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2G 4g63t block and cylinder prep?

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Prep in what way? And what are you talking about when sealing. Like in terms of a head gasket seal? Valve stem, front case, OFH?

Assuming you are talking about prepping for a head gasket I would take both to a machine shop if you don't have a reliable straight edge and have them check for flatness and make sure the valves seat properly and seal the top end.

If you are using a MLS you should have a perfectly flat surface that is smooth to ensure proper mating of the head gasket.
 
Prep in what way? And what are you talking about when sealing. Like in terms of a head gasket seal? Valve stem, front case, OFH?

Assuming you are talking about prepping for a head gasket I would take both to a machine shop if you don't have a reliable straight edge and have them check for flatness and make sure the valves seat properly and seal the top end.

If you are using a MLS you should have a perfectly flat surface that is smooth to ensure proper mating of the head gasket.

I am talking about the head gasket sealing properly. Can the short block be shaved with the pistons still in?
 
I'm not a machinist or certified mechanic. I would say no it can't because I don't know of any reliable way to block any shavings from getting into the cylinder and causing all sorts of damage to the cylinder walls. I believe you need to strip the block bare to have it decked.

On that note it is also made of iron and not aluminum like the head so unless it has seen a lot of heavy use and high hear cycles it shouldn't warp easily. Although it is still possible for warping to occur. Usually people go get their block decked, honed and bored out all in one shot.
 
I am talking about the head gasket sealing properly. Can the short block be shaved with the pistons still in?
No. If you need to deck a head or block complete disassembly is required. Flatness is checked with proper machinist tools. A machinist straightedge. Feeler gauges etc. If you feel something isn't right yiu can clean a surface and check it. Do NOT clean something with a roloc disc or some other power grinding method. You can't see thousandths of an inch with the naked eye.
 
Honestly I would still rent, borrow or buy a straight edge to check the flatness or the block since you're going to have the head off the block. Better safe than sorry. If you are just doing a routine PM by changing the head gasket I wouldn't be extremely worried about warping.

**I personally own a straight edge and I would still want to know the tolerances of both surfaces for peace of mind**

If you had a head gasket failure I would make 100% sure than both surfaces are flat. If you don't feel comfortable checking or doing the work yourself have a trusted professional do it the right way!!
 
Hello fellow DSM addicts,

I'm curious if there is a good way to prep a 4g63t short block and cylinder head to ensure a good seal?

Check lower block with straight edge, use feeler gauge, many vid demos on y.t.
Same as the head, if doesn't seem right, take to the machine shop to have it resurfaced. When all is completed, and your ready to reinstall, some guys like to use "copper sealant". I've never used it and never had problems. I'd upgrade my head bolts with ARP head studs. Spend the extra $$ on that and a good head gasket if you have the funds. And if it's your first time, When you remove the head be sure to cover the lower block, if it's in or out of the engine bay. You don't want any type of debris gettin in there and stuck between the piston rings and walls.
Make sure you put your head gasket on the right way too.
A good torque wrench and a torque angle gauge is useful. I've always used mine for the crank and rods. Just to be on the safe side. Fallow the torque sequence as well.
 
I really appreciate all the help y'all have given me. My current 4g63t is still all buttoned up in the engine bay, but I have an other 4g63t block sitting in an other parts car (don't we all) so I will probably pull that. I'll have to buy a straight edge, but most likely I'll have the block decked for peace of mind and then rebuild the head. I guess it's time for forged internals :hellyeah:
 
The problem with using a block that is verified to be flat is that it doesn't necessarily mean the block is good for using a mls gasket. If you pull the head off and its flat and throw another head gasket on you might still have sealing issues. Every manufacturer specifies a specific ra to assure head gasket adhesion.Short of buying a profilometer your pretty much in the dark. This is assuming you intend on using a mls type gasket. If you are using a composite gasket you dont need to worry about anything i said short of making sure its relatively flat and clean
 
Update: I did a wet compression test and the psi in cylinder #3 went from like 30-40psi to 90-100psi....
What is the psi on all the others? After a wet test if compression increases it indicates worn piston rings. Sounds like the rings on #3 are really bad to be that low and only increase to 100 psi max. IIRC around 170 is healthy, don't quote me on that as someone else with more knowledge will be able to confirm what healthy psi is during a compression test.
 
What is the psi on all the others? After a wet test if compression increases it indicates worn piston rings. Sounds like the rings on #3 are really bad to be that low and only increase to 100 psi max. IIRC around 170 is healthy, don't quote me on that as someone else with more knowledge will be able to confirm what healthy psi is during a compression test.

For each cylinder besides #3 they are at 150-167 psi
 
is it a 6 or 7 bolt? I believe the normal range of psi for compression i previously stated was for 6 bolt.

Although I suppose that is a moot point since you will need to at the very least install new rings, sounds like that block is in need of a rebuild. Might as well send her to a shop.
 
is it a 6 or 7 bolt? I believe the normal range of psi for compression i previously stated was for 6 bolt.

Although I suppose that is a moot point since you will need to at the very least install new rings, sounds like that block is in need of a rebuild. Might as well send her to a shop.
The car is a 1997 gst so it is a 7 bolt 4g63t. I already have an other 7 bolt 4g63t that is torn down so once I can afford it, it will be sent to the shop to be bored and decked.
 
It's always good to have spares of stuff. Thats pretty much what I'm doing with my talon, any parts I see that are quality and worth buying I see them once I get it all maintained and running smooth ill start upgrading and eventually that means rebuilding the engine so I'll be in the market for another 6 bolt when that happens. Also an awd trans that isn't broken, just stuff that is generally hard to come by.

I like to live by the "hope for the best but expect the worst" saying LOL
 
It's always good to have spares of stuff. Thats pretty much what I'm doing with my talon, any parts I see that are quality and worth buying I see them once I get it all maintained and running smooth ill start upgrading and eventually that means rebuilding the engine so I'll be in the market for another 6 bolt when that happens. Also an awd trans that isn't broken, just stuff that is generally hard to come by.

I like to live by the "hope for the best but expect the worst" saying LOL

I like that quote, literally defines a DSM
 
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