# Interference or Non-interference? That is the question! 2.0 8v mk3 jetta



## djshyc (Mar 21, 2007)

I have a 1996 2.0L 8V Jetta GL. Is this an interference or non-interference engine? I think my timing belt did the old "stretch and slip" on me. 
Thank You!
I am hearing both! Well this engine is totally stock. So what is it???


_Modified by djshyc at 4:39 PM 4-2-2007_


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## Sixtysomething (Aug 7, 2003)

*Re: Interference or Non-interference? That is the question! 2.0 8v mk3 jetta (djshyc)*

Non-Interference. Your valves should be fine. I have a Mk III Golf 8 Valve, and my mechanic told me the worst thing that would happen if my timing belt broke was that the car would stop. Still, I changed my 1st belt at 60k, and the 2nd at 130K.


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## rabbitmania (Feb 5, 2001)

*Re: Interference or Non-interference? That is the question! 2.0 8v mk3 jetta (fortysomething)*

A 2.0l crossflow from a Mk3 IS an interference motor.
Replace the timing belt every 60,000miles.


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## Electron Man (Sep 21, 1999)

*Re: Interference or Non-interference? That is the question! 2.0 8v mk3 jetta (rabbitmania)*


_Quote, originally posted by *rabbitmania* »_A 2.0l crossflow from a Mk3 IS an interference motor.
Replace the timing belt every 60,000miles.

What he said.


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## djshyc (Mar 21, 2007)

*Re: Interference or Non-interference? That is the question! 2.0 8v mk3 jetta (djshyc)*

Ok so I checked all the timing arks and they all were where they were supposed to be! YAY ! So now what? I think maybe a new distributor is needed. the hall sensor is what is throwing the code so im guessing its bad? 
Is the distributor Year specific? I ask because the local pick n pulls interchange system is saying that is the case.


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## t-jet (Jul 24, 2003)

*Re: Interference or Non-interference? That is the question! 2.0 8v mk3 jetta (fortysomething)*

My 94 2.0 blew the timing belt and yes it did bend a Valve. Just glad it did not break a piston.
tc


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## t-jet (Jul 24, 2003)

*Re: Interference or Non-interference? That is the question! 2.0 8v mk3 jetta (t-jet)*

Let me back up a second I have seen some very think 2 or 3 part head gaskets that may be why some don't bend valves.
tc


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## ABF Jeff (Nov 16, 2005)

*Re: Interference or Non-interference? That is the question! 2.0 8v mk3 jetta (t-jet)*


_Quote, originally posted by *t-jet* »_Let me back up a second I have seen some very think 2 or 3 part head gaskets that may be why some don't bend valves.
tc









Here's the deal, and it has been gone over several times.
A 2.0L IS an interference engine. That said, the amount of time the piston and valve share the same space is so small and such a small overlap that the chances of intefering with a stock cam and head at less than 5K rpms are next to nill.... I have seen several break belts near redline and not have an issue, I have seen a few sitting at a stop-light break a belt and trash one or more valves.
It's a rarity for them to bend valves and I have never heard of serious piston damage with a stock or even as large as a 268. But rest assured, if you have the opportunity to replace the T-belt and don't, you will pay for it later.
Why take the chance, replace the belt every 60K or sooner and save yourself the trouble. http://****************.com/smile/emthup.gif


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## 93wolfsburg (Feb 22, 2003)

*Re: Interference or Non-interference? That is the question! 2.0 8v mk3 jetta (ABF Jeff)*

I just stumbled across this and figured i'd try another point of view.
Technically if the valves touch for any amount of time you would not be able to turn the crank by hand. So with a valve fully open if it interferes for any amount of time the piston should stop when it comes into contact if you are turning it slowly by hand.
You have to take into account the expansion/contraction of these moving parts when you have such tight tolerances its doesnt take much. 
I have an obdII and obdI aba sitting in my garage right now i think i might give this a shot tonight.



_Modified by 93wolfsburg at 1:55 PM 5-16-2007_


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## ninety9gl (Nov 27, 2005)

*Re: Interference or Non-interference? That is the question! 2.0 8v mk3 jetta (93wolfsburg)*


_Quote, originally posted by *93wolfsburg* »_
I have an obdII and obdI aba sitting in my garage right now i think i might give this a shot tonight.

They'll make contact... the Bentley and Haynes both warn about that, if you lose timing to make sure the pistons are all about halfway down before you set the cam timing (move the valves). Once the cam timing is set then the valves are out of the way and you can correct the crank.
Honestly, if you moved the crank like that, you'd probably move the valves without even noticing it.
Better way to do it, if you wanted to risk it, would be to leave the crank at TDC and rotate the camshaft *slowly and gently* until you feel the valves make contact.
I'd be interested in seeing specs, actually... I'd much rather know how much overlap there was, but knowing how many degrees (even approximately) off the cam would have to be at with the crank at TDC would be nice to know.
Definitely, though, as stated in this thread, the 2.0L 8v is an interference engine. Any motor that can *potentially* have interference damage is - there has to be clearance under any and all circumstances in order for a motor to be a non-interference design. It might be uncommon from an odds standpoint, but it's not impossible.
This is sort of a dead thread, but if people are stumbling across it then it wouldn't hurt to get info there I suppose.
I was actually thinking of doing a nice, indepth explaination as to why it is an interference motor, though... so if you get some kind of spec or further info, I'd love to see it. Don't think writing anything big or explaining things is that important unless people start posting things like "THE GUY @ PEP BOYS SAID IT WASN'T AN INTERFERENCE ENGINE". I think it's more an issue that some people aren't 100% sure what being an interference or non-interference engine actually requires, from a definition standpoint.


_Modified by ninety9gl at 5:23 PM 5-16-2007_


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## FL 2.0L (Aug 1, 2002)

So if your belt goes bad, throw a new one on and fire it up. Chances are you'll be fine. Mine broke and I've driven the car 130K without a problem since.


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## 93wolfsburg (Feb 22, 2003)

*Re: (FL 2.0L)*


_Quote, originally posted by *FL 2.0L* »_So if your belt goes bad, throw a new one on and fire it up. Chances are you'll be fine. Mine broke and I've driven the car 130K without a problem since.

Well exactly the chances of it bending valves are slim, i've seen some instances where it has, however i'm with ninetygl about testing it i mean if this were really a hot topic i'd tear open one or both of motors and maybe put some paint on a valve or something and test.


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## ninety9gl (Nov 27, 2005)

*Re: (93wolfsburg)*

Agreed... it seems to be more common to not have any problems, but contact is certainly possible.
If you were going to tear something apart though, which I certainly haven't been motivated to do (only 1 car and only so much time off), I'd actually see how high the piston goes and how low the valve goes, see how much clearance/overlap there is with both of them as far as they can go.
That'd also be useful info when factoring in head spacers or stacked gaskets... if you knew overlap was x mm, then if you had a spacer thicker than that you'd be good (assuming you didn't have a cam that would open the valve further and have to factor that in as well).


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