Road King Performance upgrade needed!
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Seasoned HDF Member
Joined: Dec 2012
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From: Orange County
I am doing the work myself. When I purchased the Big Bore kit he asked what cam I was planning on using, at the time it was the 510G. So, he said he set it up that way, 10:1 comp, etc.
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Seasoned HDF Member
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From: Orange County
I wonder if I should go with Easy Start cams.
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Just trying to be sure on what you have. There are other cams that work well but 10 to 1 might be too much compression for them. You might still have ping issues. Like the SE 204 .
You might want to look at the
T-man Performance 510 torqster cam
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Seasoned HDF Member
Joined: Dec 2012
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From: Orange County
So your pistons have a dome to them, not flat tops.
Just trying to be sure on what you have. There are other cams that work well but 10 to 1 might be too much compression for them. You might still have ping issues. Like the SE 204 .
You might want to look at the
T-man Performance 510 torqster cam
Just trying to be sure on what you have. There are other cams that work well but 10 to 1 might be too much compression for them. You might still have ping issues. Like the SE 204 .
You might want to look at the
T-man Performance 510 torqster cam
Last edited by Road Star; Nov 10, 2015 at 12:14 AM.
Ultimate HDF Member
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From: Santa Cruz
I'd guess ya are over 10-1, maybe closer to 10.5, with those pistons. With the stock cams it would be cranking way over 210ccp. Good idea to do a compression test and see where ya really are. If that is the case some easy-starts would be a good idea and the 510s will get ya closer to 200ccp. I would think about running tw50s but I also run rpms. If ya really are at 10-1 static the stock cams should be around 195ccp. Most bagger folks like to stay under 195ccp but I don't a problem pushing 205 with a good tune and compression releases. Just don't lug it around. 37s or 510s will bring that down to the low 190s and be very tunable and ridable without releases.
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I agree with oldhippe
You need to do a compression test and be sure where you really are. Also the head gasket you used will make a difference in compression.
Did you use stock hg .045 or a thinner one like .030 to boost compression more ?
Then you can choose a cam that will work with the compression you have.
Do you have any paper work from when you bought the 98" kit ? it might say what the size, cc's , of the domes on the pistons you have.
You need to do a compression test and be sure where you really are. Also the head gasket you used will make a difference in compression.
Did you use stock hg .045 or a thinner one like .030 to boost compression more ?
Then you can choose a cam that will work with the compression you have.
Do you have any paper work from when you bought the 98" kit ? it might say what the size, cc's , of the domes on the pistons you have.
Cruiser
Joined: Oct 2010
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From: Ohio
"The stock cams and 10-1 is your ping problem."
+2
Adding 10CID and another point of compression will require larger cams to reduce cranking pressure and dynamic cylinder pressure to manage pump fuel.
I usually add about 10 degrees duration for every point of compression increase and same LSA. I'd also add a bit more duration for the additional CID in your case. This will offset the increase in static compression, the engine will crank easier and make similar power at lower rpm's, the a butt-load more power upper mid-range and top end due to the larger camshafts.
You really can run pretty high compression on pump gas, you just have to choose the correct cams, and always keep quench as tight as possible as it will reduce the timing advance required to make best power, and improve combustion efficiency at the same time.....Cliff
+2
Adding 10CID and another point of compression will require larger cams to reduce cranking pressure and dynamic cylinder pressure to manage pump fuel.
I usually add about 10 degrees duration for every point of compression increase and same LSA. I'd also add a bit more duration for the additional CID in your case. This will offset the increase in static compression, the engine will crank easier and make similar power at lower rpm's, the a butt-load more power upper mid-range and top end due to the larger camshafts.
You really can run pretty high compression on pump gas, you just have to choose the correct cams, and always keep quench as tight as possible as it will reduce the timing advance required to make best power, and improve combustion efficiency at the same time.....Cliff
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Seasoned HDF Member
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From: Orange County
Thanks for the input guys !
Thinking I should go with the 37G.
Only thing, do I need to change valve springs or pushrods?
Thinking I should go with the 37G.
Only thing, do I need to change valve springs or pushrods?
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No need to change the valve springs for the 37 cam. Not sure on the pushrods, but I don't think so. Call Andrews they'll be able to tell you.
Still you should do a compression test first, even at 10 to 1 thats more compression than andrews recommends for that cam, and your not sure exactly where your at. I'm sure you don't want more ping issues, better to check now than be sorry later.
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Seasoned HDF Member
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From: Orange County
No need to change the valve springs for the 37 cam. Not sure on the pushrods, but I don't think so. Call Andrews they'll be able to tell you.
Still you should do a compression test first, even at 10 to 1 thats more compression than andrews recommends for that cam, and your not sure exactly where your at. I'm sure you don't want more ping issues, better to check now than be sorry later.
Still you should do a compression test first, even at 10 to 1 thats more compression than andrews recommends for that cam, and your not sure exactly where your at. I'm sure you don't want more ping issues, better to check now than be sorry later.
The compression test just returns PSI, correct? Is there a formula to determine the other factors? Not sure what they are called.