New head gaskets won't start
Thread Starter
Intermediate
Joined: Jun 2013
Posts: 38
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From: Dallas Texas
New head gaskets won't start
Hey guys, just got my car put all back together after pulling heads and replacing head gaskets, plugs are in the right place, wires are all connected in the right place. The only thing I haven't done is bolt the exhaust manifolds back to the collectors I was hoping it would run enough to get it onto ramps so I can see what I'm doing down there. It turns over and every now and then pops like a cylinder or two try to fire... I'm about to pull my hair out because of this thing any help is appreciated!
Andrew
Andrew
Thread Starter
Intermediate
Joined: Jun 2013
Posts: 38
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From: Dallas Texas
I didn't move it at all, it isn't loose either. Chiltons manual says for a 1994 lt1 the ECM controls timing through cps and knock sensors and it isn't possible to adjust timing, I didn't touch either of those sensors, I'm starting to consider a valve lash issue, I lapped the valve while the heads were out the chiltons manual says to tighten rocker arm nuts to 100 inch pounds and not much else as far as setting the valve lash
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Ensure the coil is connected. Triple check all connections.
I bet is a plug you forgot to connect. Tomorrow is a new day
I bet is a plug you forgot to connect. Tomorrow is a new day
Thread Starter
Intermediate
Joined: Jun 2013
Posts: 38
Likes: 0
From: Dallas Texas
What is the Best way to ensure it is connected I felt it pop on at both connections, I swear I have been over every single plug a dozen times, ill bet it is something simple as I have put in some hours the last couple days to get her back on the road and haven't slept much..
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Le Mans Master
Joined: Sep 2009
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From: Vermilion OH
check and ensure each plug wire is correct. the first thing i would do is check for spark. check the connection at the coil and the ICM. then check to make sure the connector for the optispark did not work loose. it can happen. make sure those connectors are firmly seated and check to make sure you are getting spark.
Race Director
Joined: Apr 2002
Posts: 10,036
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From: Anaheim CA
I've seen that multiple times. "It turned out I had the plug wires on wrong".I have my doubts about the valve lash setting method. Did you rotate the engine for each pair of valves? If not then they're "all honked up". I noticed on my car (1986 L98, cast iron heads) that the nuts are all 0.2" below the top of the stud. That makes a good starting point, but may be different for your engine. The point is that the distance should be about the same for all of the rocker arm nuts.
Safety Car
Joined: Aug 2009
Posts: 3,751
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From: Melbourne, Victoria, Australia
If the valve lash is too tight the valves wont seal and you will have 0 compression, do a compression test.
I know my shop manual said at the cylinder tdc adjust the rocker nut till you cannot turn the pushrod by hand, then turn one full turn.
With my new engine i did the same, she wouldn't start turned out the new lifters only required 1/4 to half a turn...
Something for thought
I know my shop manual said at the cylinder tdc adjust the rocker nut till you cannot turn the pushrod by hand, then turn one full turn.
With my new engine i did the same, she wouldn't start turned out the new lifters only required 1/4 to half a turn...
Something for thought
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From: moraga ca
I didn't move it at all, it isn't loose either. Chiltons manual says for a 1994 lt1 the ECM controls timing through cps and knock sensors and it isn't possible to adjust timing, I didn't touch either of those sensors, I'm starting to consider a valve lash issue, I lapped the valve while the heads were out the chiltons manual says to tighten rocker arm nuts to 100 inch pounds and not much else as far as setting the valve lash
Thread Starter
Intermediate
Joined: Jun 2013
Posts: 38
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From: Dallas Texas
that's what I was afraid of but the nuts look like they are in the same place as they were when I took them off, Im going to go pull valve covers again to make sure everything is still good and possibly re-lash the valves again
Thread Starter
Intermediate
Joined: Jun 2013
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From: Dallas Texas
yea I would think so too normally I get the Haynes manual instead of the Chilton for some reason I like them a little bit better. Im pretty sure this is a valve lash issue I just went out and loosened up the valves on the pass. side and give it a quick crank it actually fired more then one or two cylinders at the same time. any tips for setting the preload?
Thread Starter
Intermediate
Joined: Jun 2013
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From: Dallas Texas
ok after going through the driver side and completely resetting the pre load I am pretty sure this is the issue, I'll post back when I get the thing fired up thanks for the help guys, hopefully I'll be cruising tonight!
Race Director
Joined: Apr 2000
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From: Texas
yea I would think so too normally I get the Haynes manual instead of the Chilton for some reason I like them a little bit better. Im pretty sure this is a valve lash issue I just went out and loosened up the valves on the pass. side and give it a quick crank it actually fired more then one or two cylinders at the same time. any tips for setting the preload?
Thread Starter
Intermediate
Joined: Jun 2013
Posts: 38
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From: Dallas Texas
the preload was the issue for sure, I set all of them again and it fired right up, all I need to do now is bolt up the collectors and maybe chase down an exhaust leak and I should be good to go! thanks again for all the help
Race Director
Joined: Apr 2000
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From: Texas
