EFI head?
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Lead Driver
Joined: Mar 2008
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From: Near Los Angeles
EFI head?
Hey guys--
I have a problem that seems to baffle the greatest minds in the 300 inline forum where I usually hang out. I pulled a head from an 81 F250 with a 300 (4.9) inline. No one can tell me why I have ridges in the combustion chambers around the bottom half of the valves. I am about to start porting, and following the advise of a pro builder and removing the ridges. But I want to know what they are and what they are for before I just remove them.
Since no one else seems to know, I thought I would try this forum in the EFI years, thinking maybe it was an EFI head on an 81 engine. It is now installed until I pull it and begin the mods. I know I can pull the thermo housing and check the numbers, but was hoping someone here might know.
<a href="http://s659.photobucket.com/albums/uu316/bobbyrogue/?action=view¤t=P1010114.jpg" target="_blank"><img src="http://i659.photobucket.com/albums/uu316/bobbyrogue/P1010114.jpg" border="0" alt="chebby valves in a FORD??"></a>
I have a problem that seems to baffle the greatest minds in the 300 inline forum where I usually hang out. I pulled a head from an 81 F250 with a 300 (4.9) inline. No one can tell me why I have ridges in the combustion chambers around the bottom half of the valves. I am about to start porting, and following the advise of a pro builder and removing the ridges. But I want to know what they are and what they are for before I just remove them.
Since no one else seems to know, I thought I would try this forum in the EFI years, thinking maybe it was an EFI head on an 81 engine. It is now installed until I pull it and begin the mods. I know I can pull the thermo housing and check the numbers, but was hoping someone here might know.
<a href="http://s659.photobucket.com/albums/uu316/bobbyrogue/?action=view¤t=P1010114.jpg" target="_blank"><img src="http://i659.photobucket.com/albums/uu316/bobbyrogue/P1010114.jpg" border="0" alt="chebby valves in a FORD??"></a>
Posting Guru
Joined: Jun 2003
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From: southwest michigan
It's kinda hard to make out in that pic. I'm not sure why, but some times that hole looks like it's recessed and other times it looks like it's sticking out...
Are the ridges you're talking about what I see here just below the vales?
Are the ridges you're talking about what I see here just below the vales?
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Lead Driver
Joined: Mar 2008
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From: Near Los Angeles
Are the ridges you're talking about what I see here just below the vales?
Yes, the humps or ridges on either side of the s.plug hole. They start on the exh. valve at about 4 o'clock, and end on the int. valve at about 9 o'clock.
Is that a characteristic of the efi swirl chamber?
Yes, the humps or ridges on either side of the s.plug hole. They start on the exh. valve at about 4 o'clock, and end on the int. valve at about 9 o'clock.
Is that a characteristic of the efi swirl chamber?
Posting Guru
Joined: Jun 2003
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From: southwest michigan
I think you hit the nail on the had
"As air is drawn into the engine a swirling motion is initiated. The air is forced into a horizontal rotary motion by the design of the air inlet port or valve. Some engines have a helical or partial vortex form of inlet port to encourage the swirl in others the inlet valve is partially masked to initiate the desired motion."
Vegburner
"The Ford 240/300 "Big Six" is a favorite of mine. Two problems were cracking pistons in the 300, and the phenolic cam drive gear in both versions. Both of these can be addressed during a rebuild with aftermarket pistons and cam gear,and you can build a dandy engine, albeit heavy for an airplane (more on this in a minute). The best heads came on the later engines with fuel injection and have swirl ramps in the intake ports. The next best heads are the closed-chamber heads from the early 240. Don't use the open-chamber smog heads from the seventies and early eighties, which are fuel-inefficient and gutless. When you rebuild, tell your machinist you want the block decked to get a squish-height of about .036-.040" which makes for an efficient, detonation-resistant engine."
300ci inline six - Page 2
"As air is drawn into the engine a swirling motion is initiated. The air is forced into a horizontal rotary motion by the design of the air inlet port or valve. Some engines have a helical or partial vortex form of inlet port to encourage the swirl in others the inlet valve is partially masked to initiate the desired motion."
Vegburner
"The Ford 240/300 "Big Six" is a favorite of mine. Two problems were cracking pistons in the 300, and the phenolic cam drive gear in both versions. Both of these can be addressed during a rebuild with aftermarket pistons and cam gear,and you can build a dandy engine, albeit heavy for an airplane (more on this in a minute). The best heads came on the later engines with fuel injection and have swirl ramps in the intake ports. The next best heads are the closed-chamber heads from the early 240. Don't use the open-chamber smog heads from the seventies and early eighties, which are fuel-inefficient and gutless. When you rebuild, tell your machinist you want the block decked to get a squish-height of about .036-.040" which makes for an efficient, detonation-resistant engine."
300ci inline six - Page 2
Thread Starter
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Lead Driver
Joined: Mar 2008
Posts: 7,190
Likes: 384
From: Near Los Angeles
Thanks for the info. The only thing I would disagree with is the statement regarding the EFI heads. Anyone who hot rods the 300 avoids the EFI head because of its proneness to cracking.
I thought surely someone here would be able to identify my head, but I guess I will just have to wait and pull the #s. Imagine that, lol.
I thought surely someone here would be able to identify my head, but I guess I will just have to wait and pull the #s. Imagine that, lol.
Posting Guru
Joined: Jun 2003
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From: southwest michigan
I didn't realize you were looking for an ID on the head, I thought you just wanted to know about the ridges.
I have no idea on the 300, but I know that on a 460, you can not mix and match carb/efi heads & intake manifolds because of the port shapes. The 81 you pulled this head, I assume it was running a carb?
I have no idea on the 300, but I know that on a 460, you can not mix and match carb/efi heads & intake manifolds because of the port shapes. The 81 you pulled this head, I assume it was running a carb?
