Anybody have experience with a failed Suburu Head gasket.
Milo was on the way from Washington to Texas and made it as
far as SZP. Then the Soob engine had a mysterious over heating
problem towing a trailer.
Paul Lamar
No experience with Soob and blown head gasket, but with a Dodge
Minivan, I
had an overheating problem that seemed 'mysterious'.
It would overheat, and when you checked the coolant reservoir it
would be
full. When the engine cooled, the reservoir would go down as expected.
The problem was a small leak in the head gasket, which would put
combustion
gas into the cylinder space, driving the coolant out of the engine and
into
the overflow reservoir.
Bill Schertz
KIS Cruiser #4045
N343BS
Bill, did you try any chemical sealants such as duraseal or steel seal?
Paul Lamar
Yes I have as that is my business and I rebuild 3 to 4 engines a
week, no
none of those sealants will work as the problem is the combustion
pressure
is pushing past the gaskets into the water system and pushing the
water out
the burp tank and so there is no way to plug the leak unless you could
get
the sealant into the combustion chamber to shove it into the hole thats
leaking, hate to say it but you are best to go for a whole engine as
you can
mill the heads when you replace a head gasket but you cannot mill the
block
and the block warps as much or more than the heads so if you put a new
gasket on a straight head and a warped block it wont last long, I can
do a
compete long block for $1500 to $1600 depending on which engine it is
and I
fix all the problems that Subaru had to make it better than new.
Give me a call if you need more info.
Ken
360-834-4089
I don't know which engine is in that Subaru, but my sister has one and it
had a bad head gasket and this is a known problem. They have an improved
replacement gasket that fixes it but they didn't do a recall and
replace it
on their dime.
Steve Brazil
The good news is as far as Milo and family are concerned is they were
able to plug
the leak with goo. After the engine cooled off it sucked all the
coolant back
out of the over flow can. That would not have happened if the leak
still existed.
That is part of the process. If the exhaust valve and intake valve is
closed
hot air in the cylinder cools off causing a low pressure in the
cylinder drawing
the sealant into the leak. This is somewhat of a crap shoot as the
leak must
occur around the cylinder that happens to stop in that sealed condition.
Also of course the coolant itself also contracts drawing coolant in
from the
over flow can.
There has been several recent breakthroughs in these stop leak type
fluids.
Prior to these breakthroughs most stop leak type products required you
to purge
the engine of antifreeze coolant. This is no longer true of the better
products.
The other breakthrough is a chemical reaction that is triggered by the
high
400 to 500 F metal temperatures that causes the goo to solidify in the
area
of the leak but not in the radiator.
Here is the web site that claims to be the best.
It is called Steel Seal. It is a clear liquid with no particulate matter
at all. It is rather expensive at $70 and they claim to have an iron clad
patent. "The product is drawn into the damaged area and seals the crack
with a thermo-chemical bonding process."
I have not tried it on a leaking rotary yet but
it sounds promising to fix the shrunk rotor housing problem due to
extreme over
heating of the rotary. Milo has some on order to test it on the soob
if the
stuff we actually used fails.
https://secure.steelseal.com/index.php/t2b
Paul Lamar
Re Overheating Soob. Most Subaru's only have electric fans and
sometimes the switch in the radiator fails to switch on and causes a
overheating porblem, can happen if people turn off the air/con, because
the air/con turns the fans on even if the engine is not hot, then
without the air/con turned on the fans you have NO fans at all!!
Can also have a overheating problem only when towing because the
radiator tubes are partly blocked internally, and so not enough reserve
cooling available, so the engine overheats, will also happen if the
radiator cap is not holding at least 14/15 psi.
John Burey
It was definitely a head gasket. IMHO here is why head gasket problems
on the Soob are common. Not enough head bolts. Too much distance
between bolts allows the aluminum head to deflect between bolts.
Paul Lamar
Here is the Chevy LS1 V8 head bolt spacing with about the same bore
and center to center spacing. Also with an aluminum head.
LS1 head gasket failures are less common.
The Soob engine needs to be redesigned.
Paul Lamar
I use ARP head studs on my race engines and offer them to people with
grocery getters for extra insurance, with these studs they will handle 45
lbs of boost at 700 plus hp, for more boost you can tap out the case and run
oversize studs as the next thing that will happen to the threads will pull
out if your replacing the head gaskets get the original OEM multi layer
steel gaskets from Subaru and if its a 2.5 ask for the gaskets for a 97
outback regardless of what year it is, that is the gasket that I put on all
my engines including the turbo engine, also spray the head gasket with
permatex copper spray, with that it should get you home but it will probably
give problems latter as chances are that the case, heads and cylinders are
warped if it has overheated and that is why I mill the case and heads and
bore the cylinders 20 over on all the engines I rebuild.
Ken
In the case of the Soob, unlike the rotary, the strength or stiffness
of the studs does not help much.
Consider the cylinder head a simply supported beam. Deflection is
proportional to the cube of the distance (l) between the bolts.
http://www.codecogs.com/reference/engineering/materials/beams/simply_supported_beams.php
Paul Lamar
Going on 7 yrs now with a Ram Engines Sube 125 hp dual port EA81 (1800 cc) in a Europa kitplane with a Marcotte M150
gearbox. No issues or problems whatsoever although total time is only 500 hrs. This engine is nowhere near stock
however as it has the custom dual port heads, 10/1 compression, custom cam, tuned intake manifold running the Ellison
TBI, tuned exhaust, teflon coating on everything, all balancing, full stud girdle to prevent case half squirm. The stud
girdle is important on the EA81 as it only has three main bearings. Probably not needed on the EJ22 or 25 as these have
five main bearings. Compression is still 78/80 on all four, burns 7.2 gph for TO (5100 MSL), 5.5 in cruise at 155 mph.
I run 100LL with Marvel oil and Decaelin lead scavenger. Plugs seem fine with no fouling, no discernible lead buildup
on valves (what I can see thru the plug holes anyway). Would love to do a rotary in something but the EA81 is doing
well for me. One possible non/issue I don't understand is the EGT's are hard to get above 1000 degrees. Would like to
run at 1240 F but impossible to get to except mid summer.
Glenn
What is the gear box ratio? Got any HP curves on that engine?
Paul Lamar
Hi Paul, the gear box ratio is 2.04. I'm using a Catto 64x62 3 blade prop - very nice! I have attached the torque
curve for the
current Ram 140 hp dual port EA81 with Tracy's EC3 fuel injection. Very flat torque curve. Got a buddy in Seattle
going with the 140 on his Europa who will use the Autoflite box with 1.9 ratio and Catto prop. Should get him a 180 mph
cruise. Not bad for a STOL bird!
glenn crowder
A Europa is a STOL? You mean it is a motor glider :)
The 1.9 box will not get the claimed max HP with a reasonable diameter prop.
He will have to run a 3000 RPM prop which sacrifices efficiency.
A flat torque curves does absolutely nothing with a fixed pitch prop.
One would be better off using a tuned intake manifold that would
increase HP at 5800 RPM.
5.5 gallons an hour at cruise assuming a .45 BSFC is 76 HP. Yes the
engine should last a long time at only 76 HP for 155 MPH cruise.
At 7.2 GPH the HP is 100 HP. Not 140 HP.
Giving the Ellison carb the extreme benefit of the doubt and assuming a BSFC of .4
the numbers are 85 HP and 112.5 HP. Not 140 HP.
These are not guesses or opinions. It is the LAW (of physics.)
Apparently the Europa is very low drag with a long wing. A motor glider more or less.
This is classic Soob AC engine hype :) Dozens of people have already found out
the HP claims for stock Soobs in AC's are highly inflated.
More like a VW powered motor glider:)
Paul Lamar
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