My motor has been destroyed....

[sheffester]

Well, I finally finished my build this summer. First few days driving the car with the new setup went amazing. Car was very fast. I was very impressed with my 20g. So, a few weeks go by, and I notice the performance getting worse and worse. By the time I got it inspected to drive it down to my house, I couldnt even boost. It would fall right on its face. Tested for boost leaks, no leaks. New plugs and wires didn't fix it. Fuel isn't an issue unless my filter is restricting my fuel flow because of my new pump. Checked timing, and I couldn't get base timing below 11 degrees. Drove it home from work that day, and thats when it happened. I'm going along and all of a sudden hear a snap and metal ringing around in the engine. I shut it off immediately. Pulled the valve cover and saw my rocker sitting in the head, and my lifter snapped. I pulled the head that night and found a snapped valve and a hole in my piston. Long story short, it destroyed my head to the point where I couldn't even remove the spark plug from that cylinder and I need a new bottom end now. The motor only had 500 miles on it. I'm lost as to what could have caused this. Regardless, I'm building a new engine. Am looking for suggestions on what to build, and how extreme to go with a 4k dollar budget. Just looking to bounce some ideas.

 

[92AWDHX40]

To make this easy what is your goal stock is fine for most, what 20g was it a real one? Also get the supporting mods for your set up, or future i would read upon the upgrade paths lots of information on it. So decide on your goal look at vendors for parts.

 

[sheffester]

My goal is 400 whp. Its a CX TD05-20g. And the only supporting mod I would possibly be lacking is in my transmission. My fuel setup is more than capable.

 

[CrawlinZX14]

Did you break in the motor before adding heavy boost at all? You know you need to break in a motor to seat everything properly and such before throwing big boost at it unless you have a really loose tolerance engine. Idea as to what happened would be one of a few things. Either valve guide was bad, or you rev'd it to high and floated a valve. Possibly broke a valve spring allowing the valve to come into contact with the piston crown pushing it up into the rocker breaking both. Just my thoughts on that without seeing pictures of what the carnage looked like after. You could have also detonated a cylinder too if you went lean, but thats doubtful.

 

[92AWDHX40]

Well get to looking at parts cx racing, i know its not a mhi turbo, i would get another mhi turbo, when you do your new build

http://www.dsmtuners.com/forums/new...ght-know-anything-about-cx-racing-turbos.html

 

[sheffester]

Yea, I know it isn't the best quality turbo, but for $300 for an entire kit, I couldn't beat it.

And when I removed it after 300 miles, it still has no shaft play, and seems to be holding up.

 

[92AWDHX40]

Yeah but a mhi 14b 16g, rebuilt will outlast the cx, while saving money, time, and possible damage to your engine if that thing grenades then youll be rebuilding another but thats another thread.

 

[9!'clipseDOHC]

It sure sounds like your timing belt slipped and jumped time. Who put the timing belt on? When you took the head off did you check to see if the marks were still lined up?

I have a similar power goal and when I built my block (over a year ago now) I went with wiseco 8.3:1 pistons on the stock 6 bolt rods. The rods are the weak link in my setup so with a $4000 budget (mine was half that) I would get a good set of rods too. If you still have the balance shafts, I would eliminate those.

I looked at your profile but it doesn't say what you are using to tune.

It also sounds like you were pushing the car pretty hard on the break in. You've got to be careful with that. My first 4G63t build only lasted 200 miles before the balance shafts spun, and I was pushing it hard. This go around I took my time with the break in. Stayed out of the boost, lots of easy miles, lots of oil changes for the first 500-1000 miles. Everyone has different ideas on how to do a break in but this one worked for me.

 

['97boostinGST]

Was your motor a stock rebuild?

With 4k, I would go all out and do a forged build.
That's just my .02.

 

[sheffester]

Yea. And yes I broke in the engine. I broke it in with less than stock boost. I didn't beat it. I drove it as I normally would all the time. And, I also know there are many ways to properly "break" an engine in. The motor had 150 miles on it before I put the 20g on.

Yes it was a stock reman unit from ATK engines in CA. And the timing belt came on the car. And before I started it this year, I checked the timing and it was spot on. I did not check before pulling the head. I was too frustrated after spending $200 on a tow and having to rip my head off in my driveway of a motor that only had 500 miles on it .

I have a donor block and head to use. I have a stroker crank as well that I will be using, provided it checks out at the machine shop. I will be going .020 over as well. I will be doing the head work myself with supervision from a guy that has some incredible knowledge

And as of right now, no tuning. Was just going conservative on everything.

 

[9!'clipseDOHC]

No tuning? How do you go conservative without the ability to tune?

 

[sheffester]

Touche. All I can say is low boost.

 

[MichaelSuch]

Easy break in, hard break in, it doesn't matter. If something wasn't done properly during the build it's going to let go regardless of the break in. It sounds like timing jumped though. I would want to find out why the failure happened before you build another engine so you can prevent it from happening again. Did you happen to check the timing marks before you pulled the head? Do you have any pictures?

 

[sheffester]

I do have pictures on my phone. And I did not check the timing before pulling the head.

I attached a picture.

 

[BogusSVO]

Doubt it was a time belt issue.
One valve lost its head, and they look like replacement valves, my best guess would be a cheap replacemeny valve of a 2 piece design. That is where the valve head is welded to the valve stem.
Stock mitsu 4G valves have 6t on the valve head.

If you look at the dish in each valve notice how it is unven from valve to valve and not centered.

ATK is a mass rebuilder and plays the odds game, hope you have all your paper work so you can warrenty refund the engine

 

[CrawlinZX14]

That right there screams valve spring broke or a retainer broke. Have you checked all your valve springs on that cylinder? Those valves came loose in there somewhere. Obviously its isolated to just that cylinder thus timing is likely not the issue. When my timing jumped on my GSX years back, I bent every valve in the head. That looks like a failure in the valve train. spring, retainer, lock, or as someone said, a poor valve itself.

May I suggest next time you get a motor, open it up and go back thru everything. I would rather spend 100 bux on a gasket set and know everything is assembled correctly then risk it. Personally I would also do ARP's and a MHG while im in there. But thats my own preference since I like to build for much more than I "need".

You can also replace valve springs and such without pulling the motor apart, it just takes a little effort. But pull a valve out of one of the good cylinders and see if it is the valve thats bad, or possibly weak springs.

 

[ExpresS]

Why waste cash when stock rebuilds are proven?

 

[mindset]

Sounds to me like ya didn't put oil in it.

 

[cyclonekid77]

Sounds to me like ya didn't put oil in it.

WTF

No oil would cause spun bearings and tossed rods. Not a dropped valve Valves ride in the guides dry all the time. Thats why you have valve seals... to keep the oil from going down the valves and burning....

 

[and1chewy]

when i broke mine in i drove it 2k miles and never took it over 5500 rmps until that time came. im on 4k miles and still no problems. I babied it.

 

[sheffester]

The engine is out of warranty sadly.

 

[TSIfreek]

Easy break in, hard break in, it doesn't matter. If something wasn't done properly during the build it's going to let go regardless of the break in. It sounds like timing jumped though. I would want to find out why the failure happened before you build another engine so you can prevent it from happening again. Did you happen to check the timing marks before you pulled the head? Do you have any pictures?

Exactly.

 

[CrawlinZX14]

Why waste cash when stock rebuilds are proven?

If that were the case, then we would not be discussing this thread......


Its all about the due dilligence.


No matter the place that rebuilds it, its still done by people pushing engines out. Meaning there are things that can get overlooked in the name of production speed. A valve spring that was tested properly can easily break and then BOOM, your head, piston and engine are TOAST.

also I asked about break in prior to seeing the picture of the head. Its obviously not a break in issue.

 

[dadnkid]

4k budget..... you can go pretty extreme and get something better than cx racing

 

[BogusSVO]

Valves ride in the guides dry all the time. Thats why you have valve seals... to keep the oil from going down the valves and burning....

You are close, the seals limit the amount of oil into the guide, you have to have some lube here to keep the guide from gaullding to the valve.