I recently installed Andrews 37g gear driven cams, .510” lift. I have been told that I should take a skim cut on the heads to increase the compression or install thinner head gaskets. I opted to install the thinner head gaskets. Stock gaskets are .060” thick I bought .030” thick gaskets. I have not installed them yet and I was wondering just how much will this improve the performance?

 

http://www.nightrider.com/biketech/h...ompression.htm

 

I run Chevron 91 octane in all my vehicles.

 

When you use thinner head gaskets/milled heads the valves will be a bit closer to the piston dome...I don't know the specs on the Andrews 37G cam but it's always a good idea to check the valve to piston dome clearance when using thinner head gaskets...Consider it an "insurance policy" to prevent a bent valve!!!

 

why? does the compression of each require it?
If not, you are actually reducing the performance.

 

My F150 has a Vortech supercharger on it that requires 91 and my other toys, 2001 YZ 250, JET Skiis (2 stroke) and 30 hp Johson outboard also a two stroke. Thats pretty much it.

 

Is this an 88", or 95??
That cam wants 9.8-10 cr, to have the "hit" off the bottom, pull hard thru the middle, and also be able to have a good top end charge.
The gasket change will help with correcting the improper squish, from the Moco, but will yield very little to help get that cam set up correctly, as far as the compression needs.
If you call the shop tommorrow, between 8-12 EST, we can run that thru one of our engine programs to tell you exactly the cc's to set the combustion chamber volume at.
Scott

 

I ran 37G's in a stock compression 88" engine for a while (had Mik 42 and V&H Pro Pipe too) and it was ok - made a difference but not stunning. Then went to 95" with 9.6/1 comp forged pistons. Big difference - much better in the mid and top - feels like the beginnings of a strong motor. Need to do heads next - with a bit more comp and probably bigger cams and carb.

More comp from milling heads will make some difference, thinner head gaskets are OK too (and this doesn't mess with the heads either until you really know where you want to go with them) although as others have said make sure your piston/valve clearances still work. But I think either a ported and milled head or a bore and raised comp pistons will really be needed to be able to get a proper "wow" factor. Just sharing my experience and perception.

 

79cc chambers work great in my motor. I also use the SE 1.725 ratio rockers which brings the lift of those cams to right at .541" At 10-1 cr my bike rips

 

I didn't prepare for this one real well I started Friday at 3:00 got it apart by six and realized that I needed more than the head gaskets, duh! The bike shop's don't stay open late just cause you are working on your bike. I went to the bike shop at 9:00 Saturday got my parts and was back at it at around 10:30 after a few trips to the auto parts store to buy a few tools that I needed due to the limited space between the back bone and the head. I started her up at 9:30 Saturday night. Works great not a whole lot more power but a bit more crisp. It was a good exercise thou I found that one of my spark plug wires had been rubbing on something and was about to start shorting out, The crossover line on the gas tank needed replacing and the breather tubes going from the head to the carb were cracked. Im going to Sturgis this year so finding this stuff out now is better than when on a trip.