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Inlet Manifold Gasket Failure

RV10inOz

Well Known Member
Is there an ongoing issue with Inlet manifold gasket failures.

We started with a brand new Lycoming IO540, at 248 hrs 5 out of 6 had cracked and were leaking badly (runs rough too).

LAME (A&P) replaced them while a/c was out of town and we have been checking torque every 50 hours, no issues there.

Now at just over 1 year and another 248 hours (yes hard to believe) we are potting the tell tale fuel dye stains and a couple of pops in the exhaust. Visual inspection suggests 2 are cracked, and we will see this week when we replace them all again.

It is not a big job to do every 200 hours, but it does seem rather odd.

Anyone else seen this? If not maybe you should all take a closer look ;)

PS: These were genuine Lycoming gaskets, the next lot will be Superior (red in colour)
 
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More Stains

Just uncowled for an oil change.
My 540 has 3&4 (center cyl on both sides) showing fuel stains at 320 Hours. It's been running fine but it looks like its time for new gaskets. Please let us know how the Superior gaskets work for you. Does anybody have a better intake gasket solution and experience?
 
I always rub every gasket I put on an engine with Titeseal for two reasons: 1. to allow for slight movement and 2. to make it easy for one to disassemble. On some rarely removed gaskets I use proseal. Never have had a single gasket leak or blow out like some intake gaskets do over time.
 
As you're checking the gaskets, take a close look at the flange face of the intake tubes. I have had this problem on a new IO540 in my Rocket, and found that there were burrs where the tube mated with the flange. A light touch with a file took care of the problems for me.
 
We used hylomar on jet engines/helicopter gearboxes.

Hylomar universal blue with and without gaskets. Rarely ever a leak.

I only used it on my fuel servo/prop gov gaskets. I will use it on intakes when it is time for replacements.
 
If you look at the cap that recieves the intake tube flange it has a detent for the tube flange. The intake tube flange needs to be centered there. Make sure that your centered and tightened to the cylinder before you slide the intake hose over the sump end and clamp. This should take care of your problem.
Ryan
 
Please let us know how the Superior gaskets work for you. Does anybody have a better intake gasket solution and experience?

No problem.......if you want to wait say 18 months for another 300 hours on the clock ;) :D:D

The Superior gasket is red and feels more substantial than the black Lycoming one. But that is about all I can tell you so far.

The size and fit is rather "agricultural" and I think most John Deere's are better made anyway :rolleyes:

Yes the tube should set into the recess. But I am not sure that is our problem.

Here are some pics.

IMG_0610.jpg


IMG_0607.jpg


IMG_0606.jpg


IMG_0604.jpg


Moral of the story is to check these every service with a small bright LED torch.

I think that the extra RAM Air effect we get with a RV means that the extra pressure we get lifts the manifol high enough above the under cowl pressure that when the inlet valve is closed small amounts of fuel and air leak out leaving the AVGAS dye behind. Makes it easy to find.

Also could explain some of the popping noises you hear from some RV's. :cool:
 
WoW! Great pictures. What kind of CHT's are you running? They look like they have been hot. Hard to believe they have only been on for a little over a couple hundred hours. Maybe they are from a bad batch of material. I havent had any problem with Lycoming gaskets but I can certainly see why you want to try something else. Hopefully it will take care of your problem.
Ryan
 
CHT's..........probably lower than yours! ;)

It is not a CHT problem, we usually have 290-310 in winter and 305-330 in summer.

The factory original gaskets were the same, and were 5 out of 6.

It is impressive to say the least! I would bet some folk have this and do not know it. It flew beautifully the day before.
 
Tolerances

It looks like the gasket is compressed more on the side that failed.

Could this happen if the intake tube is slightly too long and is not square to the cylinder face when everything is tightened up?
Could it just be a build up of tolerances preventing a good alignment?
 
Flanges are not flat.

My new IO-540 has slight gaps in the center. Now, after seeing the cause, mine are coming off before first flight to get the flange surface sanded flat then I will reassemble with hylomar.

When we prime our fuel injected engines, the fuel pours right down the tube. The reason for deterioration is from having the gap which allows fuel in and movement during pressure pulses. Hylomar or equivalent should get you three times the hours. Paying as much as we do for these engines, one would expect better fit and gaskets. We don't want any leaks on intake as it is unfiltered/heated air which throws off fuel servo fuel delivery ratios.

For those flying to check for leaks install small shop vac exhaust to fab inlet with filter in place to slightly pressurize intake tubes and use soap bubbles to check for leaks.

Edit: I can fit a .010" feeler gage on every intake tube flange between two bolts.
 
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Edit: I can fit a .010" feeler gage on every intake tube flange between two bolts.

On a brand new un run engine?????? :eek:

Its lucky we get 250 hours then!:mad:

Do tell more folks.

I have lodged a defect report with CASA which eventually makes its way to the FAA if there is merit....I will link this thread to them if there is enough eveidence.

This sucks........well it doesn't suck as much as it should I suppose :D
 
Just the standard factory test cell run approx 1 hr.

This is not caused by heating of the cast flange. On jet engines, helicopters, automobiles mating surfaces must be parallel and flat to get a good seal. They have to be cast or machined that way. I have mated many 24" X 18" accy gearbox cases with nothing but hylomar. One leak in 4 yrs. Sent it in for machining to level/flatten surface.

I don't have time to pull them right now but will before first engine start.
 
Intake gasket leak

I have a RV6 with a o320 that had the same problem.I found that the intake flanges were bent .The cure for me was to machine both the surface where the pipe flange seats & the outside surface of the flange.Its been about 400 hrs since then with no new problems.
 
Seems this is not unusual, the machining of the flange clamp I can see as possible, the heads would need to come off to do them and the thin flange on the pipe is too thin to machine.

Some super Goo may be the next treatment. Hylomar may be the answer. It just should not have to be.:mad:
 
If it makes you feel any better, I removed two bolts and lowered one flange, attempted to pull gasket loose...it fell apart. Yes, brand new engine. I have purchased better gaskets than those for my truck. I'll fix it this winter after test flights and some family trips. I can see plane maintenance and repair time staying right there with the hobbs meter. Oh but just think of all the beautiful sights from above. Think positive Wayne!
 
Interested also...

I had to change my Lyc paper gaskets at 400 hours and would like to try something better next time since my engine is carbureted and leaks in these gaskets can cause worse lean mixture probs than on an injected engine.
 
I buy mine at the local autoparts store. its a standard ford small block water outlet gasket.

bob burns
RV-4 N82RB
 
Yes these are problematic on parallel valve Lycomings. Those silicone gaskets look awesome, where can I get some? If you go back with paper gaskets I recommends buying them from ECI. The ECI brand gaskets are made out of a green colored fiber reinforced paper which does not split and fall apart like the Lycoming gaskets do.
 
The only oil leak on my 0-320 when I bought it was due to these gaskets failing. Tried small block inlet gaskets but did not like the fit. 71973 at Spruce is only $1.16, installed four of them with Hylomar Blue after making sure the flange end of the tubes were flat, no issues in 100 hours.
 
We have found that the Superior gaskets (red in colour) to be the best so far.

Those blue ones look interesting though.
 
hmm.. We just replaced an intake gasket on our little O320 this past weekend. Inspection is one of the useful side effects of a short oil change cycle. Obvious blue stains down the intake tube. Not surprised at all with a stash of new gaskets in the cabinet. Tanya had that intake tube off and back on with a new gasket in 15min. Barely worth talking about in our case.
 
If you go back with paper gaskets I recommends buying them from ECI. The ECI brand gaskets are made out of a green colored fiber reinforced paper which does not split and fall apart like the Lycoming gaskets do.


I bought from ECI those. Leaking after about 200 hours again.
 
If the poster who showed the blue gaskets could add a part number for us to source the parts... it would be great.
 
Blue Gaskets

I have searched high & low & spoken with gasket vendors (bespoke) - they are not to be found ... I believe Steve made those gaskets from Fluorosilicon.
 
The gaskets I made were water jet cut from 0.07" thick 60 durometer Fluorosilicone sheet. Most of the Regular more common Silicone sheet you find (di methyl type) is not compatible with gasoline. The Fluoro type is, and is much harder to find and is $$$ Used primarily by the military and space applications. I did try the straight, regular silicone sheet for awhile (only a few hours) they seemed to hold up OK, but switched over to the fluoro once it arrived...I felt much better and could sleep at night. The Fluorosilicone seems to be the perfect solution as it has a very low compression set with a soft (leak free) seal and is unaffected by temperature.
When I went to remove them for a check.... I loved it.... those seals just pealed off the hot cylinders all in one piece and in perfect condition...no sticking

Looks like someone should go into part time production!
 
The gaskets I made were water jet cut from 0.07" thick 60 durometer Fluorosilicone sheet. Most of the Regular more common Silicone sheet you find (di methyl type) is not compatible with gasoline. The Fluoro type is, and is much harder to find and is $$$ Used primarily by the military and space applications. I did try the straight, regular silicone sheet for awhile (only a few hours) they seemed to hold up OK, but switched over to the fluoro once it arrived...I felt much better and could sleep at night. The Fluorosilicone seems to be the perfect solution as it has a very low compression set with a soft (leak free) seal and is unaffected by temperature.
When I went to remove them for a check.... I loved it.... those seals just pealed off the hot cylinders all in one piece and in perfect condition...no sticking

Source please.........:rolleyes:

How many hours on them so far?

I think I have a source but need a .dxf file or .pdf of the gasket for them to price, as I asked, 4, 8 or 100. Does anyone have this or could make one? They need the .dxf for production if we want to get a bunch and spread out the cost.
 
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Patience....

Source please.........:rolleyes:

How many hours on them so far?

I think I have a source but need a .dxf file or .pdf of the gasket for them to price, as I asked, 4, 8 or 100. Does anyone have this or could make one? They need the .dxf for production if we want to get a bunch and spread out the cost.

Consider that the guy who made these for himself may be in the process of field testing with plans to scale up production so that we all might one day have leak-free intake seals. If so, he may not just want to give away his hard work - and I certainly wouldn't blame him for that.
 
Quick Google search brings up:
http://diversifiedsilicone.thomasnet.com/item/fluorosilicone-fs-/70-duro-3/pn-1356

Not sure what the minimum order or pricing is...

I found them earlier but they have different thicknesses.
Item # Durometer, Shore "A" Color Thickness Width Lead Time

DSP6075FS-015-36 60 Blue 0.015 in 36 in 1-3 Business days to ship

DSP6075FS-016-36 60 Blue 0.016 in 36 in 1-3 Business days to ship

DSP6075FS-032-36 60 Blue 0.032 in 36 in 1-3 Business days to ship

DSP6075FS-062-36 60 Blue 0.062 in 36 in 1-3 Business days to ship

DSP6075FS-093-36 60 Blue 0.093 in 36 in 1-3 Business days to ship

DSP6075FS-125-36 60 Blue 0.125 in 36 in 1-3 Business days to ship

DSP6075FS-250-36 60 Blue 0.250 in 36 in 1-3 Business days to ship


Didn't realize this was a tease from a potential supplier.

Sorry if I go my own way....:rolleyes:
 
Quote

Rik,

Did you get a quote on these sheets & quantity?

Most of these suppliers will cut to spec, but they have a minimum order quantity.

I'm in for a few if that will help lower the per item cost.

Ch
 
Rik,

Did you get a quote on these sheets & quantity?

Most of these suppliers will cut to spec, but they have a minimum order quantity.

I'm in for a few if that will help lower the per item cost.

Ch?z

He needs the file to work up cost. May have a friend with Auto Cad that can do it....one of these days....

Update: Another RV builder/flyer has stepped up to make the file. Should have an idea of pricing and minimum order before long.
:D
 
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Looking for beta testers. Need approximately 10 Aircraft (I have 40 test parts) that fly allot
to put more hours on them...Must agree to the following conditions:

These are experimental parts, still in development, untested, and as such, you assume all liability.
You must install them soon and fly often.
You must provide feed back ..positive or negative. This will require you checking them regularly and then removing the gaskets at the end of the test period and inspecting and assessing their condition.
PM me with your address. I will mail 40 out in about 2 weeks (US addresses only) to the first 10 requests that agree to the terms.
 
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I'm not in, but would suggest to those on the periphery to not bet the whole farm on an element that can be tested on just one intake tube.
 
VLAD...are you sure? those terms are going to require to much downtime for you...although you've got the "fly a lot" part down already.
 
... would suggest to those on the periphery to not bet the whole farm on an element that can be tested on just one intake tube.

Not a bad idea at all.

I would volunteer to beta test, but couldn't honestly fulfill the "fly a lot / fly often" end of the deal. I'm flying maybe once every 2 or 3 weekends now that Oshkosh is behind us and both avgas money and leisure time to go pleasure flying is presently in short supply for me.
 
Got pricing. .062 thickness, base price from fabricator = $4.46 each with 100 minimum. Plus tax and shipping etc. then packing and shipping out to anyone interested.
......?
Maybe wait and see how this other fellow's test group reports?

He might have better pricing??
 
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