Posts: 148
Loc: Burlington NJ



     
I Lost my 4-6RPM Power band


Yesterday was the first time I drove my truck after a few screwy things had to be fixed ( Front crank seal, Dist. O-ring, Fuel pump, and I had to re-do the fuel filter and line so it wouldn't ice up on me anymore,,,,I HOPE. Thats what killed the pump).
Anyway, Now my engine is week [censored] hell around 4-6000 RPM, were it used to really pick up.   I tried messing with the timing but it's all set correct. The cam and crank were perefectly 12 o'clock after I tightened everything and rotated it twice, before I put the cover back on. With a warm engine at 1000 RPM I have the timing set at the 8-BTDC on the cover and the Flywheel mark is just off (I think below) by 2 marks. When I set it at 0 (cover) the Flywheel mark is on the long mid mark. So thats Correct. I think the problem is that maybe when I changed dis. housings and re-installed the dis, maybe I was off a tooth or so? I don't think that would matter though since I can adjust the Dis Advanced and Retarted about an even amount. At least enough to where it's about to konk-out. So, that should be fine. I don't get it.  
-Good timing
-The plugs wires and dia cap/rotor are fine
-I tried adjusting my Weber a bit (the air/fuel is set about 1.75 screws out where it's been running fine) and the carbs bolted down fine.
-Fuel sould be fine. I did move the small inline glass filter up to the carb by the thermostat and Im now using the recomended micro filter for the universal 4-7 lb pump Iv been using, but that should be good.
I don't get it ,,,,,What am I missing here???
 

What engine? 8 valve or 16 valve? what year and type of rig??? i'm guessing a samurai 8 valve I would check your dist. first for full advance and check your line from the carb, is there a plug you have to short out to time it?

Cam timing
The crank is supposed to point up (12 O' Clock)
and the cam is supposed to point down (6 O' Clock)
when the Distributor is at firing #1

I hope that's what you meant when you said
it was at 12 on both after 2 revolutions

Also check the firing order, if the cam is
out I think it might move the plug wire
locations also  


Wild

Id bet youve got the timming belt off one notch. Double check that. Ive done that before.

Mike

Id bet youve got the timming belt off one notch. Double check that. Ive done that before.

Mike

Yea, Thats what I think it is.


Damn it!!

I know its no big deal but this will be the forth or fith time Iv taken it down to the belt this week for somthing stupid like this.

Its a 8v and I know it was the exaust stroke with them both pointing up at 12. O'well,,,,what the hell ya gona do.

I found a 4-6k power band for an 8v engine. Email me of PM me if it's yours.

So last night I got to the belt to double check the marks and It was a tooth retarted, So I fixed it, And It didn't change a thing (witch is kinda weird).  So with the timing good Im thinking It could be a fuel problem. It seems to make a little more power in that range if I run it really rich, but its definatly too rich. The only thing is, I noticed that when I remove the vac. tube from the dis. when setting the timing, the idle would normally change a bit right? Because doesn't make a difference wether its on or off. So,,, Maybe the diaphram or whatever is screwed up and its not advancing the timing with the vacume.

Think thats possible? I have an extra dis. to swap real quick.

After you moved the Cam, did you
reset the ignition timing

The cam turns the Distributor, and
is now off from 8-10* advanced
that it needs to be, you might
even try 12* advance and see if
it helps your top end, unless you
get pinging, then turn it back or
buy better grade fuel

Wild

after you moved the cam did you check the dist.? It is prob out now. May need to pull it and reinstall one tooth either way.

YEP,,,,,Everythings lined up and I adjusted the dis.

Re cap


Everything was fine,,,,,my seal blew,,,,I fixed it (I guess I was off a tooth putting it back together),,,,,I drove it all weekend, but I though it was just the 12" or snow that was keeping me back,,,,,,so when I drove on some pavement I really noticed it and then the next morning my filter got ice in it and blew the pump,,,,so I replaced the pump changed the pre-pump filter and moved the glass one up by the carb so I could see that there was gas. Now In back to the lack of power problem from when I took the belt off.
I guess Im still off with the cam or something. Everything looks fine though. I mean this isn't the first time Iv set an engine to TDC and its probably like the 30th-40th time Iv done it with a freekin Suzuki engine and never had this problem. Thats what's driving me nuts. Im probably going to have to take the cover off and double,,,,,O'yea triple check the setup.


Ya, know what? Now that Im thinking about it,,,,,When I originally took the belt off to change the seal, I had it lined up with the #4 TDC so the cam was at 12 BUT I thought (when I whent to take it off) the the crank gear was actually almost at 11 maybe 11:30. I thought It was weird but I figured If I just lined everything up right when I put it back together It wouldn't matter.

I did use a 1.3 water pump. BUT it was running fine after I changed that (that was like two weeks ago).

Allright,,,,I didn't want to post on this yet but I need some advice to save me taking a shot in the dark.

So, as I said earlier on, my cam/crank timing is most likely off a belt tooth,or (but less likely) the dis is off a gear tooth.
Im tring to narrow down weather it might be a tooth advanced or retarted. I thought it was odd that when I took the belt off ,(before this was a problem) the cam gear was at 12 o'clock but the crank gear looked like it was at 11 almost 10. That makes me want to take it off and set it back like that but thats not how its supposed to be.

--Iv noticed that it definatly starts better than it did before this. But that could be b/c Im running it a bit rich now but,,,, I have more power that way than lean.

--Also, the other day I let it run for a while and the snow back by my exaust was really black,,,,but there wasn't any smoke at all.

--It smells like "firecrackers" not gas (which is what I expected since its rich)
--It used to back fire alot now it hasn't done it once.

SO,,,,,,,,Im thinking the valves are shutting too soon and and all the exaust isn't all getting out and Im re-burning the burnt fuel, and thats probably why it runs better rich this way. WHICH SUCKS like an old tired stock 1.3 w/no gears,31's and a few hundred pounds of extra crap in it.

What'd yall think??

I wonder if you got the wrong marks
lined up on the cam, it's a screwy thing,
but there are several marks and you
could be using the wrong set.

I need to go look at the head I have sitting
here, but I think the notch in the cam sprocket
is the one to use. I'll look and get back to you

Point is power is off since you had it apart,
so somthing isn't right, it's just logical, engines
don't crap out like that.

Wild

Thats what I was also thinking. The one on the Crank is obvious,,,,but the Cam has a few "nicks" like in most book pic's BUT,,,,It has a round bump on one of the five spokes and It was Damn close to having the #1 lined up where it was supposed to be so I figured it was that. None of the other maks seemed to be legit, they all kinda looked like accidents. I guess I could put the other (like in the picks) 1.3 sprocket on there. I have extras.

I looked at the head, I don't have a sprocket
on it, so I'm not sure, but I do remember a notch
in the outer rim, I need to find the sprocket and
get a better look at it, I know one of the things
you can do to get the cam timed right is to look
at the lobes on #1, they should both be up and
look about equal in their pointing positions.

Now look for a corrosponding mark, and it should
be at the 6 O'clock position, hope this helps

Wild

FIXED!!I HAVE POWER AGAIN!! [smiley=scream.gif] [headbang]


It only took me "litteraly",,,A half hour to get to the belt check everything again and turn the CAM back 1 tooth and put it back together.

I started at 7:45 BUT didn't finish till almost 10:00 Because of having to take he water pump off and trying to weld a nut to the tiny piece of tensioner bolt that was exposed  after  it snapped when I was torqueing it DOWN then rumage through everything trying to find a new bolt and finaly scrape everything clean and put it back on.

Anyway,,,,,,,,Crap,, what a difference!!!! I didn't really have time to tweek in the carb air/fuel and idle, but what the F|removethispart|@#k It has so, much more power! I think Im going to get an adjustable cam sprocket, so I can really tune it in. this is what Iv noticed.

---Its harder to get it started,(like before) Its not "crazy bad" but if its cold it takes 2-3 tries BUT always starts.

---It backfires fairly often,(like before) Just on deceleration, BUT its not that bad. Kinda muffled, not some crazy gun shot $hit. I like it actually,,, it sounds nice and HP, like rally racer or something.

---Low end is the same if not better, AND it pulls from 4 grand-up like I spooled up a some boost!!

SOoooooMuch BETTER!!!!


Whats so weird is,,,,,, that when it was the other way IT WAS DEAD ON SPEC. I took the grill out I used a stait edge I checked the dis. and the flywheel EVERYTHING about 10 times. I deffinatly used the correct marks and nothing was bent or broken. And that LITTERALY made my low mile HP(aside from internals) 1.6 8v run like my old tired 180k stock 1.3.