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Old 05-10-2012, 12:27 PM   #97
DANIMAL
TYRE ETR
 
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Join Date: Mar 2006
Location: Hamilton
Posts: 941
May 2012 Update

Well I have had some trouble with the motor. I had a few reports last summer of the car blowing black smoke when stomping on the gas. I knew that the motor burns a bit of fluids so I thought nothing of it at the time. I also thought it was kinda low on power and I suspected some issue with the original tune so I took it to Champion Motors (A very well known/respected LSX shop). They ran the car on the dyno a few times and for some reason could only get 320ish to the wheels. Knowing that was too low, with a cam, they proceeded to run leakdown tests. The result was that Cyl 7 was actually leaking 98% of pressure.

I was concerned obviously, not because of the costs involved, really more because I thought I would have to remove the motor/trans to do the job. After thinking about it and looking at what it would entail I decided to run the repair myself, in my driveway. This last fact changed mere days before I was set to run the repair when after a brief discussion with Andy at AutoWorks(Oakville) offered to let me take up some space in his shop to re and re. Let me tell you that having access to a hoist and air tools is vital to doing this kind of work. I think it would have taken me much longer to complete on my back with motormaster chrome in my hand.

After thinking about it some more, and looking at pictures of my build, I decided that I did not need to remove the whole motor/trans to replace piston #7. All I had to do was remove the break booster/master and the head should come right off with full access to all bolts. I also had to disconnect the header from the exhaust to allow for enough movement for access. I could not completely remove the header as there is a steering shaft threaded through it.

To take the oil pan off we had to put a span hoist on the fenders to take the weight of the motor and disconnect the subframe. Once we had access to the pan we could remove the rod bolts and slide the piston out the top.

So I was expecting to see a hole in the piston but once I took it out this is what I found;
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Needless to say I was rather surprised at how much was missing and that the rest of the motor was still operable. Essentially I have been told it was a result of way way too much timing by the first guy that tuned. I only found one piece larger than shavings in the oil pan, but there was a good amount of shavings in the bottom. To be honest I'm lucky none of it got caught in the rotating assembly. I inspected the entire bottom end before buttoning it all back up and it looked good.

So after the guys at Champion Motors gave me a tested low mileage replacement I went to put it all back together. So I checked the sleeve for major damage and found;
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Not to bad at all, in fact it still had the cross hatch. After a very light bore, to allow the new rings to seat, and some sore thumbs from cleaning gasket we were all set.
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Unfortunately I do not have pics from assembly; but as Bentley says it is the reverse of removal. a new HG and some head bolts and it was all back together and good.

I ran the car out to Mosport both Saturday and Sunday to assist with the Trillium ADT school. no problems even took it on the skid pad to have some fun. Fun did indeed ensue but was short lived as I had to attend to my duties. So I brought it back to Champion to complete the tune the following week only to find that a noise had developed beyond the normal sewing machine typical of the LS valvetrain.

Champion has mad a few suggestions and I did some research. After a few hours of diagnosis I had come to the conclusion it was a collapsed lifter on the passenger side head. This was confirmed with a spongy response from the lifter when pressing down on the pushrod on the roller of cylinder #8.
So it is time to replace the lifters. I did a bit more searching and apparently the LS7 lifters are the stock replacement for the LS1/2/6/etc. The LS1/6 lifters are known to collapse under higher spring pressure. As I had changed the springs when I did the cam it should have been expected, but I did not know at the time. So because the LS7 is the replacement it does not mean they are exactly the same. The oil port on the LS6 lifter for example is in a different location than the LS1/6 lifter;
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LS7 lifter on left.

So with the LS7 lifters were installed and the rod girdles put back in place some more gasket cleaning and sore thumbs meant it was all ready to be reassembled. I am only doing one side for now. I will wait for the other side to fail or for a longer break in between events to complete the drivers side.
The LS7 lifters should be good up to 7200RPM. Eventually I would like to upgrade them beyond GM parts and turn the motor to 8k but that's likely to be part of a winter build.
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That is were I left off yesterday. The HG should be here today and I already picked up a set of ARP head bolts. So I can reassemble tonight and re-tune at Champion tomorrow. All this in hopes of attending the cruise on Saturday. Fingers crossed no more funny noises before the dyno.
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