DOHC 4 cyl head & piston replacement.

[Uber]

Hey, I was talking to someone who stated that the timing belt on his 4G63 engine (DOHC 4 cylinder) broke and now the engine requires the replacement of his cylinder head and pistons. Apparently the impact was enough to break the exhaust valve in one of the cylinder and the other 3 pistons are scuffed up as well.

Does anyone here have any experience with that engine configuration? What do you think the odds are that there might additional engine damage be possible from a broken timing belt? How much trouble is it to replace the pistons and cylinder head unit on a 4G63?

Thanks in advance.

[theskineater]

There is more than can be wrong...Just gotta look around since youll have the engine apart anyway.

Its really not hard to change out all that.

It should just be the valves though that need changing, and whatever pistons got hit possibly.
Hopefully theres no wall damage or anything.

I just took my engine apart, and am starting to put it back together. Still waiting on some parts to come in though.. If ya need some help let me know and Ill do what I can.

[fastenuf]

if you have had a timing belt break on a 4g63 and you have bent and broken valves, chances are you also damaged the valve guides. Usually people just replace the valves and end up with a smoking car and dont know why.. if you are going to rebuild a head, dont do the bare minimum to get by, you will end up spending more money or more time than if you would would of done it right in the first place..if you would like some more details give me a call on monday 309-788-DYNO ask for trent..

[Uber]

Thanks for the advice guys. The guy said that the valve had snapped off and apparently rattled around in there a bit. I was thinking that it would make more sense to find another cylinder head unit rather than repair, but I haven't seen them for sale. It looks like the going price for forged pistons is about $450 per set after shipping and that jazz. I haven't seen it myself, the guy I'm talking to is selling his TSi. Trying to figure if it's a good buy.

[speedy6963]

uber said:

Thanks for the advice guys. The guy said that the valve had snapped off and apparently rattled around in there a bit. I was thinking that it would make more sense to find another cylinder head unit rather than repair, but I haven't seen them for sale. It looks like the going price for forged pistons is about $450 per set after shipping and that jazz. I haven't seen it myself, the guy I'm talking to is selling his TSi. Trying to figure if it's a good buy.

I have a good used 4g63 head for sale, has aftermarket valves and crower springs and retianers, $500 or best offer

John Cozad

[xeiros]

Changing out your head isn't hard, but it will be time consuming. You'll have to take off your timing belt (which takes time because you have to take all the shields off the side as well as your AC and Alternator pulleys), then you'll have to take off both manifolds, and clear all the other shit out of the way as well (misc hoses and what not).

The pistons and such are more difficult and time consuming. It's generally recommended you have the engine out of the car (which makes it loads easier) but you dont HAVE to.

BTW, did this happen on the car you're thinking about buying? Is it a Black First Gen TSi AWD? I've seen that car before. Not bad looking, but it would need some work. Wouldn't pay more than $800 for it myself though.

[Uber]

Yeah, it is a Black TSi AWD; a '92 specifically. It's a little dinged up and the clearcoat isn't much to write home about, but has potential if I want to put the time and money into it.

While we're on the subject, is there any way to tell if a 4G63 motor is a 6 bolt or a 7 bolt while it's in the car?

[theskineater]

Go to dsmtuners.com

They have heads for sale for under 100 on there..... Just look around.


And ya, if your doing a complete job just take the engine out. Its not hard to do. I got mine out in a weekend by myself. First time ever pulling a motor. Besides, it sucks ass to work within the 2 inches they leave for you on the side of the engine youd be needing to get at.

[xeiros]

If it's a 92, you've got a 6 bolt. 93 was when Mitsu switched to 7 bolt.

And yes, I agree, it's a decent starting point if you've got the time, money and patience to do it. You're already starting out with a better bottom end, throttle body, and turbo (just to name a few) than us 2G'ers.

[theskineater]

Uh, no...92's can be 7-bolt also. They switched mid year.

Look at your oil pan to tell....

[xeiros]

Oops, he's right. It was mid 92 they switched. I'm pretty sure that car you're looking at was a 6 bolt though, as I looked at it myself a while ago.

[Sukkoi19]

Are you contemplating a new car Dave?

[red96GT]

You may have to replace your pistons, and depending on the absolute worst case it could do damage to the rods/crank/block, but that would be very very severe(and unlikely).

But to answer your question, most likely just the head would need to be replaced.

P.S. Smooth out the top of the piston so there are no high spots.

[speedy6963]

uber said:

Thanks for the advice guys. The guy said that the valve had snapped off and apparently rattled around in there a bit. I was thinking that it would make more sense to find another cylinder head unit rather than repair, but I haven't seen them for sale. It looks like the going price for forged pistons is about $450 per set after shipping and that jazz. I haven't seen it myself, the guy I'm talking to is selling his TSi. Trying to figure if it's a good buy.

If you are in need of a motor I do have a complete rebuild 4g63 ( auto rons rebuilt it, has about 3000 miles on it ) 1500 or best offer, message me on here for more information

[Uber]

sukkoi19 said:

Are you contemplating a new car Dave?

Just thinking about what the options are. I feel like having a sporty car again, but I want to go a little more lean and efficient this time. Ideally this would be a rear wheel drive turboed 4 cyl with a manual tranny, but there aren't too many of those.

P.S. - After posting this, I thought how besides a Grand National or Supra, nobody really gives props to 6 cylinders.... then I was thinking back to that 9 Sec GN-converted Geo Metro video I posted a couple years ago. Maybe that's what I need.

[Uber]

Thanks guitarpnk99, xeiros and theskineater for your input. That makes sense, I guess having a look at it is the only way to get a good idea what kind of condition the motor is in.

speedy6963 - Thanks, I'll have to keep that in mind, it might make some sense to do that as well.

[Sukkoi19]

I agree man, but most F/I 4s don't return that much better mileage then N/A V8s. Hell I was getting around 18 mpg after the Kurgan tune around town. Not too bad. In any case theres all that added complexity with turbo systems to be considered.

Look into MR2s if you are interested in RWD turbo 4s. They are a mid-engine to boot.

cgi.ebay.com/ebaymotors/CA-no-rust-cold-AC-low-86K-mile-clean-No-Reserve_W0QQitemZ140072676721QQihZ004QQcategoryZ15289QQrdZ1QQcmdZViewItem

[spoolin24]

uber said:

P.S. - After posting this, I thought how besides a Grand National or Supra, nobody really gives props to 6 cylinders.... then I was thinking back to that 9 Sec GN-converted Geo Metro video I posted a couple years ago. Maybe that's what I need.

Don't forget the Skyline's RB26, and 300zx VQ30 That Geo Metro is awesome. I remember seeing him once last year, he almost went into the wall. The car is so small that when he lost control. The car went completly side ways, and back, just barely crossing the centerline.


Happy huntings

[Sukkoi19]

2.3l turbo Ford! That would be a fun motor. Decent aftermarket, good power, don't see a ton of them, and RWD. I have a block, crank and head in my garage if you are interested.

Jesse

[xeiros]

Makes no difference what you go with, really. If you want something a bit simplier (in terms of help and what not) going with a DSM isn't a bad idea. They've been around long enough, and have had a hardcore enough following that just about anything you can think of (problem wise and modification wise) has been explored. On the other hand, if you're looking for originality, you'd best be suited elsewhere.

I personally went the DSM route because I loved'd these cars since their inception...not to mention being able to get 400WHP out of a 4cyl's stock internals doesn't hurt either.