Time for rebuild!!

[Derek'sTalon]

SO, ok, ... I ran with (and SMOKED) a 6-cylinder, old style Z24. Afterwards, I stopped to talk to the guy (He almost passed out when he found out I was runnin 4 cylinders! ), and left my car runnin' to cool a bit. We chatted for like, 20 mins, then I rolled home (another 20 mins) at slow, easy speeds (50-65 mph) to further cool her off. Arrived home and parked her for the nite. The NEXT day, I went to jump in and go to work, and my motor went!!! I haven't got all the specifics of what happened exactly, but ALL 4 pistons have smacked the valves, and I can pull the rockers out by hand!!!! I am looking at a major rebuld here!! 220K (roughly 135k miles on her), and not many easy ones, so I'm not mad, just wanna know what happened!! Oil has been blasted out of her, but the guy I ran with saw nothing (and he WAS behind me the whole time! !) I have done very few mods to her, but am toying with the idea of adding some nice parts to her engine. I will elaborate once I know the full extent of the dammage!! ANYONE ELSE have ANYTHING like this happen to them?? oh, yeah, just so you know just HOW bad the situation is, I can blow air down one cylinder, and it blows back out of ALL OF THEM!!! ANY help or input would be GREATLY appreciated!!!

 

[awdrst]

Sounds like your timing belt has slipped causing the valves to bend. I would pull off the head clean up the block see how the pistons look, if they are in good shape send the head to the machine shop. Get them to clean up the head, make sure its flat and replace the valves. Toss it on the block with a new mitsu composite head gasket with some arp studs and be done. Or you can pull the motor and build it up but that will cost alittle bit more money.

 

[notracing]

Just to clarify, was it a Z24 or a Z28? Z24 was a cavalier and Z28 was a camaro.

As for you question, did you remove the head yet? If you take the head off you can get a better look at the valves, pistons, and cylinder walls. However at 220K if you want to make it faster you may want to plan on doing either a full rebuild or better a replacement.

 

[Derek'sTalon]

It was a Z24, I know, I know, JUST a Cavalier but, still... HE started it!! ! ... Valves look shot.... I am sending her to a machine shop for a full evaluation,... I'll keep you posted on the results when I get 'em. Thanks for the help guys!

 

[pimpngear]

Just a quick question, but what was your Rpm’s for your 1-2 and 2-3 shift. I would assume pretty high if they caused the t-belt to jump a tooth or two...

Was the t-belt still attached to the motor before you pulled her apart, or was it dangling on the side in a fit of great defeat? If so....maybe you threw a balance shaft belt.

At any rate... Check out the piston domes for any hairline cracks or similar damage...if the valves smacked in them too hard, you might not want to re-use them.
-Rob

 

[Derek'sTalon]

Ok, motor LOOKED fine! All belts in place, nothing hanging anywhere, nothing broken (at least, to the eye!). Motor is now out, and in the hands of a professional. I am to sit down with him and plan the build this Friday, so I can then find out what he's learned from tearing her down. I will post all the dammage, in hopes of triggering any ideas as to what may have happened, if I don't know by then. Also, and on a more hopeful note, I will post the build plan!! Won't be TOO extravagant, but at least it will be some POSITIVE news. ! Thanks to all you DSMers for all the help and info, eh!

 

[Derek'sTalon]

Ok, so here's what I've got planned...lemme know if you see any glaring omissions or if you have any recommendations.... Stage 1 Stroker Kit (JAM); Crower Cams (Stage 2); Adjustable Cam gears (Anyone have a recommendation as to the brand?); injectors (was thinking Greddy 660cc); external wastegate (any suggestions?); fuel pressure regulator (again, any suggestion?); end clutch kit, and likely get the balance shaft eliminated..... What do you think?? What have I missed?? ANY help would be appreciated, you guys are the BEST resource I have access too! MANY Thanks for all the help so far, and the opinions to come!

 

[DsMWookie]

I believe your motor would be strangled by the lack of supporting mods.



Look into getting a 2.5-3" exhaust
Some kind of intercooler (preferably a FMIC kit)(i like sbr's for reference)
larger turbo ......20g sounds good for you
injectors fuel injector clinic 550-650-750
fuel management - dsmlink
HKS or forced perfomance cams



I would lean towards a 2.0 bottom end for you or shell out the change and get the supporting mods for a stroker.

 

[Injected]

1. Was the timing belt changed at the 60,000mi interval (120,000mi)? I'm very curious as to who actually gets the second belt change done. My car is at 45,000mi and I have at least two to look forward to if I don't blow this one up first.

2. If you are going to put the time and money into a rebuild, now would be a good time for a 6 bolt swap of some sort. If you want the extra displacement, choose a 2.4L hybrid (64/CS).

Remember, do it right, or do it twice. And if it isn't your daily driver, or if you can find another transport, now would also be a great time to build your engine yourself and learn a sh*t-load of things about them, save a LOT of money, and get more parts since you are saving so much. The real risk you run is becoming either addicted to this kind of work and not being able to not modify all of your cars, or become sick of it and never want to do it again (but keep the knowledge as part of this generous offer, we'll even cover the cost of shipping).

 

[Derek'sTalon]

All indications are that it was the balance shaft that caused my <POP!> . So, I'm thinking of Eliminating it. ANY pros/cons? I know of the increased vibration, but how MUCH does it increase? Any horrid side effects that anyone has ACTUALLY had? Any substantial noticed gains? I can't thank you all enough for all the helpful info! Keep it coming and maybe, just maybe, I can answer someone ELSE's question for a change, eh? !

 

[DsMWookie]

I haven't noticed any real vibration but now Im on a new rebuilt motor to and shits all balanced. But beforehand I didn't notice it. Make sure the bearings actually didn't get chucked otherwise the balance shaft may have beat up the block.

 

[Derek'sTalon]

Ok, after sorting thru all the info I could digest, and realizing (once again!) that this IS my daily driver, I have DRASTICALLY altered the build plan!!! I have leaned toward reliability with a little extra horsepower....here are the parts that I have got ordered : HKS cam (264in/272ex); Evo III 16g turbo (ported); Greddy FMIC (the smaller one, ...HOPING I can keep the running lights!); 255L fuel pump; Eagle rods; Weisco pistons (and accessories); 1g BoV; balance shaft eliminator; and 650 cc injectors.....Let me know if you see anything else I NEED , PLEASE!!! I am looking at oil pumps as well, just haven't got it sorted oot yet, eh! You guys have ALL been GREAT!! Thanks a (metric!) tonne, eh! !

 

[Derek'sTalon]

Ok! I KNOW it's been AWHILE, but I've got her back, and have posted the mods in my profile!! I COULDN'T have done this withoot all the help you guys gave me!!! THANKS SOoo Much, eh! ... small side note, maybe from sitting for so long, but my power steering pump is really 'groaning'..may have to replace it if a bleed doesn't stop the sound...! ALWAYS something, eh!? Anyway, THANKS AGAIN to you ALL!!! Special thanks to CanadianTsi for all your help! Please check my profile and feel free to hit me with any hints, tips, comments or questions, eh!