LT1 turns over, but doesn't sound like it's cranking
07-29-2008, 05:37 PM
#1
On The Tree
Thread Starter
iTrader: (11)
Join Date: May 2005
Location: Turlock, CA
Posts: 199
Likes: 0
Received 0 Likes
on
0 Posts
LT1 turns over, but doesn't sound like it's cranking Just finishing up the rebuild on my LT1 (the one in my sig). When I turn the key the engine is turning over because I can see the flywheel turning, as well as the alternator. It sounds wierd though, sounds like just the starter turning and I don't hear that typical "cranking over" sound. Every few revolutions I'll get a small flame out of one of the headers (no exhaust on it), but that's it. I can smell fuel as well. Also, when I look @ the starter from underneath, the gear on the starter stays engaged with the flywheel even when it's not turning over....shouldn't it disengage and pull back off of the flywheel?
-Could it be turning over backwards? I wouldn't think so??? The flywheel/TC are turning clockwise (standing @ rear of car looking forward) Is that right?
Your help is appreciated guys.....I really don't know where to start here!
-Could it be turning over backwards? I wouldn't think so??? The flywheel/TC are turning clockwise (standing @ rear of car looking forward) Is that right?
Your help is appreciated guys.....I really don't know where to start here!
07-29-2008, 07:32 PM
#2
TECH Fanatic
iTrader: (4)
Join Date: Feb 2008
Location: S.W. Missouri
Posts: 1,291
Likes: 0
Received 0 Likes
on
0 Posts
Sounds like the timing is off, you need ignition/fuel too cause anykind of flame out of the pipe, so you know your getting spark & fuel, make sure the valves are set right & not too tight, i'll bet its timing, most likely way off, also did you make sure the timing chain is on right? Notice i said a timing problem, it could be valve timing or ignition timing.
As for the starter staying in the flywheel with the key "ON", have you turned the key "OFF" & checked it? If i'm not mistaken, it should do this, but as you know, thats the LEAST of your worries right now
.
As for the starter staying in the flywheel with the key "ON", have you turned the key "OFF" & checked it? If i'm not mistaken, it should do this, but as you know, thats the LEAST of your worries right now
.
07-29-2008, 07:37 PM
#3
On The Tree
Thread Starter
iTrader: (11)
Join Date: May 2005
Location: Turlock, CA
Posts: 199
Likes: 0
Received 0 Likes
on
0 Posts
The timing should be okay...should be haha. The thing that scares me is the sound. It basically sounds like just the starter turning over....it is turning the motor over but it just doesn't sound like the typical "cranking" sound.
07-29-2008, 08:04 PM
#4
my 383 build sounded like the exact same thing your talking about
just a humming sound from the starter and it all turns as it should.
and i couldnt hear the compression stroke.
ended up just being i had tightend my rockers too tight which would keep the valves open when they should be closed for the compression.
just a humming sound from the starter and it all turns as it should.
and i couldnt hear the compression stroke.
ended up just being i had tightend my rockers too tight which would keep the valves open when they should be closed for the compression.
07-29-2008, 08:18 PM
#5
TECH Fanatic
iTrader: (4)
Join Date: Feb 2008
Location: S.W. Missouri
Posts: 1,291
Likes: 0
Received 0 Likes
on
0 Posts
I'm sure the internals are moveing if its spitting a flame out the header, best get to checking things out, you'll find its a valve/piston or ignition timing issue in the end. I did see you said the flywheel & TC or turning, you can bet the internals are too. The main reason your not getting that felling that you normally do is, your not hitting on compression stroke when it fires & the valves are open at the wrong times, either in relation with the pistons (timing chain allign. issue) or its not firing when it needs too (ignition timing), so its firing on the exaust stroke, soon enough, it may pop back through the intake too, if any of this is making sense lol. Once everything is in time, it'll have that resistence while cranking that your used too.
07-29-2008, 08:20 PM
#6
TECH Fanatic
iTrader: (4)
Join Date: Feb 2008
Location: S.W. Missouri
Posts: 1,291
Likes: 0
Received 0 Likes
on
0 Posts
my 383 build sounded like the exact same thing your talking about
just a humming sound from the starter and it all turns as it should.
and i couldnt hear the compression stroke.
ended up just being i had tightend my rockers too tight which would keep the valves open when they should be closed for the compression.
just a humming sound from the starter and it all turns as it should.
and i couldnt hear the compression stroke.
ended up just being i had tightend my rockers too tight which would keep the valves open when they should be closed for the compression.
07-29-2008, 08:23 PM
#7
On The Tree
Thread Starter
iTrader: (11)
Join Date: May 2005
Location: Turlock, CA
Posts: 199
Likes: 0
Received 0 Likes
on
0 Posts
my 383 build sounded like the exact same thing your talking about
just a humming sound from the starter and it all turns as it should.
and i couldnt hear the compression stroke.
ended up just being i had tightend my rockers too tight which would keep the valves open when they should be closed for the compression.
just a humming sound from the starter and it all turns as it should.
and i couldnt hear the compression stroke.
ended up just being i had tightend my rockers too tight which would keep the valves open when they should be closed for the compression.
Trending Topics
07-29-2008, 08:24 PM
#8
On The Tree
Thread Starter
iTrader: (11)
Join Date: May 2005
Location: Turlock, CA
Posts: 199
Likes: 0
Received 0 Likes
on
0 Posts
I'm sure the internals are moveing if its spitting a flame out the header, best get to checking things out, you'll find its a valve/piston or ignition timing issue in the end. I did see you said the flywheel & TC or turning, you can bet the internals are too. The main reason your not getting that felling that you normally do is, your not hitting on compression stroke when it fires & the valves are open at the wrong times, either in relation with the pistons (timing chain allign. issue) or its not firing when it needs too (ignition timing), so its firing on the exaust stroke, soon enough, it may pop back through the intake too, if any of this is making sense lol. Once everything is in time, it'll have that resistence while cranking that your used too.
