punkbek3886

before you flame me or tell me to search, i have. a lot of people say its an interference engine but a few have actually tested it to see and they say that 22re's are not interference engines. the consensus is that 20r's and 22r's are interference, but the 22re's have cutouts in the piston, so they could be non interference. could people who actually know firsthand reply so we can set this straight once and for all? thanks in advance.

Glenn

The 22RE is interference. The cutouts don't affect that.

Flamedx4

Same question for the 3.0 while you're at it...

trx125

That is what the cutout's are for! the valves occupy the same space as the pistons @ the top of the stroke! Cutouts allows valves to open with out hitting the piston(when timed correctly)! Just my dumb A@@ assessmet to the theory!

Glenn

A non-interference engine's valves should never hit the piston, even without a timing chain/belt.

Silver_Truck

3.0 is non interference

marko3xl3

I thought it was...

Jared Ajlouny

here we go again...haha

4Hummer

22RE is NOT an interferance ENGINE.. I should know I just tore the darn thing apart.

The piston only go the full lenght of the block. the intake valves when fully open do not extend past the head itself, the exhaust valve extends a few mm past the head, but the pistion is notched the exact amount the exhaust valve sticks out.


Heres the block. At top dead center the pistion does not go past the top of the block.


heres the head.



There is NO WAY the Pistions can SLAM into the valves....

tc

Are those hemispherical heads? So all you (lucky) 22R/22RE guys can tell the Dodge guys you have a Hemi too! (and be more accurate than they are as the new "Hemi" doesn't have hemispherical heads)

marko3xl3

You learn something new everyday. I never knew what HEMI meant.

kyle_22r

the '84 and older engines(20R, 22R, 22R-E) used dome top pistons that go above the deck height of the block with a hemispherical head. well, the 20R used somewhat flat top pistons, but that's irrelevant here.

these are most certainly interference engines! i have no idea what 4hummer said, it didn't make any sense.

the cutouts on the '85-up 22R and 22R-E are to enable more lift on the camshaft. rather than the hemi head with domed pistons like the '84-down engines, these have a quench style head with kidney shaped chambers that put the valves closer to the block, making the cutouts necessary. you pop the timing chain and if the cam is in the right spot, you will smacks some valves.

marko3xl3

Well then, 4Hummer got very lucky in that case, because his timing chain went and his engine seemed just fine.

44Runner

ok, you have totally confused me.

you post a picture of the bottom end. you are right, the pistons do not go above the deck height of the block. But then you post a picture of the head. What is this telling us?

Unless you went through a lot of trouble how can you tell how far the valves open with the head off the block?

Now to those who say that, oh there are notches for the valves in the piston, therefore it MUST be non interference. That makes no sense. the valves are never fully open when the piston is at the very top of the stoke so that is how they manage to miss the piston, not because there are notches for them.

also, the combustion camber on a 22RE is NOT hemispherical. I hate to burst anyones bubble. I guess it is hard too make out in the picture. Not to mention its is kind of understood in the realm of hemis that they have a top mounted spark plug, which 22REs do not...

punkbek3886

4hummer is saying that when he took his head off he saw the pistons dont come above the top of the block and the valves dont stick down past the bottom of the head, so theres no way the two can interact. i hope this is true, but so many people say they can hit.

punkbek3886

thats also a good question

44Runner

ok ok ok.....everyone here does know that when intake and exhaust valves open up, they are pushed into the cumbustion chamber right?

timing chain break does not automatically mean that a valve is gotta make contact with a piston. For that to happen the cam needs to have stopped in a position where a valve is open.

Now, keep in mind, I honestly don't know if this is an interference engine or not but everyones "evidence" so far doesn't mean anything. That is all I am saying.

44Runner

for anyone not following this, to get the block off the head you obviously pull the head bolts that screw through the head and into the block. No crap right? Well these same bolts on a 22RE also clamp the rocker assembly to the head. So with the head off the block you can not see how far the camshaft can open the valves because your rocker assembly is no longer on the head...

kyle_22r

the 20R and early 22R have an "open" somewhat hemispherical chamber. true hemi it is not, but a hemi isn't exactly a perfect engine, pretty inefficient. some think the 20R head swap is because of it's open chamber, when in reality the performance increase comes from the better port design.

the quench chamber of the '85-95 22R and 22R-E is a better design for power than the "open" chamber of the '84 and earlier engines, though...

RED 85

Well if you are talking about interferance as far as if the valves at some point can hit the piston then yes they are. Proof is when not timed right you bend valves, if this is correct then i have bent my vavles and had too get new ones. so that should clear it up unless i am not understanding this right. I don't have pics but did see with my own eyes the markes in the pistons where the vavles hit and also the bent valves.