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Cylinder Head Machining -combustion chamber matched to bore
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Author:  JRD [ Sat Sep 07, 2013 7:50 pm ]
Post subject:  Cylinder Head Machining -combustion chamber matched to bore

Now offering machining services to match the cylinder heads to your bore to reduce the chance of pinging. According to the instructions provided by Ivan with his kits, over bored cylinders should have the edge of the combustion chamber in the head enlarged to 1 mm over bore size ( along with the head gasket ) to reduce the chance of pinging.

These are Jess' H2 heads I just finished

Machined
Image

Fine emery blended and entire combustion chamber sanded.
Image

I will need to know bore size so the correct amount of material can be faced off on the lathe. Extra fine emery paper will be used to knock down the burr from machining and I will go over the entire combustion chamber. ( Note, if there are excessive "hammer" marks in the combustion chamber, they will be smoothed but not completely removed )

Price is $25 per head plus shipping. Insurance can be added for actual cost.
I can be contacted thru PM or at JRDerstine AT gmail DOT com ( removed underscored items and replace with "@" and "." )

Thanks for considering my services
Jeff

Author:  Ja-Moo [ Sat Sep 07, 2013 9:29 pm ]
Post subject:  Re: Cylinder Head Machining -combustion chamber matched to b

How are you compensating for the compression loss?

Author:  JRD [ Sat Sep 07, 2013 10:05 pm ]
Post subject:  Re: Cylinder Head Machining -combustion chamber matched to b

Ja-Moo wrote:
How are you compensating for the compression loss?


The difference is size is .04 cc on Jess' H2 heads.

edit, I used diameter instead of radius in my original calculations. .04 cc is the amount of metal removed

Author:  Jim [ Sat Sep 07, 2013 10:09 pm ]
Post subject:  Re: Cylinder Head Machining -combustion chamber matched to b

Jeff, I gotta give you credit for being able to measure the volume with the accuracy of 1/1000 of a cc. :D

Author:  JRD [ Sat Sep 07, 2013 10:13 pm ]
Post subject:  Re: Cylinder Head Machining -combustion chamber matched to b

Jim wrote:
Jeff, I gotta give you credit for being able to measure the volume with the accuracy of 1/1000 of a cc. :D


I googled it. I took the original size and the depth I cut and then used the new diameter with that depth. I subtracted the larger number from the smaller number and came up with that answer.

I did NOT do a fluid measurement.

Author:  Ja-Moo [ Sat Sep 07, 2013 10:49 pm ]
Post subject:  Re: Cylinder Head Machining -combustion chamber matched to b

So, how do you compensate? 1cc is a lot......

Author:  mraxl [ Sun Sep 08, 2013 8:36 am ]
Post subject:  Re: Cylinder Head Machining -combustion chamber matched to b

Since you're doing heads..... have you considered doing O-ring seals like Jim has done?
viewtopic.php?f=14&t=6739&p=67796&hilit=o+ring#p67796

Author:  JRD [ Sun Sep 08, 2013 9:15 am ]
Post subject:  Re: Cylinder Head Machining -combustion chamber matched to b

Ja-Moo wrote:
So, how do you compensate? 1cc is a lot......

Moo,
I used diameter instead of radius in my original calculations. The amount of material removed is .04 cc. That's less than .0005 ( half a thousandth ) off the bottom ( sealing surface ) of the head .

Author:  Ja-Moo [ Sun Sep 08, 2013 11:12 am ]
Post subject:  Re: Cylinder Head Machining -combustion chamber matched to b

I doubt that it's .04cc. You are removing at least a 1mm by .5mm ring.

Author:  magee [ Thu Sep 12, 2013 9:14 am ]
Post subject:  Re: Cylinder Head Machining -combustion chamber matched to b

I think it’s a bit silly to argue over such a very small amount of CC change. First of all who is to say that the bike had the correct comp psi in the first place? Secondly in my limited knowledge I would highly dought that without having the actual cylinders the head could be machined to be spot on. Chris Ritchie machined the heads I have and I still had to tweak them a bit (only a bit).
What impresses me the most is that Jeff does the machining for only $25.00 I think that is a plus right there. :)

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