Timing Chain

Quote :

Is that only with the modifications?

I deleted previous post. I think it is the interference type, but I'm reading mixed responses on the subject. I really hope I'm wrong and it's non-interference!

AA wrote:

The odds are also likely that the chain will never break, or at least last to 200k in a modded car. I plan to replace mine something this year. Waiting on a good reason to go in there...

I know this was dated early 2008. Procrastination or Procrastination.?

Well, I did buy the chain and sprockets shortly after posting that comment. At least I had good intentions! I probably decided it could wait till 200k, and now I'm finally there, so it really should be done.

Unless we find out it's not an interference engine...

AA wrote:

Well, I did buy the chain and sprockets shortly after posting that comment. At least I had good intentions! I probably decided it could wait till 200k, and now I'm finally there, so it really should be done.

Unless we find out it's not an interference engine...

Random question - are you using stock valvespring retainers or LS1 style retainers?

They are LS6 retainers.

When I started reading this thread I got a little worried considering my mileage and I started researching online and so far I found a couple of forums where guys are saying that the 3.8L engine is a free wheeling engine, not an interference engine. They also say that modifications such as changing the valve timing, valve lift or compression ratio can and does turn some non-interference engines into interference engines. Can anyone confirm if our motors in stock from are non-interference or not?

I would like a definitive answer as well.
Because i will put in a new chain and tensioner this summer before the winter slows me down.
Mainly because I ran the engine for about 7,000 miles with the incorrect valve retainers on it, that supposedly cause premature wear on the tensioner and chain. I now have the LS retainers on which don't pre-load the springs too much.

On older cars with distributors it was so much easier to check your timing chain. Not on this engine.

I'm thinking the same thing about the interference. They probably made the valves just clear the pistons in a worse case scenario. The 1.9:1 rockers could easily change that formula, as the valves move 20% further to open. I do not wish to find out the hard way!

AA wrote:

I'm thinking the same thing about the interference. They probably made the valves just clear the pistons in a worse case scenario. The 1.9:1 rockers could easily change that formula, as the valves move 20% further to open. I do not wish to find out the hard way!

That's what I think... The general consensus on the Web is that the 231/3800 is a non-interference motor, and I think I would probably have heard otherwise over the years if it was.

Yeah, but we're always finding things out we didn't know, and threads like this one make me wonder some:

http://www.a-body.net/forums/showthread.php?2131-Timing-gear-repair-LG3-3-8-SFI-1987-Century

AA wrote:

Yeah, but we're always finding things out we didn't know, and threads like this one make me wonder some:

http://www.a-body.net/forums/showthread.php?2131-Timing-gear-repair-LG3-3-8-SFI-1987-Century

Verrrry In-tah-rest-ing... (with a WWII Nazi accent.)

I suppose we could take comfort in the fact that most of our engines are supercharged units with low compression...

That may be true, but I sure worry for those NA folks...

I had the sprocket brake on my 87 lesabre with a 3.8. Back then they used nylon gears in those damn things, so it was a matter of time before It failed. I am pretty sure this is not an interfence engine. All I had to do was put a new chain and sprockets in, and she fired right up. I think the later 3.8s did away with those nylon sprockets.

Well fellas the 3800 in the stock format is a freewheel n engine until you change the valve springs and rockers.
As for changing the timing set the rule of thumb for the 3.8 naturally aspirated engine is 200k and they are a piece of cake to do anyone getting ready to do this let me know and I can give you some insights as I just got done doing mine. I didn't have to do it as of yet cause I only have 50k on the car but I had a bad oil leak in the timing chain cover and had to take the front of the motor apart and as long as I am there I changed everything.

I'm getting ready to do mine soon. Did you get any pictures?

I may be doing mine soon as well because doing it seems to be what has fixed this P0341 code, if all else fails, for several mechanics working on these cars. Pictures would be helpful!

I didn't take pic but it isn't to bad to do, the main thing is getting the harmonic balance r off you have to have the right puller and most people don't have it so you need to go to a parts store and borrow one, once you get that off then you have to take the alt out of the way and then take the pwr str pump out of the way, I just moved it down and close to the firewall and then take off the two pulleys well for the 95s anyway and then the two tensioners and then take off the bracket that holds the alt and pwr str pump, once the bracket is out of the way then take your two heater hoses off and the radiator hose off and then go around the cover and remove all of the bolts, Oh and I forgot there is a bolt that comes in from the rear of the pwr str pump that you have to get ,and it is right above the oil sending unit once you do all that and remove the oil pan the cover will come right out, and don't forget to be careful with the crank sensor, you have to unplug that and the cam sensor.

you also have to use a engine lift or a overhead hoist to hold your motor up cause you have to remove the front motor mount and you have to lift up pretty good to cause you have remove the bracket that the motor mount mounts to and in order to get it out you need the clearance.

AA wrote:

I'm getting ready to do mine soon. Did you get any pictures?

sorry I didn't think about taking any pic [
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how do you get images off your pc.

In the Board FAQ tab at the top, there is some info about uploading images.