This is taken from a recient question about milling down a head to increase the CR. Not a good idea in my book. If you want to raise your CR, get custom pistons, and only machine the head after you check to make sure it's flat FIRST.
Ok, here are the notes. Great "Upgrade" for valve springs here too.
Here is what I'd reccomend.
Have your machine shop measure the head first. Check it for warping, and have it straightened if it's warped. (Takes a special oven, but it can be done, and done right.)
This will keep your cam journals in the right line. (If your head is warped, and you mill the deck flat, your cams are now warped.... not a great deal, and it could lead to early failure in that area.)
Now, with a flat head, mill it to the finest RA the shop can produce. (15ra or smoother is a good goal.) I would not lap the head unless they have a microflat lapping table, and lap on that table by moving the head, not moving the lapping block.
Replace your valve seals. Only have a 3 angle valve job done if there was a leak, in my experiance, the 7M head has few valve seat problems.
I'd reccomend replacing your valve springs with Comp Cams inner Big Block Chevy ones. (They are like 70.00 total, and a great upgrade to your tired old valve springs. These springs have slightly higher seat and open pressures, and also a better bind height, so if you want to run a higher lift cam in the future, they will accomodate that too.) Do a quick search, (The part number is 975 per the note below.(REVISED to correct my prior wrong number.)
Now comes the head gasket. Please do not put a stock type head gasket on your performance motor. They suck ass. There is no nice way to candy coat this people.
Also a good metal head gasket will allow you to compensate for material lost by milling the head. Have your machinist figure out how much material was taken away, and get a MHG that is almost as thick as that amount. Depending on the MHG, there are a few things you can do to help it seal up.
If it's coated with a thin hylomar or rubber, just install it dry, and you should be fine. If it's a bare metal gasket like the Greddy I used, I reccomend coating the gasket with brake quiet. (Do a quick search, there are tons of posts on this, and somewhere a write up on how to do it right in my opinion.)
I have the same Greddy MHG on my stroker 7MGTE 3.24L 10:1 CR and it works fine. (It has been on 4 engines, and did not leak on any of them.)
Never use a gasket scraper on a MHG. Clean it up with brake cleaner, and a soft rag.
Now comes the fasteners. Save yourself time and money and just buy the ARP studs right now. Don't screw with stock bolts, or even the ARP ones. You want the studs if you want to never have to remove your head again.
Here is how to put it back on.
1) Clean everything, then clean it again.
2) DO not put the studs in first.
3) Assuming your block is flat, and has not been lapped in the car, a sure way to fuck up an engine if there ever was one, clean the block deck with a soft rag and brake cleaner. There should be no oil or dirt on the head gasket surface at all.
4) Using "The right Stuff" put down two beads of sealant about 1.5" long over the juction between the block and the front cover. This will seal up the joint there. Forget this step, and you will have oil leaks forever. Oil from the head drains down between the front cover and the engine block from the head.
5) Now, either with your brand new rubber coated MHG, or your brake quiet coated bare MHG, carefully lay the gasket in place. Do not slide it around. Do not slap it into place. Also make sure you have it lined up right, so it just locates onto the pins, and is perfectly lined up with the bores and other holes on your block. (This is especially true if you coated it with brake quiet. You get one chance to lay it down right, or you get to remove it, clean it and the block of brake quiet and start over again.) **ALSO, dont touch areas you want to seal, so only handle the gasket at the edges if your using brake quiet spray.** You want no fingerprints or areas of disturbed sealant.
6) Now with a friend, very carefully set the head down, again making sure you do not slide it around, but set it gently down over the alignment pins into place.
7) Now you install the studs. No need for loctite. Just use the Moly lube ARP provides. I found if you snip the end of the tube, you can wipe small amounts right on the stud threads, so it goes quite a long way. Put a small amount of moly lube onto the end that goes into the block side, and get your washer ready. Lube BOTH sides of the washer face, and using the stud as a guide, you slide the washer down into place as you put the stud into the hole in the head. (If you try and do this the other way, your washers will not all fit, and your pulling the studs to get them into place.. don't ask me how I found this out, the method I'm telling you is the fastest way to do this.)
Put the studs in finger tight. I did use a allen wrench to help do this, but DO NOT TOURQE the studs into place, Just finger tight/snug is all you want.
All your studs should be in the head at the same height. You will have moly lubed the threads, and both sides of the washers.
Now you put on the nuts. I like to smear moly lube onto the stud thread ends first, then put some on the face of the nut where it contacts the washer. The stud threads will lubricate the nut as you tourqe it down.
Put all your nuts on first just finger tight again.
Now wipe up all the moly lube and wash your hands.
Using a good quality click type tourqe wrench, your going to get this done right the first time.
Set the tourqe reading to 50 lbs and lock the collar. I like to use a short extension and a deep thinwalled socket works best for me. You can do this with the cams in place, but you will need to rotate the cams, so a large wrench to turn the cams will be needed.
Ok, start in the middle and work your way outwards in a X pattern. (See the TSRM for exact details.)
Your first pass goes from the middle out at 50lbs. This sets the head in place. You need to complete ALL of your tourqe passes at the same time. Don't start this unless you have time to go from setting the head to final tourqe figures.
Next pass is 60lbs. Change the setting on the tourqe wrench, and starting in the middle, tourqe them all to 60lbs.
Now change up to 70lbs. Repeat.
80lbs.
90lbs.
Now comes the final pass. I reccomend 100lbs for ARP studs on a MHG. It is not too much, or too little. My current engine has them at 103... why? I'm strange that's why.
I would not reccomend more than 110.
A key to getting the right tourqe reading is knowing how to use a tourqe wrench.
Practice some if you have never used one. (Your going to get lots of practice putting this head on, since your going to tourqe studs at 50, 60, 70, 80 and 90 lbs before your final pass at 100, so don't sweat this too much.)
The wrench has to be moving when it clicks to get an accurate read on tourqe. If you just put it on and click, you have shit for a reading. The fastener HAS TO BE MOVING to read tourqe. If it does not move, your reading friction.
After you do this for awhile, you will be able to gauge the click just before it happens, and you need to keep your movement smooth and even and then STOP when the wrench clicks. Some people like to double click, I think it makes no difference. (But I will double click anyway... LOL) BUT I don't move the wrench any further after it clicks. (There are some who say turn it 1/4 turn more... that's how fasteners get really screwed up in a hurry, so don't go there.)
Ok, here are the notes. Great "Upgrade" for valve springs here too.
Here is what I'd reccomend.
Have your machine shop measure the head first. Check it for warping, and have it straightened if it's warped. (Takes a special oven, but it can be done, and done right.)
This will keep your cam journals in the right line. (If your head is warped, and you mill the deck flat, your cams are now warped.... not a great deal, and it could lead to early failure in that area.)
Now, with a flat head, mill it to the finest RA the shop can produce. (15ra or smoother is a good goal.) I would not lap the head unless they have a microflat lapping table, and lap on that table by moving the head, not moving the lapping block.
Replace your valve seals. Only have a 3 angle valve job done if there was a leak, in my experiance, the 7M head has few valve seat problems.
I'd reccomend replacing your valve springs with Comp Cams inner Big Block Chevy ones. (They are like 70.00 total, and a great upgrade to your tired old valve springs. These springs have slightly higher seat and open pressures, and also a better bind height, so if you want to run a higher lift cam in the future, they will accomodate that too.) Do a quick search, (The part number is 975 per the note below.(REVISED to correct my prior wrong number.)
Now comes the head gasket. Please do not put a stock type head gasket on your performance motor. They suck ass. There is no nice way to candy coat this people.
Also a good metal head gasket will allow you to compensate for material lost by milling the head. Have your machinist figure out how much material was taken away, and get a MHG that is almost as thick as that amount. Depending on the MHG, there are a few things you can do to help it seal up.
If it's coated with a thin hylomar or rubber, just install it dry, and you should be fine. If it's a bare metal gasket like the Greddy I used, I reccomend coating the gasket with brake quiet. (Do a quick search, there are tons of posts on this, and somewhere a write up on how to do it right in my opinion.)
I have the same Greddy MHG on my stroker 7MGTE 3.24L 10:1 CR and it works fine. (It has been on 4 engines, and did not leak on any of them.)
Never use a gasket scraper on a MHG. Clean it up with brake cleaner, and a soft rag.
Now comes the fasteners. Save yourself time and money and just buy the ARP studs right now. Don't screw with stock bolts, or even the ARP ones. You want the studs if you want to never have to remove your head again.
Here is how to put it back on.
1) Clean everything, then clean it again.
2) DO not put the studs in first.
3) Assuming your block is flat, and has not been lapped in the car, a sure way to fuck up an engine if there ever was one, clean the block deck with a soft rag and brake cleaner. There should be no oil or dirt on the head gasket surface at all.
4) Using "The right Stuff" put down two beads of sealant about 1.5" long over the juction between the block and the front cover. This will seal up the joint there. Forget this step, and you will have oil leaks forever. Oil from the head drains down between the front cover and the engine block from the head.
5) Now, either with your brand new rubber coated MHG, or your brake quiet coated bare MHG, carefully lay the gasket in place. Do not slide it around. Do not slap it into place. Also make sure you have it lined up right, so it just locates onto the pins, and is perfectly lined up with the bores and other holes on your block. (This is especially true if you coated it with brake quiet. You get one chance to lay it down right, or you get to remove it, clean it and the block of brake quiet and start over again.) **ALSO, dont touch areas you want to seal, so only handle the gasket at the edges if your using brake quiet spray.** You want no fingerprints or areas of disturbed sealant.
6) Now with a friend, very carefully set the head down, again making sure you do not slide it around, but set it gently down over the alignment pins into place.
7) Now you install the studs. No need for loctite. Just use the Moly lube ARP provides. I found if you snip the end of the tube, you can wipe small amounts right on the stud threads, so it goes quite a long way. Put a small amount of moly lube onto the end that goes into the block side, and get your washer ready. Lube BOTH sides of the washer face, and using the stud as a guide, you slide the washer down into place as you put the stud into the hole in the head. (If you try and do this the other way, your washers will not all fit, and your pulling the studs to get them into place.. don't ask me how I found this out, the method I'm telling you is the fastest way to do this.)
Put the studs in finger tight. I did use a allen wrench to help do this, but DO NOT TOURQE the studs into place, Just finger tight/snug is all you want.
All your studs should be in the head at the same height. You will have moly lubed the threads, and both sides of the washers.
Now you put on the nuts. I like to smear moly lube onto the stud thread ends first, then put some on the face of the nut where it contacts the washer. The stud threads will lubricate the nut as you tourqe it down.
Put all your nuts on first just finger tight again.
Now wipe up all the moly lube and wash your hands.
Using a good quality click type tourqe wrench, your going to get this done right the first time.
Set the tourqe reading to 50 lbs and lock the collar. I like to use a short extension and a deep thinwalled socket works best for me. You can do this with the cams in place, but you will need to rotate the cams, so a large wrench to turn the cams will be needed.
Ok, start in the middle and work your way outwards in a X pattern. (See the TSRM for exact details.)
Your first pass goes from the middle out at 50lbs. This sets the head in place. You need to complete ALL of your tourqe passes at the same time. Don't start this unless you have time to go from setting the head to final tourqe figures.
Next pass is 60lbs. Change the setting on the tourqe wrench, and starting in the middle, tourqe them all to 60lbs.
Now change up to 70lbs. Repeat.
80lbs.
90lbs.
Now comes the final pass. I reccomend 100lbs for ARP studs on a MHG. It is not too much, or too little. My current engine has them at 103... why? I'm strange that's why.
I would not reccomend more than 110.
A key to getting the right tourqe reading is knowing how to use a tourqe wrench.
Practice some if you have never used one. (Your going to get lots of practice putting this head on, since your going to tourqe studs at 50, 60, 70, 80 and 90 lbs before your final pass at 100, so don't sweat this too much.)
The wrench has to be moving when it clicks to get an accurate read on tourqe. If you just put it on and click, you have shit for a reading. The fastener HAS TO BE MOVING to read tourqe. If it does not move, your reading friction.
After you do this for awhile, you will be able to gauge the click just before it happens, and you need to keep your movement smooth and even and then STOP when the wrench clicks. Some people like to double click, I think it makes no difference. (But I will double click anyway... LOL) BUT I don't move the wrench any further after it clicks. (There are some who say turn it 1/4 turn more... that's how fasteners get really screwed up in a hurry, so don't go there.)