Superior Gutlessness

[JustinB]

Hi. So my car's running along just fine, but it has NO BALLS! I don't mean compared to a 72 chevelle or anything, but like, I accept and expect mediocre acceleration and such but I'm really running into some problems. I've replaced all the spark stuff and it seems to have good compression. Runs smooth and is great around town, but if I'm on the freeway, going 65-70, and I run into any kind of hill, even like a 1% grade, seriously too slight to even really notice, she starts to slow. drop it into 4th, and still nothing. No power. I ended up slowing down to 45mph one day just trying to get up this hill that wasn't steep at all. There's also this snapping/popping sound from up front when it gets under a little bit of load and can't keep up. Sounds like pre-ignition sort of. thought maybe running 92 octane would help but it doesn't. Any ideas?

[datzenmike]

Check the ignition timing and see if it goes away, but if you ran better gas and it was still there you may have a tight valve or worse a burned one. Get the valve cover off and check them all. If there is no clearance the valve will be riding on the cam and the spring can't push it fully closed. When the cylinder fires it can squeeze past a poorly sealing valve. Setting the clearance is cheap and easy to do yourself and just may fix the problem.

 

Seems to have good compression? For less than the price of having it checked you can buy your own tester about $45. It may point to a low cylinder.

[ggzilla]

My datsun with 1.4 liter four-banger has a lot better accleration than a 72 Chevelle with 250 six cylinder...

 

don't discount the datsun engine. It sounds like something is wrong with yours. Check the exhaust pipe is not bent, or tailpipe is partially closed.

 

After you've done the compression test, do the valve adjustment that DM recommended. Start with the basics.

Edited November 14, 2009 by ggzilla

[KELMO]

When you replaced all the spark stuff, what type (brand) of spark plug did you use....sometimes if you don't use NGK's they can run kinda funny.

 

But first I'd check what them other two guys said......

[JustinB]

Don't recall off the top of my head. I'm thinking autolite or bosch platinums. Doesn't miss or anything. Runs really smooth. Messed with the timing a little bit but I think that where it is is best. Will look at valves. Also I was thinking maybe plugged cat?

 

P.S. Only Chevelle I ever drove was a 454, so... :)

[mklotz70]

If it runs around town fine, my bet would be on the timing....specifically, the mechanical advance. If you set the timing by ear and set it too high, you're probably getting too much advance at high rpms. If the timing at idle is set correctly(no vac adv), then the weights may be stuck. Check the timing with a timing light. Should be 10ish at idle, as you crack the throttle, you should see the mark move more advanced. As you continue gaining rpms, it should keep gaining advance until it's it about twice as far from zero as the 20deg mark is. This is just my guess based on what you've said so far.

[JustinB]

Hmm... Don't have a timing light, and the rest of that didn't really make any sense to me at all. :lol: I'll look at it in a little bit. See if a timing light costs very much.

 

I know the vac. advance on the distributor is dead. The little advance diaphragm thingy is cracked so it doesn't matter how much vac it gets, it turns nowhere. I have no idea about mechanical advance though. Like, you said something about weights, are they in the distributor? No clue. Seriously.

 

It will run fine up into high rpms, while sitting, or if I leave it in like 3rd gear I can go 50mph+ on level ground with no problem... don't know if that matters or not. It just has trouble under load. Notice a significant drop in performance, also, if I have a couple people in the car or a lot of stuff in the back.

 

So I need to check compression, exhaust flow, timing, and fuel filter now. This could take forever. Stupid car. It's lucky I love it.

Edited November 14, 2009 by JustinB

[mklotz70]

Guess you'd better get to learnin' :)

[vindats1]

Even my little 1.2 E 1 engine PL 410 4 door sedan had plenty of get up and go...so I autocross raced it for nearly 5 years. So much fun, always had the smallest engine out there, but won my class one year. Did cheat and have a 32/26 webber carb put on.

 

Yep, listen to Mike and the other gurus and you can learn alot.

[vindats1]

Oh forgot to mention...car will still start up and run, but no brakes at the moment, so it will go into the shop next for some major work...wish I had the talent of half of you folks! Well, only one way to do it...just start!

[moparvwfreak]

Oh forgot to mention...car will still start up and run, but no brakes at the moment, so it will go into the shop next for some major work...wish I had the talent of half of you folks! Well, only one way to do it...just start!

 

i can most likely do the brakes for a whole lot less than a shop would charge. let me know.

[JustinB]

That's what I'm trying to do here, is learn. Hence the questions. :) Anyway, I just want to point out that I'm not trying to say that Datsuns have no balls. I was just saying that my car seems to be underpowered compared to what it should be. I was saying I wasn't comparing it to my friends chevelle. Actually what I compare it to is the same car, ten years ago, that my cousin had. Only difference between his and mine is color, and his zipped around with no problem. Mine runs great, but on the freeway it just has no power. It's weird cause I have no problem going up hills at 20-30 mph, but going 60 everything runs all to hell. I love the car but i would like to fix it.

So what are the timing weights anyway?