Slant Six Forum :: 225 head work needed

To properly figure a good target for cutting the head, you'll need to know what your compression ratio is now. Measure the starting volume of the combustion chambers on your head with a CC kit (basically a piece of plexiglass with a small hole in it and a big graduated syringe). You'll also need to measure your deck height, i.e. how far down in the hole your pistons are at TDC. Both of these can vary from year to year based on manufacturing tolerances.

If you don't want to do that work and you're very sure the engine is stock and uncut, you can probably get away with just cutting off 0.060" or so. But I'd be very curious how you blew a head gasket in the first place. Is the ignition system and distributor stock? Are you having any cooling system issues? Fuel delivery issues or big vacuum leaks?

The Fel-pro head gasket is fine for most stock and near-stock applications. The Victor Reinz is probably better. You shouldn't need to go fancier than that for a moderate NA build.

Author:	Crizila [ Thu Sep 20, 2018 5:25 pm ]
Post subject:	225 head work needed
So, after running a leak down test and compression test on my tired 225 a few weeks ago, it was apparent that something was amiss. Pulled the head off today. Blown head gasket in #4 hole. The gasket was blown in to the spark plug chamber, which is why I noticed a little puff of smoke ( timed to #4 hole ) coming out the PCV hole when I ran the engine with the PCV unplugged. Beside that all the valves / seats look like they were leaking ( 72% leak rate in #1 hole ). It's a wonder the car moved forward at all. On the bright side, all the bores look pretty good with minimal taper. Sooooo, after redoing the head, I want to mill it some amount to perk things up a bit. What Can I safely pull off it? The bottom end will stay as is for now, Including the cam. This is a solid lifter motor. Any other suggestions would be appreciated. Thanks, John

Author:	Dart270 [ Thu Sep 20, 2018 7:02 pm ]
Post subject:	Re: 225 head work needed
What year engine, what car is it in, and what head gasket do you plan to use? Lou

Author:	67regal [ Fri Sep 21, 2018 1:29 am ]
Post subject:	Re: 225 head work needed
I'm also in the process of pulling my head to get it milled about 60 thou to try and get 9.1 compression for better throttle response and power. Already have a small cam in, and I'll be leaving the bottom end alone as well same as the OP. Cheers

Author:	67regal [ Fri Sep 21, 2018 1:30 am ]
Post subject:	Re: 225 head work needed
Quote: What year engine, what car is it in, and what head gasket do you plan to use? Lou What head gaskets are available fir the 225s? Thanks

Author:	slantzilla [ Sun Sep 23, 2018 4:13 pm ]
Post subject:	Re: 225 head work needed
I know it is a '74 Duster. Not sure what else John is planning on.

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225 head work needed https://www.slantsix.org/forum/viewtopic.php?t=62855	Page 1 of 1

Author:	SpaceFrank [ Sun Sep 30, 2018 8:10 am ]
Post subject:	Re: 225 head work needed
To properly figure a good target for cutting the head, you'll need to know what your compression ratio is now. Measure the starting volume of the combustion chambers on your head with a CC kit (basically a piece of plexiglass with a small hole in it and a big graduated syringe). You'll also need to measure your deck height, i.e. how far down in the hole your pistons are at TDC. Both of these can vary from year to year based on manufacturing tolerances. If you don't want to do that work and you're very sure the engine is stock and uncut, you can probably get away with just cutting off 0.060" or so. But I'd be very curious how you blew a head gasket in the first place. Is the ignition system and distributor stock? Are you having any cooling system issues? Fuel delivery issues or big vacuum leaks? The Fel-pro head gasket is fine for most stock and near-stock applications. The Victor Reinz is probably better. You shouldn't need to go fancier than that for a moderate NA build.

Author:	67regal [ Wed Oct 17, 2018 7:51 pm ]
Post subject:	Re: 225 head work needed
Quote: To properly figure a good target for cutting the head, you'll need to know what your compression ratio is now. Measure the starting volume of the combustion chambers on your head with a CC kit (basically a piece of plexiglass with a small hole in it and a big graduated syringe). You'll also need to measure your deck height, i.e. how far down in the hole your pistons are at TDC. Both of these can vary from year to year based on manufacturing tolerances. If you don't want to do that work and you're very sure the engine is stock and uncut, you can probably get away with just cutting off 0.060" or so. But I'd be very curious how you blew a head gasket in the first place. Is the ignition system and distributor stock? Are you having any cooling system issues? Fuel delivery issues or big vacuum leaks? The Fel-pro head gasket is fine for most stock and near-stock applications. The Victor Reinz is probably better. You shouldn't need to go fancier than that for a moderate NA build. Thanks for the info frank, sorry for the novice question but when measuring the cc of the combustion chambers, is it just plain old water in the syringe? Cheers

Author:	SpaceFrank [ Mon Oct 22, 2018 9:09 pm ]
Post subject:	Re: 225 head work needed
Yes, just water in the syringe. It also helps to spread a small amount of grease around the perimeter of the combustion chamber to make a good seal with the plastic. Fill the syringe, use it to fill the combustion chamber through the hole in the plastic, and then subtract what's left in the syringe. You'll need a syringe that holds about 60 cc (aka mL) unless you want to do it in multiple stages. Best to do all 6 of them and take the average, but there shouldn't be much variation between cylinders.

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