Bought a 1g tsi for 300 bucks has bent valves!

[1995gsxawd]

So i puled the head off and the pistons look like they are barely hit. My question is can i still use the pistons? Its a 90 talon tsi. Here are some pictures!

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[BogusSVO]

ok....

1) Rotate the pistions so all are mid stroke in the block

2) pour about an inch or so of oil on top of each piston, so all 4 have equall amounts

3) walk away for several hours, overnight

4) come back and check..

a) if all pistons still have appox the same amount of oil on top, the rings should be fine
b) if one piston or two have much less or no oil left on them, you have ring issues.


Others will pipe up and tell you how to de burr the pistons.

 

[Solace Lost]

Cant tell by the pic very well.. but is that the valve heads buried into your #1 cylinder?

 

[1995gsxawd]

ok....

1) Rotate the pistions so all are mid stroke in the block

2) pour about an inch or so of oil on top of each piston, so all 4 have equall amounts

3) walk away for several hours, overnight

4) come back and check..

a) if all pistons still have appox the same amount of oil on top, the rings should be fine
b) if one piston or two have much less or no oil left on them, you have ring issues.


Others will pipe up and tell you how to de burr the pistons.

Will do. Other than that the pistons are fine?

Cant tell by the pic very well.. but is that the valve heads buried into your #1 cylinder?

No thats just the reflection with the flash

 

[chadillac2820]

Well you're already half way there and you got a very small amount invested. I say go all out and bore that puppy, slam some Pistons and rods in that guy and build it up!

 

[BogusSVO]

You will have to deburr the pistons where the valves hit to remove any sharp edges.

A peice of sandpaper and some time is all it takes.

Avoid getting grit and trash down by the rings.

A quick search on bent valves/piston damage will give more in depth info on it.

 

[1995gsxawd]

Well you're already half way there and you got a very small amount invested. I say go all out and bore that puppy, slam some Pistons and rods in that guy and build it up!

Yeah you are right but I have no desire at the current moment to rip it all out. Nor do I have the funds ha ha ha. It did come with a small 16 g though! I'm. It sure if the injectors are stock or not. They dont appear to be

You will have to deburr the pistons where the valves hit to remove any sharp edges.

A peice of sandpaper and some time is all it takes.

Avoid getting grit and trash down by the rings.

A quick search on bent valves/piston damage will give more in depth info on it.

Will do sir. Thanks for your help! A shop vac and sandpaper!!

 

[Mr PopUps]

Having built quite a few engines, i will tell you NO. You have broken the coating and you WILL get hot spots that can ruin your fresh rebuild when you go crazy racing some Honduh or 350Z. Stock pistons are cheap enough (used is fine if they arent like yours) to not go ahead and replace them. You dont need to stroke/bore it at all either.

 

[90 Talon AWD]

same thing happened to me, mine looked identacle, took them to the machine shop an they said jusy de burr them, been running them ever since, that was 7k miles ago and still running flawless, at 25 psi with my 20g....just deburr them and reasemble!

 

[Spyderman7]

Drop the pan and get a torque wrench.NPR Rings and clevite rod bearings will run about 70.00.Its really not that much more work.
If you dont pull the piston and rods out and put some fresh rings and rod bearings in, it would be a waste of time to put a fresh head on IMO

 

[bryanwheat]

I don't see it being a waste at all if you check the rings by pouring oil in the cylinders. Thousands of people have gotten by with throwing a new head on and had much success. It will cost you the price of the head, top end gaskets, timing belt and components. IF there is a problem with the bottom end than the new head, timing belt and components will still be ready to use if you have to rebuild the bottom end.

 

[1995gsxawd]

Im not rebuilding the whole head. Im replacing the bent valves and lapping them. That is all. I will build at a later date. All this car has to do is run and drive good. Its not going to be my rce car just yet. It just has to keep the miles of my srt4.

 

[obsidian]

I concur with the deburr and go statements.

If it blows up later then at least you've had time to save money. The only downside I see to this is if these pistons explode under high pressure/load then you could destroy the block in the process.

In the end it is your choice and no one elses. You should be fine.

 

[bryanwheat]

Im not rebuilding the whole head. Im replacing the bent valves and lapping them. That is all. I will build at a later date. All this car has to do is run and drive good. Its not going to be my rce car just yet. It just has to keep the miles of my srt4.

IF you have bent valves you will have cracked guides. IF the guide is cracked it needs to be replaced. After the guide is replaced the seat will need to be re-cut to get it concentric with the guide. It's more work than just installing new valves and lapping them. I would recommend buying a known good working head and clean it up, lap the valves and install new valve seals in it.

 

[BogusSVO]

IF you have bent valves you will have cracked guides. IF the guide is cracked it needs to be replaced. After the guide is replaced the seat will need to be re-cut to get it concentric with the guide. It's more work than just installing new valves and lapping them. I would recommend buying a known good working head and clean it up, lap the valves and install new valve seals in it.

THIS is spot on ^^^^^^

OP some reading for you.

http://www.dsmtuners.com/forums/newbie-forum/341218-how-change-valve-guides-4g63t-head.html


http://www.dsmtuners.com/forums/cylinder-head-short-block/420045-how-have-4g63-head-rebuilt.html

 

[BogusSVO]

Having built quite a few engines, i will tell you NO. You have broken the coating and you WILL get hot spots that can ruin your fresh rebuild when you go crazy racing some Honduh or 350Z. Stock pistons are cheap enough (used is fine if they arent like yours) to not go ahead and replace them. You dont need to stroke/bore it at all either.

What coating?

 

[bryanwheat]

What coating?

That's what i was thinking.

 

[HaydenGSXdude]

I had the same problem. One piston had been touched by the valves so I just got a used OEM piston and put in along with a whole new set of rings/ bearings on all four. Worked out good so far. Just figure out what your budget is, make a plan and stick to it.

 

[Addicted]

How do the valve guides look? That's how I got my car, free with bent valves. Fortunately nothing other than the valves were damaged. You can order the valve spring compressors from amazon for 35-50 bucks. Its the only place I could find compressors that fit down in the head. Has been running fantastic for over a year now of 15 psi on the T25

 

[Mr PopUps]

What coating?

Youre supposed to be on my ignore list.

That's what i was thinking.

Ill have to find the 'proof' of it. I dont remember if it was a factory warning or something the Talon Digest found out about. This means crawling manually over dsm.org through the Way Back Machine.