Switchtr3

So I registered my Z yesterday with the plan of daily driving it. It's currently my only registered vehicle. I guess the last time I had the engine apart I rushed it and forgot to torque the cam gear bolt which backed off after a few hundred miles while I was driving and it basically went bang.

Should I just get a new engine or can I get away with pulling this one apart and replacing the two valves that probably got mashed? I've got another engine laying on the side of my shed that is no good, but I can take the valves out of it at least, although I doubt that's the only damage. Does anyone know what actually would have gotten broken?

WildmaN

I would think if you smashed a couple of valves. That your pistons could be messed up also. I wouldn't half **** it. I would say, take off your cylinder head, and see what it looks like inside the engine. Then you can determine what you need to do. I would say, you would probably have to rebuild or replace the engine. But not until you see how it is inside. Good luck.

NismoPick

^^^ Yup... if it mashed the valves, the pistons probably have holes in them if they are flat tops.

vg30_s12

Ok, noob minuet,
Slipped timing on a chain driven motor? Iv been around cars for sometime, but how does that happen? And arent l28 chains double chained like the fj20 and ka24de?

NismoPick

^^^ First post...

Switchtr3

Yeah, pretty much the main thing wrong with this engine that allowed it to slip- the guy who touched it last.

And yeah that's exactly what I was fearing. Some dents/ gouges on the pistons I can live with for now (until I have to switch to lower compression over the winter...) but holes in the piston not so much. I'll update you on the carnage once I get in there and see what's really up for myself.

WanganDevilZ

Depending on how long it takes me to get my turbo build finished, I may have some flat-top pistons available, I also have some dished available too, however, they will not have rods, just the piston

Switchtr3

Okay so just an update.

I got the head off and it looks like only one of the pistons got tagged really good. There's a nice little divot in it but no hole or crack. 4 of them tapped the valve but barely even made a mark and the valves seem to be straight, there's really not even a mark on the valve where it got hit and seems to sit well in the head. I'm just going to change the one bent valve for now and keep the same pistons. At least this should get me back on the road fairly quick and hold me over till I do the turbo swap.

Also after looking at it more it is apparent that I did not forget to torque the bolt but the big lock washer was not there... heh oops. I'm gonna double check the f*ck out of everything this time.

vg30_s12

dunno how much it would cost but see if someone could pressure check it, would hate to tear down again after no compression cause the valve was off the seat by a lil bit

Switchtr3

Eh, I would hate that very much as well but i've really got no time or money. I'd just do the turbo swap now if I had the time and money but I need this car back on the road asap to look for work. I also have a 2-2.5 hour drive (about 125 miles) crossing two state lines that I need to make on the 13th (yep in two weeks), and I'd like to not have to drive my unregistered truck down there. Halfassed? yes. Does the thought of that make me cringe? you bet. But can I afford to care at this point? I guess not. As long as it runs well enough to be relied upon I don't mind if it's not perfect. I did check them in the dark putting a flashlight through the port and looking for light around the valves, the other ones seem fine except that one



Also, unrelated but I noticed it last time I had the head off and seeing it again reminded me- most of my pistons are stamped with a die and some read 34 while the others read 45. Anyone know what that means? Does this hold any relevance at all? Is it normal that they don't match/ are those numbers even factory?

Oh and while I'm at it- are the headbolts TTY on the L28e or can I re-use them?

.