2G Is Cylinder Head too low? Valves hit pistons.

[rafadsm]

Hey guys.
I've rebuild my engine, did everything correctly, put the engine on time and everything, but when i turned the car on - had no compression on cylinder 4 and the others were not good too (around 120).

Took the head off and all the intake valves were bent, the exhaust ones are all good. I measured my head and it is 131.6mm (around 5.181 to 5.185 - the minimum height factory recomends).

The question is - my timing was off or my head is too low that hit the intake valves on pistons?

So, after that I bought used valves, put in my head and tried again. All the 16 valves hit the pistons - the machine shop I bought the valves from sent me the valves in a wrong size (higher than the original size). They are rebuilding my head and are going to pay the costs. (this time the cause wasn't the head size, was the valves size they sent me)

The thing i am afraid of is putting a original size headgasket and all the bend the valves again. Should i still go with original size gasket or try using a higher one?

I don't know if in the first time I build it was off timing or my head is too low.

(I'm newbie at mechanics, that's the first time I'm doing the engine)

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[pauleyman]

Did you bleed the lifters down before install?

 

[dwb]

Measure your valve to piston clearance next time before you finish installing the head.

 

[1990TSIAWDTALON]

Put some silly putty on the piston crown and slowly rotate the assembly to check piston to valve clearance. This sounds like an installation issue to me. I bought a car that was off by one tooth and still running, though not as well as it should have been, and never bent any valves.

 

[rafadsm]

Did you bleed the lifters down before install?

yep.

Put some silly putty on the piston crown and slowly rotate the assembly to check piston to valve clearance. This sounds like an installation issue to me. I bought a car that was off by one tooth and still running, though not as well as it should have been, and never bent any valves.

Yeah, i'll try putting play doh on the pistons to see if it's hitting before assembling again. And yeah, i think it could be installation issue, but i fear doing it for the third time and hitting the valves again because the head is too low.

 

[1990TSIAWDTALON]

Has the head been cut so much that it is below the standard service limit points on it? If not, you shouldn't have a "head too low" problem. Check those points and see if it is on the limit.

 

[dwb]

Yeah, i'll try putting play doh on the pistons to see if it's hitting before assembling again. And yeah, i think it could be installation issue, but i fear doing it for the third time and hitting the valves again because the head is too low.

One thing you also have to do is make sure you have zero lash for this test. Which means a solid lifter or shimming a fully blead HLA. I used a HLA, with a washer and some layers of aluminum foil in the bottom of the bore to achieve zero lash.

Keep in mind that decking the block, not just the head, can lead to clearance issues. Same goes with your piston choice. If you indeed have clearance issues, a thicker head gasket might be your only way forward.

 

[pauleyman]

Yeah, i'll try putting play doh on the pistons to see if it's hitting before assembling again. And yeah, i think it could be installation issue, but i fear doing it for the third time and hitting the valves again because the head is too low.

With the head off you can clearly see where the valves are and rotate cams at will to make sure valves seal. Double check you don't have the wrong cams. Intake on exhaust etc. Has this car ever ran with the parts you have in hand? There are many possibilities. Wrong cams. Wrong gears. Installed out of place. Improper lifter install. It isn't just deck height. I would double check all of this before risking it again.

 

[1990TSIAWDTALON]

If possible, post a picture of the front of the motor with it "in time" and let us take a look at it. That would include timing gears, crank gear, oil pump sprocket and balance shaft gear if you still have balance shafts.

 

[pauleyman]

Timing plate can also be installed backwards.

 

[DSMPT]

my timing was off

Most likely yes.

my head is too low that hit the intake valves on pistons?

No. Even if the head has been resurfaced many times more than its limit, usually you have much more margin in the piston to valve clearance if you have the stock pistons or usual off the shelf piston kit for turbo 4g63 (If you are using very high compression custom pistons or other car's pistons, the story would be different). Even if you have a thinner gasket or the head height is below the factory spec, you won't immediately bend the valves. That usually happens at high RPM after the engine gets hot. So it sounds you are doing something improperly.

Should i still go with original size gasket or try using a higher one?

The head gasket thickness was not the reason why you bent the valves, so it doesn't matter a little difference on the thickness, just go with standard thickness gasket and rebuild properly.

Do not try to fire up the engine without checking, make sure everything is good before cranking by starter. At least slowly rotate the crank by hand to make sure the valves are not contacting with the pistons and the rods are not contacting with balance shaft.

 

[rafadsm]

Has the head been cut so much that it is below the standard service limit points on it? If not, you shouldn't have a "head too low" problem. Check those points and see if it is on the limit.

The measurement is on the post, the head is 131.6mm right now (aprox 5.181 inches). But i've seen in many posts people even using 131.2mm so think it's not the problem.

One thing you also have to do is make sure you have zero lash for this test. Which means a solid lifter or shimming a fully blead HLA. I used a HLA, with a washer and some layers of aluminum foil in the bottom of the bore to achieve zero lash.

Keep in mind that decking the block, not just the head, can lead to clearance issues. Same goes with your piston choice. If you indeed have clearance issues, a thicker head gasket might be your only way forward.

Yeah, now i sent the head to a shop to do everything. The head is the one i was running with the car before, just trimmed .01 because i blew the headgasket. The engine is all Standard OEM, original cams, only thing different i'm using is ARPS and metal cometic headgasket.

With the head off you can clearly see where the valves are and rotate cams at will to make sure valves seal. Double check you don't have the wrong cams. Intake on exhaust etc. Has this car ever ran with the parts you have in hand? There are many possibilities. Wrong cams. Wrong gears. Installed out of place. Improper lifter install. It isn't just deck height. I would double check all of this before risking it again.

I was running with all this parts, just changed the headgasket and put ARPs. Changed the valves too after they got bent the first time. The cams are in the right place - i use 98 cams, have the CAS sensor in the admission cam. I'll double check everything.

If possible, post a picture of the front of the motor with it "in time" and let us take a look at it. That would include timing gears, crank gear, oil pump sprocket and balance shaft gear if you still have balance shafts.

Sure, i'll put some photos here. The Balanceshaft looks out timing but it is the angle of the photo.
The last picture is a mark i did just to be easier to see when the engine is in PMS.

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Most likely yes.

No. Even if the head has been resurfaced many times more than its limit, usually you have much more margin in the piston to valve clearance if you have the stock pistons or usual off the shelf piston kit for turbo 4g63 (If you are using very high compression custom pistons or other car's pistons, the story would be different). Even if you have a thinner gasket or the head height is below the factory spec, you won't immediately bend the valves. That usually happens at high RPM after the engine gets hot. So it sounds you are doing something improperly.

The head gasket thickness was not the reason why you bent the valves, so it doesn't matter a little difference on the thickness, just go with standard thickness gasket and rebuild properly.

Do not try to fire up the engine without checking, make sure everything is good before cranking by starter. At least slowly rotate the crank by hand to make sure the valves are not contacting with the pistons and the rods are not contacting with balance shaft.

Thanks for all the advices. I'll rotate it manually, did it the last time but couldn't feel or listen the valves contact the pistons. Engine was rotating fine and easy.

Here are some pictures of the valves that were sent the wrong size and of my bottom end. The black valve on my hand is the old one and the ones in the head are the wrong size, you can see they're much longer.

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[Mikealj]

Hopefully the place you ordered them from will take care of you...

 

[rafadsm]

Hopefully the place you ordered them from will take care of you...

I ordered the valves with them, they just accepted they sent the wrong size valves and said "Send the head to us that we are going to fix it for you with no cost", they are very famous here in Brazil for the engines they build. Its "Stumpf Cabeçotes" the name of the place.

 

[donniekak]

You didn’t pump the lifters up with oil did you? The lifters need to all be left empty if they’re new, or bled back down if they aren’t new.

 

[rafadsm]

You didn’t pump the lifters up with oil did you? The lifters need to all be left empty if they’re new, or bled back down if they aren’t new.

No i haven't, all the lifters were empty. But when i get the head back i'll double check everything and empty them if needed.