Today's Message Index:
----------------------
1. 06:20 PM - 701 trim tab angle (Larry Bohannon)
2. 08:01 PM - Valve Guides (Tim & Diane Shankland)
3. 10:01 PM - Re: 701 trim tab angle (Chuck Deiterich)
4. 10:32 PM - Re: Valve Guides (Don Walker)
Message 1
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| Subject: | 701 trim tab angle |
--> Zenith-List message posted by: "Larry Bohannon" <lbohannon1@mindspring.com>
Hi Ya'll,
I just completed my 701 stabilizer and elevator and installed the trim tab.Plans
say to set tab angle to up +/-30 degrees and down +/- 30 degrees.The trim
tab hinge is riveted on the trailing edge which was factory prebent to 18
degrees. Question: Do I take into account the already in place 18 degree bend
when setting the trim degrees?What do I use for a reference line for neutrel or
zero degrees,the bent trailing edge or what it would be without the bend?
Another question: Exactly what is the purpose of this trailing edge bend?I'm kinda
guessing but maybe it somehow takes the place of a counterweight?
Thanks.
Larry Bohannon
Winder, Georgia
701 #5040
rudder,stablizer and elevator completed
Message 2
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--> Zenith-List message posted by: Tim & Diane Shankland <tshank@megsinet.net>
I know this topic was quite hot a month or so ago when several people
reported problems with loose valve guides. It seemed odd that a few
people seemed to have most of the problems. I also thought that some of
the explanations, like both ignitions being on, were off the mark. I
occurred to me the other day that back in the old days when I was in
college I used to repair snowmobiles. The Yamaha's that I worked on had
dual carburetors and it was very important to "balance" the carbs. This
was done with a device like a venturi that was placed over each carb and
the linkage was adjusted until the air volume was equal. As I recall the
failure mode of unequal volumes was burning a hole in a piston. Now
these engines were running a lot hotter than the Suburu's but I wonder
if an unbalanced airflow is causing one bank to get a disproportionate
amount of load and heat. I know the Stratus engines have a small balance
tub, but I wonder if it is adequate. Just a thought.
Tim Shankland
Message 3
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| Subject: | Re: 701 trim tab angle |
--> Zenith-List message posted by: "Chuck Deiterich" <cfd@thegateway.net>
Larry,
The upturn on the trailing edge of my elevator overpowered the trim tab. I
had to bend the trailing edge down so the tab could be more centered . ZAC
had to do the same on their 701. The bend stiffens the trailing edge but
there should be a little bend in both the top and bottom skins.
Chuck D.
N701TX - Jabiru 2200
----- Original Message -----
From: Larry Bohannon <lbohannon1@mindspring.com>
Subject: Zenith-List: 701 trim tab angle
> --> Zenith-List message posted by: "Larry Bohannon"
<lbohannon1@mindspring.com>
>
> Hi Ya'll,
> I just completed my 701 stabilizer and elevator and installed the
trim tab.Plans say to set tab angle to up +/-30 degrees and down +/- 30
degrees.The trim tab hinge is riveted on the trailing edge which was
factory prebent to 18 degrees. Question: Do I take into account the already
in place 18 degree bend when setting the trim degrees?What do I use for a
reference line for neutrel or zero degrees,the bent trailing edge or what it
would be without the bend?
> Another question: Exactly what is the purpose of this trailing edge
bend?I'm kinda guessing but maybe it somehow takes the place of a
counterweight?
>
> Thanks.
> Larry Bohannon
> Winder, Georgia
> 701 #5040
> rudder,stablizer and elevator completed
>
>
Message 4
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| Subject: | Re: Valve Guides |
--> Zenith-List message posted by: "Don Walker" <dwalk3dw@msn.com>
Hi Tim,
The intake on the Stratus is designed so that the front cylinders run
richer..#3and#4. regardless of what the carbs are doing. But these failures
are occurring with valve guides that have been pulled, then knurled on the
outside and replaced. Rather than replacing with oversized guides, heating
the head and freezing the guides, these knurled guides have simply been
pressed into the head. This knurled steel against the aluminum head defeats
the purpose as it is driven in. Stratus continues to this day to use or to
leave knurled guides in their heads as reported by one of our fellow Stratus
owners who just had his heads reworked by Stratus. After spending $500 to
get it done, he checked them out before replacing them on the engine. The
guides popped out with little effort, one shooting across the room. I
personally pulled one of mine out with my finger tips.
It may also be that the compression ratio on the Stratus requires a
higher octane fuel than they have recommended. I have checked my plugs
frequently and found that fuel burn has been balanced well between carbs,
but leaner in the back, as mentioned earlier. I have had a failure in the
front/rich cylinder as well as in the back/lean on the other side of the
engine. Go figure.
We have found that Ram Engines.com is very knowledgable about these
issues and has a fix. He is using mag/bronze oversize guides with a shoulder
on them. He modifies the length of the guides to fit the cam, and he
preheats the heads and cools the guides before pressing them in, shooting
for a .002 difference, I think.
Mine have been okay since I had a shop here replace with oversize guides
and heat/cold press fit. But I may redo them with the shouldered guide for
comfort sake. Don Walker HDS TD 272 hours.
----- Original Message -----
From: "Tim & Diane Shankland" <tshank@megsinet.net>
Subject: Zenith-List: Valve Guides
> --> Zenith-List message posted by: Tim & Diane Shankland
<tshank@megsinet.net>
>
> I know this topic was quite hot a month or so ago when several people
> reported problems with loose valve guides. It seemed odd that a few
> people seemed to have most of the problems. I also thought that some of
> the explanations, like both ignitions being on, were off the mark. I
> occurred to me the other day that back in the old days when I was in
> college I used to repair snowmobiles. The Yamaha's that I worked on had
> dual carburetors and it was very important to "balance" the carbs. This
> was done with a device like a venturi that was placed over each carb and
> the linkage was adjusted until the air volume was equal. As I recall the
> failure mode of unequal volumes was burning a hole in a piston. Now
> these engines were running a lot hotter than the Suburu's but I wonder
> if an unbalanced airflow is causing one bank to get a disproportionate
> amount of load and heat. I know the Stratus engines have a small balance
> tub, but I wonder if it is adequate. Just a thought.
>
> Tim Shankland
>
>
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