Help! Replaced headgasket and head and it bent valves?!

[jay92889]

Hey, I have a 91 Ex I bought that had a snapped camshaft after cylinder 2. I replaced the camshaft to see what would happen and I was almost able to get it to start, but it never would or didm and it made a terrible clicking sound. I bought a new head and head gasket to put on it and I saw as I removed the crankshaft that all of the valves were fully raised by their springs besides the exhaust valves on cylinder two, which is weird because the camshaft snapped AFTER cylinder two. Anyway, new head gasket on with a new head, put in the new camshaft and reassembled, I cranked it and it seems to have bent only one exhaust valve on cylinder two and only one exhaust on cylinder four! I didn't do a valve adjustment after reassembled everything. What's gone wrong?? As it is it would run for no more than a couple seconds before dying and making the same clicking noise. I took the rockers arms off and just kept the camshaft bolted down and cranked and hardly any clicking noises, and one of the two recessed valves raised back up. What's wrong?!!

[bigbadnothing85]

sounds like you need to replace some valves bro...

[deevergote]

sounds like you need to replace some valves bro...

Obviously.

When you reinstalled everything, did you make sure everything was properly lined up? Did you have the proper cylinder at TDC, and the crank pulley and cam gear TDC marks both pointing straight up?

The only thing I can think of is that when you reinstalled the head, the pistons weren't where they should have been... and the result was something similar to a snapped timing belt.

[Flatline]

Obviously.

When you reinstalled everything, did you make sure everything was properly lined up? Did you have the proper cylinder at TDC, and the crank pulley and cam gear TDC marks both pointing straight up?

The only thing I can think of is that when you reinstalled the head, the pistons weren't where they should have been... and the result was something similar to a snapped timing belt.

Yep yep. You should always triple check your timing three times. I know it sounds weird but 3 x 4 = 12. and im not kidding. You should really check it over and over. Sometimes putting the T-belt on can shift the timing a bit.

[jay92889]

Obviously.

When you reinstalled everything, did you make sure everything was properly lined up? Did you have the proper cylinder at TDC, and the crank pulley and cam gear TDC marks both pointing straight up?

The only thing I can think of is that when you reinstalled the head, the pistons weren't where they should have been... and the result was something similar to a snapped timing belt.

Pistons 1 and 4 were definitely at the top of their stroke, and I used what I think looked like the tdc mark on the flywheel (it wasn't very pronounced..)

Anyway, the "up" marking on the cam gear isn't supposed to be pointed exactly straight up, right? Isn't the engine in the bay at a negative angle?

While doing the swap and all I used a coat hanger to suspend the timing belt while the gear and head were gone.

Other than those few things I know nothing else about how to be sure I was at TDC!

Does one bent valve out of the two in a cylinder bank sound characteristic of just bad tbelt timing?

And if I swap the valves using valves from the old head that weren't bent, well, would this work? Can I reuse my barely been torqued down for days head gasket again? I really need this car running and gone.

[deevergote]

One out of two definitely sounds suspicious... The only things I could think of other than improper timing would be bad valve springs, allowing those valves to remain in the cylinder when they should be snapping shut... or possibly detonation. Is there any sign of detonation at all? I would think that would damage more than just one of the two valves, though...


My vote goes to the springs.


As for the marker on the cam gear, I forget... I've only worked with my H22 for the longest time. I believe the H22 has the UP marker straight up at the same time as the crank pulley marker... but that doesn't mean the F22 is the same... and I'm also not 100% on either. I've never had to remove my head, and I have yet to change my timing belt (really... really... stupid... )

[James Matteu]

Mistakes are lessons

You had a Crankshaft that bent Valves. You did some work to fix the damage, but failed to prevent further damage to the Valvetrain. You can either replace the Valvetrain again, or identify the bent valves and try again.

The clicking sound you hear are Valves hitting the tops of Cylinders. Why? Because in the first failure, the timing was thrown off as the Crankshaft broke, and the second failure was a result of the timing being off during assembly and at start-up.

You should bear in mind that by hand cranking the motor, the clicking can be heard if the timing is off; i.e. you do not have to try to start the motor to hear this catastrophic misalignment. You will hear a much less pronounced, and much less destructive, tapping when the valves hit the tops of the Cylinders. This is an easy way to tell if the timing is off, and much less destructive than turning the key and seeing what happens. Besides, you have a good idea what can, and your curiousity should be satisfied.

Replace the Valvetrain or damaged Valves, then reset the timing. Be sure to check for free movement in both the Cranshaft and Balancer Shafts prior to installation of the Timing Belt and Balancer Belt. Be sure to adjust the Valves after installing the timing belts* and then re-check for free play. The motor should be relatively easy to turn by hand and remember, if the motor does not move in an acceptable manner when turned by hand, it should never be started up.

* Do a search for a DIY in timing belt installation, it will give you all sorts of great tips, including how to set the Cam Gear to TDC; which by the way is with the UP at 12 o'clock and with the two notches at 9 and 3 o'clock (level with the deck of the Valvetain).

Mistakes are lessons. If you do not learn the lesson the first time, you are likely to repeat the lesson until you have the knowledge needed to avoid the mistake.

[johnl]

Yep yep. You should always triple check your timing three times. I know it sounds weird but 3 x 4 = 12. and im not kidding. You should really check it over and over. Sometimes putting the T-belt on can shift the timing a bit.

And, then never crank the motor on the starter unless you have rotated the crankshaft several times by hand to ensure that valves are not contacting the pistons.

It's easy, just take the spark plugs out and rotate the front pulley by hand. If you encounter any sudden resistance and/or hear any unusual noise then you have to find what is causing it before using the starter motor.

Pity it's too late for your engine, you need to tear it down and fix whatever damage has now been done. You should be able to use a good valve from one head in the other head, but the seats (both in the head and on the valve) may need refacing, or at least bedded in to each other using grinding paste.

The gasket should be OK to re-use since it hasn't been subjected to engine running temperatures, but since it's already been compressed once I would personally use a sealing compound suitable for use with head gaskets. And, I'd re-torque the head studs after the engine has been heat cycled a few times, even if the gasket instructions say that re-torquing isn't necessary.

[Heffe55]

Great info Im getting ready to dig in to a 93 ex which a timing belt snapped and still havnt taken the head off to see what damage if any is there. The lady I bought the car from said she was getting ready to leave a parking lot and the car died and rolled it to the side of the road. Sad part is that she tried to start it again not knowing the issue. I figured im changing the timing and balancer belts might as well do the water pump too. Any other things I should keep an eye out for? This is my first CB7 and learning alot from this fourm so thanks for all the great information.

[wed3k]

check the valve guides when it comes to bent valves.

[johnl]

And check the piston crowns for damage. You'll get away with light denting, but more severe could suggest the chance of piston damage that may not be visible from the top.

[deevergote]

And check the piston crowns for damage. You'll get away with light denting, but more severe could suggest the chance of piston damage that may not be visible from the top.

Very true. And if the pistons are scored and have rough edges, that could lead to detonation... and much more serious damage.

[jay92889]

And check the piston crowns for damage. You'll get away with light denting, but more severe could suggest the chance of piston damage that may not be visible from the top.

The only damage visible from when the original head was removed was very very slight scraping in the piston crowns, nothing to set off any red flags.

And, then never crank the motor on the starter unless you have rotated the crankshaft several times by hand to
ensure that valves are not contacting the pistons.

It's easy, just take the spark plugs out and rotate the front pulley by hand. If you encounter any sudden resistance and/or hear any unusual noise then you have to find what is causing it before using the starter motor.

Pity it's too late for your engine, you need to tear it down and fix whatever damage has now been done. You should be able to use a good valve from one head in the other head, but the seats (both in the head and on the valve) may need refacing, or at least bedded in to each other using grinding paste.

The gasket should be OK to re-use since it hasn't been subjected to engine running temperatures, but since it's already been compressed once I would personally use a sealing compound suitable for use with head gaskets. And, I'd re-torque the head studs after the engine has been heat cycled a few times, even if the gasket instructions say that re-torquing isn't necessary.

I did try rotating the crank by hand and it wouldn't budge at all! Do the spark plugs absolutely have to be out though when attempting this? I have done it in the past with success with the old head on with its bent valves, but am not sure if the plugs were in at the time or not. All I do know is that it wouldn't budge for a damn!

Would you say a copper spray would work as a sealing compound? Is it absolutely necessary in your opinion?

Would you say I'm better off just buying another head from the junkyard for $40 or so? I've never removed a valve, and honestly know nothing about the process other than using a valve spring compressor.

You had a Crankshaft that bent Valves. You did some work to fix the damage, but failed to prevent further damage to the Valvetrain. You can either replace the Valvetrain again, or identify the bent valves and try again.

The clicking sound you hear are Valves hitting the tops of Cylinders. Why? Because in the first failure, the timing was thrown off as the Crankshaft broke, and the second failure was a result of the timing being off during assembly and at start-up.

You should bear in mind that by hand cranking the motor, the clicking can be heard if the timing is off; i.e. you do not have to try to start the motor to hear this catastrophic misalignment. You will hear a much less pronounced, and much less destructive, tapping when the valves hit the tops of the Cylinders. This is an easy way to tell if the timing is off, and much less destructive than turning the key and seeing what happens. Besides, you have a good idea what can, and your curiousity should be satisfied.

Replace the Valvetrain or damaged Valves, then reset the timing. Be sure to check for free movement in both the Cranshaft and Balancer Shafts prior to installation of the Timing Belt and Balancer Belt. Be sure to adjust the Valves after installing the timing belts* and then re-check for free play. The motor should be relatively easy to turn by hand and remember, if the motor does not move in an acceptable manner when turned by hand, it should never be started up.

* Do a search for a DIY in timing belt installation, it will give you all sorts of great tips, including how to set the Cam Gear to TDC; which by the way is with the UP at 12 o'clock and with the two notches at 9 and 3 o'clock (level with the deck of the Valvetain).

Mistakes are lessons. If you do not learn the lesson the first time, you are likely to repeat the lesson until you have the knowledge needed to avoid the mistake.

Thanks for the breakdown scenario, however I'm still baffled as to why this happened as yes, the camshaft did snap, but the cam gear and timing belt and it's timing were absolutely untouched as this happened and were still rotating together just fine. I did my best to ensure that after slipping the belt off the cam tension was held on it so it didn't jump any teeth!

One out of two definitely sounds suspicious... The only things I could think of other than improper timing would be bad valve springs, allowing those valves to remain in the cylinder when they should be snapping shut... or possibly detonation. Is there any sign of detonation at all? I would think that would damage more than just one of the two valves, though...


My vote goes to the springs.


As for the marker on the cam gear, I forget... I've only worked with my H22 for the longest time. I believe the H22 has the UP marker straight up at the same time as the crank pulley marker... but that doesn't mean the F22 is the same... and I'm also not 100% on either. I've never had to remove my head, and I have yet to change my timing belt (really... really... stupid... )

Make sure you get on that timing belt before you have to deal with as much of a mess as I'm in!

There were absolutely no signs of detonation at all, and the valve springs seemed fine when the head was outside of the car, if this makes sense. Also, it was a 140k mile head!

If I wanted to just start the timing all over again from scratch, how would you do this? Apparently something is seriously wrong. This car should have been running by now and out of my hair!

[johnl]

I did try rotating the crank by hand and it wouldn't budge at all!

That's because one of the pistons was contacting an at least partially open valve. If the valve timing is out when assembling the engine then it's quite possible that when you torque the head down you're bending a valve in the process...

Do the spark plugs absolutely have to be out though when attempting this?

No, it just makes turning the crankshaft by hand a lot easier because you aren't also compressing the air in the cylinder by hand...

I have done it in the past with success with the old head on with its bent valves, but am not sure if the plugs were in at the time or not.

If a valve is bent then when the crank is turned there will be no resistance from compressing air in that cylinder because it will leak past the valve seat instead of compressing (which is the problem with bent valves, they won't seal so you get little if any compression...). This doesn't mean that the engine won't refuse to turn over if a valve is contacting a piston.

Would you say a copper spray would work as a sealing compound? Is it absolutely necessary in your opinion?

Possibly not absolutely necessary, you'd most likely get away without it, but I would personally use a copper spray or a similar agent just to help seal the gasket since it's already been compressed once, and it won't compress in the quite the same way again...

Would you say I'm better off just buying another head from the junkyard for $40 or so? I've never removed a valve, and honestly know nothing about the process other than using a valve spring compressor.

If I could get another good head for $40 then I wouldn't hesitate in preference to rebuilding a damaged one. I would however strip it down and give it a proper clean up and a valve grind (i.e. with valve grinding paste). Before you buy any head make sure that it's flat across the face, i.e. doesn't need machining flat.

[904Rastalude420]

hey

i finished my f22a1 rebuild sat and cranked the motor heard a lil knocking and we waz checking it out revin the engine a lil and the f**kin timing belt broke any suggestions and which is better h22a1 or h23a1 and i think i know that both of this are better then the f22a1:bang head: