Pontiac G8 Forum banner

1 - 20 of 20 Posts

·
Registered
Joined
·
260 Posts
Discussion Starter #1
So last week cylinders 1 and 2 decided they didn't like the comfy confines of my cylinder block and decided to harshly exit the block through the oil pan. Not sure exactly what happened on my mild cam only build that has been running great for the last 50,000 miles. I just sent the heads out to hopefully be repaired (machine shop said definitely fixable from the pics i sent). I have a local source that has a few fresh from the machine shop blocks waiting for homes so I'm covered there. trying to plan out this new build and stay within a a 5k budget. I want something reliable "N/A", no boost and a mild street cam that I can enjoy without being too high strung and afraid that I will break something again. A few months prior I had reached out to a couple cam suppliers when I was thinking of rebuilding my now bad engine. Based off of my cam sheet I was spec'd a
219/223 612/599 112+1.
Now that my heads will have to be resurfaced and milled, I'm sure that changes things. I won't know how much until they come back of course but would a cam like that be affected by milled heads in a good way or bad way?
Also, I have the choice of either going 6.0 again or 6.2. There's a $500 difference in the cost between the 2. However, being on a budget, I need to save every penny I can so I can have a running, driving, TUNED car with little to no overspending. Are those .2 liters that much better than the 6.0 that I should I splurge on it?
 

·
Registered
Joined
·
626 Posts
Being in a similar situation... I'm sticking with the 6.0, giving it forged guts (stock crank still), and spending the "extra" money on Johnson lifters, ATI balancer, ARP main studs, etc. All the stuff that hopefully aids in that "hop in and go" capability.

I don't think anyone would say that the 6.2 is a bad idea, but if it's a matter of going 6.2 or getting better parts for the 6.0, I'd take the better parts. Or... what are you doing for a converter?
 

·
Registered
Joined
·
260 Posts
Discussion Starter #3
Being in a similar situation... I'm sticking with the 6.0, giving it forged guts (stock crank still), and spending the "extra" money on Johnson lifters, ATI balancer, ARP main studs, etc. All the stuff that hopefully aids in that "hop in and go" capability.

I don't think anyone would say that the 6.2 is a bad idea, but if it's a matter of going 6.2 or getting better parts for the 6.0, I'd take the better parts. Or... what are you doing for a converter?
I hear what you're saying about saving the $500 for better parts and I'm kind of swaying towards staying with the 6.0. The cam that's listed above is spec'd for the stock stall. For the type of driving I do, a stall converter does not make any sense and would actually be counterproductive towards my cause. I drove my first cam, converter car two weekends ago (3200 stall) and while it was really, really fun in straight line, that all ended as soon as I put it in manual and wanted to take curves. I don't think the car will ever see a drag strip on real tire ever again. Just not my cup o' tea i guess. Don't think I'm splurging for Johnson lifters or an ATI balancer, rather save that extra coin for the tune.
 

·
Registered
Joined
·
626 Posts
I hear what you're saying about saving the $500 for better parts and I'm kind of swaying towards staying with the 6.0. The cam that's listed above is spec'd for the stock stall. For the type of driving I do, a stall converter does not make any sense and would actually be counterproductive towards my cause. I drove my first cam, converter car two weekends ago (3200 stall) and while it was really, really fun in straight line, that all ended as soon as I put it in manual and wanted to take curves. I don't think the car will ever see a drag strip on real tire ever again. Just not my cup o' tea i guess. Don't think I'm splurging for Johnson lifters or an ATI balancer, rather save that extra coin for the tune.
Yeah, there are days I wish I still had the stock converter for that reason, but I do enjoy the ZL1 converter. Manual mode still works nicely, and the stronger lockup is pretty nice too. Tuning of course makes a big difference.

In my case, I went with things like the ATI balancer because I got the LSA version that I can simply bolt the supercharger drive pulley to when I'm ready. :) Other things like the lifters were the "while you're in there stuff". I don't want to be "back in there" any time soon.

Not sure I even want to open this can of worms, but.... who's going to tune it? lol
 

·
Registered
Joined
·
260 Posts
Discussion Starter #5
I thought about the ZL1 converter but the gain vs cost wouldn't be worth it in my opinion. I was told that the cam I was spec'd will surge even less than the one I have now and it's been pretty comfortable with the OE converter. I have no plans to go FI and just want something with a little more power and to run well for another few years. I'm working on getting Jeremy Formato from Fasterproms to tune it.
 

·
Registered
Joined
·
626 Posts
I thought about the ZL1 converter but the gain vs cost wouldn't be worth it in my opinion. I was told that the cam I was spec'd will surge even less than the one I have now and it's been pretty comfortable with the OE converter. I have no plans to go FI and just want something with a little more power and to run well for another few years. I'm working on getting Jeremy Formato from Fasterproms to tune it.
I was going to keep my stock converter originally as well, but then I lucked into a local sale on a basically new ZL1. So I jumped on it.

Awesome on Jeremy, and hoping he'll post a video of a certain blue G8 he just tuned.
 

·
Registered
Joined
·
260 Posts
Discussion Starter #7
I was going to keep my stock converter originally as well, but then I lucked into a local sale on a basically new ZL1. So I jumped on it.

Awesome on Jeremy, and hoping he'll post a video of a certain blue G8 he just tuned.
Yea, if I was looking into an LSA build I would definitely go with a ZL1 converter. Sounds like you're gonna have a really nice setup in the future. There was a picture of it on the last video, would be nice to see it run on the dyno for sure.
 

·
Registered
Joined
·
340 Posts
I noticed no one answered your question about milling the heads. Yes, as a matter of fact if you can mill them a LOT that is a good thing. Many on here have done it, Rick G - which your new cam specs look very close to - recommended a .035" mill which is what I did. Our motors are a bit low on compression, as they are using heads designed for a 6.2L on a 6.0L. So in the LS3 the CR is 10.7:1 while ours is 10.4. Once you increase cam timing you are bleeding off more cylinder pressure at low rpm due to later intake valve closing, which can in particular make for a soggy bottom end. That is why you will usually seem recommended CRs rise as cam timing rises.... So in short, yes, with a cam you want more CR. Milling .035" took my CR up to 11.1:1. And I love it, lots of part-throttle "pop" at low RPM. In theory a higher CR should make a touch more torque and power. Now, the downside is less piston-to-valve clearance. I measured mine and I'm around the minimum recommended. There is no problem sealing the intake - confirmed with Rick and I've had no problems sealing (traditionally if one mills heads that much one would need to get their intake manifold angle milled).
 

·
Registered
Joined
·
260 Posts
Discussion Starter #9
I noticed no one answered your question about milling the heads. Yes, as a matter of fact if you can mill them a LOT that is a good thing. Many on here have done it, Rick G - which your new cam specs look very close to - recommended a .035" mill which is what I did. Our motors are a bit low on compression, as they are using heads designed for a 6.2L on a 6.0L. So in the LS3 the CR is 10.7:1 while ours is 10.4. Once you increase cam timing you are bleeding off more cylinder pressure at low rpm due to later intake valve closing, which can in particular make for a soggy bottom end. That is why you will usually seem recommended CRs rise as cam timing rises.... So in short, yes, with a cam you want more CR. Milling .035" took my CR up to 11.1:1. And I love it, lots of part-throttle "pop" at low RPM. In theory a higher CR should make a touch more torque and power. Now, the downside is less piston-to-valve clearance. I measured mine and I'm around the minimum recommended. There is no problem sealing the intake - confirmed with Rick and I've had no problems sealing (traditionally if one mills heads that much one would need to get their intake manifold angle milled).
Thanks for the reply. My cam supplier who works with Rick said that cam will have no PTV clearance issues. I've never heard anyone in the G8/L76/LS3 world mention any issues with the intake sealing after milling heads. .035 is the MAX I would go on these heads and my quest for a reliable street build.
 

·
Registered
Joined
·
260 Posts
Discussion Starter #10
Well, I picked up the car last night. Running a little rough on the start-up/base tune but that is to be expected...it idles smooth and doesn't stall at stops. It's pig rich or so my eyes and nose tell me. I need to put another few hundred miles on the car before it hits the dyno. Looks like the tuner I had lined up is just too cool on youtube now to worry about the little guys. We had to reach out to an old friend for a base tune because the promised tweaks needed to get the car running never arrived despite multiple attempts at making contact.
I belong to a group called Tri-State Holdens and they all swear by HorsePower Addicts in Delaware. In talks with them now to schedule an appointment. Hopefully the car will be running like a top in the next week or so.
 

·
Registered
Joined
·
626 Posts
Awesome. And you beat me to it. What did you/are you doing for break in?

Sucks that a certain tuner won't get back to you. Seems to happen to the best of them.
 

·
Registered
Joined
·
260 Posts
Discussion Starter #12
Well i may have beaten you but I'm really not that happy. For what I paid and the time I had to wait/times the build was pushed back, I expected a little more attention to detail. I'm having a pretty loud tick and praying that it's just the exhaust. Sounds like its coming from underneath the car. My alternator light cam on yesterday after driving it for a day putting break in miles on the motor and my ABS and Track Control lights are on. Tried running a steering angle reset but the snap on scanner wasn't able to communicate with the car for that specific test/reset. The device is capable but there is a problem somewhere.
I have a tune scheduled with Horse Power Addicts next Wednesday so I need to get these issues figured out.
I was told to drive easy for another 250-500 miles and then change the oil after the dyno. I haven't revved it past 2500 rpm since I got the car. Obviously, driving the car with the base tune is somewhat challenging lol
 

·
Registered
Joined
·
626 Posts
Damn. Who worked on it? I know who did your original build, but this sounds like someone else did it this time.

I hear ya on the noise too. I fought exhaust leaks for months after my first build, enough that I was getting O2 codes. Finally said eff it and had to give up on the shop I was using. Of course it meant repaying/redoing a bunch of the work I had done, but great decision.
 

·
Registered
Joined
·
260 Posts
Discussion Starter #14
Damn. Who worked on it? I know who did your original build, but this sounds like someone else did it this time.

I hear ya on the noise too. I fought exhaust leaks for months after my first build, enough that I was getting O2 codes. Finally said eff it and had to give up on the shop I was using. Of course it meant repaying/redoing a bunch of the work I had done, but great decision.
Not naming names but I don't use anyone except for one person. He is coming up to my place on Saturday to make things right, which is why I continue to use him. I'm just praying he doesn't have to load it on a trailer and take it with him. I changed the donut gaskets at the collectors the other day...how that ring turns into a fullfledged "donut" is beyond me but oh well lol.
The strange thing for me is that one exhaust tip sounds different than the other. Drivers side has a nice rumble and passenger sounds like a metallic clank/missfire issue. Maybe I have a chunk of piston stuck in the muffler hahaha.
 

·
Registered
Joined
·
626 Posts
Haha! Could be something stuck in there. I had extra noise when my cats started to blow out, but I don't think you have that issue. ;)

And hopefully it's fixed this weekend.
 

·
Registered
Joined
·
260 Posts
Discussion Starter #16 (Edited)
Well bad news. Got the car up to HPA and we started to do a few logs on the dyno. Never got the chance to even go full throttle. My fears that the "clank" sound coming from the passenger side tailpipe being a missfire were true. Tuner saw that the O2 sensor was reading kind of funky or slow. We pulled the plugs on the passenger side and cylinder 2 was black. All the other plugs were perfect. Swapped plug, coil and wires with no change in performance. Did a compression test and only have 25 PSI on that cylinder. Performed a leak down test and the air is blowing right out of the cylinder through the exhaust. Can even hear it coming out of the tailpipe. I'm at a loss for words. Wasted a day of work and $375 for the Dyno/shop's time. My mechanic said he pressure tested the heads before dropping the motor in the car and everything held just fine. Not sure what could have happened but I expressed that I felt like the car was missfiring when I picked it up but was told it should be fine once tuned. He mentioned that he will come pull the head and I trust his skills. I'm just not 100% confident in the other head now. I want to do a full compression test but will probably wait until he's there to do it. I'm more than capable of removing and reinstalling the head but just don't want to touch it without him.
 

·
Registered
Joined
·
626 Posts
Damn, that sucks. Not sure what else to say, just sucks. Definitely do a full compression test.
 

·
Registered
Joined
·
260 Posts
Discussion Starter #18
Damn, that sucks. Not sure what else to say, just sucks. Definitely do a full compression test.
Well, pulled the head on Friday morning and we found that both valves on cylinder 2 looked a bit funky. You could actually see daylight coming from the gap on the exhaust valve when it was spun to a certain point. Not sure how it held air on the initial build. We threw in two good valves, bolted it all back together and compression is 150-155 across the board. Been driving it for the past couple days and there's no more missfires that I can feel. Dyno next Wednesday. Just praying that all goes well lol. Hats off to my buddy/mechanic. Drove over an hour and a half to my place the day after his vacation and had it broken down and reassembled in about 4 hours.
 

·
Registered
Joined
·
626 Posts
Awesome. Glad it's back up and running. Were the valve stems bent?
 

·
Registered
Joined
·
260 Posts
Discussion Starter #20
Awesome. Glad it's back up and running. Were the valve stems bent?
The stems themselves were not bent. It was right by where the stem meets the head of the valve. The exhaust valve was easy to see with the naked eye. The Intake valve was just ever so slightly tweaked. I put the intake valve in a drill and just barely wobbled, so we replaced it.
 
1 - 20 of 20 Posts
Top