240 cast in valve guides
#1
05-29-2018, 10:45 PM
240 cast in valve guides
As much as I can tell all 1965 - 74 240 heads with smog holes have cast in valve guides, is that correct or do all 240 heads have the cast in valve guide?
How do you repair / replace a broken valve guide that the top section broke off from the wider bottom section?
If one has broke should you replace all 12?
How do you repair / replace a broken valve guide that the top section broke off from the wider bottom section?
If one has broke should you replace all 12?
#2
05-30-2018, 09:30 AM
Fleet Mechanic
Not sure if you read fordsix first but there ya go:
All 240 / 300 are (originally) cast in head guides. You can repair a broken guide. The first thing I would do is mill off the broken part with a piloted mill / drill. Then the guide can be bored and reamed to .500". Then a new bronze guide can be driven in. Then the top can be machined down to accept a PC seal with a special cutter. Then the guide has to be sized for the valve you are using and the desired clearance with a Sunnen Stem Hone or equivalent. Once the guide is in place and sized you can press on a new PC seal and install the valve using a special "bootie" to push the seal over the end of the valve and tap it into place with a guide seal driving tool.
This requires specialized equipment not normally found in an enthusiasts garage. I recommend having a machine shop do it. You could ask how much to do all 12 as the setup time is about the same for one or twelve.
All 240 / 300 are (originally) cast in head guides. You can repair a broken guide. The first thing I would do is mill off the broken part with a piloted mill / drill. Then the guide can be bored and reamed to .500". Then a new bronze guide can be driven in. Then the top can be machined down to accept a PC seal with a special cutter. Then the guide has to be sized for the valve you are using and the desired clearance with a Sunnen Stem Hone or equivalent. Once the guide is in place and sized you can press on a new PC seal and install the valve using a special "bootie" to push the seal over the end of the valve and tap it into place with a guide seal driving tool.
This requires specialized equipment not normally found in an enthusiasts garage. I recommend having a machine shop do it. You could ask how much to do all 12 as the setup time is about the same for one or twelve.
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