I would wonder how that big DENT got in the firewall just behind the engine mount gear tube? :oops: Looks like something hit the firewall which, in turned, caused some of the cracking....:unsure:

Most -4s are going to have some cracking. I would suggest when you have the engine off to take the engine mount off as well, have it sand-blasted and make sure it is intact. Replacing the firewall? Pretty large undertaking....... Stop-drilling the cracks would be a minimum.....
 
Roadjunkie1 said:
I would wonder how that big DENT got in the firewall just behind the engine mount gear tube? :oops: Looks like something hit the firewall which, in turned, caused some of the cracking....:unsure:

Most -4s are going to have some cracking. I would suggest when you have the engine off to take the engine mount off as well, have it sand-blasted and make sure it is intact. Replacing the firewall? Pretty large undertaking....... Stop-drilling the cracks would be a minimum.....
Click to expand...
Roger that on the engine mount sand blasting. Stop drilling the cracks are enough is what you saying ?
 
What generation fuselage to engine mount weldments are installed?
They may be cracked as well. In which case the aircraft is grounded.
If they are the older, thinner,and especially if they are 1st gen split units, an upgrade is highly recommended.
That job is easier since the engine will be off the plane.
Do one mount at a time. Structural screws can be used in lieu of rivets.
The firewall proper can likely be repaired.
There are quite a few outstanding threads on the repair.
 
anatolianeagle said:
Stop drilling the cracks are enough is what you saying ?
Click to expand...
I think once you get the engine and eventually the mount off, the extent of the damage to the firewall will be easier to assess and repair recommendations made from there. The information on Post #4 is pretty important. Search this as there is a lot of information on this forum about all of this...

About that dent................? :unsure:
 
andoman said:
What generation fuselage to engine mount weldments are installed?
They may be cracked as well. In which case the aircraft is grounded.
If they are the older, thinner,and especially if they are 1st gen split units, an upgrade is highly recommended.
That job is easier since the engine will be off the plane.
Do one mount at a time. Structural screws can be used in lieu of rivets.
The firewall proper can likely be repaired.
There are quite a few outstanding threads on the repair.
Click to expand...
The air aircarft was built in 1994 October. I am not a builder or very experienced person. However i will ask a mechanic to review those weldments you mentioned. Thank you for the response. I will definitely consider the upgrades
 
Very common on RV-4s, and I've seen more with buckles and dents than without. I built my -4 and have repaired others. The firewall is 2 piece, and VANS will sell the bottom half only. Pretty easy job...a friend did his a year ago, and the part from VANs was less than $50 if I recall. The firewall is non structural and wrinkles/cracks easily. Check your longeron weldments and make sure they aren't the old style and cracked.
 
fixnflyguy said:
Very common on RV-4s, and I've seen more with buckles and dents than without. I built my -4 and have repaired others. The firewall is 2 piece, and VANS will sell the bottom half only. Pretty easy job...a friend did his a year ago, and the part from VANs was less than $50 if I recall. The firewall is non structural and wrinkles/cracks easily. Check your longeron weldments and make sure they aren't the old style and cracked.
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Thank you sir. Nothing on the top part. The bottom is the one got wrinkled and cracked
 
Hi
Just saw your post. A couple of things to consider. First you have to support the plane before you can take the engine mount off, this support has to be sturdy enough so you can buck rivets from inside the plane. From the pictures the bottom of the firewall should be a 90 deg. bend riveted to an aluminum angle that goes across the the bottom of the plane and is tied into the steel corner brackets. I think you will find that this angle will be bent so will need replacing. When replacing the ss firewall bottom half, the new one has to be match drilled and riveted, alot of that will have to be done without being able to see where the bucking bar is placed, the stainless firewall dents very easily so be very careful.
After a ding like that nothing is square so it becomes more involved than first thought.
The dent is from hard landings, probably more than one, usually there is an audible oilcanning of the firewall when taxing.
I suggest if you haven't done much building to get some help if you can from someone who has, it's not the place to start learning the skills.
You will also need some tools you may not have, small angle drill, long drill bits, bucking bars hole finders etc.
I have done 2 of these repairs and still would find it a bit of a challenge.
Good luck
Chris
 
1rv4 said:
Hi
Just saw your post. A couple of things to consider. First you have to support the plane before you can take the engine mount off, this support has to be sturdy enough so you can buck rivets from inside the plane. From the pictures the bottom of the firewall should be a 90 deg. bend riveted to an aluminum angle that goes across the the bottom of the plane and is tied into the steel corner brackets. I think you will find that this angle will be bent so will need replacing. When replacing the ss firewall bottom half, the new one has to be match drilled and riveted, alot of that will have to be done without being able to see where the bucking bar is placed, the stainless firewall dents very easily so be very careful.
After a ding like that nothing is square so it becomes more involved than first thought.
The dent is from hard landings, probably more than one, usually there is an audible oilcanning of the firewall when taxing.
I suggest if you haven't done much building to get some help if you can from someone who has, it's not the place to start learning the skills.
You will also need some tools you may not have, small angle drill, long drill bits, bucking bars hole finders etc.
I have done 2 of these repairs and still would find it a bit of a challenge.
Good luck
Chris
Click to expand...
Chris, thank you for such explanation and advice and feedback. I can't do the repair. I am looking for someone in Seattle area to do the work
 
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