turning crankshaft with timing belt off - 6-bolt

[pgt1996]

To all,

I am reading up about changing the timing belt on my 6-bolt motor and had a question concerning the crankshaft moving while trying to loosen the cranshaft pulley bolt. I imagine the crankshaft is going to move (from past experience on changing timing belts on non-interference motors) when I either bump the starter to loosen this bolt, or use a strap wrench to loosen this bolt, but the timing belt change procedure on the vfaq site warns against the crankshaft moving with the timing belt off. (http://www.vfaq.com/mods/timingbelt-1G.html) If all of the valves are closed at this point in time, and the timing belt off, what would be the problem with turning the crankshaft clockwise, or even counterclockwise to re-align my timing mark? Any help would be greatly appreciated. Thank you,

-Tim

 

[1badtsi]

just dont do it safe>sorry

 

[NOSLO2PT0]

Problem with bumping the crankshaft is that you lose your TDC setting. Big deal. Set the motor back to TDC and all is back to normal. As for the crank actually turning, don't let it turn counter-clockwise. This isn't good for the bearings.

 

[pgt1996]

Originally posted by NOSLO2PT0
Problem with bumping the crankshaft is that you lose your TDC setting. Big deal. Set the motor back to TDC and all is back to normal. As for the crank actually turning, don't let it turn counter-clockwise. This isn't good for the bearings.

Thanks, guess I can spin clockwise till marks realign, making sure too that balance shaft is in correct position.

 

[GTM]

Originally posted by pgt1996
Thanks, guess I can spin clockwise till marks realign, making sure too that balance shaft is in correct position.

YOU CANNOT ROTATE CRANKSHAFT WITH BELT OFF!!!!!!!

Put the car in 5th gear if 5 speed and set the brake and chock wheels then you can break the bolt loose.

Please check before you take ANY person's advice on any site you visit. Some of these replies are going to get you in bad trouble.

I'll be happy to explain other choices and dispel urban legends from people who know less than you.

Cheers,
GTM

 

[pgt1996]

Ok,

I understand now why its not a good thing to do, (turn w/o timing belt) I got another response from our local DSM club, I was basing the possibility of turning the cranshaft w/o the timing belt from the following from widely accepted vfaq procedure...

"Make SURE the camshaft sprocket timing marks are still lined up - this makes sure all valves are closed. If the marks are not lined up, some valves could be open, and the following procedure could bend valves.
Put a 1/2" breaker bar in the end of the crank sprocket bolt
Place the bar up against the axle (to the rear of the axle)
Remove the MPI fuse (near the battery) so the car won't start
Place your foot on the breaker bar, pressing it into the crank bolt, so the downward slant of the axle doesn't throw the breaker bar out and break the breaker bar (TRUST me on this, it can happen)
Bump the starter (very quickly, it only takes a split-second)"

Note the first sentence "Make SURE the camshaft sprocket timing marks are still lined up - this makes sure all valves are closed"

This tells me ALL valves are closed, but apparently this is not true since, quoting from my friend here, "They (vfaq) mean TDC on number one, because that is TDC on compression
stoke for that cylinder. So all four valves are closed. BUTTTTTT
this motor has an equal firing order, so somewhere in the motor,
valves lie open. Use caution!

Originally posted by GTM
YOU CANNOT ROTATE CRANKSHAFT WITH BELT OFF!!!!!!!

Put the car in 5th gear if 5 speed and set the brake and chock wheels then you can break the bolt loose.

Please check before you take ANY person's advice on any site you visit. Some of these replies are going to get you in bad trouble.

I'll be happy to explain other choices and dispel urban legends from people who know less than you.

Cheers,
GTM

 

[GTM]

Originally posted by pgt1996
Ok,
...
I understand now why its not a good thing to do, (turn w/o timing belt)
...
Use caution!

When TDC #1 firing, #4 is on the rock... meaning the exhaust is closing and the intake is opening with their respective cam overlaps.

I have not tested to see how many cogs either cam can be off before it fouls a piston.

If you set the timing mark at 9:00 all 4 pistons will be level in the block and you can remove ALL the cam followers which will then NEVER foul a valve because they are all closed. You can remove any cam follower when the lobe is pointing up for that cylr. Again you will make no mistakes this way. If the belt is off you can remove the cam towers and lift the cam up if you can't pop the followers out.

So just because #4 is on the rock, #3 is opening and #2 is closing so if you are off on your cam setting by 1 cog these also can foul.

Just be careful, fully understand, tripple check, argue with yourself that you are right. If you have any doubts pull the followers or release the cam bearings.

No mistakes.

Cheers,
GTM

 

[BISHILVR]

ok, heres the deal bro' ..... when the cams are installed in the head, there will always be at least one or more valves that are not completely shut period!!.....if you turn the crankshaft over and make the pistons move up and down and the cams are not in time (phase) with the moving pistons, you can easily and unknowingly bend a (some) valve(s)...really it's just that simple....now if you are an experienced mechanic you will realize that there is a certain amount you can safely move the crankshaft with the belts off and not do any damage (maybe a few teeth either way)...so if your talking about a few degrees of movement then you'll be fine just make sure that you put everything back in time before trying to start the engine. besides it's highly unlikely that you would bend any valves just using a basic ratchet on the end of the crank pully without using a pretty big breaker bar on the ratchet since the valves are hardened steel, you would know if you put that much force on the valves that you were screwing something up!!

 

[GTM]

Originally posted by BISHILVR

...
besides it's highly unlikely that you would bend any valves just using a basic ratchet on the end of the crank pully
...

You can bend these valves with a standard drive 3/8" rachet. I'm not talking about the severity you see when the belt breaks but enough so you will have "0" compression. The problems is overcoming the friction of a resting engine can be enough to foul the valves and tweak them without doing severe damage.

If he has a friend stand on the brakes in 5th gear he can use a breaker bar for there is no possibility of the cank rotating except a few degrees to take up all the windup in the power train. If he is going to use the starter then he had damn well have those cam followers out of there, reinstall the belt, or remove the cam bearing caps so no valve can open. In the length of time it took to write this he could have had all the followers out. He doesn't need to flirt with disaster when an extra 10 min will completely remove the possibility.

He's backed himself in a corner by removing the belt before breaking the crank pulley loose and now he has to recover from that mistake.

Cheers,
GTM

 

[BISHILVR]

yep...in the future dude try not to remove the t-belt until it's the only thing left to do.....best thing you can do right now is use an air impact on the bolt...totally safe and easy (quick)

 

[pgt1996]

Originally posted by BISHILVR
yep...in the future dude try not to remove the t-belt until it's the only thing left to do.....best thing you can do right now is use an air impact on the bolt...totally safe and easy (quick)

Actually, I haven't even bought the parts yet, I am doing the research and reading the timing belt changing procedure BEFORE I dig in. I have had some experience changing timing belts on non-interference motors in the past, they are not so particular. Just wanted to make sure what I do is right, the first time. Thanks for all the responses.

 

[pgt1996]

One more thing....

Seems to me that the widely accepted vfaq procedure on timing belt
changes might need a revision for morons like me.

The following steps:

"Make SURE the camshaft sprocket timing marks are still lined up - this makes
sure all valves are closed. If the marks are not lined up, some valves could be
open, and the following procedure could bend valves.
* Put a 1/2" breaker bar in the end of the crank sprocket bolt
* Place the bar up against the axle (to the rear of the axle)
* Remove the MPI fuse (near the battery) so the car won't start
* Place your foot on the breaker bar, pressing it into the crank bolt, so the
downward slant of the axle doesn't throw the breaker bar out and break the
breaker bar (TRUST me on this, it can happen)
* Bump the starter (very quickly, it only takes a split-second)"

come AFTER step 13, "Remove and discard the camshaft timing belt".

The way the first sentence is written seems to indicate that the belt would be
off when loosening the crank sprocket bolt, since you go to the trouble of
lining up the timing marks on the camshafts, and that ALL valves are closed on
ALL cylinders. If this is not the case, it should read otherwise since bumping
the starter "very quickly" is subjective, and without the timing belt could
cause much damage. Just my $.02.

 

[GTM]

Originally posted by BISHILVR
yep...in the future dude try not to remove the t-belt until it's the only thing left to do.....best thing you can do right now is use an air impact on the bolt...totally safe and easy (quick)

I don't know if you are following my posts on this board but don't keep tossing out things which are not always going to work.

It is not true that an _impact_ wrench is the best nor safe method. I looked at your profile and is said mechanic then you should know that there is yet another tool which engages the starter ring gear and locks it into a non rotating position for both auto trans and stick so the crank cannot be rotated. I don't know too many people who have air compressors at home much less impact wrenches and related tools but they too can cause the crank to rotate backwards.

What what I have described will alway work.

Cheers,
GTM

 

[GTM]

Originally posted by pgt1996
One more thing....

Seems to me that the widely accepted vfaq procedure on timing belt
changes might need a revision for morons like me.
...
Just my $.02.

You have to remember that in many cases these are written by non professionals and who's experience may be quite limited. From what I see there are a lot of people who think these will substitute for a manual or are so simplified that they give a false sense of security in performing some task and they get in over their head which results in disaster.

Your approach was wise in asking before you leap, the unfortunate part is you have received info from some who are not qualified to give answers but you don't know who is who. Yes, those Vfaqs do need to be re-written / improved upon. The fact you have found flaws is a siqn you have a good grasp on the subject along with the potential problems ahead.

Since you have not started then the breaker bar and the starter can be used as well as the 5th gear on a stick.

Is your car an auto or stick?

The most important tool which will not be in your tool box will be the tensioner eccentric which you can buy or make.

I saw some company offering the belt kit with bearings and belts for $110 which isn't such a bad deal. The water pump may be a prudent investment for my son deciede to cut corners and 6 mo later it started leaking presumably because the new belt put additional strain on the seal. ??

When were you considering this adventure.

Cheers,
GTM

 

[Morphius]

Originally posted by GTM
If he has a friend stand on the brakes in 5th gear he can use a breaker bar for there is no possibility of the cank rotating except a few degrees to take up all the windup in the power train

What type of clutch are you running? Because I've got a ACT2600 on my 90 and I've NEVER been able to use the reistance of the powertrain to break that damm bolt loose. Never on any other car I've worked on either for that matter.

Here is the method I use that works every time:
Pull the lower flywheel cover off the bottom of the trans. Looking at the lower lip of the bell housing you'll notice what looks like a notch or trough cut in the bell that runs length wise in the tranny. Push a 3/8 or bigger screwdriver in that slot. It's located near the slave on a manual. Near the t/case on an auto.

See the pics below. Auto.

 

[Morphius]

Here's the manual.

 

[Morphius]

Originally posted by NOSLO2PT0
As for the crank actually turning, don't let it turn counter-clockwise. This isn't good for the bearings.

Since when? Explain this.

 

[pgt1996]

Originally posted by GTM

Is your car an auto or stick?.........

When were you considering this adventure.

Cheers,
GTM

5 speed, I plan on starting as soon as I can round up the parts, most likely start the weekend after this weekend (1/11). $110, good price for belts and tensioners, although they may not be OEM parts, and well, lets not get into that one. I am sure Gates (or whatever) belts "meet or exceed all manufacuturer specifications", but, posts on this site are making me lean more towards the OEM parts, simply based on personal experiences.

 

[Morphius]

Originally posted by GTM
YOU CANNOT ROTATE CRANKSHAFT WITH BELT OFF!!!!!!!

I hate to argue with a wiseman, but I disgree. You can rotate the engine with the belt off. Or in my case the crank rotating independant of the cams. Rightly, I still wouldn't recommend it. But it can be done.

Here's the low down. My RWD project car before I stripped it. I picked that car up not running. A quick scan of the ECU showed no faults. It was getting fuel and spark and yet it wouldn't start. All the while it had a strong cranking sound. No indication of a bad belt. At this point I pulled the timing covers off to find that the belt had chewed the teeth off right at the crank. The cams had stopped exactly where they need to be for timing them. I had cranked that engine over NUMEROUS times in attempts to start it. So, I changed the belt. And started it. It ran fine. Compression was 155+ across the board. No dinged valves.

If I recall, two cylinders have valves just starting to open with the cams timed at TDC. Given the dish of the head, I don't think the valves stick below the surface of the head. Yet. The pistons come up just flush with the deck of the block. So, I could see how they would not touch if the crank is rotated.

I've got an extra rebuilt head here, I'll have to check tommarrow to verify how much those two cylinders valves are open.

 

[BUCK]

Put a 1/2 Breaker Bar in the Crank Bolt - push it up against something solid (NOT YOUR FREAKING HAND) & hit the starter with the Timing Belt ON!

If you've screwed up & took the Timing Belt off - or it popped, ETC... Buy a pair of those Welder Vice Grips - they are kinda like Ice Tongs - Very handy for lots of things - Remove the T/belt & clamp them on in a position where they will bear against something solid - They fit great in the Cogs of the Crank Pulley & will hold it as you break the Nut - an Impact COULD spin the crank just as easily as a wrench so I still would want something holding the Crank Sprcket just to be safe...

I too had the EXACT same experience as Morph - no bent vavles - knocked the tan carbon off the edge of one - I was BLESSED with some old pistons that had obviously lost out in a few Valve Battles & had "extra big" valve reliefs - but no bent vavles - I was just damn lucky - don't do it.

At some point in the TiMinig Belt Install the Manual actually tells you to rotate the crank a little bit counter clockwise but then somewhere else tells you not to do it ???

Congrats to GTM on a well deserved promotion... but I think for some Viscous Coupling reason or something his method doesn't work for me either - I have done that on every OTHER Freaking car I owned - but this IS a DSM of course...

 

[GTM]

Originally posted by Morphius
Since when? Explain this.

Please, let's not go there, all you are doing is inviting more wrong information.
.............

If you couldn't break the bolt loose in 5th gear with a stock clutch I'd guess you were using 1st gear. This won't work because you have more torque advantage by virtue of the gear ratio which will overpower the brakes.

Depending on the stick trans _design_ you can engage 2 gears which will lock the tranny. My guess that is possible because there are 2 shift levers on the DSM.

Every factory tool I've seen bolts through the starter hole and engages several teeth of the ring gear. Where you having been placing the screwdriver is a particularly thin casting where it could wedge and crack the case. The fact the cover bolts are 5-6mm should tell you the strength is questionable and run the risk of damaging teeth.

Needless to say I've been at this for a very long time and I've seen all the mistakes and botched jobs from shade tree mechanics as well as my peers.

Go look at my profile and get back to me with what you have been doing for the last 5 decades.

GTM

 

[BISHILVR]

Originally posted by Morphius
I hate to argue with a wiseman, but I disgree. You can rotate the engine with the belt off. Or in my case the crank rotating independant of the cams. Rightly, I still wouldn't recommend it. But it can be done.

Here's the low down. My RWD project car before I stripped it. I picked that car up not running. A quick scan of the ECU showed no faults. It was getting fuel and spark and yet it wouldn't start. All the while it had a strong cranking sound. No indication of a bad belt. At this point I pulled the timing covers off to find that the belt had chewed the teeth off right at the crank. The cams had stopped exactly where they need to be for timing them. I had cranked that engine over NUMEROUS times in attempts to start it. So, I changed the belt. And started it. It ran fine. Compression was 155+ across the board. No dinged valves.

If I recall, two cylinders have valves just starting to open with the cams timed at TDC. Given the dish of the head, I don't think the valves stick below the surface of the head. Yet. The pistons come up just flush with the deck of the block. So, I could see how they would not touch if the crank is rotated.

I've got an extra rebuilt head here, I'll have to check tommarrow to verify how much those two cylinders valves are open.

BRAVO!!!! well said.....now behave yourself and stop chasing the old men around on here and tryin' to dis thier sh*t like i supposedly do....

 

[BISHILVR]

the reason i can "deem an impact safe" is that i personally use them EVERY DAY on crankshafts without them moving even the SLIGHTEST amount!!! and believe it or not i can even remove a frozen bolt from something as small as a caliper while holding the caliper with my bare hands!! the caliper won't move an inch... also i believe mitsu itself shows the use of an impact on the crankshaft in the service bullitens at the dealership level, so draw your own conclusion on that one folks....to me it's alot safer than using a caveman approach with a friggin breaker bar and the starter...i witnessed that very approach this summer at the dsm shootout and all it ended up doing was property damage and allmost a trip to the emergency room for onlookers...really not the right way to go about things....

 

[Morphius]

Originally posted by GTM
Please, let's not go there, all you are doing is inviting more wrong information.

Well, given your experience you qualify to clarify. I just wanted some clarification. Thoughts of my engine Dieseling, rotating counter clockwise on it's last sputter and tearing out the bearings ran rampant in my head.

Originally posted by GTM
If you couldn't break the bolt loose in 5th gear with a stock clutch I'd guess you were using 1st gear. This won't work because you have more torque advantage by virtue of the gear ratio which will overpower the brakes.

I'll admit I have not used 5th. Typically 2nd and 4th. I'll try that next time. I was simply VERY surprised as I've tried this over and over with no luck.

Originally posted by GTM
Every factory tool I've seen bolts through the starter hole and engages several teeth of the ring gear. Where you having been placing the screwdriver is a particularly thin casting where it could wedge and crack the case. The fact the cover bolts are 5-6mm should tell you the strength is questionable and run the risk of damaging teeth.

True. Potential. But take alook at the pics. Thats one of the thicker sections on the bellhousing. Especially on the auto.

Originally posted by GTM
Go look at my profile and get back to me with what you have been doing for the last 5 decades.

Hmm, not sure what exaclty I said that you thought, that I thought you were't knowledgeable. If I did, it wasn't intended. But if you want to compare here is an exerpt from my resume on a few things I've wrenched on for the past 2 decades:

·Repair of hydraulic and fuel systems on Fiat-Allis FG85 motor grader.
·Repair of mechanical, hydraulic, and fuel systems on the following: (diesel unless noted by g (gas) after model number): Model 950, 1150 M-Moline, Model Cg, Hg, Mg Farmall [Power steering conversions], Model 1010g, 2010g, 4010, 4020, 5010, 5020 John Deere, Model ST325 Stieger, Model 750 Versatile, Model 84g, 504g, 544g, 606g, 666, Hyro86 International, Model 870, 1170 Case Tractors; Model 800, 200 John Deere and Model 201 IH swathers; Model 830, and 850 New Holland balers.
·Splitting a Case 580 backhoe and a John Deere model 5020 tractor to repair internal hydraulic pumps.
·Repair of mechanical and fuel systems on various GM, Ford, Jeep, Dodge ½, ¾, and 1½ ton trucks. Repair included complete drivelines (engines, carburetors, transmissions, transfer cases, drive shafts, axles).
·Tuning of gas engines (timing & carburetion) Included rebuilding carburetors (FMC, Holly, and Rochester).
·Operation of welding and machining equipment.

Oh and forgot the D9 cat. Worked on that too. I come from a ranch family. Ranching background and have turned wrenches for as long as I can remember. I also have a MS and BS in mechanical engineering. So, I'm not your typical DSM owner. And certainly not one of those engineers that can't turn a wrench. I've been on both sides of the fence.

Hmm, well that said. I think we can agree we both have alot of experience. We both made a contribution to this effort. And hopefully you'll agree I'm on your side.

 

[BUCK]

posted by BISHILVR the reason i can "deem an impact safe" is that i personally use them EVERY DAY on crankshafts without them moving even the SLIGHTEST amount!!! and believe it or not i can even remove a frozen bolt from something as small as a caliper while holding the caliper with my bare hands!! the caliper won't move an inch...

Your day will come - I OWN an Impact & there is no "magical aura" about them which makes a crank or a caliper freeze in place. I would not bet MY valves - or someone ELSES vavles on that "magic". It COULD MOVE - & that's all I should have said & I revised my post to reflect that.

You are TOTALLY correct that the Breaker bar method can be Very dangerous - I included a cautionary statement - I have done it safely with no problems & only advised doing it IF he had the Timing Belt still on.

- No hard feelings on my part - Happy New Year...