My LQ4 427 build
07-14-2016, 11:24 AM
#44
Launching!
Thread Starter
Haha - I'm running Adjustable Harland Sharp Roller rockers since I have the short travel lifters. Makes it easy to set preload with the adjusters. We didn't see any float on the Dyno and with the Cam swap I'll be doing I should be good to 7200ish rpm if the cam/intake will spin that high.
09-14-2016, 08:55 PM
#45
Man, this is a great build thread. I have a bunch of questions for yah.
How has the motor been for the past couple of months?
How long did it take you to build the motor?
I'm debating about giving it a try, more intimidating than anything.
Did you need any special tools?
Any info would be appreciated
Thanks
How has the motor been for the past couple of months?
How long did it take you to build the motor?
I'm debating about giving it a try, more intimidating than anything.
Did you need any special tools?
Any info would be appreciated
Thanks
09-14-2016, 09:05 PM
#46
Launching!
Thread Starter
It's been good - been chasing some tuning issues - the transient from idle to wot creates a terrible lean condition but drives great everywhere else. Also chasing some split STFTs from B1 to B2 which I'm not sure why - waiting for my new O2 sensors to come in to see if that alleviates the issue - they are the stock 100k mi O2's so they may be tired. I swapped out the ported manifold thinking it was the culprit but it doesn't seem to be the case so I'll probably Dyno ported vs stock to see the differences if any. I also switched to The 1 Bar Enhanced SD tune but have yet to do any tuning at all. Also with the SD tune I'll be ditching the MAF and installing an air temp sensor fir more accurate fueling and timing.
Other than the tuning issues its been great - had another adjuster back off on me again so I decided to get another cam that was a bit less aggressive with lower lift. Should be installing it this weekend.
Thanks for the compliments and I'll try to keep this thread updated.
Other than the tuning issues its been great - had another adjuster back off on me again so I decided to get another cam that was a bit less aggressive with lower lift. Should be installing it this weekend.
Thanks for the compliments and I'll try to keep this thread updated.
09-14-2016, 10:43 PM
#47
If you are having stft variances from one side to the other you could have a vacuum or exhaust leak, a leaking injector or possibly a weak plug/plug wire... Have seen leaking intake gaskets through fuel trims off by as much as 5-10% had a suburban that the bank 1 stft was -.5 and bank 2 was 6-8 ended up being flattened intake gaskets, also threw lean code, misfire codes, and something else all related to bank 2 being lean as hell from a weak gasket...
09-14-2016, 11:11 PM
#48
Launching!
Thread Starter
If you are having stft variances from one side to the other you could have a vacuum or exhaust leak, a leaking injector or possibly a weak plug/plug wire... Have seen leaking intake gaskets through fuel trims off by as much as 5-10% had a suburban that the bank 1 stft was -.5 and bank 2 was 6-8 ended up being flattened intake gaskets, also threw lean code, misfire codes, and something else all related to bank 2 being lean as hell from a weak gasket...
I've sprayed around all gaskets and potential vacuum leak points with carb cleaner and found nothing.
I've done the power balance test to check injectors and they checked out ok
I'm fairly confident that I'm running on all 8 as it idles nice - well as nice as it can with the big cam.
Verified with an IR temp gun on the headers too all cylinders are consistent at idle.
I swapped the O2 sensors from one side to the other and the trims got really weird but that could be because of the loose adjuster but again (actually I'm very confident that it is the reason for the weird split)
I'm also pretty confident I don't have an exhaust leak as the O2s are in the header collector and the only real place there would be a leak would be at the head and I don't hear anything and have done a stethoscope check around the flanges and came up with nothing.
If the new O2s don't help then I don't know what I'm gonna do.
Injectors hold pressure for a long time after key is off, so I doubt they are leaking.
I do have a 90deg T fitting on B1 fuel rail vs a smooth mandrel fitting on the B2 rail - maybe that's causing slight cavitation causing the fuel delivery to be off side to side - tuner says that he sees that all the time and has never know that to cause an issue before.
Only real thing I haven't checked yet are plugs - im running TR6IX gapped at .040" and have been thinking about changing out to just regular TR6 plugs gapped down a little
Wires are new granatelli's and I've verified the click on each plug and coil.
If it's none of that then I think it could be the cam - it is a second hand cam used for racing one season and it's technically not a street cam, it's a blower cam spec'd for a 408 with cathedral heads. New cam is spec'd the the head/intake combo I have and 427ci - when I pull the cam I'm gonna throw the calipers on it to see if it's in spec or if there's a variance between bank lobes.
I'm hoping when the new cam goes in with the new O2 sensors I'll have a better time tuning in SD than with the MAF.
Again - keep y'all posted - I'm going to go back to a load cell type of Dyno to really dial in my VE and see if I can get a little closer to the 500 mark. I'd really like to put the hi ram back on after I get my tuning situated and see what I'm really giving up down low as compared to the L92 - that and compare it to my ported L92 as well.
09-15-2016, 12:47 AM
#49
I'm no rocker expert, but installing a less aggressive cam because you are having issues with the rocker adjusters back off doesn't make any sense to me. What are the cam specs on the cam you say is a problem?
You don't need adjustable rockers to help set preload. Put some stockers on there. Probably rev faster, be more reliable and you can keep the good cam.
Throw the harlands in the trash. Get some stockers, rebuild with the trunion kit from comp and be done. Probably cheaper than trying to swap cams. Especially if the new cam is gonna be ground on a different base circle (push rod change also).
You don't need adjustable rockers to help set preload. Put some stockers on there. Probably rev faster, be more reliable and you can keep the good cam.
Throw the harlands in the trash. Get some stockers, rebuild with the trunion kit from comp and be done. Probably cheaper than trying to swap cams. Especially if the new cam is gonna be ground on a different base circle (push rod change also).
09-15-2016, 01:09 AM
#50
Launching!
Thread Starter
That's not why I changed out the cam - current cam is a .653/.660 lift cam. I was told at around .625"ish lift the stock rockers would beat on the valve tips and cause guide wear - so I got rollers. I called Lunati and told them my cam specs and they spec'd me their .660 dual valve springs. Back then I didn't understand installed height and coil bind and all that jargon, and trusted on what they said would work. This cam is beating right at coil bind and I'm sure isn't good for them.
New cam is alread purchased and sitting in my living room with a little better cam profile and lower .62x/.593 I'm betting it will help with the adjusters coming loose and yes if I had to do it over again I would probably go bronze reunions and not so much lift, but in here so I'm trying to make it work. If anyone has a set of LS3 rockers with trunions they want to let me borrow - I'll try them out and get Dyno numbers and see if the HS rockers are really garbage.
New cam is alread purchased and sitting in my living room with a little better cam profile and lower .62x/.593 I'm betting it will help with the adjusters coming loose and yes if I had to do it over again I would probably go bronze reunions and not so much lift, but in here so I'm trying to make it work. If anyone has a set of LS3 rockers with trunions they want to let me borrow - I'll try them out and get Dyno numbers and see if the HS rockers are really garbage.