I'm looking at a '91 RS and it has a 305 in it. Now I've asked some people about it and I've gotten different responses. Some told me it lasts a long time, but others say they die out after about 70,000 miles. I don't really care 'cause I'm getting the car anyways, but I want to know if I should be ready to buy another engine soon. The 305 in it has 113,000 miles on it, so obviously it didn't die out at 70,000 miles.

 

Its a roller motor and I can tell you that if taken care of I have seen them go 150000 to 200000 miles.


Brian

 

I agree the roller motors last a long time, as the valvetrain seems to be the weak point in most other SBC motors.

My 305 has over 130k on it and runs out very strong still. And i've got no reason to believe the previous owner took care of the motor at all! =)

 

Thanks, that's good to hear. Well at least I'll have fun driving it until the Winter I turn 18 and put a bigger engine in.:rockon:

 

Whoever said they only last 70k miles, probably didn't take care of the motor. When I had mine it had 190k miles when I did a cam change (which ended up killing the motor). When we did the cam change and took off the valve covers, I literally scraped out 2 handfuls of old oil deposits in the heads. And this was a non roller motor. Just make sure the motor and car were taken care of. Ask when the last oil change was, look for a specific milage just not 2000 miles ago.

 

Depends. The latest one I had went to 150k before it kicked the bucket. Of course you could end up with a lemon that shears the wrist pin on the #6 rod at 44,000 miles for no reason at all.

I'd say the norm would be if it didnt have well over 100k miles theres something amiss.

 

I had 221,000 on my 87 and it was still going fine. I pulled it however and installed a 327. Valve guides were getting pretty worn and didnt think rebuilding heads on a 221,000mile motor was a cost effective option.

 

Oh, yeah, check out the Appearance board, I believe there is a topic "How many miles does your 3rd Gen Have?" or something similar.

 

Pulled the engine out on mine when I first bought it cause it was bad. Still ran ok, just smoked. Come to find out, 4 lobes on the cam were gone. Everything else in the engine looked fine though considering the 120k miles.

 

The 305 in my Safari Wagon went 185K before the timing chain broke and I whanged some valves with the pistons. I had a buddy with a 350 he was dying to put in something, so I gave him the Wagon for the motor swap

 

168k, 300 horse on my little 305. I did the cam swap about 10 thousand miles ago. Oil pressure is still excellent, and there was very little in the way for oil deposits in the motor. Its an 86, so its not a roller motor. It really depends on how well it was taken care of. My motor was all highway miles before i owned the car, and then it gets beat on everyday since i have owned it. It doesnt run right the next unless i step on it atleast once

Anyways, with 70k on that motor the only thing it is going to need soon is the heads rebuilt. Sooner or later, the guides get so shot the thing will start with a big cloud of smoke and puff a little at idle. But don't worry, your motor will be fine for a long time!

Steve

 

The people that told you the 305 was only good until about 70K miles, were they older people? Like in there early 30s?

If so, I can explain from experiance (which I'm sure a few others can to). GM did not know how to make cams for the 305. They thought that since it was a small motor, that they could use lead camshafts. They were VERY soft.

It wasn't until they figured out how to fix the problem that they decided to use a roller cam anyway, and then the problem went away. But a pre-87 305 would typically wear the cam lobes down around 70-80K miles.

I don't know if they accidently used racing valve springs in there or what, but if you had a 305, there was a 80% change that you were gonna have to replace the cam at around 70K miles.

AJ