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Another intake question

Vlad

Well Known Member
50 more hours on new O-320 time to change the oil. Total 150 since new. Engine was run hard during these last 50 hours and consumed close to two quarts but oil temperature rare went to 170F mostly 150-160 I have larger cooler and plenum.

Discovered interesting phenomenon three out of four intakes had these strange oily tracks. It's not exactly pure oil but a strange tar like substance. It's easy to clean with 100LL. What is it?



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All 8 intake bolts need to be tightened. There are two washers on each flat and crush. What proper torque values are for those?

I burned some gallonage of unleaded fuel 90+ octane mixed with 100LL if it helps. Running lean most of the time.


In this thread http://www.vansairforce.com/community/showthread.php?t=52548&highlight=intake+leak there is a suggestion of push rod tubes leak but I doubt I have 3 cylinders pushrod tubes leaking. Any explanation and advice appreciated.
 
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Hello Vlad,

If it’s not the push tubes, maybe some assembly/preservative oil finally warmed up enough to run down out of there ? with the help of a little gas if the nuts are a bit loose ?

Just guessing, haven’t heated up my new Lycoming yet, be interesting to see what you find. Like post #4 in the thread you list says, there should not be oil in the intake tube.

pk
 
Have you checked the oil return lines from rockers? Clamps of mine were not tightened enough. For a while I thought I had cylinder base leak. I even replaced a o-ring for nothing.
 
Check with your engine builder, but I suspect this to be some kind of gasket prep used on the intake gasket. I know Aerosport does not prep the gasket, they just put them in dry as many builders do, but some do use gasket sealer. It would likely melt down and leave a sticky substance after trail as you are witnessing.
Just a guess.
 
Changed oil, tightened intake bolts. Ground run with cowling off OAT 40F. Got oil temp to 120F and did couple of high speed taxi runs. Tiny streaks of dark liquid appeared again :confused: Gaskets look dry and hard. Engine is still on warranty will call Lycoming tomorrow and post the results.
 
Have you checked the oil return lines from rockers? Clamps of mine were not tightened enough. For a while I thought I had cylinder base leak. I even replaced a o-ring for nothing.

I didn't check them Ted. Will do on Friday.
 
Looks like there is some of the same stuff running down around the base of the bottom spark plug in the last picture.
 
Looks like there is some of the same stuff running down around the base of the bottom spark plug in the last picture.


Steve, brown around the base of the plug is different. It was there from the very beginning it's baked preservative oil I believe. Completely dry and very dark brown color.
 
No intake leaks anymore

I replaced intake gaskets about 40 hours ago and there are no leak streaks on intake tubes anymore :)

I ordered new gaskets from Sky Ranch they are very cheap. I also read somewhere on the Web somebody used a sealant. I bought some too and first installed gasket with light application of the sealant. Several people cautioned me on that and their arguments were valid. I scraped off the nasty goo and put gaskets dry. It's very easy job to replace intake gaskets.


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Old gaskets were dry and crumbling.



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La Comedia Finita :D



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Thank you all for good advice!
 
There is no valid reason to put on a gasket dry. I have yet to replace ANY paper gasket on ANY airplane that I've installed them on with a light coat of Titeseal. Period!
 
700 hours on the engine

Set of gaskets started leaking again after almost 550 hours on them.
The procedure is simple and doesn't take much time.






Scrape old paper, clean, degrease. I left light coat of titeseal on one old gasket and it was very easy to remove RocketBob was right. The intake hoses are kind of hard. Do they have a lifespan?







Innards of cylinders get cleaned up lots of lead there.







Plugs cleaned and regapped.







Good to go. Vroom! Engine works like a Swiss clock :D
 
Across many forums and this one included....plugs gapped EVERY 50 hours to 0.016-0.018" and the inlet gaskets........wel they seem to last 250 hours :mad: And that is sad to say.

Last weekend I found two intake leaks on a RV7 that had 140 hrs.

If it helps the red SUPERIOR gaskets seem to last longer.

Glad you are onto these things! :)
 
800 hours

If it helps the red SUPERIOR gaskets seem to last longer.


David do you know where to order red SUPERIOR gaskets from? ACS seems don't have them. Also I would appreciate part ## on intake hoses. I would like to replace them they became very hard and edges are crumbling. O-320 here :)


 
Interesting.

We built my IO-360-A1A in 2006, it has 1100+hours now, runs beautifully, never messed with intake gaskets and has never given any signs of an intake leak.
 
Yes mostly 100LL however recently it has been mostly pure 92. Been doing the MOGAS in the right tank, 100LL in the left tank thing with great results.

Do you suspect it?s the MOGAS that is causing this problem?


I burn a lot of ethanol laced premium gas straight from the pump. I suspect it affects certain rubber parts and gaskets. I don't have access to pure 92.
 
1,024 hours

... aaand here we go again :D





I thought Aero-in-stock have Superior gaskets but they sent me regular. So far I tried three different supplies of intake gaskets. All leak after couple hundred hours. Or maybe I install them wrong.


I also bought and replaced intake hoses. They look very funny totally deformed but didn't leak.


















All new.



 
Just thinking out loud...

I've been thinking about the silicone hoses most often seen in turbo plumbing on cars. The stuff comes in all kinds of sizes (and colors)... Anybody ever used them as intake tube couplers on the Lycomings? In theory, they should remain pliable longer than the rubber based stock stuff.
 
Vlad.....you confirm my thoughts.

A good reason to do a GAMI lean test high and low. It shows up the leaks. ;)

Did you get some of the Superior gaskets?
 
Hate to bump a super-old thread, but figured this was the right place to get the information listed.

Was wondering if anyone could provide any guidance in replacing these intake gaskets and couplers...

Is it as simple as:
1. Remove flange bolts & intake coupler
2. Clean gasket surfaces, replace coupler
3. Bolt back up?

Any torque values for the tube-flange-to-head fasteners?

Thanks!
 
Found it!

For future reference: O-320 Intake flange nut torque is 96in-lb (basically 100) per Lycoming manual.

Any other tricks/tips to get these off/on? I don't need any special tools? Just remove nuts, replace gasket, bolt back on?

Thanks!
 
The intakes don't have nuts, they have bolts. The exhaust has nuts (on studs).

Remove bolts, scrape old gasket junk off, ensure tube retainers are not bowed, Install new gaskets, ensure tube is centered in retainer, tighten to spec.

Next step - buy the SDS intake kit so it's on hand when you need to replace the next cracked intake gasket (and it WILL happen).
 
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The red Rubber intake connectors are available through Continental

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If it helps the red SUPERIOR gaskets seem to last longer.

Glad you are onto these things! :)

It appears that the red high temp rubber connectors that David & Michael mentioned are available through Continental. Are used on their Titan experimental engines. You can see some photographs of them on the recent thread linked below.

http://www.vansairforce.com/community/showthread.php?t=169487

The close proximity of your exhaust pipes to those rubber connectors sure isn't doing them any favor. Is there any room to possibly install a heat shield between those parts?

Charlie
 
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