POWER!

Well you can always do an Alsworth conversion to a 150 lycoming....problem solved. Tim

[jCandlish]

Re: Lust for POWER!

Well you can always do an Alsworth conversion to a 150 lycoming....problem solved. Tim

I've searched and not found the 'Alsworth' conversion.

[astjp2]

Re: Lust for POWER!

They were all done by FIELD APPROVALS, no STC here for the conversion. You can call Glen Alsworth in Port Alsworth Alaska and he might be able to help you get you an engine mount...Tim