99-04 Heads vs 05 heads
#1
01-10-2006, 06:49 PM
99-04 Heads vs 05 heads
Submitted by: springer_ (V Twin Forum) & http://www.bigboyzcycles.com/
99-04 Heads vs. 05 Heads
This thread is to show the differences between 05’ Twin Cam heads and the previous 99-04 heads. In 05’ the Twin Cam heads received design changes that were already in use in Buell’s and 04’-present Sportsters. Both of which will rev much higher than a big twin and they both put the valves through greater stresses.
The changes include 7mm valves, valve guides, springs, top collars, bottom collars (spring cup), keepers, and valve seals. All these changes are easily noticeable just by looking at the parts side by side. But there are some other changes that don’t just jump out at you. In the following posts I will point out many of the changes and what the effects could be.
Guides & Ports
The first area to look at is the exhaust and specifically the guides. The 05’ heads, used for this post, were brand new take offs and had no carbon in the exhaust port. This made taking pictures of the 05’ port very difficult. You can see the used port with carbon took a much better picture (Picture 1).
When you compare the 2 exhaust ports you can see that the valve guide protrudes further into the port on the earlier heads. The valve guide height is between the yellow and green arrows (Picture 1). In the 05’ heads, the valve guide doesn’t block as much of the port. Compare the distance between the green and red arrows (Picture 1).
Picture 1
In the 05’ heads the valve stem is only 7mm as compared to 5/16” (8mm) (Picture 4). So the 05’ heads with the, shorter valve guides, also have thinner valve stems that block the port less than the thicker stems in the earlier heads (Picture 2,3). This means the Port has considerable less stuff in the way and actually yields a larger port volume with less obstruction. This is the case with both the intake and exhaust port comparisons shown (Picture 1,2).
The valve guides have the same OD but the ID is obviously different to accommodate the different valve stem sizes (Picture 3).
Picture 2
Picture 3
Picture 4
Valve Seals
The earlier valve seals were small press on metal seals. They have a single rubber seal/wiper. The 05’ seals are much larger and are attached to the bottom spring collar. It uses a thicker rubber seal with many wiping ribs. Compare the Green arrows (Picture 5), this creates the seal around the valve stem. The seal is securely held down by the spring pressure on the bottom collar when installed.
Picture 5
The yellow arrow (Picture 6) points to where the seal contacts the outside of the valve guide, creating the seal with the guide. For the seal to work properly, it must seal out oil at both the valve stem and the valve guide.
The green arrow (picture 6) shows that the old seal relies on a metal to metal contact with the guide. TIP: A little green loctite helps hold the seals on and helps them seal better to the guide. DON’T GET ANY IN THE GUIDE OR ON THE VALVE STEM.
Picture 6
The 05’ valve guide is shorter than the earlier guides (Picture 7, yellow line), this allows room for the thicker rubber valve seal to contact with the valve stem. This also allows for an increased valve lift with a performance seal. The wall is also thicker on the 05’ guide making it much stronger (red arrow).
Picture 7
I saw it posted somewhere that the valve seal was held in place with a cutout on the head at the spring base. It was also suggested that the Moco quality control
99-04 Heads vs. 05 Heads
This thread is to show the differences between 05’ Twin Cam heads and the previous 99-04 heads. In 05’ the Twin Cam heads received design changes that were already in use in Buell’s and 04’-present Sportsters. Both of which will rev much higher than a big twin and they both put the valves through greater stresses.
The changes include 7mm valves, valve guides, springs, top collars, bottom collars (spring cup), keepers, and valve seals. All these changes are easily noticeable just by looking at the parts side by side. But there are some other changes that don’t just jump out at you. In the following posts I will point out many of the changes and what the effects could be.
Guides & Ports
The first area to look at is the exhaust and specifically the guides. The 05’ heads, used for this post, were brand new take offs and had no carbon in the exhaust port. This made taking pictures of the 05’ port very difficult. You can see the used port with carbon took a much better picture (Picture 1).
When you compare the 2 exhaust ports you can see that the valve guide protrudes further into the port on the earlier heads. The valve guide height is between the yellow and green arrows (Picture 1). In the 05’ heads, the valve guide doesn’t block as much of the port. Compare the distance between the green and red arrows (Picture 1).
Picture 1
In the 05’ heads the valve stem is only 7mm as compared to 5/16” (8mm) (Picture 4). So the 05’ heads with the, shorter valve guides, also have thinner valve stems that block the port less than the thicker stems in the earlier heads (Picture 2,3). This means the Port has considerable less stuff in the way and actually yields a larger port volume with less obstruction. This is the case with both the intake and exhaust port comparisons shown (Picture 1,2).
The valve guides have the same OD but the ID is obviously different to accommodate the different valve stem sizes (Picture 3).
Picture 2
Picture 3
Picture 4
Valve Seals
The earlier valve seals were small press on metal seals. They have a single rubber seal/wiper. The 05’ seals are much larger and are attached to the bottom spring collar. It uses a thicker rubber seal with many wiping ribs. Compare the Green arrows (Picture 5), this creates the seal around the valve stem. The seal is securely held down by the spring pressure on the bottom collar when installed.
Picture 5
The yellow arrow (Picture 6) points to where the seal contacts the outside of the valve guide, creating the seal with the guide. For the seal to work properly, it must seal out oil at both the valve stem and the valve guide.
The green arrow (picture 6) shows that the old seal relies on a metal to metal contact with the guide. TIP: A little green loctite helps hold the seals on and helps them seal better to the guide. DON’T GET ANY IN THE GUIDE OR ON THE VALVE STEM.
Picture 6
The 05’ valve guide is shorter than the earlier guides (Picture 7, yellow line), this allows room for the thicker rubber valve seal to contact with the valve stem. This also allows for an increased valve lift with a performance seal. The wall is also thicker on the 05’ guide making it much stronger (red arrow).
Picture 7
I saw it posted somewhere that the valve seal was held in place with a cutout on the head at the spring base. It was also suggested that the Moco quality control
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