Alcor TCP

How to keep the Cessna 170 flying and airworthy.

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pauldpilot
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Alcor TCP

Post by pauldpilot »

So, what about that Alcor TCP? We are running it with great success. The plugs look just great and no valve problems so far.
Is the TCP really needed in the 170?
Not that I would really put in an unapproved fluid from a red can, but say I did, does it do away with the need for the TCP?
I do run the unnamed red fluid in my car, and it likes it just fine! But my car only has 180,000 miles on it. I should probly run it a little longer, before jump to any conclusions about the red fluid. :lol:
pauldpilot
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GAHorn
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Post by GAHorn »

TCP does indeed get rid of lead deposits. I use it whenever at home, but I don't carry it around the country with me. (It's not supposed to be carried onboard an airplane and I don't like the messy dispensing system. I wish Alcor would use the same type container as Stabil (c) brand-name of gas treatment does, which allows one to squeeze the calibrated amount of product into a self-contained spout and then just pour it in the tank.) (No, I don't use Stabil (c) in my airplane, because I don't use mogas. If I used mogas I would strongly consider it, though.)
I had a lengthy conversation with the TCM field rep. about TCP. He said it was unnecessary with 100LL because the current production "100 octane" valves don't have a problem with the increased lead in 100LL. (It would be a good thing however, if you were to find any original 100/130 fuel.)
I also had a conversation with Alcor. (They are nearby in San Antonio.) Their advertising claims TCP is "Continental Approved". But they've never been able to produce any such documentation in the three years and three reminders I've given them. TCM says it is not approved by them. (It's also not specifically dis-approved except in turbocharged engines.)
Alcor also claims TCP is FAA approved. I haven't pushed them on that. I'm still waiting for their proof of Continental approval.
Alcor also cannot provide TCP reliably. It seems that only two sources world-wide exist for tetraethyl lead, Russia and China. Alcor makes up TCP only on demand, and the real demand comes from those places. Alcor makes it up in 55-gallon drums and ships it by container to China and Russia, but try finding any at your local airport on any reliable basis. Last time I tried, Aircraft Spruce didn't have any either, although they list it in their catalog. So I called Alcor directly, talked to "Alan" in their San Antonio factory, and he didn't have any there either. He said he intended to "make up a batch someday". (They only mix it up occasionally as it's dangerous to handle. The basic ingredient is mixed up with Toluene, an ingredient of avgas, to make it penetrate the fuel system quickly and to provide a conveniently dispensable concentration.)
If you don't want to fool around with the stuff, remember to aggressively lean during ground operations as well as in flight, and be comforted in the thought that TCM says it's unnecessary and that 100LL doesn't really have four times the amount of lead as the old 80/87. It's only allowed to, if necessary due to poor base stocks. Not a problem here in the U.S.

The red-stuff doesn't do anything about lead. (Lead combustion by-products make little hard, glass-like balls in the combustion chamber and under the valve head that are unaffected by solvent. Almost all of it is blown out the exhaust. Some lead by-products are blown like ash into the crankcase, but oil softens that up immediately, and most of it drains out the crankcase with AD oils. That which doesn't stays soft and relatively harmless while in the crankcase. Remember that lead is pretty far down the periodic chart and doesn't attack other common engine metals.)

MMO is a solvent/light lubricant. (Aviation Consumer claims it's kerosene, dye and perfume.) While it's solvent qualities will soften carbon and varnish deposits when poured into the crankcase, and has a reputation for improving sticky valve problems due to valve-stem build-up of crankcase deposits,...it probably actually increases carbon build-up in the combustion chambers. (Which is proof that combustion chamber deposits have less to do with 100 octane valve sticking than valve-stem deposits do because of oil coking.) Since MMO (and most other crankcase additives) are highly solvent, they wash build-ups off of non-moving internal engine parts. Those build-ups actually are beneficial in preventing oxidation (rust). Removing the deposits not only exposes the internal parts to oxidation, it also sends all that junk throughout the engine, and poses a risk to oil screens/filter bypass valves and plain and babbit bearings.

(I know, I know. There is a story I've repeated about the airlines in the days of turbo-compound engines having some success using MMO and improving dispatch reliability by reducing valve-sticking. But those valves/stems ran at much higher temperatures than our little C-145/O-300's, and those engines didn't sit around for two or three weeks between flights, they sat around a couple of hours at most. They didn't have an internal rust problem with those engines. Their engines got exchanged/overhauled every three to six months.)

Nothing is as good for an engine as good, clean engine oil regularly flown, properly filtered, and frequently changed.
Last edited by GAHorn on Tue Apr 01, 2003 6:10 pm, edited 1 time in total.
zero.one.victor
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Post by zero.one.victor »

gahorn wrote: I had a lengthy conversation with the TCM field rep. about TCP. He said it was unnecessary with 100LL because the current production "100 octane" valves don't have a problem with the increased lead in 100LL. (It would be a good thing however, if you were to find any original 100/130 fuel.)
I guess that would be a valid point if you did indeed have "current production '100 octane' valves". What does Continental consider current production? And does this apply only to TCM-brand valves? Lots of old engines running around out there that were last majored or topped 20 years ago,or had recent cylinder work done, but with the old valves reinstalled.
I use mainly cargas,with some 100LL every few tank-fulls as per EAA & Peterson cargas STC recommendations. I do add a shotglass full of Mystery Oil to every can of car gas. I don't necessarily recommend it to anybody else,but it works for me. Don't forget the hokey-pokey and the car-gas mantra if ya try it though!
By the way,George,if the TCM rep you talk to is Corey Thompson,tell him the Port Townsend crew says hi!

Eric
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GAHorn
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Post by GAHorn »

Corey is the man!! Good guy, and returns phone calls promptly and courteously.
100 Octane valves were introduced in the mid-70's and I know of no one who didn't install them as standard practice since 1980. Virtually all valves made since then are, but the actual part numbers should be confirmed. Two primary differences are alloy and seat angles.
pauldpilot
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alor TCP

Post by pauldpilot »

Thanks for the reply George. Sounds like I should put my last can of TCP on E-Bay!
And I do the hockey-pockey, along with the MMO matra when I put it in my car.
I always heard that the mystery in the name is because of the mystery in why anybody would buy it.
pauldpilot
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N3243A
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Post by N3243A »

gahorn wrote:If you don't want to fool around with the stuff, remember to aggressively lean during ground operations as well as in flight, and be comforted in the thought that TCM says it's unnecessary and that 100LL doesn't really have four times the amount of lead as the old 80/87. It's only allowed to, if necessary due to poor base stocks. Not a problem here in the U.S.
George,
So a quality gasoline base stock has enough detonation resistance that the avgas refiners do not need to add the full amount of 2 grams lead per gallon? I guess the bottom line question is do the avgas refiners only add enough lead to make the gasoline qualify for the 100 octane rating and the the recipe for 100LL does not ALWAYS include 2 grams of lead per gallon but varies depending on base stock quality batch to batch? What is the rough average lead content of avgas currently, something like 1.5 grams/gallon?

Bruce
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GAHorn
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Post by GAHorn »

Correct. (But I don't know the "average" amount of lead in avgas around the country.)
goodair
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Re: Alcor TCP

Post by goodair »

I know this is an old thread. I have been using TCP for years in just the low HP (below 200) Continentals. I have read here that some folks believe, Continental included, that the 100 octane valves solve the problem of lead deposits and valve sticking. I do not agree with that. I ran a shop for 25 years and the low HP continentals just stick valves. Changing the valve material and even seat angle and such has not in my opinion stopped these valve from sticking in the lower HP engines. It is the build up material in the valve guide area that causes a valve to stick. I have run into stuck valves with the new exhaust valves that are stuck so hard they wouldn't budge with the rope trick and some good blows with a hammer.
SO, what does the TCP do. It simply makes the deposits softer and more likely to exit the engine in suspension with the exhaust gases, and less likely to stick to areas inside the engine, namely valve guides. After replacing 2 cylinders in our little 150 after numerous stuck valves, we started using TCP. Over 500 hours later and not only no valve sticking, but no plug fouling either. we use it in our 170 as well. I do not know if MMO red stuff has similar properties, as we have no experience with it.

The higher HP engines have higher BMEPs and much higher temps and pressures. These engines seem to scavenge the lead out the exhaust more readily and although the can still stick valves, it is much less common.

Aggressively leaning a carbureted engine at idle doesn't really do what you think it does. At idle, the mixture control on most Marvel carbs does nothing. The main metering jet of the carb is not even in use during idle, as the fuel is being drawn through the idle jet which is up against the side of the venturi where the butterfly is in close quarters to, and once the butterfly is opened with the throttle, the carb will then transition to the main metering jet. The mixture knob only changes the fuel that goes through the main metering jet. Pull it all you want if it gives you that warm and squishy, won't hurt anything. Now if you taxi at high power and ride the brakes, you might actually be doing something.

My 2 cents. Worth what you paid for it:)
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Bruce Fenstermacher
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Re: Alcor TCP

Post by Bruce Fenstermacher »

I had thought TCP was out of production. Maybe it was. But Spruce has it at $37.95 qt. Not including shipping that raises the cost of fuel 12¢ a gallon if you use it per the instructions.
CAUTION - My forum posts may be worth what you paid for them!

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cessna170bdriver
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Re: Alcor TCP

Post by cessna170bdriver »

goodair wrote:....

Aggressively leaning a carbureted engine at idle doesn't really do what you think it does. At idle, the mixture control on most Marvel carbs does nothing. The main metering jet of the carb is not even in use during idle, as the fuel is being drawn through the idle jet which is up against the side of the venturi where the butterfly is in close quarters to, and once the butterfly is opened with the throttle, the carb will then transition to the main metering jet. The mixture knob only changes the fuel that goes through the main metering jet. Pull it all you want if it gives you that warm and squishy, won't hurt anything. Now if you taxi at high power and ride the brakes, you might actually be doing something.

My 2 cents. Worth what you paid for it:)
I understand carburetors mostly on a superficial level, so I’m not trying to be argumentative, just trying to understand better: If the mixture control only affects the main jet, how does the idle cutoff function work? Why do I see a slight rise in EGT when pulling the mixture slowly at 700 RPM? Why does the engine roughen but not quit at some point in that slow pull at 700 RPM?

BTW, the only really stuck valves (and rings) I’ve had were running Amoco Premium Unleaded and MMO. Carbon was always the culprit. After switching to straight avgas (NO additives) and getting in the habit of leaning on the ground, that problem went away. I don’t know which actually solved the problem, but with 25+ years of success I’m going to keep doing what I’ve been doing.
Miles

“I envy no man that knows more than myself, but pity them that know less.”
— Thomas Browne
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Joe Moilanen
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Re: Alcor TCP

Post by Joe Moilanen »

Same here Miles, not a stuck valve in 30+ years. Lean on the ground and everywhere, and I don't go to full rich on landing until short final.

Joe
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ghostflyer
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Re: Alcor TCP

Post by ghostflyer »

I also agree with Miles on this . Due to long taxi distances on our airport I lean and taxi at about 700rpm. With my new engine [4 banger] initially the engine was having a sticky valve until CHT reached 380deg. When you have a new engine I was told to run fully rich all the time . Tried MMO and TCP to stop the issues having with my engine . No success . Then I went off to Oshkosh and talked with the “experts” at different engine manufactures with my issues. The consensus reached was that all valve guide materials are not the same . Even when they have approvals (PMA) ,s or same part numbers and have the FAA sticker. Reaming the valve guide to exact dimension was very important. So valve stem clearance was critical .
Every body also was blaming the fuels initially but I tried 91 , 95 ,98,and 100 ll .[and a fuel called Mogas ,and what spec that is ,I do not know]. This is the range of fuels available in my country. 4 tanks of each fuel was used and the engine was now well and truly run in by this stage . Still had a issue with valve sticking and in flight once after 250 hrs . That scared the hell out of me as I was over tiger country . By this time I was mad as hell over this issue and contacted the manufacturer of the engine demanding 4 new cylinder assemblies.i had removed the rocker covers and done different inspections and nothing found . My problem was the valve sticking issue was intermittent . If it happen on taxi ,I would shut the engine down wait about 5 minuets and start it again and it would purr like a kitten . Then I had the privilege of a chief engine manufacture technical rep fly with me [and it wasn’t his engine ] told me to red line it on RPM and watch the CHT/oil temp ,he had slightly leaned the engine ,and we flew for about 2.5 hrs . . I had 100ll in the tanks at that time . No issues then and or since . No valve sticking issues.
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ghostflyer
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Re: Alcor TCP

Post by ghostflyer »

PS... 91 and 95 and 98 is auto gas that is available here and a strong rumour is that the fuel companies here sell 98 as it’s old 100ll that is too old for aviation use . Some of my friends use 98 in their race cars instead of 100ll and they have said they can’t tell the difference . We also have that rubbish fuel with alcohol in it and I will not even clean my paint brushes in it.
The issue was resolved before the engine manufacture had the chance to respond to my request . I notified my engine manufacture what we have done and who had helped me and they responded he was the best guy for the job. They spoke very highly of him.
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DaveF
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Re: Alcor TCP

Post by DaveF »

Yes, the mixture control does control the idle mixture. Fuel in the idle circuit doesn't flow out of the main jet, but it is picked off downstream of the mixture valve.

Some good pics and descriptions here:
http://www.kellyaerospace.com/articles/ ... ry_AMT.pdf
http://www.insightavionics.com/pdf%20fi ... Manual.pdf

It's easy to demonstrate with the digital fuel flow gauge. Full rich idle 3.5gph, lean idle 1.5gph, idle cutoff 0.0gph.
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bsdunek
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Re: Alcor TCP

Post by bsdunek »

TCP is a lead scavenger, and as that, seems to work very well. Back in College in the 1950's, we did testing in the auto lab, and it worked well. (We called it Tom Cat Piss then. I still call it that.) I have used it in my 170 since 1985 and have had no problems with excessive lead deposits on spark plugs or valves - no valve sticking. I know that's not scientific, but it works good for me. Oh, I do tend to lean aggressively but not excessively.
Bruce
1950 170A N5559C
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