5.7 '97 Tahoe - Interferance Design engine?

[themadhatter]

Hi guys, first post here.

 

I have a '97 Tahoe (2dr) with the 350 motor, I have two questions:

 

 

Is the 350 an interferance design motor?

 

 

Also, does this motor use a timing chain or a timing belt. If it's a belt, how often should I go about changing it?

 

Thanks!

Ron

[bassdog]

Welcome

 

I believe it is a timing chain, don't think the belt would be strong enough.

 

Not sure about the first question, someone should jump in soon

[americanmuscleman]

I'm not sure what you mean by an interferance designed motor?

 

The Vortec 350 uses a timing chain (as does every small and big block engine). Its not something they will likely have to replace unless you have a ton of miles (200k+). If you have the engine apart though, its best to change it. Timing chains stretch after a lot of miles and can throw off the timing sequence of the camshaft and crankshaft.

 

The only belt you have on there is the serpentine belt. You should replace it if you start to see cracks in the rubber. Incase you've never changed one, there is a belt tensioner you pull back with a breaker bar or large ratchet that will allow you to pull the belt off and put a new one back on.

 

[GM GIMP]

Hatter, your 5.7 is a non interferance engine.

[kawboy579]

okay, ill bite: what is an interference engine?

[SteveCZ]

Going out on a limb here, but I beleive an interference engine has something to do with the timing of the valves and the piston.

 

In an interference engine, when the valves open, and the timing is off, there is a chance that the piston can come in contact with the valves. In a non interference engine, this won't happen (as much?) dunno....

 

Like I said, this is what I thought it meant, but I could be wayyyyyyyy off

 

anybody else????

 

[Charlie in TX]

DING DING DING, we have a winner. A interference design is one where the piston will hit a valve if the valve is fully open while the piston is TDC.

 

Usually interference motors are the smaller, hi-strung engines in the imports and cars. They are also usually OHC engines (but a OHV engine can be interference and a OHC can be a clearance).

 

The order it happens in is;

1. A broke timing belt will cause at least one valve to be held open.

2. The piston comes up and hits the valve.

3. The mechanic puts on a new head. $

[SteveCZ]