Blown Engine / Part 2

[HaLo]

Yesterday, I opened up the valve cover for inspectiong part one. I took many pictures, but I will post some tonight...

For people that did not know, I blew the engine about 1 week ago, 0 compression on 3 cylinder

Cyl 1-2-4 are completely dry (upon inspection)
Cyl 3 is humid.
Oil level is perfect, even after 50km drive
Prestone level is perfect
Valve, springs, rockers are all in place, seem Ok (new) upon inspection
Same goes for cams.

Now here is the catch. I put the main crank at 0 BDTC...
Both Silver marked links are in place... But Sprokets dots are about 120 degres ADVANCED... My timing chain had to jump a lot of teeths... Apart from a faulty tensionner, what could do this?

Could that explain my no compression, the car running bad and my broken sparkplugs?

and why the hell would a timing chain jump so many teeths, espacially if the teeths all seem nice with no wear?...

[usctom]

well if it jumped that many teeth the valves would be bent to and cause you to have zero compresion. I kind of had a similar problem but more my fault witht the timing chain. I replaced the head then found out after that my rings in three were bad and had rod knock.

[HaLo]

if engine is 120 degree off timed, compression is fucked for sure... think about it... valves are closed when piston is completely down or almost. Compression will be off by a lot.

I don't have any blow-by, and I insist that I did not burn any oil. So, somehow, the rings have to be ok.

No knocking sound, no metallic sounds.

[Steeles]

fix the chain put it back together and see what she dies :)

[HaLo]

I should try that... would be funny the car working properly... just a real pita to do... :(

[Steeles]

yeah but beats being without it for a long time and really whats it gonna hurt at this point?

[HaLo]

True... But I have already put my car in storage (insurance and registration)... Plus, I found another seat for my last 2 events... I have already ordered some bearings for my new engine... I am really going for 9.5:1. But I will still try to put the chain back on where it's supposed to be.
;)

[orion::S14]

Crank it around again, and it'll be 80 degrees retarded...

And again, and it'll be 60 degrees advanced...

And again, and it'll be 20 retarded, etc...

It takes a LONG time to get it all in just the right place...many, many rotations.

And a timing chain in most Nissan RWD motors CANNOT jump teeth.

I've done enough KA cams swaps to know that it sucks to get the gears marks to line up with the right link on the chain at the same time it's at TDC.

If you're chain jumped a tooth...well, then it'll be the first time I've ever heard of that happening on an SR or KA.

I'd still bet you detonated...why the hell else did the spark plugs look like that?

Next time you get a chance, turn the motor some more and line it back up after a few rotations, and it'll still be off, but in a weird, new way.

Then keep turning until you get it set and all lined up.

Let us know the results.

- Brian

[HaLo]

Crank it around again, and it'll be 80 degrees retarded...

And again, and it'll be 60 degrees advanced...

And again, and it'll be 20 retarded, etc...

It takes a LONG time to get it all in just the right place...many, many rotations.

And a timing chain in most Nissan RWD motors CANNOT jump teeth.

I've done enough KA cams swaps to know that it sucks to get the gears marks to line up with the right link on the chain at the same time it's at TDC.

If you're chain jumped a tooth...well, then it'll be the first time I've ever heard of that happening on an SR or KA.

I'd still bet you detonated...why the hell else did the spark plugs look like that?

Next time you get a chance, turn the motor some more and line it back up after a few rotations, and it'll still be off, but in a weird, new way.

Then keep turning until you get it set and all lined up.

Let us know the results.

- Brian

I did 6 full rotations of the chain and the this is the closest I've gotten:

http://www.apaspeed.com/oktay/head/IMG_0470.JPG

http://www.apaspeed.com/oktay/head/IMG_0510.JPG

http://www.apaspeed.com/oktay/head/IMG_0511.jpg

Here are some more pics
Valve cover off:
http://www.apaspeed.com/oktay/head/IMG_0448.jpg

http://www.apaspeed.com/oktay/head/IMG_0449.jpg

#1: intake
http://www.apaspeed.com/oktay/head/IMG_0450.jpg

#2: intake
http://www.apaspeed.com/oktay/head/IMG_0451.jpg

#3: intake
http://www.apaspeed.com/oktay/head/IMG_0452.jpg

#4: intake
http://www.apaspeed.com/oktay/head/IMG_0453.jpg

#1: exhaust
http://www.apaspeed.com/oktay/head/IMG_0455.JPG

#2: exhaust
http://www.apaspeed.com/oktay/head/IMG_0457.jpg

#3: exhaust
http://www.apaspeed.com/oktay/head/IMG_0458.JPG

#4: exhaust
http://www.apaspeed.com/oktay/head/IMG_0459.JPG

[orion::S14]

Keep going...

I know, it sucks...but you'll get there.

Unlike Supras or VWs with timing belts, it's near impossible for a timing chain to jump a tooth unless you loose all oil pressure. Even then it's hard to move the chain around with everything in place.

I've spent so much time of my life doing this exact thing...hours I wish I could have back! But my left arm gets a great workout in the process!

- Brian

[wootwoot]

hey now, dont say that about vw's and their timing chains, they fail repeatidly. the chain tensioners wear through and the chain has enough slack to eventually skip a tooth or two and then byebye valves.

[RBS14]

I'm confused, what does cranking it over and over do? lines what up with what?

[orion::S14]

...dont say that about vw's and their timing chains...


I didn't...I said "timing belt" for one, and I was also saying that they do skip teeth.

I've had a GTI with a 2.0 8V die like that with only 2 days before I had to take it on a 800 mile road trip...got new timing belt + tensioner, new head, new HG and studs, slapped it back together, and drove the piss out of it for 3 days straight...hehe. But that's off topic...sorry.

- - - - -

RBS14 -

Eventually, lots of turnng will get the darker links to line up with the dots on the cam gears while you're at TDC. That's the way to check everything is still timed correctly (and the way you reinstall everything properly).

- Brian

[wootwoot]

ai..... you can hit me if you want

[HaLo]

how many turn do you usually do?

I did 6 today, a few last monday...

[orion::S14]

...you can hit me if you want

Yeah...that road trip I was talking about with the VW...that was to South Florida. I'll bring my ass down there again, smack you around, and return promptly to my hurricane-ravaged corner of the state. You'll hear a knock at your door in 4hrs or so...answer it, be prepared for the beat-down, and come back here and cry to all of Zilvia how you got hit by "orion".

Biatch.

Hehehehe...j/k.

[orion::S14]

how many turn do you usually do?

Dunno...it's a-fucking-lot. Probably +20...

Not fun, but it'll get there.

Just keep turning, watch for the important links to come around, and stop when you get it.

Or just give up and know that there's a 99.997% chance the chain did not skip, and you just detonated badly.

Use the energy that would've been spent turning that motor on kicking your tuner's ass. ^^^ Or come down here and join me in hitting that "wootwoot" guy...hehe.

- Brian

[TokyoNights]

Yeah its almost impossible to have the chain skip like that..btw on my previous sr I tried turning the crank to make shure the marks line up and after like 10 rotations it still didnt..

[HaLo]

ok guys, you convinced me... i'll take the head off. :)

[fliprayzin240sx]

How sure are you off the TDC and points being off??? I hope u didnt just look at the marks on the pulley and ASSUME that its at TDC. *dont mean sound to be a dick but just wanna be sure* Cuz ive had people put back an engine and say screw the marks on the chain. they just made sure its definitely at TDC *stick a socket extension down #1 and make it raise all the way up* and line up the cams at 10 and 12 oclock respectively.

[The Riot Hero]

broken plugs? hmm sur eyou didnt detonate enough to bust a plug and end up with it jammed holding your exhaust valve open or something? the ceramics can easily score the block enough to need to be bored. pull the head off.

[HaLo]

I have another bloc to build... that one, if damage, will be for sale, CHEAP. :)