Are V8s often "interference" motors ?

[Dan Timberlake]

Some of the detractors of belt driven cams complain about "interference" engines that suffer damage when a belt breaks. Not all are.

Seems like many of the popular V8s needed piston machining just to create safe running clearance if a very frisky cam is installed.
Or, start missing on a few cylinders if my punk cousin downshifted his hot mom's stock V8 Mustang into second at full speed.
So, if the chain broke or even wore and jumped a link or 3 the wrong way I'm guessing the pistons could whack the valves in more engines than suspected. Surely Ford 302s and inline 6s were among the ones that had plastic sprockets that would fail badly at mileages approaching 100K.

[George]

SBFs will take the valves out if the chain breaks.

[Deuces]

Both 5.0L Fox ponys I've bought new came with a double roller timing chain set...

[pila38]

Did you just call your aunt hot?

[hotroddon]

Originally Posted by pila38

Did you just call your aunt hot?

[Mr48chev]

A majority of cars came with plastic tooth timing gears from the factory as they were a bit quieter then metal gears and didn't fostered the engine making noise complaints on new cars that a metal gear might.

And yes there are a number of non ohc cars that will bend a batch of valves if you loose a timing gear.

[King Karl]

Originally Posted by pila38

Did you just call your aunt hot?

That's all I got out of that too! LOL
Something isn't hitting on all 8 but not sure if it's the motor or not!
I take that back... Lets see a picture of your hot aunt, then we'll decide.

[Heo2]

Originally Posted by pila38

Did you just call your aunt hot?

We need pics

[49ratfink]

I lost a timimg belt on my OT Volvo. called a Volvo repair/parts place and this dingy lady answers the phone. always right, and always argumentative. quite the bitch.

first I ask for one of the guys, they are all busy, so I ask her if the 1976 2.1 is an interfereance motor or not. she doesn't know what this is, so I tell her some motors valves hit pistons when the belt goes, while others it does not. I would like to know which type this is.

she tells me I have to bring it in and they will have a look.

I explain it again what I am talking about and I get the same line. 2-3 times we go through this, I'm also asking to speak to someone else during all this with no response. finally as I was about to tell her she is a stupid so and so I just hung up.

found out later this motor does not hit the valves when the belt breaks. that lady is crazy, it is not the first time i have had problems with her.

[squirrel]

235 Chevy is an interference motor, if the timing gear breaks the rods hit the cam and the engine locks up

[Truckedup]

My daughter had the timing chain slip on the original plastic tooth sprocket. on her shit box 307 Chevy....bent some push rods and bent a few valves.

[Thumper]

Originally Posted by pila38

Did you just call your aunt hot?

Well then.........whats your granny like....?......Is she spry...?

[falcongeorge]

Originally Posted by heo2

we need pics

ailf??

[brad chevy]

Lets see maybe you should have called him your stupid punk cousin if he can't drive no better than that. Any engine that jumps time can cause damage. The damage is not always the same either. Just because an engine has a 100 thousand miles doesn't mean its going to jump time.What is your point anyway. You throw your rice burner into second at top speed and see what happens to it.

[Madnomad]

Screw the engine...Let's see your hot aunt!

[rustynewyorker]

Originally Posted by 49ratfink

I lost a timimg belt on my OT Volvo. called a Volvo repair/parts place and this dingy lady answers the phone. always right, and always argumentative. quite the bitch.

first I ask for one of the guys, they are all busy, so I ask her if the 1976 2.1 is an interfereance motor or not. she doesn't know what this is, so I tell her some motors valves hit pistons when the belt goes, while others it does not. I would like to know which type this is.

she tells me I have to bring it in and they will have a look.

I explain it again what I am talking about and I get the same line. 2-3 times we go through this, I'm also asking to speak to someone else during all this with no response. finally as I was about to tell her she is a stupid so and so I just hung up.

found out later this motor does not hit the valves when the belt breaks. that lady is crazy, it is not the first time i have had problems with her.

Translation: "I have no idea" ....


I found out how to make a 301 Pontiac an interference motor. Throw a rod and bounce the piston off the valves and it comes down and interferes with the crank.

But some replacement pistons can have different reliefs in them not because the motor is necessarily interference but because the pistons are made to fit multiple years where heads or valve angles were changed at different points in production, so they can sell one piston for all of them instead of two or three different ones.

[squirrel]

The term "interference motor" really only applies to engines that have a rubber band connecting the crankshaft to the camshaft. If it has a chain, it doesn't matter, because they don't generally break after 75,000 miles.

[moefuzz]

Most over head valve engines will bend valves if the timing chain/belt/gears let go.
Overhead valve engines have been around for 100 years.


.

[woodypecker]

Get a flathead it does not have that problem.

[Traditions Racing]

I'm not sure I understand the question.