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  #21  
Old 03-14-2009, 10:01 AM
chaskuss chaskuss is offline
 
Join Date: Mar 2005
Location: SE Florida
Posts: 1,499
Default The Trick

Quote:
Originally Posted by AlexPeterson View Post
Is it just me, or are these engine mounted fuel pumps a real PITA to install? I have rotated the engine until the plunger is as far up as it goes. I can get the pump in all the way, as long as it is tilted a little bit. So far, so good. The problem arises when I try to get the socket head cap screw started. Because of interference between the screw head and the pump casting, I'm not able to get it properly aligned for starting the threads. The only way to get alignment of the screw is to pull back the fuel pump a little, which causes the lever to pop up above the plunger. AARRGG.

Any tricks would be appreciated. I have glued the gasket to the pump, so that "trick" is already used.

Thanks!
Alex,
I apologize for giving advice "after the fact". The problem you describe was also common on auto engines (prior to 1986) when they had engine driven fuel pumps. One trick to keep the push rod from falling down is to coat it's length with grease prior to inserting it. This will prevent gravity from lowering the push rod.
That will allow you to back the pump up that critical 1/4". I still have nightmares about the first time I tried to install an engine driven fuel pump (age 19) I spent hours, only to have a "real" mechanic come over and install it in 15 minutes! That's how I learned about the grease trick!
Charlie Kuss
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  #22  
Old 03-14-2009, 02:52 PM
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N941WR N941WR is offline
 
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Location: SC
Posts: 12,887
Default

Here's the scanned image from the Lycoming OH manual:

Note how the wires are on the left side of the bolts.
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RV-9 (Yes, it's a dragon tail)
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Last edited by N941WR : 03-15-2009 at 04:37 PM.
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  #23  
Old 03-14-2009, 07:58 PM
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AlexPeterson AlexPeterson is offline
 
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Location: Maple Grove, MN
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Default

Quote:
Originally Posted by chaskuss View Post
Alex,
I apologize for giving advice "after the fact". The problem you describe was also common on auto engines (prior to 1986) when they had engine driven fuel pumps. One trick to keep the push rod from falling down is to coat it's length with grease prior to inserting it. This will prevent gravity from lowering the push rod.
That will allow you to back the pump up that critical 1/4". I still have nightmares about the first time I tried to install an engine driven fuel pump (age 19) I spent hours, only to have a "real" mechanic come over and install it in 15 minutes! That's how I learned about the grease trick!
Charlie Kuss
Charlie, thanks. I've put quite a few of the old auto fuel pumps on - they are a piece of cake compared to this monster. I absolutely could not get grease to hold that plunger up - too much oil all around that area. Larry V. called me today with his tip - again, after the fact! He said you need a bubba helping, pushing and snorting on the pump (I can't use the exact words here on this family site) until it is done. Something about getting one screw started.

It has been a while since I had to do it, but I do remember it went quite well when Pete was there to help. Solo is a non-starter unless the engine is not on the plane.
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  #24  
Old 03-14-2009, 09:11 PM
DENMACRES DENMACRES is offline
 
Join Date: Aug 2008
Location: MONTGOMERY, TX.
Posts: 89
Default FUEL PUMP BOLTS

I HAD TO REPLACE MINE ALSO, ENDED UP GRINDING THE HEAD OF THE CAP BOLT TO A ROUNDED SHAPE. ALSO DID A LITTLE CLEARANCING ON THE FUEL PUMP CASE. THE BALL ALLEN WRENCH REALLY HELPED. DENNIS. RV-6/IO-360 ANGLE.
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  #25  
Old 03-15-2009, 12:04 AM
Captain Avgas Captain Avgas is offline
 
Join Date: Oct 2005
Location: Melbourne, Australia
Posts: 1,868
Default Fatal installation

Bill R, it was good of you to post the scan of the safety wiring as per the Lyc OH Manual. That was very interesting indeed.

Incidentally for those that might be tempted to take the fuel pump installation lightly here is an NTSB report on an RV7 that crashed in Feb 08 killing the pilot. Compulsory reading. This is not an area where it is good to learn from your mistakes.....because you might only get to make ONE.

http://www.ntsb.gov/ntsb/brief.asp?e...21X00223&key=1
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Last edited by Captain Avgas : 03-15-2009 at 09:35 PM. Reason: Added URL
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  #26  
Old 03-15-2009, 07:48 AM
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mburch mburch is offline
 
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Location: Northwestern USA
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Quote:
Originally Posted by erich weaver View Post
One last warning - be sure to use a sealer on the screw threads, as the holes for them penetrate through into the interior of the engine case, and you risk an oil leak (the reason for my forced second removal/reinstallation).
Erich,

What did you use to seal the threads when you put your pump back on? I didn't think to seal mine and now I'm pondering taking the bolts out and putting on some permatex (or other?).

thanks,
mcb
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  #27  
Old 03-15-2009, 12:29 PM
kcameron kcameron is offline
 
Join Date: Jan 2005
Posts: 210
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A couple of years ago I engaged in a two-day struggle to install a new pump on my RV-4. It was complicated by the RV-4's tight engine compartment. I had to remove the lower two engine mount bolts and lift the engine to get clearance to the firewall footwells. After I did that, I ran into the same frustrations as you are having: keeping the plunger up and out of the way and lack of clearance between the bolts and pump body. I spent a lot of time cussing the designers of the pump. Why couldn't they have built the flange a little wider? Ugh.

One thing that caused me some grief: I had turned the engine until I thought It was in its most upward position. When I sought help from a mechanic, he found that it still had a ways to go. So be really sure it won't go higher.

Using grease on the plunger didn't help me either. It was just too slippery for that to work. We finally got the plunger to stay up by wrapping a loop of waxed lacing cord around it. We ran the lacing cord to the top of the engine where I held tension on it while the mechanic worked on getting the pump in place and the bolts started. He ran the bolts in most of the way until just before the lacing cord started being squeezed. Then I released one end of the lacing cord and pulled it out. After that it was relatively straight-forward to tighten and safety-wire the bolts.

My arms looked like Larry's after the ordeal but I took it to another level. Before I test-ran the engine I decided to turn it over to see if I could detect any binding in case the fuel pump arm was riding on the side of the plunger. I was tired by that time and not exhibiting proper respect for the prop. As I pushed the prop past a cylinder's compression stroke, the blade jumped out of my hand and the other blade came around and struck me on the back of my upper arm. Ouch! I jumped around and cussed for a few minutes. It felt like I might have cracked the bone and there was a fair bit of blood from a cut. I had never seen anything like that. At first I thought it was just the compression giving the prop enough momentum to push the blade around and into me. When I ran the engine, I found that the left mag would not turn off. At some time in the two days of struggling with the pump, I had put tension on the p-lead and pulled it out of an improperly crimped terminal. This was before I reworked the electrical system and found many problems. The builder just doesn't know much about electrical stuff. I went to the emergency room later and found that the bone was OK but the cut in my arm was nearly an inch deep. So lesson learned: always be on guard of the prop when moving it. If my arm hadn't stopped it, the engine might have started and the outcome might have been even worse.
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  #28  
Old 03-15-2009, 02:12 PM
chaskuss chaskuss is offline
 
Join Date: Mar 2005
Location: SE Florida
Posts: 1,499
Default To late, to late!!!

Quote:
Originally Posted by AlexPeterson View Post
Charlie, thanks. I've put quite a few of the old auto fuel pumps on - they are a piece of cake compared to this monster. I absolutely could not get grease to hold that plunger up - too much oil all around that area. snipped.
Alex,
I often run into problems like that. I always keep at least a case of aerosol brake parts cleaner around my shop. It's available at any auto parts store. It's essentially trichlorethylene. It absorbs oil and grease, evaporates and leaves no residue behind. It's great for cleaning off oil & grease. It also works well as a cleaner prior to using Locktite on parts. A few squirts of brake parts cleaner would have cleaned off all the oil in the area.
I also use it to clean grease and oil off of clothing, since it's basically dry cleaning fluid!
Charlie
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  #29  
Old 03-15-2009, 04:33 PM
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n5lp n5lp is offline
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Location: Carlsbad, NM
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Default

Quote:
Originally Posted by N941WR View Post
Here's the scanned image from the Lycoming OH manual:

Note how the wires on the left side of the bolts.
I didn't notice, until I saw this diagram, that the pump does not mount level. Not realizing this probably made it harder to get the bolts started as the far hole is hidden and I was probably trying to make it go on with the pump level.

By the way, for any future person that runs on to this thread because they are having trouble with high fuel pressure and carb flooding and can't figure out why, swapping the engine driven pump out does indeed seemed to have solved those problems with my engine. Today, all I saw was 4 and 5 PSI and a great running engine (go figure). Before the fuel pump swap I was often seeing 8 and 9 PSI right after a start and around 7 most of the time. When it would get to 9 after a start, I could barely keep the engine running.
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  #30  
Old 03-15-2009, 07:42 PM
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AlexPeterson AlexPeterson is offline
 
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Location: Maple Grove, MN
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Quote:
Originally Posted by mburch View Post
Erich,

What did you use to seal the threads when you put your pump back on? I didn't think to seal mine and now I'm pondering taking the bolts out and putting on some permatex (or other?).

thanks,
mcb
Matt, I did not use any sealant and haven't seen any leaks in somewhere around 300 hours. I sure as heck wouldn't take the rotten things out (which means pulling the pump itself back about 1/4 inch or so...) unless they were leaking - a lot. Even then, some sealant around the head would likely cure it after cleaning with solvent, since the flange is gasketed all around.
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