I disassembled my 28 wood boss today for a possible port job. Can someone tell me the purpose of the drop down hump in the top of the intake port.I am assuming it is there to support the rings when the piston is BDC. I am sure someone here has ported one of these saws before. Any advice on how to deal with this hump would be greatly appreciated.
28 wood boss porting concerns
- Thread starter wheelman
- Start date
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i think the general consensus is to work around that nipple and widen the intake port.
but everyone knows i would grind that sucker out of there. i got rid of the intake nipple in my 084 without any ill affects.
but everyone knows i would grind that sucker out of there. i got rid of the intake nipple in my 084 without any ill affects.
It is there to support the rings and keep them from hanging on the port. I would profile it a little and widen the port
Thanks for the input. The only other saw that i have ported is a ms 460, and of course it did not have this feature. I did'nt figure it would bother flow much being that it is in the top of the port. I have picked up on the fact that piston diameter plays a role in how tight to set squish, do I need to go any looser with the 28 than I did with the 460. The 460 is set at .021.
Leave it. It's not hurting anything. Most of your intake flow happens as the piston opens the bottom of the port anyway.
rickyrooster
ArboristSite Guru
.020-024 is what most feel comfortable with the squish. if your going to port it anyway, you might as well do that to. Rick!
FullCry
ArboristSite Operative
My profession is that I'm an auto tech and have worked on Honda cars for ten years at a dealership. I started out growing up fooling with go-carts and other small engines that were on the equipment that my father used. I also grew up incapable of paying someone to repair my car and with my father's help learned enough to repair my own cars and never take them to the shop except for tires, alignments etc. something I couldn't do for lack of equipment.I had a lawn care business for seven years and repaired all of my lawn tractors,mowers, damn weedeaters, etc.
I also was into hot rodding while a teen and into my early twenties. I had enough wrecks and tore up enough cars to give that up for foreign gas o miser cars except for a 78 k-10 hunting truck which I still have.Whenever I get into a hobby I read everything about it that I can find and I found out about a flow bench for heads and what it was for. Also when I worked at Honda some of the younger guys had hot rods and would take the heads off and what they would call hog them intake ports out....just grind them out big and wide as possible.These were for drag car purposes but they didn't understand that they weren't getting every port the same dimensions and they would never know how the head actually flowed. In my humble opinion, on an old say a 69 Chevy 350 with 300 horse heads on it from the factory those heads are made...intake ports and exhaust ports.. to provide maximum torque and hp at a certain rpm. Now if you go porting on those heads other than just grinding a casting mark out, then the engine may run worse than before and they don't know it without putting it on a dyno.
The proper way to do this is pay someone to port the heads a little at a time untill they get maximum FLOW using a flow bench which measures the flow of the head.
Now the reason for all this car crap on this post is I wonder how you guys actually know that your helping a saw run faster or have more torque by porting out the intake manifold. How do you get everything even and know for sure it has helped the saw? I'm not being a butt hole about this it's just I know about how it works on cars and am curious about the saws for I may try it if I get some good answers. Has it been done so much that everyone is handing down what worked on a particular make and model of saw?
On a car head they say that you can cc a chamber. Fill it with water that is measured so if the intake port holds 50cc you can cut the chamber out and all intake chambers don't have to be evenly cut but if the first one holds 55 cc you make them all 55cc and it should work fine. I believe in the flow bench but it is expensive to have that work done. Any comments on any combustion engine...especially saws will be appreciated. Another saw question, how does a small engine tach work? Do you have to just hook it to the plug wire like a timing light? Thanks everybody and no offense intended I'm just trying to learn about this porting on small engines. FullCry:greenchainsaw:
I also was into hot rodding while a teen and into my early twenties. I had enough wrecks and tore up enough cars to give that up for foreign gas o miser cars except for a 78 k-10 hunting truck which I still have.Whenever I get into a hobby I read everything about it that I can find and I found out about a flow bench for heads and what it was for. Also when I worked at Honda some of the younger guys had hot rods and would take the heads off and what they would call hog them intake ports out....just grind them out big and wide as possible.These were for drag car purposes but they didn't understand that they weren't getting every port the same dimensions and they would never know how the head actually flowed. In my humble opinion, on an old say a 69 Chevy 350 with 300 horse heads on it from the factory those heads are made...intake ports and exhaust ports.. to provide maximum torque and hp at a certain rpm. Now if you go porting on those heads other than just grinding a casting mark out, then the engine may run worse than before and they don't know it without putting it on a dyno.
The proper way to do this is pay someone to port the heads a little at a time untill they get maximum FLOW using a flow bench which measures the flow of the head.
Now the reason for all this car crap on this post is I wonder how you guys actually know that your helping a saw run faster or have more torque by porting out the intake manifold. How do you get everything even and know for sure it has helped the saw? I'm not being a butt hole about this it's just I know about how it works on cars and am curious about the saws for I may try it if I get some good answers. Has it been done so much that everyone is handing down what worked on a particular make and model of saw?
On a car head they say that you can cc a chamber. Fill it with water that is measured so if the intake port holds 50cc you can cut the chamber out and all intake chambers don't have to be evenly cut but if the first one holds 55 cc you make them all 55cc and it should work fine. I believe in the flow bench but it is expensive to have that work done. Any comments on any combustion engine...especially saws will be appreciated. Another saw question, how does a small engine tach work? Do you have to just hook it to the plug wire like a timing light? Thanks everybody and no offense intended I'm just trying to learn about this porting on small engines. FullCry:greenchainsaw:
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With a small cylinder like that, I wouldn't hesitate at all to go down to .017".
Crofter
Addicted to ArboristSite
FullCry, good questions. A chainsaw combustion chamber and crankcase volume can be done similarly. I would use oil for the base cause of the bearings and alcohol or water for the combustion chamber. measurements an a bit of math can predict how much compression change will result from a given amount taken off the cylinder base or what the effect of raising a port a certain distance will to to compression and port duration. It is not everyone's approach but it can save some trial and error.
The tachs are induction triggered and you can usually hold them close enough to the plug or wire even when running the saw in the cut. Some of them come with an antenna jack and you can wrap a wire around the plug wire to mount or hold the tach further away.
The tachs are induction triggered and you can usually hold them close enough to the plug or wire even when running the saw in the cut. Some of them come with an antenna jack and you can wrap a wire around the plug wire to mount or hold the tach further away.
