Help on Milled Heads
Thread Starter
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Intermediate
Joined: Jun 2017
Posts: 29
Likes: 2
From: Wisconsin
Help on Milled Heads
Good evening all,
I bought a '03 Electra Glide Classic this past summer and while winterizing it, I checked the plugs and it was quite difficult to remove the rear plug, to my dismay the plug was installed cross threaded and all the threads came out with the plug. So I decided rather than dicking around with a helicoil I am just going to replace the rear head. A buddy of mine has a pair of stock heads that were ported, shaved .054", and rebuilt with big valves and springs that he got in a trade, he is willing to part ways with them for a real good price. The bike has SE-203 cams installed and the pistons are stock. My question is can I use these heads? Should I be using the .03 or stock gaskets?
From what I have read SE-203 cams on a heavy bike like a 9.5 - 9.7 compression ratio and I read that heads milled .050 with .030 gaskets puts you at about 9.5, so the extra .004 off the heads would put me closer 9.6. I am very new to the compression side of performance but am eager to learn. So please let me know what I need to know!
I bought a '03 Electra Glide Classic this past summer and while winterizing it, I checked the plugs and it was quite difficult to remove the rear plug, to my dismay the plug was installed cross threaded and all the threads came out with the plug. So I decided rather than dicking around with a helicoil I am just going to replace the rear head. A buddy of mine has a pair of stock heads that were ported, shaved .054", and rebuilt with big valves and springs that he got in a trade, he is willing to part ways with them for a real good price. The bike has SE-203 cams installed and the pistons are stock. My question is can I use these heads? Should I be using the .03 or stock gaskets?
From what I have read SE-203 cams on a heavy bike like a 9.5 - 9.7 compression ratio and I read that heads milled .050 with .030 gaskets puts you at about 9.5, so the extra .004 off the heads would put me closer 9.6. I am very new to the compression side of performance but am eager to learn. So please let me know what I need to know!
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Joined: Dec 2007
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Good evening all,
I bought a '03 Electra Glide Classic this past summer and while winterizing it, I checked the plugs and it was quite difficult to remove the rear plug, to my dismay the plug was installed cross threaded and all the threads came out with the plug. So I decided rather than dicking around with a helicoil I am just going to replace the rear head. A buddy of mine has a pair of stock heads that were ported, shaved .054", and rebuilt with big valves and springs that he got in a trade, he is willing to part ways with them for a real good price. The bike has SE-203 cams installed and the pistons are stock. My question is can I use these heads? Should I be using the .03 or stock gaskets?
From what I have read SE-203 cams on a heavy bike like a 9.5 - 9.7 compression ratio and I read that heads milled .050 with .030 gaskets puts you at about 9.5, so the extra .004 off the heads would put me closer 9.6. I am very new to the compression side of performance but am eager to learn. So please let me know what I need to know!
I bought a '03 Electra Glide Classic this past summer and while winterizing it, I checked the plugs and it was quite difficult to remove the rear plug, to my dismay the plug was installed cross threaded and all the threads came out with the plug. So I decided rather than dicking around with a helicoil I am just going to replace the rear head. A buddy of mine has a pair of stock heads that were ported, shaved .054", and rebuilt with big valves and springs that he got in a trade, he is willing to part ways with them for a real good price. The bike has SE-203 cams installed and the pistons are stock. My question is can I use these heads? Should I be using the .03 or stock gaskets?
From what I have read SE-203 cams on a heavy bike like a 9.5 - 9.7 compression ratio and I read that heads milled .050 with .030 gaskets puts you at about 9.5, so the extra .004 off the heads would put me closer 9.6. I am very new to the compression side of performance but am eager to learn. So please let me know what I need to know!
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Happy to help.
Scott
Thread Starter
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Intermediate
Joined: Jun 2017
Posts: 29
Likes: 2
From: Wisconsin
Thank you for the responses, however I do know my alternative options and they are not the routes I would like to go. Inserts is not the way I want to go, especially on the rear cylinder head. I also don't want to just dig into the heads for a stock outcome, if I am going in there I would like some sort of performance gain, no matter how little. I can get these heads for $150 for the two of them, so this is the route I would like to go. I know they can be used, I just need to know what needs to be done to ensure proper fit and what needs to be done if not.
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Thank you for the responses, however I do know my alternative options and they are not the routes I would like to go. Inserts is not the way I want to go, especially on the rear cylinder head. I also don't want to just dig into the heads for a stock outcome, if I am going in there I would like some sort of performance gain, no matter how little. I can get these heads for $150 for the two of them, so this is the route I would like to go. I know they can be used, I just need to know what needs to be done to ensure proper fit and what needs to be done if not.
If you are intent on doing it yourself, I would advise purchasing an FSM, and downloading some I-sheets for SE performance pistons so you can understand some of the checks you will need to perform.
Last edited by Ed Ramberger; Feb 15, 2018 at 08:40 AM.
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Thread Starter
|
Intermediate
Joined: Jun 2017
Posts: 29
Likes: 2
From: Wisconsin
I would recommend having it done professionally. Cody already answered your question. This reads like someone who hasn't built an engine and doesn't understand clearances and piston reliefs, and your safest bet might be just paying to have it done right. Additionally, the heads came from a trade - I didn't see mention of going through them, checking springs/heights, seats/faces and replacing guide seals.
HDF Community Team
Joined: Jun 2006
Posts: 12,776
Likes: 2,607
From: san antonio
I won't be having this professionally done, I want to know how to do this myself. If there is anything done to any of my vehicles, I do it so that I know how to fix it in the future. I have taken Cody's advice and added it to my list of things to check. Currently I plan to get the CC of the head and use modeling clay to check piston to valve clearance.
The contact will usually be on the intake side as TDC lift is higher and the OEM valve reliefs are not cut out toward the edge of the piston enough; see the attached pics for clarification. It is a hit/miss proposition and, as has been pointed out, one that should be checked carefully; you can ding a valve real easy. If you have to open up the valve reliefs, you can do it with the pistons in place with a Dremel tool and the right attachment. Of course, you will have to seal off the piston to wall "gap" to insure that no shavings can enter the cylinder bore.
You should carefully remove the heads being replace and secure the cylinder to the crank case to avoid disturbing the cylinder to crank case o-ring seal.