Factory heads? - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

GsxrMe · 07-04-2016, 09:51 AM

I'm seeing a lot of builds building just the short block and using head studs. How rough and tough is the factory valve springs?

Dream20b · 07-04-2016, 10:01 AM

Haven't done any research on this but...
I haven't seen any of these broken yet, so I assume fairly strong.

gramicci101 · 07-04-2016, 10:20 AM

I know Full Blown has stage 1-3 head packages (hehe), so the need has been identified. They also push 700+ hp though, so maybe the OEM head is only an issue at those levels.

@FullBlown, at what level did the head become an issue?

spitfire481 · 07-04-2016, 10:30 AM

Doing valve springs helps keep the rockers from shooting out the valve cover. We do them on every built motor and check that the lash is correct

Matt@Cosworth · 07-04-2016, 01:11 PM

the factory springs are far too light for any reasonable amount of boost
if you're rebuilding the engine I'd swap them out for something heavier

weederr33 · 07-04-2016, 01:58 PM

[QUOTE=gramicci101;2696432]I know Full Blown has stage 1-3 head packages (hehe), so the need has been identified. They also push 700+ hp though, so maybe the OEM head is only an issue at those levels.

Head packages are a serious thing..... hehe

wbradley · 07-04-2016, 04:38 PM

If going high power, a lot of people have swapped the valve springs. Some people have actually broken a spring. If you are 300 HP or less probably not needed in most cases,from what I have read.

Matt@Cosworth · 07-06-2016, 07:44 AM

Quote:

Originally Posted by wbradley

If going high power, a lot of people have swapped the valve springs. Some people have actually broken a spring. If you are 300 HP or less probably not needed in most cases,from what I have read.

I agree with that - although the standard spring cover is so small that even a stock engine would benefit from a slightly heavier spring to help with over-rev's
my analysis showed a max safe rpm with the stock cam is 7800rpm....

admittedly a loss of valve control is something that you can often get away with for a while until the valve head falls off 10,000 cycles later

Ultramaroon · 07-06-2016, 12:40 PM

Quote:

Originally Posted by Matt@Cosworth

I agree with that - although the standard spring cover is so small that even a stock engine would benefit from a slightly heavier spring to help with over-rev's
my analysis showed a max safe rpm with the stock cam is 7800rpm....

admittedly a loss of valve control is something that you can often get away with for a while until the valve head falls off 10,000 cycles later

I was about to interject/ask about this mysterious relationship of valve spring rate to power but fortunately you came into the picture.

07-04-2016, 09:51 AM	#1
GsxrMe Senior Member Join Date: Jul 2015 Drives: Late 2014 Subaru BRZ Location: Cape Coral, FL Posts: 557 Thanks: 20 Thanked 183 Times in 139 Posts Mentioned: 5 Post(s) Tagged: 2 Thread(s)	Factory heads? I'm seeing a lot of builds building just the short block and using head studs. How rough and tough is the factory valve springs? __________________ 2014 Subaru BRZ FBM Turbokit: GTX3076R - ECUTEK HRI FlexFuel tune - FBM 3" Turboback Exhaust - 550cc Injectors - Walbro 485 Fuel Pump - 4bar Map Sensor - FBM Oil Pan - ACT SB7-XTSS - AMSOIL all fluids - Forester XT Oil Cooler - Cusco engine, trans mounts - Whiteline rear differential bushings - Perrin shifter bushing - Firehawk 235/45/17 - AEM Failsafe

07-04-2016, 10:01 AM	#2
Dream20b Y u do dis? Join Date: May 2014 Drives: 2013 Scion FR-S Location: Northbrook, IL Posts: 465 Thanks: 832 Thanked 194 Times in 107 Posts Mentioned: 3 Post(s) Tagged: 0 Thread(s)	Haven't done any research on this but... I haven't seen any of these broken yet, so I assume fairly strong. __________________ Dat Hot Lava Doe Clearly you have no clue what you are talking about. Everything you said was completely and utterly the ramblings of a babbling idiot regurgitating garbage from his mouth. Everyone here is now dumber from reading your post. Please die now.

07-04-2016, 10:30 AM	#4
spitfire481 Senior Member Join Date: Mar 2013 Drives: 2JZ FRS Location: Pure Automotive Performance Posts: 1,378 Thanks: 97 Thanked 1,354 Times in 621 Posts Mentioned: 27 Post(s) Tagged: 2 Thread(s)	Doing valve springs helps keep the rockers from shooting out the valve cover. We do them on every built motor and check that the lash is correct __________________ Pure Automotive Performance MoTeC Build Thread @spitfire481

07-04-2016, 01:58 PM	#6
weederr33 Airborne at your service Join Date: Sep 2014 Drives: '17 BRZ Series.Yellow Location: El Paso, Texas Posts: 6,327 Thanks: 4,529 Thanked 5,587 Times in 2,929 Posts Mentioned: 33 Post(s) Tagged: 2 Thread(s)	[QUOTE=gramicci101;2696432]I know Full Blown has stage 1-3 head packages (hehe), so the need has been identified. They also push 700+ hp though, so maybe the OEM head is only an issue at those levels. Head packages are a serious thing..... hehe __________________ Series.Yellowbird - http://www.ft86club.com/forums/showthread.php?t=122135 MS, CSCS, TSAC-F, CPT

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Does your BRZ still turn heads?	Grimlock	BRZ First-Gen (2012+) -- General Topics	50	05-27-2014 02:29 PM
Wtb FA20 heads	Wonderbar	Want-To-Buy Requests	6	08-23-2013 08:38 AM
Heads Up BRZ Available In So Cal	ZmZMWagon	Southern California	17	06-18-2012 03:10 PM

07-04-2016, 10:20 AM	#3
gramicci101 Off Topic Join Date: Feb 2014 Drives: 2014 Subaru BRZ Limited Location: Vegas, baby! Posts: 4,610 Thanks: 2,369 Thanked 4,243 Times in 2,170 Posts Mentioned: 43 Post(s) Tagged: 3 Thread(s)	I know Full Blown has stage 1-3 head packages (hehe), so the need has been identified. They also push 700+ hp though, so maybe the OEM head is only an issue at those levels. @FullBlown, at what level did the head become an issue?

07-04-2016, 01:11 PM	#5
Matt@Cosworth Senior Member Join Date: Dec 2015 Drives: blue - Cosworth SC stage 3.0 Location: Northants - UK Posts: 330 Thanks: 3 Thanked 388 Times in 182 Posts Mentioned: 34 Post(s) Tagged: 1 Thread(s)	the factory springs are far too light for any reasonable amount of boost if you're rebuilding the engine I'd swap them out for something heavier

User Name		Remember Me?
Password