Chevette LS1 Swap, overheating
07-01-2016, 06:13 PM
#41
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Jack up the front of the car to get the radiator inlet as high as possible. Than pull one of the steam vents at the front of the motor as you fill the radiator. Keep going until water comes out of the vent, then put the vent back in.
That will get all the air out. I pop one of the vents everytime I fill or drain the system.
You also know pulling the thermostat will open the water pump bypass. This makes the water just circulate inside the pump and not go through the block. Never run an LS without a thermostat.
That will get all the air out. I pop one of the vents everytime I fill or drain the system.
You also know pulling the thermostat will open the water pump bypass. This makes the water just circulate inside the pump and not go through the block. Never run an LS without a thermostat.
Andrew
08-29-2016, 07:32 PM
#42
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Okay, i bought a 2000 ls1 shortblock, 799 heads, finished the build and put it all back into the car. I took pictures of everything (sensors, connections etc) before removing the old engine. Everything appears correct. It will not start now though, it backfires a little when cranking and visible gas fumes come out the intake. I have a little obd display but it does not show any present fault codes. Crank and cam sensors are both installed, i aligned the cam and crank sprockets dot to dot. I also pulled a plug and it is getting spark, fuel pump is functioning. Any obvious things you guys can think of?
08-29-2016, 07:35 PM
#43
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I must also mention that I had what I thought was a ground on the starter (picture i took was misleading on removal) which was actually the sensor grounds and I had a power wire hooked to the block (looked like a chassis ground) which caused some sparking when hooking up the battery. These issues are now fixed. Probably not related but thought i'd mention it.
08-29-2016, 07:38 PM
#44
I must also mention that I had what I thought was a ground on the starter (picture i took was misleading on removal) which was actually the sensor grounds and I had a power wire hooked to the block (looked like a chassis ground) which caused some sparking when hooking up the battery. These issues are now fixed. Probably not related but thought i'd mention it.
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08-29-2016, 08:01 PM
#45
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That crossed my mind too. My obd display can read all the engine vitals and im getting spark. Could it still have fried it? Its like the timing is off but I dont know how it could be with everything hooked up.
08-29-2016, 09:20 PM
#46
Pop N Wood- That method might just work, its only lower by an inch or two. I'll try that once I put it back together. I did not know that at all, that would explain why only the engine was getting warm. Thanks for all the help!
Update: Got heads pulled, i'll mention so maybe you guys can make sense out of whats going on here. The passenger head is ported while the other head is untouched. Also #7 cylinder has a new std. piston and cylinder has a long gouge. I dont see any cracks in the head or block yet. Using a straight edge they seem flat so far. I will verify with feeler gauges though. Any of you guys see anything obvious?
The new guy, std. bore
left bank
8&6
4&2
Right bank head
Left bank head
Update: Got heads pulled, i'll mention so maybe you guys can make sense out of whats going on here. The passenger head is ported while the other head is untouched. Also #7 cylinder has a new std. piston and cylinder has a long gouge. I dont see any cracks in the head or block yet. Using a straight edge they seem flat so far. I will verify with feeler gauges though. Any of you guys see anything obvious?
The new guy, std. bore
left bank
8&6
4&2
Right bank head
Left bank head
ahhh that piston isn't new.....lol.
08-29-2016, 09:34 PM
#47
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At first I thought it was just bake cleaned from the coolant but it was in fact a new piston. Luckily I only have about $1000 total into the new ls1 shortblock and ls6 top end. Just need to get it running!
08-30-2016, 07:18 AM
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The sensor grounds are no longer on the starter, I fixed the wiring issues. Theyre now grounded on the back of the head.
I didn't check but I believe all LS1's have 24 tooth wheels.
I didn't check but I believe all LS1's have 24 tooth wheels.
09-01-2016, 08:29 PM
#51
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I decided to do a compression check, i'm getting 35psi on the two cylinders I checked with throttle wide open. My guess is the 799 heads were milled at some point and now my intake and exhaust valves are sticking open because the pushrod is too long causing the backfire. Anyone else have any thoughts? Its late otherwise Id be working on it more, just something to think about at work tomorrow.
09-01-2016, 09:26 PM
#52
I decided to do a compression check, i'm getting 35psi on the two cylinders I checked with throttle wide open. My guess is the 799 heads were milled at some point and now my intake and exhaust valves are sticking open because the pushrod is too long causing the backfire. Anyone else have any thoughts? Its late otherwise Id be working on it more, just something to think about at work tomorrow.
09-01-2016, 09:30 PM
#53
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Exactly, I was just saying I only measured two cylinders and both had 35psi compression . I didnt see the point in doing all if there was clearly a problem.
09-01-2016, 10:18 PM
#55
This is the point where (if it was my project) I'd probably say '**** IT' & slap a used 5.3 in it. Even if I had to pay for a different tune, it would be quicker (& probably cheaper) than trying to repair the current engine.
And I'm pretty confident that the OP will never miss the 20-odd cubic inch difference between the two engines in that tiny little chassis...
And I'm pretty confident that the OP will never miss the 20-odd cubic inch difference between the two engines in that tiny little chassis...
09-02-2016, 08:02 AM
#56
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I honestly am getting nervous about cranking over this engine anymore since it was not prelubed, has not started yet, and potentially could have a PTV issue. I will do a leakdown test with the rockers backed off to figure for sure what is happening.
This engine that is in it has what look to be new bearings and is very clean, id much rather run this than a heavier smaller displacement 5.3 (although it would work fine). I don't think this will end up being an issue with the shortblock and rings if that's what youre thinking. I'm leaning more towards open valves due to wrong pushrods or jumped cam timing due to the intake backfiring but we will see.
This engine that is in it has what look to be new bearings and is very clean, id much rather run this than a heavier smaller displacement 5.3 (although it would work fine). I don't think this will end up being an issue with the shortblock and rings if that's what youre thinking. I'm leaning more towards open valves due to wrong pushrods or jumped cam timing due to the intake backfiring but we will see.
09-02-2016, 08:06 AM
#57
I honestly am getting nervous about cranking over this engine anymore since it was not prelubed, has not started yet, and potentially could have a PTV issue. I will do a leakdown test with the rockers backed off to figure for sure what is happening.
This engine that is in it has what look to be new bearings and is very clean, id much rather run this than a heavier smaller displacement 5.3 (although it would work fine). I don't think this will end up being an issue with the shortblock and rings if that's what youre thinking. I'm leaning more towards open valves due to wrong pushrods or jumped cam timing due to the intake backfiring but we will see.
This engine that is in it has what look to be new bearings and is very clean, id much rather run this than a heavier smaller displacement 5.3 (although it would work fine). I don't think this will end up being an issue with the shortblock and rings if that's what youre thinking. I'm leaning more towards open valves due to wrong pushrods or jumped cam timing due to the intake backfiring but we will see.
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09-02-2016, 09:09 AM
#58
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That's true, I just happened to find a good appearing ls1 shortblock for $400 locally. At the time I planned on re-using the heads until i found out how beat up the valve seats were (home porting gone wrong). The L33 is still a little new and doesnt pop up too often in my area.
09-02-2016, 01:59 PM
#60
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Yes, I went over those and all the injectors several times and everything is plugged in exactly how it was. This thread has jumped around a lot but I'm getting low compression and backfiring which sounds to me like valves sticking open.