Unexpected rebuild - LS1TECH - Camaro and Firebird Forum Discussion

Notices
Generation III Internal Engine 1997-2006 LS1 | LS6
Sponsored by:
Sponsored by:

Unexpected rebuild

 
Old 11-29-2018, 06:45 PM
  #1  
Teching In
Thread Starter
 
Join Date: Oct 2017
Posts: 15
Default Unexpected rebuild

99 Z28, M6, 853 heads, long tubes, lid and filter, unknown tune, stock cam, underdrive pulley, stock 10 bolt and gearing

Unknown mileage as speedo was unhooked when I bought car last year. Previous owner said itís around 170k. Various leaks and internal wear are in line with that. Developed very noticeable squawk puttsing around town. Ruled out accessory drive so figured it was lifter. Upon tear down found 1 lifter tray cracked and allowed 1 lifter to rotate sideways. Just ruined the roller on the lifter and corresponding lobe on cam. Cam journals and bearings donít show any signs any trash went thru the oil (engine ran maybe 15 mins total trying to track down noise). I havenít had a chance to remove main or rod caps to look at those. When parked engine had excellent oil pressure so hoping bearings are all clean.

Future plans have been accelerated, didnít plan on rebuilding for a couple years. Being realistic with myself I am shooting for 400hp at crank, to wheels would be bonus. Daily driver when weather is nice, canít say I wouldnít go to the drag strip a couple times of year, but street would be 90% of use.

I am confident i could open up the heads w hand porting. Just canít decide on opening up the 853s or if I should brave the cold and rip some 5.3 heads out of a truck and open those up. Drawback there is machining for 2Ē intake valve. Looking at cams but I think I should know which heads I am going to run (to know compression) before I pick one. With cam, better flowing heads, and the long tubes I think it makes sense to look into a used LS6 intake manifold as well. After work is complete would take it to a good tuner.
Just looking for some advice on head selection so I can move on with putting it back together.

Thanks



Petemw01 is offline  
Old 11-29-2018, 07:14 PM
  #2  
"I MAID THEESE"
iTrader: (3)
 
Mavn's Avatar
 
Join Date: Jul 2011
Location: Houston
Posts: 1,478
Default

Stock 243 heads
tsp 228r cam
Ls6 intake
Speed eng 13/4 headers
Tune
400 rwhp
Mavn is offline  
Old 11-29-2018, 07:30 PM
  #3  
Teching In
Thread Starter
 
Join Date: Oct 2017
Posts: 15
Default

Sounds simple enough to me. Can stock injectors handle 400 or would I be on borrowed time with those? From what I can see in the intake runners on the head they were all spraying well/evenly.

I know the 853 heads are frowned upon. I know the 243 are a better casting and people love them. What in particular lends them to flow so much better? Runner cc or shape? Finish? I wouldnít mind sitting down and doing my best for 25-30 hours working with the 853s. The only Ďgoodí thing I can say about these in particular is they donít have the pry location cast in to them. I guess Iím just wondering what area of the 853 would need the most attention to get it to flow equal to or even a little greater than a STOCK 243.

Dont mean to come across as cheap. I enjoy taking things I already have and making them better. I have no problem spending the $ where necessary.

thanks for the quick response!
Petemw01 is offline  
Old 11-29-2018, 07:47 PM
  #4  
TECH Senior Member
 
Join Date: Jun 2016
Location: Central Cal.
Posts: 9,393
Default

The best porting on heads nowadays is done CNC, as it is repeatable forever. Hardly anyone hand ports anymore.
G Atsma is offline  
Old 11-29-2018, 08:21 PM
  #5  
"I MAID THEESE"
iTrader: (3)
 
Mavn's Avatar
 
Join Date: Jul 2011
Location: Houston
Posts: 1,478
Default

Originally Posted by Petemw01 View Post
Sounds simple enough to me. Can stock injectors handle 400 or would I be on borrowed time with those? From what I can see in the intake runners on the head they were all spraying well/evenly.

I know the 853 heads are frowned upon. I know the 243 are a better casting and people love them. What in particular lends them to flow so much better? Runner cc or shape? Finish? I wouldnít mind sitting down and doing my best for 25-30 hours working with the 853s. The only Ďgoodí thing I can say about these in particular is they donít have the pry location cast in to them. I guess Iím just wondering what area of the 853 would need the most attention to get it to flow equal to or even a little greater than a STOCK 243.

Dont mean to come across as cheap. I enjoy taking things I already have and making them better. I have no problem spending the $ where necessary.

thanks for the quick response!
No reason to hand port 5.3 heads . Just wasting your time imo .

katech charges 500 for a Cnc port work. But then again a stok 243 flows more and can get them for $300 all day.
Mavn is offline  
Old 11-29-2018, 08:31 PM
  #6  
Teching In
Thread Starter
 
Join Date: Oct 2017
Posts: 15
Default

Agreed CNC is the for sure way to go. I have read quite a bit of everyoneís experiences on here and other forums. Im still up in the air which way to go. Originally was sure I was going to pick up some 5.3 heads and go that route for the compression boost. But machining for the intake valve kind of turned me off that idea. And it seems milling the stock heads may hurt flow somewhat.

Back to the cam-112 or 114 lsa matter? Choppy doesnít bother me, but not a necessity. Would rather not have a lopey idle to the point the ecm is hunting for the right rpm, weak brake vacuum, ac controls messing up, etc. Hopefully tune can take care of that? And looking at the dyno graph itís not a very smooth climb. Is that common among the aftermarket cams aimed to meet this goal? Would rather move the power band down than up. After the long tubes is off road Y with SLP loud mouth. Anything past 6k is quite harsh (I donít mind but neighbors in the next county might)
Petemw01 is offline  
Old 11-29-2018, 08:33 PM
  #7  
"I MAID THEESE"
iTrader: (3)
 
Mavn's Avatar
 
Join Date: Jul 2011
Location: Houston
Posts: 1,478
Default

Go check my built thread out m I'm running 5.3 heads . A baby cam and an og fast .

We maxed the injectors and stock fuel pump out at 5000 rpm . Lol it has alot of Information you might need/want to read .

Its Mavns summit cam build thread.
Mavn is offline  
Old 11-29-2018, 09:13 PM
  #8  
Teching In
Thread Starter
 
Join Date: Oct 2017
Posts: 15
Default

Good info-would be interested to see what kind of numbers you get.
Petemw01 is offline  
Old 11-29-2018, 09:27 PM
  #9  
TECH Senior Member
iTrader: (3)
 
99 Black Bird T/A's Avatar
 
Join Date: Nov 2001
Posts: 6,060
Default

99-00 fbody LS1's have 26# injectors. New ~ 450 whp was possible with the stock system. Injectors were static and spraying with intake valve closed.

My 99 TA made 418 whp and ran that way for 15 years & 130,000+ mile. ​​​​​However the stock fuel system definitely wasn't able to support that in the later years. The car "woke up" with a new Racetronix fuel system probably because the old stock fuel pump couldn't maintain the pressure at higher rpm.

I wouldn't trust a 99-00 LS1 stock fuel system in a 20 year old car to be able to support a good heads and cam package. New better fuel pump, filter and bigger injectors will help make sure the car makes good hp & keeps making good hp in the years ahead.

As Mavn said I skip the hand ported heads. You'll really have no idea what you've got unless all 8 ports are flow tested. There are a lot of good CNC probably and a few exceptional ones. You might get lucky and find a good set of ported used 5.3's with 2 inch or better valves or used ported243's on the classified section. Some 5.3's were prone to crack so be careful with getting a used 5.3 heads either ported or unported.

Looking forward to you'd build.
99 Black Bird T/A is online now  
Old 11-30-2018, 10:00 AM
  #10  
Teching In
Thread Starter
 
Join Date: Oct 2017
Posts: 15
Default

Based on consensus I guess Iíll keep my eyes peeled for a set of 243/799s. Maybe I can make some table lamps out of the 853s🤔

With cams that have lift around the .600 range would there be any benefit to milling the 243 heads? Or am I making more work for myself with cutting reliefs?
Petemw01 is offline  
Old 11-30-2018, 10:24 AM
  #11  
"I MAID THEESE"
iTrader: (3)
 
Mavn's Avatar
 
Join Date: Jul 2011
Location: Houston
Posts: 1,478
Default

Originally Posted by Petemw01 View Post
Based on consensus I guess Iíll keep my eyes peeled for a set of 243/799s. Maybe I can make some table lamps out of the 853s🤔

With cams that have lift around the .600 range would there be any benefit to milling the 243 heads? Or am I making more work for myself with cutting reliefs?
228R cam from TSP is your best bet.

You can mill your 243's .030 and still run that cam and have PLENTY of clearance.

Mavn is offline  
Old 11-30-2018, 03:18 PM
  #12  
TECH Addict
iTrader: (2)
 
Join Date: Apr 2006
Location: Pittsburgh
Posts: 2,117
Default

I like the 228/232 split better. Or a Cam Motion Titan 2. Split cams tend to carry power a bit higher. Pick your poison.
wannafbody is offline  
Old 11-30-2018, 04:53 PM
  #13  
TECH Fanatic
 
Join Date: Oct 2016
Location: PDX-OR-USA
Posts: 1,116
Default

Whichever combo you pick,, it has to be tested by hand on the block, once you change cams.
Don't need the crank in, but you put the cam and valve train & heads in/on,, and check the valve sweep on every single one.

Some will say not necessary but I've been burned twice with "stock" heads with different pocket heights,, and not just a little off..

Example I did my 4 cylinder jeep head, had to cut 6 of the 8 spring pockets for a Clay Smith .560(IIRC) lift cam. YMMV..
pdxmotorhead is offline  
Old 11-30-2018, 05:15 PM
  #14  
Teching In
Thread Starter
 
Join Date: Oct 2017
Posts: 15
Default

I have been accused of being pretty **** upon reassembly. I can add this to the list.

on the suggested cam selections I will be a little more specific for the goal. If I had a choice between 400hp at a relatively lower rpm with more power down below and 425hp at a higher rpm with less low end, Iím going to pick the first. The 18 year old in me hates mid 30ís, more reasonable me.

Not saying the needle wonít see above 6k rpm couple times a week. I just donít need an uber aggressive setup and go overboard at the expense of reliability.

thank you all
Petemw01 is offline  
Old 11-30-2018, 05:33 PM
  #15  
"I MAID THEESE"
iTrader: (3)
 
Mavn's Avatar
 
Join Date: Jul 2011
Location: Houston
Posts: 1,478
Default

I love my summit cam I put in my trans am in my build thread . I'm liking it more and more every day!

Maybe it should be more for what you want than a bigger cam .

Just my $.02
Mavn is offline  
Old 11-30-2018, 05:52 PM
  #16  
LS1Tech Premium Sponsor
iTrader: (2)
 
Join Date: Apr 2016
Posts: 3,941
Default

Our high lift asa and milled (.030) unported 243s made 430/420 on a 99 m6 ta.

We also carry all of the rebuild/rering/reseal parts for the best price out there. Mix and match.

Our high lift asa cam and pac beehive springs are also on sale for $499 as well.

Great price, one stop shop, and everything you need. It has a 110 lsa so it has a very aggressive idle but will also peak a little sooner and give you much more useable power! Seems like exactly what you want.

tech@WS6store is offline  
Old 12-08-2018, 01:44 PM
  #17  
Teching In
Thread Starter
 
Join Date: Oct 2017
Posts: 15
Default

Went around to multiple junkyards today and the only 243 heads to be had werenít for sale. They didnít want to part out a good engine🙄. I found a few dozen 862 or 706 castings on 5.3 however.

I can get whatever heads I can find at LKQ for $50 each. So with being able to get a set of 862 or 706 for $100 would it be worth to go that route and use the savings to install the 2Ē intake valve in them? Or wait patiently for a 243 head engine to roll in and pray no one beat me to it (they would be $50 each too)? Would have to then pay to get the 243 heads milled...

Petemw01 is offline  
Old 12-08-2018, 02:47 PM
  #18  
TECH Senior Member
 
Join Date: Jun 2016
Location: Central Cal.
Posts: 9,393
Default

Look for 799's as they are identical to 243's and are in most pickups with a Gen IV 5.3.
G Atsma is offline  
Old 12-08-2018, 03:03 PM
  #19  
Teching In
Thread Starter
 
Join Date: Oct 2017
Posts: 15
Default

I forgot to mention my search was for 799 and 243. Everything that SHOULD have had them was already picked over.

I know there are some for sale all the time but if I can get a pair for $100-200 local I would rather do that than $400-500 shipped. But I may have no choice!
Petemw01 is offline  
Old 01-02-2019, 10:03 PM
  #20  
Teching In
Thread Starter
 
Join Date: Oct 2017
Posts: 15
Default

Got some 243 heads out of a 2007 Tahoe. Are the stock rockers the same between these and the stock 99 853 heads? Also I plan on an ls6 Intake. The 243s came with different steam tube and block off blocks. Will these work with the ls6 intake? Assuming the stock ls1steam tubes will not work with the flat bottom ls6 intake?

thank you
Petemw01 is offline  

Thread Tools
Search this Thread

About Us Archive Advertising Cookie Policy Privacy Statement Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: