My head is twisted!
#22
03-17-2017 | 05:22 AM
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I agree with Kirby. Take both heads & put them together with the locating dowels. They should match up perfectly. I don't think I ever seen a set that didn't BUT I have seen where one head had some machine work done to it when the other one didn't.
Here's an example: Guy drops a valve. Pulls the head to have it fixed. After the work is done they machine the gasket surface to clean it up & get the CC's to match. Let's say they cut.050 [just an example]. Put the head back on & the manifold won't line up. Most times they don't notice but they can't figure out why it's leaking. it's the little things that get overlooked.
Here's an example: Guy drops a valve. Pulls the head to have it fixed. After the work is done they machine the gasket surface to clean it up & get the CC's to match. Let's say they cut.050 [just an example]. Put the head back on & the manifold won't line up. Most times they don't notice but they can't figure out why it's leaking. it's the little things that get overlooked.
I agree.
Simple as probably setting the heads in a fixture in a vertical mill, and trimming the intake pads as needed.
Piece-o-cake.
Scott
#23
07-15-2017 | 11:34 AM
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And the saga continues some more...
So I was never ever able to get it to idle properly. I finally pulled the front head and started measuring. I set the head gasket surface on a piece of 3/4" thick glass and measured down from the rocker surface through the stud holes and all measurements were within less than one thousands. .0008". I then determined the angle from the head gasket surface to the intake surface and it was 90 degrees. Then I made some brass dowel pins with a snug fit for the dowel pin holes in the head. Using a straight edge against the dowel pins I figured the intake surface is 20 degrees from 90 or 110 degrees. It's been my experience that Harley likes using easy whole numbers in it's designs. I could find nothing wrong with this head so I went to the rear head. Here I checked the gasket surface to the intake with a square and found it was not 90 degrees! WTF? I put it on the glass and found the gasket surface out by .0025". I set it up in the mill and took the smallest cut I could to clean it up and got it at .0008" also. This helped but the intake surface was still not square with the gasket surface. I then took both heads and mated the gasket surfaces together with the dowel pins lining them up. With a 4" straight edge across the intake surfaces I was able to get a .003" feeler gauge under it at one end of the surface and .008" on the other. So the surfaces are not only not the same height but not the same angle. I'm hoping this is enough of a difference to affect the seals. I will be setting it back up in the mill on a rotary table and indicating the dowel pins and rotating 20 degrees and taking a clean up cut to make them the same. I sure hope this cures it as I can't think of anything else. Thanks to Kirby and Hillside for helping me think outside the box!
So I was never ever able to get it to idle properly. I finally pulled the front head and started measuring. I set the head gasket surface on a piece of 3/4" thick glass and measured down from the rocker surface through the stud holes and all measurements were within less than one thousands. .0008". I then determined the angle from the head gasket surface to the intake surface and it was 90 degrees. Then I made some brass dowel pins with a snug fit for the dowel pin holes in the head. Using a straight edge against the dowel pins I figured the intake surface is 20 degrees from 90 or 110 degrees. It's been my experience that Harley likes using easy whole numbers in it's designs. I could find nothing wrong with this head so I went to the rear head. Here I checked the gasket surface to the intake with a square and found it was not 90 degrees! WTF? I put it on the glass and found the gasket surface out by .0025". I set it up in the mill and took the smallest cut I could to clean it up and got it at .0008" also. This helped but the intake surface was still not square with the gasket surface. I then took both heads and mated the gasket surfaces together with the dowel pins lining them up. With a 4" straight edge across the intake surfaces I was able to get a .003" feeler gauge under it at one end of the surface and .008" on the other. So the surfaces are not only not the same height but not the same angle. I'm hoping this is enough of a difference to affect the seals. I will be setting it back up in the mill on a rotary table and indicating the dowel pins and rotating 20 degrees and taking a clean up cut to make them the same. I sure hope this cures it as I can't think of anything else. Thanks to Kirby and Hillside for helping me think outside the box!
#24
07-16-2017 | 10:11 AM
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From: Newcastle, OK
Well I would agree with everyone. I have never seen this before either but like my friend says, I seem to find problems that he's never seen either! I like the idea to mate it to another head and see how it lines up. I have a spare set of stock heads laying around so I could easily do that.
I finished the dowels and put them in and it looks great. The old Ram Jett intake has .0015" clearance evenly around. When I feel inside the port lines up nicely and the air cleaner bosses are lined up. So it all came in with a .0075" offset on the dowels. Actually when I first did it I was twisting the head while I tightened the nuts and it was too much so I let it relax and it came right in.
As far as the dowels and the head gasket, the gasket doesn't know the difference, it's just rotated slightly. The bore is still in the middle and the nuts went right in, I don't see where rotation would hurt anything. I mean it's barely more than a RCH!
I consider that the castings are set up on a fixture for machining. In a mass production process the thought that there will never be a little chip stuck on the fixture causing a misalignment is wishful thinking unless all the machined surfaces are done with the same set up.
From the looks of the intake sealing surface it doesn't look like they flycut it when ported. I'm only running 9.3 compression so I doubt they shaved them since I'm using thinner head gaskets.
I appreciate the comments and I'm with everybody, I ain't never seen nothing like this before!
As well as it's lined up right now I'm going to go back together and hopefully it will cure my intake and exhaust leak.
I finished the dowels and put them in and it looks great. The old Ram Jett intake has .0015" clearance evenly around. When I feel inside the port lines up nicely and the air cleaner bosses are lined up. So it all came in with a .0075" offset on the dowels. Actually when I first did it I was twisting the head while I tightened the nuts and it was too much so I let it relax and it came right in.
As far as the dowels and the head gasket, the gasket doesn't know the difference, it's just rotated slightly. The bore is still in the middle and the nuts went right in, I don't see where rotation would hurt anything. I mean it's barely more than a RCH!
I consider that the castings are set up on a fixture for machining. In a mass production process the thought that there will never be a little chip stuck on the fixture causing a misalignment is wishful thinking unless all the machined surfaces are done with the same set up.
From the looks of the intake sealing surface it doesn't look like they flycut it when ported. I'm only running 9.3 compression so I doubt they shaved them since I'm using thinner head gaskets.
I appreciate the comments and I'm with everybody, I ain't never seen nothing like this before!
As well as it's lined up right now I'm going to go back together and hopefully it will cure my intake and exhaust leak.
Last edited by ChickinOnaChain; 07-16-2017 at 11:50 AM.
#26
07-16-2017 | 03:39 PM
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Joined: Dec 2005
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From: poway
While I'm having trouble understanding what you are saying exactly, I suspect that you are really chasing off the wrong direction..
From what I read, the mating surface for the manifold is off a few thou from mating up with the manifold.. This should not be an issue. As long as the 2 spigots are close and the flanges can support the manifold well enough to set them in line with the ports, you should not have leaks. They only have to be close enough.. You can have 0.010-0.020 difference in gap and not have an issue.. If you start getting above that the seal can squish between the manifold and head then leak.
I suspect that you have something else going on.
Are the heads 06 up heads?
Did you change the flanges if you they are? Are they straight?
What is the diameter of the Ramjet spigot?
What manifold seals are you using?
What carb?
After the manifold flanges are 1 turn from tight and greased, can you move the manifold up or down from where it is going to sit a couple degrees?
Are the manifold bolts hitting the manifold and pushing it to one side?
Have you looked for cracks in the manifold?
How well is the carb backing plate spaced to the head?
From what I read, the mating surface for the manifold is off a few thou from mating up with the manifold.. This should not be an issue. As long as the 2 spigots are close and the flanges can support the manifold well enough to set them in line with the ports, you should not have leaks. They only have to be close enough.. You can have 0.010-0.020 difference in gap and not have an issue.. If you start getting above that the seal can squish between the manifold and head then leak.
I suspect that you have something else going on.
Are the heads 06 up heads?
Did you change the flanges if you they are? Are they straight?
What is the diameter of the Ramjet spigot?
What manifold seals are you using?
What carb?
After the manifold flanges are 1 turn from tight and greased, can you move the manifold up or down from where it is going to sit a couple degrees?
Are the manifold bolts hitting the manifold and pushing it to one side?
Have you looked for cracks in the manifold?
How well is the carb backing plate spaced to the head?
#28
07-17-2017 | 12:39 PM
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2002 heads
New manifold
In place it will hold 20 inches of vacuum with the both intakes closed. I'm thinking that the amount of vacuum the engine actually makes is more than 20 and starts to leak. The problem is only at idle.
I only used the RamJett to check alignment.
I've used stock, blue silicones and black ones with the imbedded washer.
3 carbs, Stock, Mikuni 42 and a Bob Wood CV
Manifold is fine, nothing hitting, it's free and the backing plate is a K&N but I've also tried a stock backing plate for the CV's.
I believe that machining the intake surfaces will help with alignment because no matter how careful I am assembling the intake and carb it always want's to pull to one side. While I have it all lined up I'm taking a skim cut off the backing plate mounting surface just to be sure it's all square.
I put 156,000 miles on my old 91 FLHS and never had any vacuum leaks. I also have a Buell Ulysses with almost 50,000 on it and had some problem getting it sealed but once it did it's been great for many years. I've done conversions to CV's on friends bikes and none of them leak either so my method of lubricating the seals and tightening them down a little at a time and evenly has worked well over the years, just not on these heads.
What sucks is I took my heads to a builder for porting etc. and he sent two sets of heads in for the same thing. Mine did not come back first and I had a big trip planned so he gave me the other guy's heads since he wasn't in a hurry. I've had problems ever since. That's why I'm trying to make everything spot on to eliminate any errors I can think of.
The fact is I agree with you totally, I should not be having a problem.
New manifold
In place it will hold 20 inches of vacuum with the both intakes closed. I'm thinking that the amount of vacuum the engine actually makes is more than 20 and starts to leak. The problem is only at idle.
I only used the RamJett to check alignment.
I've used stock, blue silicones and black ones with the imbedded washer.
3 carbs, Stock, Mikuni 42 and a Bob Wood CV
Manifold is fine, nothing hitting, it's free and the backing plate is a K&N but I've also tried a stock backing plate for the CV's.
I believe that machining the intake surfaces will help with alignment because no matter how careful I am assembling the intake and carb it always want's to pull to one side. While I have it all lined up I'm taking a skim cut off the backing plate mounting surface just to be sure it's all square.
I put 156,000 miles on my old 91 FLHS and never had any vacuum leaks. I also have a Buell Ulysses with almost 50,000 on it and had some problem getting it sealed but once it did it's been great for many years. I've done conversions to CV's on friends bikes and none of them leak either so my method of lubricating the seals and tightening them down a little at a time and evenly has worked well over the years, just not on these heads.
What sucks is I took my heads to a builder for porting etc. and he sent two sets of heads in for the same thing. Mine did not come back first and I had a big trip planned so he gave me the other guy's heads since he wasn't in a hurry. I've had problems ever since. That's why I'm trying to make everything spot on to eliminate any errors I can think of.
The fact is I agree with you totally, I should not be having a problem.
Last edited by tootal; 07-17-2017 at 12:49 PM.
