What can/should I replace if I were to take the engine apart?

[Dihtung Glava]

I haven't found a thread like this, so I'm just gonna ask for myself - after compression testing my 1st gen 4G63, I found the cylinders only seal 8.25, 7.5, 6.5 and 9.25 bars of pressure (in order) which is way out of spec. I'm really pissed we didn't check the piston rings when we were doing the headgasket last year and we only found this now.

I believe this, along with the transmission going out AND my plans to replace the entire wiring harness justifies pulling the engine over the winter.

I wanted to ask, what else do you guys recommend I replace? I don't want to just replace the rings and then have to take the engine apart again next year for pistons or rods or camshafts or something else that people upgrade...

I also have a 14B turbo on it, with plans to upgrade down the line if that's something that matters in this.

thanks.

You must be logged in to view this image or video.

 

[curt-s]

Depends on your goals. The multitude of 300hp threads here give a solid base to start on but if you want more, you'll have to pay more. Be careful on the trans issues as rebuilding them is quickly becoming an impossibility due to lack of available parts.

 

[Dihtung Glava]

Depends on your goals. The multitude of 300hp threads here give a solid base to start on but if you want more, you'll have to pay more. Be careful on the trans issues as rebuilding them is quickly becoming an impossibility due to lack of available parts.

Yeah, I saw a couple post kind-of down this alley in my recomended after posting this... I was just hoping there was some "almost standard" upgrades to get while you are in there.

I guess I am, or will be, looking for 300 or 400 when all is said and done.

I have a used transimission in my GS parts car so hopefuly that can replace the current one. But yeah, after that I'm out of transmissions.

 

[97egl]

Rings, Rod bearing, main bearings, balance shaft bearings (if you still have them). You will need to measure all the cylinder bores for out of round and taper to see if you'll need to have it bored, and check the main and rod journals to make sure they are within spec as well. Also since you are a 99 make sure you get the correct main bearings. 97.5-99 engines have a split thrust main bearings.

I would also replace your oil squirters or block them off. Which way you go is up to you. You don't really need any upgrades to the bottom end for 300-400 horsepower. I would go with closer to 300~350. Makes a fun street car and the transmissions are well know to hold up to that without issue unless you abuse it.

I'd also do all the gaskets/seals. Front and rear main seals, front cover gasket, ofh gasket, oil pump drive sprocket seal, balance shaft seal, timing belt, water pump, cam seals. Any seals that are behind the timing belt cover.

 

[Dihtung Glava]

Solid suggestion, thanks!

Just to be clear, the car is a 99, the engine is from a galant, from around the 1G DSM era.

Why should one replace/block the oil squirters?

 

[1990TSIAWDTALON]

You will have a 6 bolt motor if it is from a 1g. The oil jets are different than those on a 2g motor. 6 bolt engines have seperate pieces that are bolted to the main oil galley inside the engine. They have a check valve and a jet/squirter that bolts in with crush washers to seal them. I keep mine in the same cylinder that they came out of so I know they didn't have any interference issues with the piston skirts. You will see them when you pull the oil pan off and look at the cylinders from the bottom.

 

[BLACK'98DSM]

You said you have a spare transmission on a GS, correct? The GS is a non turbo model.

If it's a 1g, the transmission would technically fit and bolt up. But the internals differ from turbo cars. I wouldn't trust it to handle 300hp. Not when it was designed for 140hp. The turbo trans is internally different for a reason.

If it's a 2g, the transmission will not work at all. Literally everything about it would be different, coming from a 420a engine.

 

[Dihtung Glava]

It's a 2G GS so it has a 4G63 n/a engine and trans. I thought they would be the same appart from the clutch... I guess we are rebuilding then.

 

[BLACK'98DSM]

Ah, I just noticed you're not in the U.S... It should have been obvious when you listed compression in bars and not PSI. So yes it would have a 4g63. I'm not sure what differences that transmission would have. If it is the same as a turbo trans then you're obviously good to use it. It may be the same as the 1g NA transmission which is a no go. You'll have to identify it first. Best of luck.

 

[Dihtung Glava]

Do you guys by any chance have some 300-400HP threads followed that you could link? I've been reading a couple but I don't think I've found everything I need yet. That said, I havent even started pulling the engine yet so I'm not exactly a hurry, I'd just like to read up some more before I get into it. Thanks.

 

[Dihtung Glava]

Disregard that last post, I found a couple threads. One more thing I wanted to ask, should I be replacing the pistons? The engine is a 6 bolt N/A so it has different compression pistons from a turbo. But I have a turbo... what do you think?

I have the engine apart now but I have not ordered anything yet. Just want to make sure I get everything right so I don't have to take it apart again too soon.

 

[pauleyman]

It isnt just the compression ratio, its the construction of the piston as well. Piston to wall clearances are different also. If you're rebuilding with the intent of turbocharging I would change pistons also.

 

[Dihtung Glava]

It isnt just the compression ratio, its the construction of the piston as well. Piston to wall clearances are different also. If you're rebuilding with the intent of turbocharging I would change pistons also.

It's been turbocharged for years, I just want to prevent any damage down the line by simply rebuilding it as a n/a engine while I have the chance. I don't think that's why the piston rings went but I'm sure it didn't help. Any brand suggestions for pistons/rods?

 

[pauleyman]

It's been turbocharged for years, I just want to prevent any damage down the line by simply rebuilding it as a n/a engine while I have the chance. I don't think that's why the piston rings went but I'm sure it didn't help. Any brand suggestions for pistons/rods?

As stated nt pistons aren't just different compression ratio. Pick a piston appropriate to your goals, budget and driving. Stock nt piston isn't it. If all you want is 300 a stock turbo piston would do that. If you think you will keep climbing during this conversion plan ahead for something better. You are 100% sure this is a 6bolt motor? Either way lots of options are available

 

[Dihtung Glava]

1000% - I have the 6 bolts on my desk. Unless they also swapped heads or something but I doubt that. As I said, I don't want some crazy hp numbers, but given that I want to change the turbo eventualy and give it a proper tune, I do want the engine at 100%. How would I be able to tell what compression pistons are even in there now other than going by what the rest of the block is?

 

[pauleyman]

You could measure but there isn't really a point in doing so I would think. Is there a concern with compression ratio? I assume no matter what you aren't going to be using these pistons?

 

[Dihtung Glava]

I was totally gonna reuse the pistons if the cylinders turned out to be within spec. Compression ratios never even occured to me - a friend brought up the idea that the engine probably had the wrong pistons for turbo-ing since it's originally n/a. So now I am only making sure I have all the information before I pull the trigger on expensive new internals. Either way - I'm waiting for a shop to inspect the block first, I'll figure out what to do after.

 

[pauleyman]

I was totally gonna reuse the pistons if the cylinders turned out to be within spec. Compression ratios never even occured to me - a friend brought up the idea that the engine probably had the wrong pistons for turbo-ing since it's originally n/a. So now I am only making sure I have all the information before I pull the trigger on expensive new internals. Either way - I'm waiting for a shop to inspect the block first, I'll figure out what to do after.

I would not reuse the NT pistons. At least buy a set of stock turbo pistons. They're cheap. NT ringland is different. It's all different.

 

[Dihtung Glava]

Alright, got the block and crank back from the shop. They're both in spec. I've also just about made up my mind in regards to pistons and rods - I think I'm gonna go with the least expensive forged piston & rod combo from Extreme PSI; eagle H-beams and Manley 8.5 compression pistons. I know it's more than overkill for the power I want but I don't want to wake up one day years later and curse at myself for getting stock internals when I had the block in my hands and so many options. I think I'll just wake up tomorrow and curse at myself for spending money on shit I shouldn't even be able to afford.