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Intake problem fix

PerfTech

Well Known Member
....I have been watching the threads on intake gaskets and their shortcomings. This is and has been a problem with Lycoming engines since their conception. This is one of the main causes of rough idle and a lean cylinder out of sink with others etc on carburated engines. There have been some efforts here recently to solve this issue with " Fluorosilicone Intake Gaskets" and this was a step in the right direction, but not necessary. I didn't say anything about this until now because it appeared a considerable amount of effort and expense had went into getting gaskets made and distributed. I didn't want to look like the party spoiler, but now it seems to have died down so here it is. We solved this problem in the mid seventies, haven't used a Lycoming intake gasket on any of the engines built or serviced by us since, and have never had a failure or problem. As a matter of fact we reuse our gaskets over and over. The gaskets you want (Spruce # 77611) are actually copper exhaust gaskets. They have the exact same bolt center distance and bore as the intake ports and will last the full life of your engine and then some. We usually coat them with a very thin film of high temperature silicone if re-using them. This gasket has a crush ring, is made of solid copper, and is literally blow out proof. This will solve all your Lycoming intake leak problems permanently. This is one of those "rock and hard spot" situations! Some having had a need for gaskets will be mad that we didn't post this sooner, and others involved in making or distributing the fluorosilicone, that we posted it at all! We are not trying to rock the boat, just offering a 100% solution to the problem. Regards all, Allan..:confused:.:eek:.:eek:.:).:D
 
Well I for one , Thank you Allen ! Although I do not at present time have a leak , I will keep this information in my memory banks ! :) Ho Ho Ho Merry Christmas !
 
I was thinking about it couple years ago but decided against the exhaust gaskets. Mostly because of difference in bolt holes I was afraid I couldn't dead center the bolts and may have a leak. Anything engine related I was very cautious to deal with.


Below are some pictures to compare.














Thickness.







For a seasoned A&P it's very easy to center oversize hole but for a freshly baked repairman who shoveled all his biannual pocket cash for that new motor it's kind of scary :D


The flurosilicone gaskets are much easier to install just watch the torque it's so low. Almost 200 hours on beta and nothing to report ... :)








 
I tried installing one of the silicon ones and never felt comfortable with the torque. It seemed they were squeezing out.
 
Feedback

It's bedn a couple of years since Allen offered this bit of advice and I was wondering if anyone had any feedback plus or minus?
Thanks and happy new year!
 
Exhaust for Intake

I experimented and liked the results. This is how the gasket looks after 400+ hours still reusable if you flip it. The challenge is to perfectly center it while installing. It accepts torque values for paper gaskets and stays leak free.

exhaust%20for%20intake%20-%201%203.jpg



exhaust%20for%20intake%20-%201%201.jpg
 
I experimented and liked the results. This is how the gasket looks after 400+ hours still reusable if you flip it. The challenge is to perfectly center it while installing. It accepts torque values for paper gaskets and stays leak free.

exhaust%20for%20intake%20-%201%203.jpg



exhaust%20for%20intake%20-%201%201.jpg

.... It is actually very easy to center them. You simply rotate them as far as possible against the studs, and they will self center the bolt hole radius, then tighten them up and you are good to go. They will last the life of the engine, not get loose, leak or come apart. Happy New Year everyone. Thanks, Allan...:D
 
rotate them as far as possible against the studs, and they will self center the bolt hole radius
A real mechanic makes it so easy!
 
Allan,
I have a project right up your alley - it will solve the F/A distribution on all O-320/360 engines... I'll call this week to discuss.
 
Leak

I have customs made intake tubes and the standard lycoming gasket won't stay sealed. Tried the no-blow gasket today with poor results. Guess I didn't get them centered up. Wished I could find some -m1B intake tubes.
 
I have customs made intake tubes and the standard lycoming gasket won't stay sealed. Tried the no-blow gasket today with poor results. Guess I didn't get them centered up. Wished I could find some -m1B intake tubes.

The gaskets that have been recommended in this thread are not the no-blow brand exhaust gasket (all steel with the laminated crush area).

They are 100 % copper

Though I am not endorsing or recommending against there use.... I have zero personal experience with this modification.
 
77611 varies

Thanks Scott.
The 77611 I got from spruce is not copper but rather appears to be steel outer with a crush ring inner. They look like no-blow.

Update: Just got back from Aircraft Spruce and PN 77611 will get you steel no-blow gaskets. The Spruce part number for the cooper exhaust gaskets is (07-03090) . The lycoming part number is 75118.
 
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Gasket

I had a intake leak on #1 that I could not find for the last 25 hrs and it made a loud sound that you could here in the cockpit like a vacuum leak finally found it with a cheap HF stethoscope as the end crossed the tiny leak that was so loud.An AI on the field that works on turbine engines gave me a small piece of high temp gasket material that is used its about 3 times as thick as a regular intake gasket I used a exacto knife and a hole punch to make new one and its working great I will find out brand of material and post.
Bob
 
Sorry to resurface this thread, but in post #1 Allen recommended the 77611 exhaust gasket which is a steel outer section with a compressible inner ring seal. Later on it is stated that this is not the seal that is the best, but that the copper gaskets P/N 75118 is the proper number. The 75118 is what seems to be shown in Vlads post.

I am guessing that Allen knows the proper number that he uses (77611) and that the other number (75118) is a different recommendation. Can anyone confirm and or update with their experience.
 
Gaskets no more

I eventuality cut off the ends of intake tubes and went with o-rings from Ross Farnham and sealing problems went away. No more gaskets to worry about.
 
exhaust gaskets for intake?

Brian the gasket above is of a copper/asbestos sandwich. The space rubber examples went back to the developer lab. That's how they looked. Version 1.0.


blue%20gaskets%20-%201_1.jpg

So the copper / asbestos sandwich are the exhaust gaskets allen was talking about? And you are still happy with the performance?
thanks..
 
Part # ?

....I have been watching the threads on intake gaskets and their shortcomings. This is and has been a problem with Lycoming engines since their conception. This is one of the main causes of rough idle and a lean cylinder out of sink with others etc on carburated engines. There have been some efforts here recently to solve this issue with " Fluorosilicone Intake Gaskets" and this was a step in the right direction, but not necessary. I didn't say anything about this until now because it appeared a considerable amount of effort and expense had went into getting gaskets made and distributed. I didn't want to look like the party spoiler, but now it seems to have died down so here it is. We solved this problem in the mid seventies, haven't used a Lycoming intake gasket on any of the engines built or serviced by us since, and have never had a failure or problem. As a matter of fact we reuse our gaskets over and over. The gaskets you want (Spruce # 77611) are actually copper exhaust gaskets. They have the exact same bolt center distance and bore as the intake ports and will last the full life of your engine and then some. We usually coat them with a very thin film of high temperature silicone if re-using them. This gasket has a crush ring, is made of solid copper, and is literally blow out proof. This will solve all your Lycoming intake leak problems permanently. This is one of those "rock and hard spot" situations! Some having had a need for gaskets will be mad that we didn't post this sooner, and others involved in making or distributing the fluorosilicone, that we posted it at all! We are not trying to rock the boat, just offering a 100% solution to the problem. Regards all, Allan..:confused:.:eek:.:eek:.:).:D

Allan, Any change you meant part number #75118? If so what are you torquing them to for the intake?
 
So the copper / asbestos sandwich are the exhaust gaskets allen was talking about? And you are still happy with the performance?
thanks..

Yes, Jeff very happy. No leaks for long time. These types.





Paper gasket is there for comparison only. I don't use them at all.
 
part number?

Yes, Jeff very happy. No leaks for long time. These types.





Paper gasket is there for comparison only. I don't use them at all.

Thanks Vlad. Where did you get them? Do you know the part number. One per intake? Or 2? I saw some copper exhaust gaskets on line that said they had to be used in pars on each inlet.
 
Thanks Vlad. Where did you get them? Do you know the part number. One per intake? Or 2? I saw some copper exhaust gaskets on line that said they had to be used in pars on each inlet.

I don't remember Jeff. These came with new Lycoming engine then exhaust came with own gaskets all metal.
 
Looking at the pictures, it appears that many are putting the gasket between the tube and the intake port. I noticed that there is a relief cut in the intake port face that is the same depth as the thickness of the flange on the tube. I put the gasket behind the tube flange so that it sits between the tube flange and the retaining bracket. This creates a nice tight seal and creates no wear on the gasket. It does however, require the flange to be clean and flat. Seeing the relief on the intake port, I can't imagine this not being the way it was designed. The gasket seals any air leaks that exist in the metal to metal interface of the tube flange and intake port because it is compressed tight against the backside of the tube flange.

Larry

You mean to put the intake tube directly to the cylinder and have the gasket outside? I don't understand what the gasket would actually do in that scenario.

If you look at the copper gaskets they have a raised portion that I would suspect would go in that relief area you mentioned.
 
You mean to put the intake tube directly to the cylinder and have the gasket outside? I don't understand what the gasket would actually do in that scenario.

If you look at the copper gaskets they have a raised portion that I would suspect would go in that relief area you mentioned.

Please disregard this. I did not remember correctly and was incorrect. I had remembered the relief was in the port and it is actually in the hold down plate. I deleted this post for that reason.
 
Cool hearing there is an easy repurpose solution.

Just installed the SDS carb intake flange seal kit.

No leaks with paper, but it was time to upgrade from paper.

$15 updated channel locks were good for the tension clamps, but take a few minutes of practice.

No leaks after. All 4 paper gaskets came out intact, I think they were dressed in Hylomar.
 
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Found this thread while replacing my intake hoses and gaskets at near 1000 hours. Did not have leaks, just doing preventive maintenance after 10 years.

Searching the part number from Allan's first post (77611) brought up the solid exhaust gaskets with silver-colored inner portion. Reading later posts, I'm not sure that was the intended one.

Meantime, I discovered my old gaskets are the copper/asbestos sandwich ones pictured in some previous posts. Since I haven't had problems, thought I'd replace them with the same. Spruce does not show them. My guess is they have been discontinued due to the asbestos. For what it's worth, I did find some after searching for 'Lycoming 65321 exhaust gaskets'.

Does anyone have a proper torque value for these copper/asbestos gaskets?
 
Found this thread while replacing my intake hoses and gaskets at near 1000 hours. Did not have leaks, just doing preventive maintenance after 10 years.

Searching the part number from Allan's first post (77611) brought up the solid exhaust gaskets with silver-colored inner portion. Reading later posts, I'm not sure that was the intended one.

Meantime, I discovered my old gaskets are the copper/asbestos sandwich ones pictured in some previous posts. Since I haven't had problems, thought I'd replace them with the same. Spruce does not show them. My guess is they have been discontinued due to the asbestos. For what it's worth, I did find some after searching for 'Lycoming 65321 exhaust gaskets'.

Does anyone have a proper torque value for these copper/asbestos gaskets?

They probably discontinued the copper gaskets because they weren't selling many :D
 
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