Timing Belt Broke Today :(

[c2ypt1c]

Well, it finally happened...belt snapped right in half while cruising. Here's a little back story on it. A week ago the crank sensor died on me while driving, so I threw in a 1g cas and it worked great...until now.

From what I can tell, I think a chunk of the old sensor took out the bs belt which took out the timing belt. First thing I did was take the valve cover off to check the rockers. I was able to wiggle a few, so I'm pretty sure I bent some valves. Also, I'm concerned that the crank may have walked given the crank sensor is chewed up

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Looks like I have some decent work ahead...couldn't have come at a worse time. In hind sight, I probably should have taken out the crank sensor, inspected the damage, and removed any debris...lesson learned (the hard way).

Anyway, anyone have any suggestions/thoughts? How would you go about it? I really don't want to take it to a machinist. I'm hoping the valve guides aren't cracked and then thinking of throwing some new (lapped) valves and beefy springs in it and call it done.

 

[biglady112]

Broken timing belt+stock head=broken iron valve guides and bent valves. No getting around it.

 

[Miasma]

I'd delete the bs' when rebuilding it. The balance shaft belt can lead to a lot of problems, as you are experiencing. So I wouldn't take the chance with it a second time.

 

[kenuwine4g63]

If you do keep the bs, use a Kevlar belt (gates) and the timing belt as well. They don't really break very strong

 

[c2ypt1c]

Broken timing belt+stock head=broken iron valve guides and bent valves. No getting around it.

Damn, that really sucks...might just pick up a used head then, or I might just install new guides myself. Thanks for the heads up.

If you do keep the bs, use a Kevlar belt (gates) and the timing belt as well. They don't really break very strong

Yeah, I plan to remove the bshafts and I'll be using a Gates timing belt for sure.

 

[BogusSVO]

Yes BigLady is correct. I will agree on the cracked guides and bent valves.

You can change the guides with some special tools, but the seats will need to be cut (lapping will not work) to index the guide centerline to the seat.

http://www.dsmtuners.com/forums/newbie-forum/341218-how-change-valve-guides-4g63t-head.html

 

[Roberti 2G]

Sorry to hear the bad news man. I am running the Gates belts on my car still have BS. I am actually going to inspect everything once I get home since ive been away from the car and just did the timing job about a year ago now. Good luck man.

 

[DSM_ThuNDeR]

I would check for crank play just due to the fact the crank sensor stopped working unexpectedly, then this happened.

 

[c2ypt1c]

I would check for crank play just due to the fact the crank sensor stopped working unexpectedly, then this happened.

Yup, this is what concerns me most of all. If it did walk, I'll be looking into a 6bolt swap at some point.

 

[BogusSVO]

Simple enough to check.

Quick check

Push with all you have towards the clutch, then pull towards you.

If it has "clunk" it is done.

If it barely moves, then get a dial indicator on it and measure by the text book

spec is .003-.010

 

[Joethefallen23]

Quick suggestion if you do plan on using a Kevlar belt: use the OEM Evo IX belt. Part number 1145A038. It's Kevlar reinforced from the factory and far cheaper than the Gates and HKS belts. Only difference is it's uncolored. Still even had the same funky smell to boot.

 

[c2ypt1c]

Well, I have some semi-good news. Crank play measured only .0035 (low end of spec!), so I'm very happy she hasn't walked

Hey Bogus, is it recommened to replace all vavles and guides or can I just replace those that are bent (and maybe lap all the others, just for good measure)? From what I can tell, I only have two bent valves, and I wouldn't mind taking the opportunity to use the saved money to install stiffer springs (BC perhaps)...

 

[BogusSVO]

No issue with just fixing whats broken.

Pull the cams and do a quick fluid test to confirm you only need valves.

http://www.dsmtuners.com/forums/newbie-forum/420313-how-fluid-test-4g63-cylinder-head.html

 

[c2ypt1c]

No issue with just fixing whats broken.

Pull the cams and do a quick fluid test to confirm you only need valves.

http://www.dsmtuners.com/forums/newbie-forum/420313-how-fluid-test-4g63-cylinder-head.html

Will do. You're the man! Thanks for the help.

 

[BogusSVO]

Post up some pics of the head once you have it off.

 

[c2ypt1c]

Took the head out over the weekend. Sorry for the crappy cell phone pics...

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valves need to be cleaned:

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The pistons have some damage to the tops:
piston 1

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piston 2

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piston 3

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piston 4

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Pistons 3 and 4 are the worst, but all show signs of valve contact. Which makes me think all valves are shot.

I'm able to turn the crank smoothly and the cylinder walls look pretty good. Should I be concerned about the rod bearings?

Also, is it possible to salvage the pistons?

 

[BogusSVO]

That is common, some oil, a file or sand paper or a small grind stone on a die grinder will fix that.

If you search for "bent valve" or "dinged pistons" you will find the same basic info over and over again.

Looks like new intake valves, and intake guides will be needed, along with a valve job and surface.

 

[c2ypt1c]

Well I'm happy to report that the head rebuild and timing job was a success. Everything went pretty smooth. Here's the run down on what I did:
- brought head to local machine shop
- ended up bending 9 valves which were replaced + new guides
- head was cleaned and resurfaced
- oil port mod
- installed bc springs and stem seals
- felpro head gasket
- replaced crank and oil pump seals
- replaced all relevant gaskets with felpro
- arp head studs (torqued to 85 ft/lbs)
- rear balance shaft delete
- gates racing belt and water pump
- new tensioner
- egr, vacuum line, and fps delete
- I'd like to mention that the felpro oil pan gasket is bad ass (no more scraping rtv)
- most parts were ordered from rock auto, so I think they deserve a shout out
- and thanks to Dale (BogusSVO) for helping me out on the side!

Tension and timing is spot on (not bad for not using any "special tools"), not one leak, and compression is 180 across the board. Car runs cooler and she even sounds meaner (springs?).

To top it off, it's my birthday! I could not have given myself a better birthday present!!

 

[Bud92gsx]

I Was expenting ALOT more damage..Looks like u got lucky as hell.

 

[BogusSVO]

Please tell me that is NOT the front case/oil pump you have installed in your car!

 

[c2ypt1c]

Please tell me that is NOT the front case/oil pump you have installed in your car!

I cleaned it up after I took that pic. Made it spotless, new gasket, and packed the oil pump with grease. Unless you're talking about something else?

 

[BogusSVO]

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You did not see how chewed up that pump casting is??? WTF

Get that front case pump off, before you trash the engine!

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Look at those two, and I junked both of them.

Look over page 4 of this thread, and you will see how chewed up yours is.

http://www.dsmtuners.com/forums/newbie-forum/466655-balance-shaft-removal-engine-still-car-4.html

 

[c2ypt1c]

I'm pretty sure it is grease from the gears sticking to it. I did some test fitting prior to taking the photo. It's black assembly lube but it does look like shadows in the pic.

 

[Jermoturbo]

Whats up with your oil pump gear housing cover? In the pic it looks like the gear was grinding up against the housing cover. Maybe its just the way the pic was taken?

 

[c2ypt1c]

Yeah it's the black assembly lube/grease that I used from test fitting it. I would've immediately noticed and shit my pants if it was chewed up like that.