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96 GST rebuilt engine or no?

Muddy_Lotus

Probationary Member
13
2
Oct 12, 2020
Puyallup, Washington
So I just picked up a 1996 Eclipse Gst. I ended up picking it up for only 700$ but this car is a little odd. For starters it only has 57K on the engine. According to the oil change sticker on the dash it's only put on 1000 miles since 2003. So it hasn't really ran much in the last twenty years.

According to the guy I bought it from once upon a time it had a huge turbo on it, was dynoed at 480HP and it still has a old nos setup in the car. He bought it two years ago and never really got it running. It kept jumping timing for whatever reason. Currently I can see into the long block since he was mid-rebuild and there is damage from valves on the top of the pistons.

I cannot decide if I should rebuild this block, since it only has 57K on it. Or do I buy a new rebuilt block? How likely is it that something wrong with the long block is causing the timing issue? Or is it more likely an external component?

Thanks for any help!
 

95FullSend99

Proven Member
329
173
Dec 3, 2019
ledyard, Connecticut
Assuming the pistons arnt destroyed, If I were in your position, I would pop off the oil pan and give it a very through inspection for bearing material. If you dont see anything, I would reassemble the motor and immediately do a leak down/compression test. Verify the rings are good. If all checks out, start it up. The only reason I can think of for continuously jumping timing is someone that doesn't know how to set timing.
 

John Miller

Proven Member
168
62
Jan 27, 2020
Watertown, Wisconsin
Like the previous guy was saying, take of the oil pan/strainer and look for any bearing material. Anything that looks out of place and check for excessive crank shaft play side to side. If the motor checks out, then I would replace gaskets, oil pump, timing components ect and then do arp headstuds. The timing tensioner is kinda tricky to set, and if not set with the specific tool, it could jump timing. Once you get it all back together, run it and see. Also I would recommend doing a more conservative tune or going down to a 16g turbo.
 

TK's9d2TSi

Supporting Member
4,686
1,950
Sep 11, 2017
Cincinnati, Ohio
There are two hydraulic tensioners available for the 2g which depends on your cars built date. It’s on your vin tag on the door jam. I recent did a timing belt and the PO had the tensioner pulley on backwards which mean that they obviously didn’t set the tension correctly. This caused the timing belt to have a lot of slack on the idler side which can easily cause it to jump timing.

As long as the crank, oil pump sprocket, front balancer sprocket and cams rotate, and the tension is set correctly, it shouldn't jump timing.
 

Muddy_Lotus

Probationary Member
13
2
Oct 12, 2020
Puyallup, Washington
Assuming the pistons arnt destroyed, If I were in your position, I would pop off the oil pan and give it a very through inspection for bearing material. If you dont see anything, I would reassemble the motor and immediately do a leak down/compression test. Verify the rings are good. If all checks out, start it up. The only reason I can think of for continuously jumping timing is someone that doesn't know how to set timing.

We will definitely need new pistons so I will have to wait on those. I think you are probably right and the guy who had it before me didn't know how to set the timing properly. Looking at the gears and tensioners more last night they also look pretty old. Might have something to do with it.

There are two hydraulic tensioners available for the 2g which depends on your cars built date. It’s on your vin tag on the door jam. I recent did a timing belt and the PO had the tensioner pulley on backwards which mean that they obviously didn’t set the tension correctly. This caused the timing belt to have a lot of slack on the idler side which can easily cause it to jump timing.

As long as the crank, oil pump sprocket, front balancer sprocket and cams rotate, and the tension is set correctly, it shouldn't jump timing.

I did not know about the two different tensioners. I'll check my vin and make sure I get the right one thanks so much!

Like the previous guy was saying, take of the oil pan/strainer and look for any bearing material. Anything that looks out of place and check for excessive crank shaft play side to side. If the motor checks out, then I would replace gaskets, oil pump, timing components ect and then do arp headstuds. The timing tensioner is kinda tricky to set, and if not set with the specific tool, it could jump timing. Once you get it all back together, run it and see. Also I would recommend doing a more conservative tune or going down to a 16g turbo.

Is this going to be the correct tool I need? https://www.extremepsi.com/store/Extreme-PSI-Timing-Belt-Tensioner-Tool-4G63T-DSM-and-EVO.html
Definitely more conservative tune and also probably a smaller turbo. This is going to be my first fully built car and I'm not going for anything extreme. I really want reliability over more power.
 

TK's9d2TSi

Supporting Member
4,686
1,950
Sep 11, 2017
Cincinnati, Ohio
It’s by the production date. You’d want to make sure it’s the original block. Go to post#9

https://www.dsmtuners.com/threads/decoding-engine-block-numbers.384520/

D762F2B6-1ECD-43B2-A60A-40219BE6178B.jpeg
 

95FullSend99

Proven Member
329
173
Dec 3, 2019
ledyard, Connecticut
We will definitely need new pistons so I will have to wait on those. I think you are probably right and the guy who had it before me didn't know how to set the timing properly. Looking at the gears and tensioners more last night they also look pretty old. Might have something to do with it.



I did not know about the two different tensioners. I'll check my vin and make sure I get the right one thanks so much!



Is this going to be the correct tool I need? https://www.extremepsi.com/store/Extreme-PSI-Timing-Belt-Tensioner-Tool-4G63T-DSM-and-EVO.html
Definitely more conservative tune and also probably a smaller turbo. This is going to be my first fully built car and I'm not going for anything extreme. I really want reliability over more power.
You will need the timing tool set. There are 3. And if your pistons are destroyed then you should commit to a full rebuild. Just my opinion.
 

John Miller

Proven Member
168
62
Jan 27, 2020
Watertown, Wisconsin
We will definitely need new pistons so I will have to wait on those. I think you are probably right and the guy who had it before me didn't know how to set the timing properly. Looking at the gears and tensioners more last night they also look pretty old. Might have something to do with it.



I did not know about the two different tensioners. I'll check my vin and make sure I get the right one thanks so much!



Is this going to be the correct tool I need? https://www.extremepsi.com/store/Extreme-PSI-Timing-Belt-Tensioner-Tool-4G63T-DSM-and-EVO.html
Definitely more conservative tune and also probably a smaller turbo. This is going to be my first fully built car and I'm not going for anything extreme. I really want reliability over more power.
That is correct, it basically threads in from the side to put tension on the tensioner until the grenade pin can be moved freely.
 

Muddy_Lotus

Probationary Member
13
2
Oct 12, 2020
Puyallup, Washington
You will need the timing tool set. There are 3. And if your pistons are destroyed then you should commit to a full rebuild. Just my opinion.

I don't know what defines destroyed. They definitely made contact with the valves. I say this because I once bought a mini cooper that was straight missing piston 3. She was gone, Smashed to smithereens in the oil pan kind of destroyed.

I hear ya, but honestly I will probably be replacing almost everything else in this car because it is really old, bad or plain missing. Brand new head assembly everything brand new for timing. All my external components. Fuel pump, water pump oil pump radiator turbo new tubing possibly a new harness transmission clutch etc. All of these internals are supposed to be forged. If they are good and I can reuse them I would really like too. I suppose I wont really know until I open it up this weekend and see what I'm looking at though.
 

95FullSend99

Proven Member
329
173
Dec 3, 2019
ledyard, Connecticut
I don't know what defines destroyed. They definitely made contact with the valves. I say this because I once bought a mini cooper that was straight missing piston 3. She was gone, Smashed to smithereens in the oil pan kind of destroyed.

I hear ya, but honestly I will probably be replacing almost everything else in this car because it is really old, bad or plain missing. Brand new head assembly everything brand new for timing. All my external components. Fuel pump, water pump oil pump radiator turbo new tubing possibly a new harness transmission clutch etc. All of these internals are supposed to be forged. If they are good and I can reuse them I would really like too. I suppose I wont really know until I open it up this weekend and see what I'm looking at though.
Throw up a photo of the top of the piston. I've deffinatly seen people grind some gouges down and it work for them.
 

DSMPT

DSM Wiseman
1,357
900
Jun 12, 2014
Japan / Mexico, Arizona
So I just picked up a 1996 Eclipse Gst. I ended up picking it up for only 700$ but this car is a little odd. For starters it only has 57K on the engine. According to the oil change sticker on the dash it's only put on 1000 miles since 2003. So it hasn't really ran much in the last twenty years.

According to the guy I bought it from once upon a time it had a huge turbo on it, was dynoed at 480HP and it still has a old nos setup in the car. He bought it two years ago and never really got it running. It kept jumping timing for whatever reason. Currently I can see into the long block since he was mid-rebuild and there is damage from valves on the top of the pistons.

I cannot decide if I should rebuild this block, since it only has 57K on it. Or do I buy a new rebuilt block? How likely is it that something wrong with the long block is causing the timing issue? Or is it more likely an external component?

Thanks for any help!
If I were you, for sure I would fully overhaul the engine. And I would rebuild properly. Have all components inspected and then replace/repair/recondition/line hone/hone or bore, if necessary. Yes it would cost some but I believe this would probably save your time and money in the future.
Most of time pistons would survive when you bend valves. but you can't be 100% sure about anything until you would physically inspect, which means, to make yourself 100% sure, you would need to disassemble the engine. And since the car has been sitting many years, plus you are not sure how the pre-previous and the previous owner had actually maintained the car. There are so many unknown factors that would cause issues.

Well it's just my opinion, because I don't like driving my car being worried about something from the previous owners.
 

1990TSIAWDTALON

Moderator
7,536
3,606
Nov 14, 2013
Independence, Kansas
I had this experience with all 16 valves. All made contact with the pistons so I disassembled a basically new motor to make SURE that the ring lands weren't compacted, making the rings stick in them. They were fine (all forged internals and Supertech Nitrided valves). The valves all bent flat to the pistons but no other (sigh...) damage. I pulled mine down to everything except the main bearings since it was only a 1000 miles old and all bearings looked almost new. I did it for piece of mind. Glad that I did so I don't wonder if something else was wrong, it is all back together now and awaiting my 3rd gear repair in my 5 speed and it will be going again.
I am hoping for the best for you! :thumb:
 

randman2011

Proven Member
383
167
Feb 26, 2012
Indianapolis, Indiana
When Volvo rebuilt my B5254T3 under warranty because of a failed timing belt, they elected to not replace the pistons even though they were damaged. I found this out last year when the timing belt broke AGAIN and I could clearly see both sets of dents from each event on the tops of the pistons. There were no rough edges that would cause hot spots. Just two distinct sets of dents for every valve. I elected to not touch the bottom end; new head, gaskets, and timing components and we've been driving the car for three months now. God, I hate this car.

When the timing belt broke in the DSM the damage was no worse than the Volvo but I seized the opportunity to bump up the compression ratio by going with aftermarket pistons. Plus rods, bearings, etc. That was definitely a good decision.
 

95FullSend99

Proven Member
329
173
Dec 3, 2019
ledyard, Connecticut
When Volvo rebuilt my B5254T3 under warranty because of a failed timing belt, they elected to not replace the pistons even though they were damaged. I found this out last year when the timing belt broke AGAIN and I could clearly see both sets of dents from each event on the tops of the pistons. There were no rough edges that would cause hot spots. Just two distinct sets of dents for every valve. I elected to not touch the bottom end; new head, gaskets, and timing components and we've been driving the car for three months now. God, I hate this car.

When the timing belt broke in the DSM the damage was no worse than the Volvo but I seized the opportunity to bump up the compression ratio by going with aftermarket pistons. Plus rods, bearings, etc. That was definitely a good decision.
I wish I bumped up my compression ratio when I had the opportunity
 

Muddy_Lotus

Probationary Member
13
2
Oct 12, 2020
Puyallup, Washington
If I were you, for sure I would fully overhaul the engine. And I would rebuild properly. Have all components inspected and then replace/repair/recondition/line hone/hone or bore, if necessary. Yes it would cost some but I believe this would probably save your time and money in the future.
Most of time pistons would survive when you bend valves. but you can't be 100% sure about anything until you would physically inspect, which means, to make yourself 100% sure, you would need to disassemble the engine. And since the car has been sitting many years, plus you are not sure how the pre-previous and the previous owner had actually maintained the car. There are so many unknown factors that would cause issues.

Well it's just my opinion, because I don't like driving my car being worried about something from the previous owners.

Yeah I think that's what I have decided to do. Replacing pistons for sure along with all rings and bearings. Having it honed and inspected at a shop. Only thing I am really hoping to be able to reuse is the crank and connecting rods.
 

Muddy_Lotus

Probationary Member
13
2
Oct 12, 2020
Puyallup, Washington
Do you guys have any recommendations for find a manual gst transmission? I've already looked on ebay craigslist fb marketplace etc. I also found a shop that sells rebuilt racing transmissions for a pretty penny. Are there any other sources? I'm trying not to have to pay more than like 1200$ if its possible but I may end up just having too if I cant find one cheaper.
 

Muddy_Lotus

Probationary Member
13
2
Oct 12, 2020
Puyallup, Washington
Throw up a photo of the top of the piston. I've deffinatly seen people grind some gouges down and it work for them.

Here’s those photos of the pistons.
 

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DSMPT

DSM Wiseman
1,357
900
Jun 12, 2014
Japan / Mexico, Arizona

Muddy_Lotus

Probationary Member
13
2
Oct 12, 2020
Puyallup, Washington
Most likely no problem with the pistons. but I agree that you are planning to inspect all parts, it is a good idea.
Check the link below. A similar case.
https://www.dsmtuners.com/threads/can-i-use-these-pistons.532075/
I agree ^^^

I'd run that all day long. I'd take each piston to TDC throw a bit of grease around the edge so shavings don't get down there and very carefully sand down any rough edges to prevent hot spots. Then send it.

According to the part number on these piston's it looks like these are the stock pistons though not forged pistons like I had thought. Does that look correct?

I swear I've never bought one of these car's that didn't leave me with a lot of unanswered questions. Supposedly this car used to run 30lbs of boost. That seems like a whole lot on stock internals.
 

95FullSend99

Proven Member
329
173
Dec 3, 2019
ledyard, Connecticut
According to the part number on these piston's it looks like these are the stock pistons though not forged pistons like I had thought. Does that look correct?

I swear I've never bought one of these car's that didn't leave me with a lot of unanswered questions. Supposedly this car used to run 30lbs of boost. That seems like a whole lot on stock internals.
Yes. Those are stock pistons. The stock bottom end can handle quite a bit. Its all about airflow and correct tuning. Stock 2g turbo at 30psi is very different than a bigger turbo at 30psi. If the guy was running 30psi on the stock turbo or even a 16g then I wouldn't be surprised. But, you could easily destroy an engine at 20 psi on a stock turbo if you dont know how to tune.
 

Muddy_Lotus

Probationary Member
13
2
Oct 12, 2020
Puyallup, Washington
Yes. Those are stock pistons. The stock bottom end can handle quite a bit. Its all about airflow and correct tuning. Stock 2g turbo at 30psi is very different than a bigger turbo at 30psi. If the guy was running 30psi on the stock turbo or even a 16g then I wouldn't be surprised. But, you could easily destroy an engine at 20 psi on a stock turbo if you dont know how to tune.

Ido what this turbo so but this is what used to be on it.
 

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