LS2, New Heads, lost power? Ideas anyone?
Teching In
Joined: Dec 2005
Posts: 27
Likes: 0
If it were a shaft Yella terra with someone else's springs I might be a little concerned, but we have never had the float issues that most people have had with a yella terra that some have. Also are you running the ultralight's? or the shaft type? and were the rockers on before with the other heads?
The rockers were on in the original tune.. The ONLY thing that has changed since the original tune is the heads, LS7 lifters and clutch.. Nothing else has been done to the motor..
I'm a newb, so please don't take my question as anything other than curiousity.
Why don't you look at the injector pulse widths from the run and compare the left and right bank. If they're the same, why no look at the fuel rail and see if something got messed up during the swap.
Why don't you look at the injector pulse widths from the run and compare the left and right bank. If they're the same, why no look at the fuel rail and see if something got messed up during the swap.
Teching In
Joined: Dec 2005
Posts: 27
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So I'm wondering if it's the valve seals that's causing the oil leak.. There is a fresh set of plugs in the motor now and I'm driving it over the weekend.. I'll be pulling the plugs on monday to see if they come out the same..
I'll be sure to post updated pix..
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Verdad Gallardo Teching In
Joined: Dec 2005
Posts: 27
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I took the plugs over to the tuner for him to have a look see and from the mechanics there and him they all agree that the build up on the plugs is oil.. Which would make sense since with the stock heads I had a valve seal go bad and the plug looked exactly like that..
So I'm wondering if it's the valve seals that's causing the oil leak.. There is a fresh set of plugs in the motor now and I'm driving it over the weekend.. I'll be pulling the plugs on monday to see if they come out the same..
I'll be sure to post updated pix..
So I'm wondering if it's the valve seals that's causing the oil leak.. There is a fresh set of plugs in the motor now and I'm driving it over the weekend.. I'll be pulling the plugs on monday to see if they come out the same..
I'll be sure to post updated pix..
TECH Fanatic
Joined: Aug 2005
Posts: 1,691
Likes: 1
From: Sunny London, UK
Fueling under WOT would be the same bank to bank, but under part throttle can be different, especially if you have an exhaust leak etc on one bank. O2 sensors will see lean and dump in fuel. Check your fueling etc. Though if you are just doing WOT pulls on the dyno then ignore me 
Thread Starter
Staging Lane
Joined: Oct 2006
Posts: 59
Likes: 0
It's been awhile since we could do any work. We did a leakdown test yesterday and also checked the plugs which we put in since the last post. I have pics of it, I just need to upload them.
The plugs all looked like they were burning evenly and clean.
The leakdown test looked perfect, with cylinders registering less than 8 or 9 for loss. We checked valve seating, and air wasn't leaking around the valves either. Each cylinder was placed at TDC as per leakdown procedures.
Haven't done a compression test yet, but honestly the motor appears fine especially with such good results on the leakdown and the plugs burning evenly.
So:
Valvetrain was checked and is good (clearance, tolerance, PTV, geometry, etc--none of which should matter from what I've heard from several builders regarding these heads and the engine setup)
Leakdown is within spec
Plugs look good
.. So what next? Ideas? Try a different dyno just for kicks?
The plugs all looked like they were burning evenly and clean.
The leakdown test looked perfect, with cylinders registering less than 8 or 9 for loss. We checked valve seating, and air wasn't leaking around the valves either. Each cylinder was placed at TDC as per leakdown procedures.
Haven't done a compression test yet, but honestly the motor appears fine especially with such good results on the leakdown and the plugs burning evenly.
So:
Valvetrain was checked and is good (clearance, tolerance, PTV, geometry, etc--none of which should matter from what I've heard from several builders regarding these heads and the engine setup)
Leakdown is within spec
Plugs look good
.. So what next? Ideas? Try a different dyno just for kicks?
Launching!
Joined: Aug 2008
Posts: 206
Likes: 0
From: a place
when was the first dyno done from the last setup to this setup? that makes a big difference. humidity, temp, every dyno is different at reading numbers. dynos are a tunning tool and thats all i would use it as who cares what the hp is, thats just for bragging rights. run it down the track and see if it made a difference or not then.
Thread Starter
Staging Lane
Joined: Oct 2006
Posts: 59
Likes: 0
No.. the original dyno was done in the summertime. The new setup with the most recent dyno was done a few weeks ago in much colder/less humid weather. So, even if there were stock heads on there, there should be more power.
IMHO..
IMHO..