What are you guys using for fixing pushrod pinch areas that are broke into on cast iron heads? I know some are brazing them. I figure Bill and Larry have done this a ton and know what not to do.
shawn
cast iron pushrod pinch
Moderator: Team
cast iron pushrod pinch
hi,
What are you guys using for fixing pushrod pinch areas that are broke into on cast iron heads? I know some are brazing them. I figure Bill and Larry have done this a ton and know what not to do.
shawn
What are you guys using for fixing pushrod pinch areas that are broke into on cast iron heads? I know some are brazing them. I figure Bill and Larry have done this a ton and know what not to do.
shawn
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automotive breath
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Re: cast iron pushrod pinch
Hi Shawn, Bill posted an interesting way to widen the pinch; it could be just what you need for the repair.shawn wrote:hi,
What are you guys using for fixing pushrod pinch areas that are broke into on cast iron heads? I know some are brazing them. I figure Bill and Larry have done this a ton and know what not to do.
shawn
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bill jones
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-It depends somewhat on what heads you are working on.
-If the heads have a hole for the pushrod then you likely could use thinwall tubing and press & epoxy that tubing in there.
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-If the heads are wide open like older SBC production heads then maybe you could braze them----I haven't actually ever brazed or silver soldered that area of a cast iron yet but I would practice first on a junk head until I felt like I had the process down really good.
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-I installed an old set of .220" offset intake rockers on aluminum heads---cut the pushrod pinch completely away--then I made a press that flattened the thin wall tubes---and epoxied the tubes in there with Edelbrock or Manley two part epoxy putty and never had any issues.
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-For singular repairs where you bubbled up the wall and broke thru and just want to patch that one area I have also used a piece of metal like a thin curved 3/4" wide metal tape measure---cut a section the full length of the outer port wall---lightly ground off the painted surfaces of the tape measure metal and formed/narrowed the edges so it fit in there real nice and used JB Weld epoxy over the full length.
-Never had any issue with that repair on street and/or race engines (not yet anyway).
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-Tell us what you are working with---maybe send a photo or two---and maybe I can get more specific about what I'd do.
-If the heads have a hole for the pushrod then you likely could use thinwall tubing and press & epoxy that tubing in there.
------------------------------------------
-If the heads are wide open like older SBC production heads then maybe you could braze them----I haven't actually ever brazed or silver soldered that area of a cast iron yet but I would practice first on a junk head until I felt like I had the process down really good.
---------------------------------------
-I installed an old set of .220" offset intake rockers on aluminum heads---cut the pushrod pinch completely away--then I made a press that flattened the thin wall tubes---and epoxied the tubes in there with Edelbrock or Manley two part epoxy putty and never had any issues.
------------------------------------------
-For singular repairs where you bubbled up the wall and broke thru and just want to patch that one area I have also used a piece of metal like a thin curved 3/4" wide metal tape measure---cut a section the full length of the outer port wall---lightly ground off the painted surfaces of the tape measure metal and formed/narrowed the edges so it fit in there real nice and used JB Weld epoxy over the full length.
-Never had any issue with that repair on street and/or race engines (not yet anyway).
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-Tell us what you are working with---maybe send a photo or two---and maybe I can get more specific about what I'd do.
It's just a set of iron eagle darts. No tube to push a sleeve in there, so I can't do that. The holes are more "bubbles" where they have broke through. Maybe 5/8" tall by 1/4 wide. Normally I would just use the moroso/manley epoxy. Just clean out the hole real well with a deburring tool to get ride of the "thin" spots, rough up both the port side and the pushrod side to get a good grip, kneed up a ball of epoxy and form it on both sides of the port. It's always seemed to work in the past i just thought there might be a better way. That thing with the tape measure tape sounds pretty neat. Feels a lot safer then having that epoxyhanging in there. I know some people have had trouble with epoxy in the past so i gotta feel like my time is running out without a failure.
shawn
shawn
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automotive breath
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After reading Bill’s post I was thinking; the same thing could be done with this stainless steel shim stock. Something like 0.015” thick would add plenty of strength to the epoxy, it would bend easily around the bore of the pushrod area of the head and it wouldn’t add much thickness in the area. I have a set of heads in the shop that someone cut through; I’m planning the repair this way.shawn wrote:...That thing with the tape measure tape sounds pretty neat. Feels a lot safer then having that epoxyhanging in there. I know some people have had trouble with epoxy in the past so i gotta feel like my time is running out without a failure.
shawn
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bill jones
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-the thing about the metal & the curve of the tape measure material is that it is strong and when you run a piece in there up and down the entire pushrod wall you have lots of surface area for the JB Weld to stick to----and the JB Weld is thin enough that it will oooze out and leave the thinnest possible repair that I know of.
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-How are you measuring the wall thickness---getting that thin and still blowing bubbles thru it?
-Maybe you need to run a finger on the outside of the port wall when you start getting that close so that you can feel the heat and the metal flex when the cutter is starting to deflect that thin area.
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-If I had enough room on the outside of the ports to slide the tape measure metal down in there on an assembled engine---I would probably epoxy all those areas and install the 8 sections of metal shim on all the ports----then port the walls until I see the epoxy up the full length.
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-How are you measuring the wall thickness---getting that thin and still blowing bubbles thru it?
-Maybe you need to run a finger on the outside of the port wall when you start getting that close so that you can feel the heat and the metal flex when the cutter is starting to deflect that thin area.
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-If I had enough room on the outside of the ports to slide the tape measure metal down in there on an assembled engine---I would probably epoxy all those areas and install the 8 sections of metal shim on all the ports----then port the walls until I see the epoxy up the full length.
Sorry to hijack your post Shawn, but I was wondering about the ins and outs of installing the thin wall tubing correctly. What kind of interference is required, and how much clearance would be required on the drift used to insert it. I have a few ports on my W2 heads where the port has broken through to the pushrod pinch. Who usually stocks this tubing????
Thanks
AL...
Thanks
AL...
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bill jones
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-Various sizes of thin tubing is real easy to find here in the states at hobby shops.
-It is like .015" thick so it's not going to like to be press fitted very tight.
-I would rather slip fit the hole to the tube and then use red or green loctite or your favorite thin and slow curing epoxy.
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-I find that if you have holes thru the heads for the pushrods---that the pushrods are usually about .080" or so from touching the outside of the port wall.
-So I made up a press die where I can press the tube into a D shape---then I install that D in there with the flat on the port wall side---and I use JB Weld the full length of that tube---and leave a littler tube sticking out above and below the pushrod hole so that I can get epoxy all the way around the tubes at the top and the bottom.
-Doing this virtually guarantees NO LEAKAGE.
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-Then I port right thru the pushrod wall---into the epoxy and be real careful when you start to see the brass tubes.
-If the metal of the head tries to chip away at the wounded area then I scrape the loose edges away and smear some more fresh JB Weld in there on the port wall side---let it set up and then lightly buff it down with a sanding roll.
-It is like .015" thick so it's not going to like to be press fitted very tight.
-I would rather slip fit the hole to the tube and then use red or green loctite or your favorite thin and slow curing epoxy.
------------------------------------------------------
-I find that if you have holes thru the heads for the pushrods---that the pushrods are usually about .080" or so from touching the outside of the port wall.
-So I made up a press die where I can press the tube into a D shape---then I install that D in there with the flat on the port wall side---and I use JB Weld the full length of that tube---and leave a littler tube sticking out above and below the pushrod hole so that I can get epoxy all the way around the tubes at the top and the bottom.
-Doing this virtually guarantees NO LEAKAGE.
---------------------------------------------
-Then I port right thru the pushrod wall---into the epoxy and be real careful when you start to see the brass tubes.
-If the metal of the head tries to chip away at the wounded area then I scrape the loose edges away and smear some more fresh JB Weld in there on the port wall side---let it set up and then lightly buff it down with a sanding roll.