Hi all,

I picked up some comments on a different thread regarding a 96-103 conversion using a thinner head gasket and it sounds like an interesting topic by itself.

I am doing a Factory HD SE 96-103 conversion kit with 255 SE cams using my stock head with manual CR's for my 07 Road King.

Can any one comment on what issues or concerns they had with running a thinner gasket on a similar setup?

 

The reason for the thinner gasket is to raise compression slightly. What you have to watch is the CCP #'s with the cam you are using. If you're going to go with the 255 you're on the edge depending on altitude of the magic number of 200 for a street motor and it may be difficult to tune. Most people recommend going thinner on the gasket with later intake closing cams.

 

As Todd-67 said, the thinner head gasket raises compression because there is less area to compress the volume of the cilinder into. With a SE-255, I wouldn't think raising the compression would be a good idea but you should check with an engine builder that knows.

 

One other thing that a thinner HG does, is help with the activity of the burn- and as a general rule, a more active burn helps with efficiency. Who's tuning this, and with what?

 

I am running a a power commander 3. The SE103 kit comes with SE255 cams. I already have the K&N air filter, 02 delete, stock heads, and my D&D two into one exhust exhaust. So that tune setup is already an active download from the power commanders web site.

I was going to run with that pre selected setup. If I put the thinner head gasket on it, I assume I am going to have to tweak that tune because as you say, that added compression is going to effect the burn efficiency. I am still curious if anyone ran that set up and if they had any issues? Like, does the gasket blow out sooner? Do yo have to run different plugs, that kind of stuff...

I am thinking I am probably going to pass on the thinner gasket for my project, due to the fact I did not beef up the studs and other stuff and I will be around 10:1 compression already. But if it's not a big deal then I may consider it. On the other thread, it seemed like it was a no brainier to go that route for a cheap bang for your buck. But I got a feeling there is something more to it and there is some kind of trade off for longevity.

 

the trade off of the minimal boost in compression versus longevity is my concern as well.

 

While a thinner gasket will increase compression, the real reason for them is more “squish” for better combustion turbulence = better mixing and burn. Static Compression should be adjusted with proper milling, combustion chamber area and/or piston dome/dish. I have not heard of leakage problems with thinner head gaskets in twin cams.

 

 

Who is going to do the install?

 

All the stock beeehives from 05-present ( unless damaged/broken) can handle the lift of the SE255 cams; they work very well at 10:1, with that pipe, & a good tune, I would expect 110-112 TQ and 89-91 HP.