Rebuilding Motor!

[Sik95TSI]

So today I got the news that I need a rebuild Shop called me and said they did a compression test and got 120-125 across on all four, also they did a leak down test and it failed that too WTF This is funny because I only have about 150 Miles on this new set up!!! My last mechanic who did all the work told me everything checked out and looked good before doing all mods "Head checked out at machine shop too" Anyways I have a few question's. I'm sticking with my 7 Bolt anyone have any suggestions on what to get I was looking at the MANLEY 4G63/4G64 ROTATING ASSEMBLIES anyone ever use this set up? Money is not a problem. I will most likely pull the motor myself and send it out to shop to be built I will also provide all parts needed. Second is there anything in specific that can cause low compression besides rings,valves,seals??? Any info would be great thanks guys!

 

[BogusSVO]

What percentage was the leak down?

Do you have cams?

Dit you check the timing marks/belt?

 

[Sik95TSI]

What percentage was the leak down?

Do you have cams?

Dit you check the timing marks/belt?

Yes I have BC 272's and according to shop timing is Correct. Why?

 

[BogusSVO]

Larger cams will drop your static compression due to increased overlap.

A timing belt that has "jumped a tooth" or two would do the same thing.

How did the car run and drive?

 

[Sik95TSI]

Larger cams will drop your static compression due to increased overlap.

A timing belt that has "jumped a tooth" or two would do the same thing.

How did the car run and drive?

I didn't ask what the percentage was on the leak down test I will tomorrow. But according to shop timing is correct. Ever since I got the car back from the first mechanic the idle has been horrible and the low end power is just not there. I honestly do believe my timing is off my 1+2 teeth.

That and I have a 5 angle valve job and mild Port and Polish.

 

[BogusSVO]

You may what to check out the tech VFAQ, and check the timing belt yourself.

That way you can confrim what they have told you.

 

[Sik95TSI]

You may what to check out the tech VFAQ, and check the timing belt yourself.

That way you can confrim what they have told you.

Ok I will. It's so frustrating man when someone tells you one thing and another shp tells you different

 

[BogusSVO]

This fourm is good for getting pointed in the right direction. But you will need to learn the search.

About anything you need to know can be found on here.

 

[Sik95TSI]

This fourm is good for getting pointed in the right direction. But you will need to learn the search.

About anything you need to know can be found on here.

Yeah totally understand that. But sometimes it's more helpful when talking to someone to better understand things you know? I really appreciate what people do on this forum and knowledge they give out to help people.

 

[NHerron]

Bogus, is there any pistons with a low enough compression profile to fit this description? Or does that not matter since it failed a leak down anyway? Thanks

 

[Rich_Howell]

Learn to work on your own car.

You have no idea the amount of ####ups I have seen from "shops". I did the timing on a 3g last night (4g64). Shaking so bad the hood prop was moving fore/aft about 3 inches. I expected to get under the timing cover to find a broken balance shaft belt...all was good, so I didn't know what the problem was. I proceeded with the work and as it turns out I was right: the oil pump/balance shaft was installed with the timing mark lined-up correctly, but with the BShaft out-of-phase. The owner bought this car used from a dealership and has been driving it this way since last August.

Not many average mechanics take the time to understand these cars...especially modified turbo cars. You're going down a very expensive road of not getting very far.

You've been warned.

And I just realized that I didn't provide anything overly helpful to your thread, so in the spirit of that: the only thing you didn't mention that can cause compression issues is a blown head gasket.

 

[fierosail]

in my town good luck finding a shop that will even look at a dsm they are scared of them

 

[boost97gst]

Learn to work on your own car.

You have no idea the amount of ####ups I have seen from "shops". I did the timing on a 3g last night (4g64). Shaking so bad the hood prop was moving fore/aft about 3 inches. I expected to get under the timing cover to find a broken balance shaft belt...all was good, so I didn't know what the problem was. I proceeded with the work and as it turns out I was right: the oil pump/balance shaft was installed with the timing mark lined-up correctly, but with the BShaft out-of-phase. The owner bought this car used from a dealership and has been driving it this way since last August.

Not many average mechanics take the time to understand these cars...especially modified turbo cars. You're going down a very expensive road of not getting very far.

You've been warned.

And I just realized that I didn't provide anything overly helpful to your thread, so in the spirit of that: the only thing you didn't mention that can cause compression issues is a blown head gasket.

Well stated. To the OP: this is the truth. Ive been the victim of a "professional" very recently. I quickly decided that i HAVE to make time to be my own mechanic again. Time is money at a certain point in your life, but these cars..... Theyre something else . YOU have to learn them. You cant really take a mechanics opinion anymore. God knows why the 4g63 is THAT complicated but ive seen it first hand and heard about it more than a few times, a mechanic fn things up, that is.
To your original concern: I too believe that your timing needs to be verified. And while your at it, maybe you could grab a leak down tester and do the test yourslef. I know it sucks, but what sucks worse is having that car in pieces for a month doing an unnecessary rebuild due to someones misdiagnosis. Good luck to you.

 

[assassin3117]

A +1 on all the replies you received. All of these guys are correct. When it comes to your DSM you should be the one working on it. I have never trusted my DSM in the hands of anyone. The guys that work with me in the shop don't even touch them. If one comes in the owner makes sure it comes to me. I guess since i drive one he figures I should work on everyone's .

 

[Sik95TSI]

I want to learn more about my car! I'm pretty mechanically inclined I'm just a little to scared to mess with timing belt and internal's of motor :-/

 

[Redslayer]

I want to learn more about my car! I'm pretty mechanically inclined I'm just a little to scared to mess with timing belt and internal's of motor :-/

I feel your pain . I was scared to death of messing with my timing belt, I didn't want to do it at all. And this is on a 420a! The engine where almost every forum I visited was full of people who had it skip time or just not line up right when they were finished. But I did it anyway because I didn't have the money to pay someone else to do it.

It's really not as hard as it sounds when talking about it. Just find some guides + threads online and make sure you double and triple check everything. I had to take the belt back off a couple times when I was doing it (which is pretty much a guarantee), but when I was finished and started it up, it was good the first time.

It's really not as hard as it seems, just don't over think things and get disheartened, I did that and my car sat an extra 3 months for nothing.

 

[BogusSVO]

Sik.. You are not the first DSMer to be a tad overwelmed to crack into an engine.

The tech, support, and help you need is all right here.

There is more than a few that the DSM has been the first timing belt, and first engine build.

 

[slinkmerc]

not to long ago I did a timing belt change on my 420A and I was terrified but this site gave me more than enough info on what to do and what not to do, i ended up doing the timing belt twice because i got it wrong the first time and got p1390 CEL but got it the second time, dont be afraid to work on your own car and save yourself A LOT of money

 

[Sik95TSI]

Well I got the car back home and got paper work and info with it. So comperssion test read Cylinder #1-120 #2-122 #3-128 #4-130 that's dry compression. He said on wet test the numbers went up just a little. On the leak down test cylinder #1 would leak air into cylinder #2. Cylinder #3 was leaking from head and cynlinder #4 was leaking from rings. about 40% on 3 and 4 and about 35% on 1 and 2. He checked the timing and it all checked out! He highly recommended to take motor out and take it apart to check for cracks or warped head or block. Any input guys thanks!

 

[BogusSVO]

What are you going to do?

 

[Sik95TSI]

What are you going to do?

I'm not sure man. What do you suggest? Those results pretty bad.

 

[jofe4]

I just yesterday pulled the head on my 1g tsi and found that it needs a rebuild bad due to a ton of knock (previos owner unpluged the knock sensor unknowing to me ).

Coming from someone that has rebuilt DOHC hondas and chevy small blocks that 4G63 is anoing to take apart, for some reason mitsubishi thought you need 10 million vacume/boost lines to go to every thing.

Not to discurage you from tearing the girl apart but make sure you get a chiltons or get AllData DIY(online) for your car they both have step by step on what to do and will help a ton. I recomend AllData is easy to find exactly what you need rather then fliping page by page to find it.

Let us what you decide and post pics!

 

[MichaelSuch]

Are you burning any coolant? I know you said the head was redone, was the bottom end redone as well? The compression seems about right for a higher mileage motor with cams, but the leakdown test results don't sound that good. Might've been an issue with the head surface or block deck not being completely flat. Was the cometic HG you installed a MLS gasket?

 

[BogusSVO]

Yes what they said dose not sound good.
Sounds at a min the head has to come off.

First thing is the basics.
Grab a Chiltion/ Haynes repair manual, and check the time belt

 

[Sik95TSI]

Are you burning any coolant? I know you said the head was redone, was the bottom end redone as well? The compression seems about right for a higher mileage motor with cams, but the leakdown test results don't sound that good. Might've been an issue with the head surface or block deck not being completely flat. Was the cometic HG you installed a MLS gasket?

Yes I do have a Chilton book. I have the Cometic Head Gasket (1.3mm) & Bore size 85.5MM. The car only has 81k original miles (I got it with 70k) I bought from a old guy who bought it back in 1994 from the dealer The mechanic also told me since I have the 5 Angle valve job on original guides that can cause for the valves not to sit right from the guides being worn down, is this true? I asked my mechanic "who did the work on car" to ask the machine shop to check everything on head and they said everything checked out except the seals which they replaced. I was going to get new springs,retainers,guides ect. but since they said everything was tip top I didn't



I'm not burning coolant that I know of yet. Wouldn't the Leak down test tell me that? Oil is clean.