Angle Mill Help
 

My Crower Cam needs a minimum of 10.25 to 1 Compression Ratio which means I need my AFR 210 heads skimmed to 58cc.

Contacted AFR and there is no problem in milling to 58cc but this needs to be an angle mill. Apparently the heads are spot faced, so there should be no problem with the head bolt seating, but I am worried about rocker geometry and push rod length.

AFR have said dont worry just mock it up when you get it and it may need releiving for the push rods and a different length of push rod.

I really do need some help from you guys with experience as this has frightened me to death , especially as I dont have loads of money to waste and if I get it wrong.......

Firstly is it easier than it sounds and are different sized push rods readily available off the shelf. Also should the rockers be OK - I am using roller Rockers with solid roller cam.

The other question is am I complicating things. The cam is a Crower 00427 290R which asks for a minimum CR of 10.25 to 1.
I can get 9.5 to 1 with parallel mill, so is the CR that important if I am using the car on the street.

Honestly I would be very grateful for your advice or comfort especially if you have done it as the implications following angle milling really worries me.

Anything else to watch out for

Thanks in anticipation of your help.

A very worried Mike.

What is your general goal here?

I mean, it sounds like you have a CAM that is dictating the engine build.

Think about the fuel you are using. If you are out for premium fuel, then 10 to 1 or better. Get a piston that forces that much compression with your heads. Milling heads for compression is a bit rough in todays market.

Start out with a list of wants.

Stop entering all these problems into the mix. Get a block. Pick a piston that will give you your desired compression. balance and blue print the assembly.

Personally I would work with the heads as they are and unmolested. You can build that top fueler after you have this one under your belt.

Just my $0.02

Mikey,

First, suggest you contact Wilf Leek. He's from UK, runs a DAC, and posts here frequently. He might have some suggestions as to where to get machine work done, and what is practical for your setup.

Second, keep it simple, and practical for a street Cobra. You don't need a solid roller cam for the street, or 10.25 CR for at best 93 octane fuel. Do not mill these heads. Pick a piston that will give you 9.5 to 9.75 CR. Get a warmstreet grind cam hydraulic, hydraulic roller rerofit, or solid flat tappet (if you don't mind adjusting them periodically).On a Cobra, you need to spend you money on suspension, brakes, wheels, tires, and creature comforts.

Mike:

I have not forgot about you, just been VERY busy and will get you out an e-mail later tonight. Sorry for the delay but just been one of those weeks with lots of calls and e-mails.

Thanks Jack and thanks guys

I know Wilf, hes a great guy, what you would call an ambassador for the club.

I have the parts unfortunately and with the cost being in excess of £11,000 I dont want to skimp on the last bits.

Engineers and engine builders over here ddont tend to angle mill, so I think it is more inexperience in the issues rather than a no no. Kenny coleman is a builder of known repute over here, and he has never done it so I prefer to keep clear and settle with parallel mill and 9.5 to 1.

The reason the issue came up is the unit I brought in is a mowtown with piston dishes a bit ilke Mare Equilibrium on the moon so its virtually impossible to get adecent CR withoy going OTT. I will try it I think and see how she is mannered.

Thanks again guys
Mike.