Timing belt slipped

[Turbo Shogun]

The piston made contact with the #1 cylinder spark plug and now the crank won't turn over. I think the spark plug threads on the #1 cylinder have been stripped as well.

Any idea as to the extent of the damage? I think I just bent a rod, warped the head, bent valves and possibly screwed the crankshaft over. I know the motor's going to have to be pulled for this ...

It happened when I was looking for a leak that coated my timing belt with oil. I had forgotten to place the crankshaft pulley bolt in and the timing belt slipped off the cog.

I'll post pics later. Right now I need to cool off ...

Any help is greatly appreciated.

 

[DSMcrazy3]

What do you mean it hit the spark plug? I don't see how that's possible really. I'm assuming you meant to say the piston hit a valve, in which case the only way to tell the extent of the damage is to take the engine apart and do some measuring.

Sorry to hear

 

[GTM]

The piston made contact with the #1 cylinder spark plug and now the crank won't turn over. I think the spark plug threads on the #1 cylinder have been stripped as well.

Any idea as to the extent of the damage? I think I just bent a rod, warped the head, bent valves and possibly screwed the crankshaft over. I know the motor's going to have to be pulled for this ...

It happened when I was looking for a leak that coated my timing belt with oil. I had forgotten to place the crankshaft pulley bolt in and the timing belt slipped off the cog.

I'll post pics later. Right now I need to cool off ...

Any help is greatly appreciated.

I doubt the piston hit the spark plug unless it broke, more likely a valve head broke off and has locked the engine up. Since you have notheing to loose you can try rotating the engine backwards (CCW) with a large ratchet or breaker bar. That failing top gear and rolling backwards a foot or so, that failing remove the starter and use a prybar on the ring gear teeth.

Did you remove the #1 plug, again nothing to loose for the head quite possibly is history. The crank could be bent along with a rod and of course piston. The block however could be just fine or could have some massive scoring. And like the crank the cam(s) could be bent.

Sorry to read this. You can start by pulling the head, cleaning the block mating surface so you can eat off it and then Xing with straight edge to check for warpage. It would be best to dial indacate as well as use feeler gage to measure piston height for this will be your first clue whether the crank is bad.

Let us know what you find.

Cheers,
GTM

 

[Turbo Shogun]

Thanks guys, for the sincere and informative replies thus far.

I'm in the process of taking the engine apart (once again ). What I found so far was that the spark plug that came from the #1 cylinder came out absolutely annihilated. I also spotted a large gash on the piston surface, along with the ceramic insulators and the electrode of the spark plug inside. I was wondering myself, how the piston could have hit the sparkplug, but you could be right, GTM. At least, that's the only possible way that makes sense.

The motor does turn CCW, but it stops there as well. I should have the entire thing apart by the end of the week.

I hate to think I'm pretty much going to need a new motor ... What's ironic is that yesterday I was reading up on similar horror stories and thinking to myself, "man, that really sucks". Well, there goes the 2006 Road Racing/Auto-X season.

 

[GTM]

Thanks guys, for the sincere and informative replies thus far.

how the piston could have hit the sparkplug, but you could be right, GTM. At least, that's the only possible way that makes sense.
...

Aw c'mon, give me a little more credit than that. There is no way in he*l for this to happen with a dished piston and the combustion chamber is also concave with the plug at the top.

Are you saying you can rotate the engine at least 300 degrees? Because if you can't you have other valves fouling so don't force anything. If you can get it to 90 degrees either way from TDC then all pistons will be level and you can pop the cam followers out and not bend any more valves. Use a 14mm(?) open end wrench, place small block of wood next to the hydraulic adjuster and pry them off the pivot to the side. This way you don't bump pistons and valves. You may have to rock the crank back and forth to get them off the lobe max lift. With all the cam followers out and the engine at TDC you can try to do a halfarsed leak down to see if you have any compression or wiped out all the valves. It's hard to say what is salvageable until you pull it down. You might be able to insert a dowell or screwdriver in #1 to flip the valve head into a more favorable location that will allow the engine to rotate.

Cheers,
GTM

 

[Turbo Shogun]

Well, here's what I found. Haven't been able to post 'cause of the forum downtime, though.

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I've already decided I need a new head. The rod seems alright. Lucky this happened around idle ... As you can see from the pic, it reached TDC. I've already got a set of 2G pistons waiting to go in, but I need to send my rods out to the machine shop first.

 

[jott5555]

looks like you broke a vave, there is really no way for the pistion to hit the plug its umm impossiable unless you put way long plugs in and then it wouldnt have started period..

 

[GTM]

Well, here's what I found. Haven't been able to post 'cause of the forum downtime, though.

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I've already decided I need a new head. The rod seems alright. Lucky this happened around idle ... As you can see from the pic, it reached TDC. I've already got a set of 2G pistons waiting to go in, but I need to send my rods out to the machine shop first.

I take it that you then did not put a straight edge across the block and measure the actual deck height of each piston. Failing to have done this may find you have a bent crank unless you are sending it out for checking. You can of course check it with new pistons when the rods return for it too has to be suspect.

Cheers,
GTM

 

[prostreetdsmx1]

ouch. sorry to see it bro. build it bigger and better and enjoy it. best of luck bro.

 

[Turbo Shogun]

I take it that you then did not put a straight edge across the block and measure the actual deck height of each piston. Failing to have done this may find you have a bent crank unless you are sending it out for checking. You can of course check it with new pistons when the rods return for it too has to be suspect.

Cheers,
GTM

I do have a straightedge, I just eyeballed it, though. I discussed the bent crank theory with my dad and we got into an argument again (He's SAE Certified,and was a Union monkey back when the UPS strike happened in '94 or something ... Anyway, he thinks he knows better and swears up and down that the motor's fine)!

I'm gonna have the rods checked for straightness at the machine shop when they drill out/narrow the pin ends for the 2G Pistons I got. So hopefully things fall in my favor ... I'll check it all again when I get the rods back and the pistons on. Your advice is duly noted, GTM.

And thanks, Marti. I plan to do a little Corvette hunting at the local road course when this is all over!

I'm having a hard time finding wrist pins/bearings and piston rings for the 2G pistons. I used to order from Spartan Mitsubishi, but they no longer do mail-orders, and the Conicelli site doesn't work. Anyone know a good place?

 

[GTM]

I do have a straightedge, I just eyeballed it, though. I discussed the bent crank theory with my dad and we got into an argument again (He's SAE Certified,and was a Union monkey back when the UPS strike happened in '94 or something ... Anyway, he thinks he knows better and swears up and down that the motor's fine)!

I'm gonna have the rods checked for straightness at the machine shop when they drill out/narrow the pin ends for the 2G Pistons I got. So hopefully things fall in my favor ... I'll check it all again when I get the rods back and the pistons on. Your advice is duly noted, GTM.
...
and the Conicelli site doesn't work. Anyone know a good place?

Far be it from me to cause an argument between father and son. You are welcome to ask any questions about my profile which doesn't include any union membership. I don't know what SAE Certified means... perhaps you meant NIASE> ASE?).

There are others on this site who _have_ bent cranks with a lot less damage than I saw in your picts. Realize that .020" will probably drop your compression by 1 full ratio point. Your SCCA handbook may have this information. For the 20-30 minutes it will take to check them all it's in your best interest to do so.
....................

I don't understand the problems you are having with parts? A good automotive machine shop should be able to make and fit the bushings and supply the pins and rings. I am surprised the pistons didn't come with the pins?? Was it an open set??

Are you planning on racing this?

Cheers,
GTM

 

[Turbo Shogun]

Nope, I got the 2G pistons on their rods still, so yeah, the pins are there.

And yeah, I meant ASE. Whoops. ... I wanted to go into technical school after high school, but parents wouldn't have it, so now I'm going into law school next year. So unfortunately I have to rely on my father who thinks everything on the internet is a farce (he keeps asking me where I get my advice from let's just say he's not a supporter of this site). This has to be the 100000000th time we've argued over what to do with the damn car.

I'm just trying to be cautious and take everything into consideration and so far you guys have been very helpful (especially you, GTM). But I digress ...

Yes, I have been and still plan on competing in auto-x and time attacks around the chicagoland area this year, so I just wanna get things straightened out and hit the tarmac ASAP!!!!

Would any irregularities in a compression test show a bent crank?

 

[Talonman92]

Dang that looks bad compareds to when my timing belt broke...

I was going about 35mph when my timing belt broke on me. Tryed to start the car afterwords thinking it was something else... When we take apart the head we found a few valves layin bent on top of the pistons . Not nearly that kind of damge to the pistons and your valves are completely trashed. Mine just broke off and bent. Come to think of it this ###### explains why after about 5-10k miles after this episode, and crashing into a lightpole, my car spins a rod bearing!

 

[gsx-box]

That is some ugly damage. I have some bent valves in my VR4 (low compression in two cylinders) and I am dreading pulling the head but I have a 2.4 crank to toss in so I don't need to worry about my crank. Measure the distance from the deck ecach pistion is at at TDC. It is chaep insurance and if it checks out you can do a rebuild w/o pulling the trans.

 

[steve]

I'm having a hard time finding wrist pins/bearings and piston rings for the 2G pistons. I used to order from Spartan Mitsubishi, but they no longer do mail-orders, and the Conicelli site doesn't work. Anyone know a good place?

Conicelli is now JNZ Tuning http://www.jnztuning.com/
I also use Rockville Mitsubishi http://www.mitsupartsdirect.com/
Some people have had good luck with Mentor Mitsubishi but I've never used them. http://www.trademotion.com/partlocator/index.cfm?siteid=213934
It's not too hard to convince the local dealers to provide you with whatever their shop discount rate is if you buy enough stuff. Biggers gives me their normal 15% when I use them.

Steve

 

[Turbo Shogun]

I actually ordered a few parts from SubaruPartsPeople.com (got a non-running '92 Subaru SVX ... Never thought I'd come across a car with more tranny problems than a DSM), and their prices were pretty good. Apparently they sell Mitsubishi parts, too.

Thanks for the links!

As of now I'm a bit torn about the 2G piston/1G rod combo. I talked to Mitch today at EngineTecs and he said it would weaken the pin end rod because of the overboring, and for the price ($200 + 150 for reconditioning) he said it wasn't worth it. Can anyone please share their thoughts on this?

So now I may just go and order one used 1G piston and call it a day with the bottom end. That is, provided my crank checks out okay ...

 

[GTM]

That is some ugly damage.
...
Measure the distance from the deck ecach pistion is at at TDC. It is chaep insurance and if it checks out you can do a rebuild w/o pulling the trans.

Yup, 'em a good'un.

.................

Sorry, while you are correct in identifying a basic procedure to do the job right only requires a nominal more knowledge.

It is critical to identify ABSOLUTE TDC, this you "aint't not finding in any repairs manual no where. Essentially 3 degrees BTDC and ATDC will all look the same but you are looking for shades of gray which are quite measurable with a conventional .001" dial gauge. Important is marking the pully or flywheel either side of an assumed TDC with fingernail polish. If you are really serious or preparing a race engine you will use a degree wheel

You put the dial indicator anywhere on the piston, when the dial stops moving you make a mark, you continue again until it starts moving again and then make a mark. You then take samples from other pistons and record their positions. You now have gathered enough info to make an intelegent guess by splitting the difference where TDC is for each Cylr. While the straight edge is used for normal measurements when all is clean this is about as close as it comes to KNOWING your own Crank.

Any questions.

Cheers,
GTM

 

[Turbo Shogun]

Yup. I kinda figured the procedure went like that.

Luckily my dad runs a turf/farm equipment repair shop, so I have access to some tools, among them a straight-edge with a dial gauge in the middle. So I'll be using that when the time comes.

But I still have questions about the 1G/2G pistons as per my previous post ...

 

[GTM]

...
among them a straight-edge with a dial gauge in the middle. So I'll be using that when the time comes.

But I still have questions about the 1G/2G pistons as per my previous post ...

You touch that and if your father doesn't kill you I will. That's a depth micrometer and not the proper tool. Forgive the outburst but you need a magnetic base and then a dial indicator. I don't want you to spend the money if it's going to sit on the shelf and gather dust but you can buy those 2 pieces for under $35 from Harbor Freight.

My apologies, there are site sponsors who may have them at attractive prices so check them also.

Don't panic, it's just familiarity, the dial goes around and produces numbers. I swear it's a 10 minute learning curve once you grasp the concept. Because I always think in binary it's 0's and 1's... (joke)

......................

I'm the wrong person to ask about 1g 2g pistons. Perhaps if we understood your question again others could help.

Hey, get away from my tool box.

Cheers,
GTM

 

[GTM]

...
I wanted to go into technical school after high school, but parents wouldn't have it, so now I'm going into law school next year.
...
Would any irregularities in a compression test show a bent crank?

Hooray for you, do your under grad in math for it's the best teacher of logic and reason. Let me know when you get to advanced lattice theory.

When you get your degree you can hire those of us who could not argue the value of 0.

While I may be just as cynical as your dad he can contact me off list and we can discuss the problems at hand. I didn't get to be a Wiseman because I'm a BS artist, I rarely ever suggest anyone spend money for parts or tools. When I suggest a course of action it is with the least amount of time which is a very precious part of a persons life.

Chances are it takes more time to solidify ideas and to write them out than to actually perform tests Always conditional logic will prevail when understanding has been achieved. You can't change a tire without a jack, you can't get a jack without opening the trunk etc. Granted these are easy dichotomies but there are those of us who did manage to not fall off the turnip wagon or contradict Darwinian theory.

Cheers,
GTM

 

[Turbo Shogun]

Hahahaha, I was always bad at math. Ever since 4th grade. English has always been my forte, but if I'd been any better I would have gone into mechanical engineering (a friend's taking a course at the University of Illinois and he's building a race car for a project ). My SAT Math score was less than half of my english/verbal (I managed to score an 800, stroke of luck, the next time I took it I had a 775 verbal score, but I did pull up my math up)!

Anywho ...

Hm. I think we have something like that laying around in the shop, but I'll have to check (I only work during holidays and summer vacation). Is that anything like the tool they use to check crankshaft endplay in the shop manuals (flexy-neck section thing with a dial indicator at the end of it)? If not, $35 isn't all that bad. I can write it off as an "educational expense" and reach into my scholarship.

What I meant by my question about 1G/2G pistons is, will machining (overboring) the pin-end of the 1G rod significantly reduce the strength of the rod at the pin end enough to make it unsafe for use? I'd especially like to hear some input from people who've done this.

Thanks again in advance!

 

[GTM]

Hahahaha, I was always bad at math. Ever since 4th grade. English has always been my forte, but if I'd been any better I would have gone into mechanical engineering (a friend's taking a course at the University of Illinois and he's building a race car for a project ). My SAT Math score was less than half of my english/verbal (I managed to score an 800, stroke of luck, the next time I took it I had a 775 verbal score, but I did pull up my math up)!
...
Is that anything like the tool they use to check crankshaft endplay in the shop manuals (flexy-neck section thing with a dial indicator at the end of it)? If not, $35 isn't all that bad. I can write it off as an "educational expense" and reach into my scholarship.

What I meant by my question about 1G/2G pistons is, will machining (overboring) the pin-end of the 1G rod significantly reduce the strength of the rod at the pin end enough to make it unsafe for use? I'd especially like to hear some input from people who've done this.

Thanks again in advance!

It would be worth your while to investigate math programs even in the adult education programs which are held in the evening at public schools. Some are for credits and some may not. Just like Junior / Community colleges they offer the biggest bang for the buck in the US!!!! $26 / per unit compared to $2,800+ my son is paying for being in one of the top 8 conservatories in the world.
........

There are several college/universities that participate in a particular formula car consturction which is then raced. I see nothing wrong with the programs when so many automotive engineering students have little hands-on experience.
............

Yes, yes, yes, the goose-neck will work just fine. You can buy just the rigid rod and screw it in to the base if you suspect the goose neck is flexing. Your dad may have this as well as other dial gauges which are lever rather than plunger operated. These may only measure in .0001" or .001" but will be limited to .050 trave which is just fine for this application. I prefer the lever when dialing a cam profile but a simple roller attachment can change this. You will get even better results if you use the flywheel ring gear to rotate the crank rather than the front crank pulley.

..................

Might I suggest you start a new thread for the piston pin issue in the advanced technical forum if it's available to you. You won't be dealing with so many novices which can muddle a thread. Limit the scope so you get the info and objective replies you need. I don't want to open what could be a can of worms here but will be happy to monitor that thread. Because it requires a lot of specific knowledge unique to DSMs and in some cases, modifications I don't spend a lot of time there.

Cheers,
GTM