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Old 11-19-2011, 08:17 PM   #1
Reziel_1983
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Installed new engine today, think that I might have an Exhaust Leak.

Hey guys, I put my 377 in today and when we fired up the engine to do the break in I heard a sort of high pitch ticking type noise coming from what seems to be the passenger's side of the engine. I didn't notice until we had the engine at about 2k rpms but one of the pipes or whatever on the header was red hot. Whenever we were putting the headers back on we accidentally bent one of the gaskets. Could this be an exhaust leak?
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1983 Chevy lwb: 400 sbc destroked to 377, comp cams xe 268, Holley Street Dominator Intake, Holley Street Avenger 670 cfm, headers, flowmasters. SOLD

1998 Trans am, mostly stock with magnaflow catback

My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=454329
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Old 11-19-2011, 08:51 PM   #2
INSIDIOUS '86
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Re: Installed new engine today, think that I might have an Exhaust Leak.

if you bent it you may have cracked it and it simply blew out

another posibility is if you dont have a notched pan the crank on 377's hits the side of the pan for some odd reason
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Old 11-19-2011, 10:01 PM   #3
Reziel_1983
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Re: Installed new engine today, think that I might have an Exhaust Leak.

That could be it too... we just used the stock 400 sbc oil pan that came with the block...
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1983 Chevy lwb: 400 sbc destroked to 377, comp cams xe 268, Holley Street Dominator Intake, Holley Street Avenger 670 cfm, headers, flowmasters. SOLD

1998 Trans am, mostly stock with magnaflow catback

My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=454329
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Old 11-19-2011, 10:06 PM   #4
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Re: Installed new engine today, think that I might have an Exhaust Leak.

Do you have the link of the oil pan I would need? I'm gonna change the header gasket tomorrow to see if it's fixed, but if not I guess I'll order a new pan. But the noise did sound like it was coming from the header.
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1983 Chevy lwb: 400 sbc destroked to 377, comp cams xe 268, Holley Street Dominator Intake, Holley Street Avenger 670 cfm, headers, flowmasters. SOLD

1998 Trans am, mostly stock with magnaflow catback

My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=454329
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Old 11-19-2011, 10:27 PM   #5
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Re: Installed new engine today, think that I might have an Exhaust Leak.

did I understand you to say that one of the eight header tubes was red hot? and the other 7 weren't?

If so I'd be pulling that valve cover too to check everything for that cylinder.
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'68 GMC short step - NIB '09 LY6 6.0L crate motor w/mods, NIB '12 crate 4L85e w/billet 3k stall Circle D, 3.73 posi 12 bolt, DynaTech f-swap headers, 3/4 drop, handling mods, etc. - my toy
'72 Chevy LWB C-10 Highlander - 350/350 ps/pb/tilt/ac - not original but close
'06 Chevy TrailBlazerSS - LS2/4L70e - little black hot rod SUV - my DD
'18 Kia Sorento - wife's econo-driver
'95 Chevy S10 - reg cab shortbed, LS, 4.3, auto...

my '68's powertrain and chassis build -links broken
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Old 11-19-2011, 10:42 PM   #6
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Re: Installed new engine today, think that I might have an Exhaust Leak.

Yes, that's correct, one tube. What should I be checking for when I pull the valve cover?
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1983 Chevy lwb: 400 sbc destroked to 377, comp cams xe 268, Holley Street Dominator Intake, Holley Street Avenger 670 cfm, headers, flowmasters. SOLD

1998 Trans am, mostly stock with magnaflow catback

My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=454329
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Old 11-19-2011, 11:11 PM   #7
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Re: Installed new engine today, think that I might have an Exhaust Leak.

Seems like the spark plug wire for #6 has been burned through. This is the same cylinder that was red hot on the header tube. Put a new gasket on, noise still there... I think you're right about the pan cause it sounds like its coming from the bottom.
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1983 Chevy lwb: 400 sbc destroked to 377, comp cams xe 268, Holley Street Dominator Intake, Holley Street Avenger 670 cfm, headers, flowmasters. SOLD

1998 Trans am, mostly stock with magnaflow catback

My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=454329
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Old 11-19-2011, 11:24 PM   #8
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Re: Installed new engine today, think that I might have an Exhaust Leak.

New wire on, tube still getting red.
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1983 Chevy lwb: 400 sbc destroked to 377, comp cams xe 268, Holley Street Dominator Intake, Holley Street Avenger 670 cfm, headers, flowmasters. SOLD

1998 Trans am, mostly stock with magnaflow catback

My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=454329
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Old 11-20-2011, 12:37 AM   #9
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Re: Installed new engine today, think that I might have an Exhaust Leak.

pull the valve cover....and check your p-rods/rocker arm for proper installation/movement and make sure your intake and exhaust valves are opening all the way.
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'68 GMC short step - NIB '09 LY6 6.0L crate motor w/mods, NIB '12 crate 4L85e w/billet 3k stall Circle D, 3.73 posi 12 bolt, DynaTech f-swap headers, 3/4 drop, handling mods, etc. - my toy
'72 Chevy LWB C-10 Highlander - 350/350 ps/pb/tilt/ac - not original but close
'06 Chevy TrailBlazerSS - LS2/4L70e - little black hot rod SUV - my DD
'18 Kia Sorento - wife's econo-driver
'95 Chevy S10 - reg cab shortbed, LS, 4.3, auto...

my '68's powertrain and chassis build -links broken
A surprise phase - carb to efi -links broken
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Old 11-20-2011, 12:49 AM   #10
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Re: Installed new engine today, think that I might have an Exhaust Leak.

Alright, I will do that tomorrow. Thanks.
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1983 Chevy lwb: 400 sbc destroked to 377, comp cams xe 268, Holley Street Dominator Intake, Holley Street Avenger 670 cfm, headers, flowmasters. SOLD

1998 Trans am, mostly stock with magnaflow catback

My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=454329
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Old 11-20-2011, 01:47 AM   #11
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Re: Installed new engine today, think that I might have an Exhaust Leak.

I had to change oil pans on my 383 stroker dont remember what was hitting it (rod bolt I think) one of the shops tried to bang on it to get the clearance needed since it was just barely hitting it but that didnt work out to good so i installed a moroso #20182 pan worked out well
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Old 11-20-2011, 02:47 AM   #12
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Re: Installed new engine today, think that I might have an Exhaust Leak.

you can see dents in the bottom from where the rods made thier own clearance lol

i used hamburgers 1088 oil pan. comes with gasket and pickup, but it wont tell you that on summit
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3''spintech prostreet mufflers xpipe 1 3/4 headers
build thread !http://67-72chevytrucks.com/vboard/s...d.php?t=577217
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Old 11-20-2011, 09:08 AM   #13
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Re: Installed new engine today, think that I might have an Exhaust Leak.

Is this a destroked 400 or is it a std bore 350 with 3.75 400 crank?
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Old 11-20-2011, 10:10 AM   #14
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Re: Installed new engine today, think that I might have an Exhaust Leak.

Quote:
Originally Posted by rs72z View Post
Is this a destroked 400 or is it a std bore 350 with 3.75 400 crank?
Destroked 400.
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1983 Chevy lwb: 400 sbc destroked to 377, comp cams xe 268, Holley Street Dominator Intake, Holley Street Avenger 670 cfm, headers, flowmasters. SOLD

1998 Trans am, mostly stock with magnaflow catback

My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=454329
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Old 11-20-2011, 10:27 AM   #15
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Re: Installed new engine today, think that I might have an Exhaust Leak.

No need wording about the rods hitting the pan then. Make sure you don't have any vacuum leaks also. Pull the header back off and check the gasket.
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Old 11-20-2011, 01:37 PM   #16
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Re: Installed new engine today, think that I might have an Exhaust Leak.

mine is a destroked 400 as well, maybe you have a valve not closing on the exhaust and that ticking is the combustion exiting the valve into the exhaust causing it to glow
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377 sbc thumpr cam autogear m23 muncie 3:73 Detroit trutrac
3''spintech prostreet mufflers xpipe 1 3/4 headers
build thread !http://67-72chevytrucks.com/vboard/s...d.php?t=577217
Iroc gauge threadhttp://67-72chevytrucks.com/vboard/s...d.php?t=554511
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Old 11-20-2011, 01:47 PM   #17
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Re: Installed new engine today, think that I might have an Exhaust Leak.

Yeah your exhaust valve is probly not closing all the way, and that could burn that valve really quickly.
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Old 11-20-2011, 03:11 PM   #18
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Re: Installed new engine today, think that I might have an Exhaust Leak.

Thanks, I will try and figure out if it's not closing and how to make it close if it's not, lol.
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1983 Chevy lwb: 400 sbc destroked to 377, comp cams xe 268, Holley Street Dominator Intake, Holley Street Avenger 670 cfm, headers, flowmasters. SOLD

1998 Trans am, mostly stock with magnaflow catback

My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=454329
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Old 11-20-2011, 03:51 PM   #19
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Re: Installed new engine today, think that I might have an Exhaust Leak.

new motor.....not surprising to have the valve lash adjustment or something else be off somewhere...easy to do.
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Kurt -

'68 GMC short step - NIB '09 LY6 6.0L crate motor w/mods, NIB '12 crate 4L85e w/billet 3k stall Circle D, 3.73 posi 12 bolt, DynaTech f-swap headers, 3/4 drop, handling mods, etc. - my toy
'72 Chevy LWB C-10 Highlander - 350/350 ps/pb/tilt/ac - not original but close
'06 Chevy TrailBlazerSS - LS2/4L70e - little black hot rod SUV - my DD
'18 Kia Sorento - wife's econo-driver
'95 Chevy S10 - reg cab shortbed, LS, 4.3, auto...

my '68's powertrain and chassis build -links broken
A surprise phase - carb to efi -links broken
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Old 11-20-2011, 09:21 PM   #20
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Re: Installed new engine today, think that I might have an Exhaust Leak.

readjusted valves, noise still there. Didn't test the header though because we want to get the noise resolved before that. But there's also a lower pitch kind of knocking sometimes... usually when the engine is revved a little. We don't know for sure but think it could possibly be a main bearing... going to have someone come look at it tomorrow...
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1983 Chevy lwb: 400 sbc destroked to 377, comp cams xe 268, Holley Street Dominator Intake, Holley Street Avenger 670 cfm, headers, flowmasters. SOLD

1998 Trans am, mostly stock with magnaflow catback

My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=454329
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Old 11-20-2011, 09:30 PM   #21
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Re: Installed new engine today, think that I might have an Exhaust Leak.

check the pan near the pan bolts by the flywheel if you see notches that werent there its the rod smacking the pan

idk why mine did considering these motors are shorter stroke so one would think there wouldnt be a clearance issue? oh well i like my hamburgers pan alot lol
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3''spintech prostreet mufflers xpipe 1 3/4 headers
build thread !http://67-72chevytrucks.com/vboard/s...d.php?t=577217
Iroc gauge threadhttp://67-72chevytrucks.com/vboard/s...d.php?t=554511
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Old 11-20-2011, 09:57 PM   #22
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Re: Installed new engine today, think that I might have an Exhaust Leak.

I'll check that tomorrow. There are two distinct noises though that we're hearing, and then there's the header tube glowing. We think that we're most likely gonna have to pull the engine again...
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1983 Chevy lwb: 400 sbc destroked to 377, comp cams xe 268, Holley Street Dominator Intake, Holley Street Avenger 670 cfm, headers, flowmasters. SOLD

1998 Trans am, mostly stock with magnaflow catback

My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=454329
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Old 11-20-2011, 10:00 PM   #23
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Re: Installed new engine today, think that I might have an Exhaust Leak.

Another weird thing is, the higher pitch noise isn't always there, only sometimes... and whenever we changed the timing, it would sometimes get worse.
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1983 Chevy lwb: 400 sbc destroked to 377, comp cams xe 268, Holley Street Dominator Intake, Holley Street Avenger 670 cfm, headers, flowmasters. SOLD

1998 Trans am, mostly stock with magnaflow catback

My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=454329
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Old 11-21-2011, 02:34 PM   #24
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Re: Installed new engine today, think that I might have an Exhaust Leak.

sounds like something isnt right in the valvetrain, did you use break in oil for the engine?
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3''spintech prostreet mufflers xpipe 1 3/4 headers
build thread !http://67-72chevytrucks.com/vboard/s...d.php?t=577217
Iroc gauge threadhttp://67-72chevytrucks.com/vboard/s...d.php?t=554511
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Old 11-21-2011, 03:19 PM   #25
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Re: Installed new engine today, think that I might have an Exhaust Leak.

Quote:
Originally Posted by INSIDIOUS '86 View Post
sounds like something isnt right in the valvetrain, did you use break in oil for the engine?
We used Delo 15w-40 for it. That is what our machinist told us to use.
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1983 Chevy lwb: 400 sbc destroked to 377, comp cams xe 268, Holley Street Dominator Intake, Holley Street Avenger 670 cfm, headers, flowmasters. SOLD

1998 Trans am, mostly stock with magnaflow catback

My build thread: http://67-72chevytrucks.com/vboard/s...d.php?t=454329
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