LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts - Performance Forum

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LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Wednesday, June 12, 2013 6:15 PM
3.4L LQ1 DOHC V6 91-97 years:

Possible valve spring to use with the Secret Cams or straight up L.O.'s when using the LD9 2.4L Twincam valvetrain, which has the 33mm lifters, lighter than the Quad 4's stock valvetrain to rev up to 6500-7000 rpms and still be on the safe side. Especially considering higher mileage with fatigue, making them more prone to floating valves.

http://www.fme-cat.com/overlays/part...-1562&pt=Valve Spring&lu=1992 CHEVROLET LUMINA&vin=
3.4L LQ1 Clevite valve spring part number 212-1489

This 3.4l has the same style 35mm lifters in the earlier years as the quad 4's and the later years of the 3.4l shares the 33mm lifters as the 2.4L.

The Twincam's valve spring has a installed height of 1.4370' at 50-55lbs and the LQ1 has 1.4' with 72lbs for these Sealed Powered springs. Might work using the 2.4's retainers on top and keepers and with the 33mm lifter since the 3.4l's springs are skinny on top.

Quad 4 valve spring http://www.fme-cat.com/overlays/part...-1530&pt=Valve Spring&lu=1994 PONTIAC GRAND AM&vin=

Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Wednesday, June 12, 2013 6:42 PM
im honestly wondering if these arent the mantapart "sport" springs. when i compared jay's manta springs with stock LD9 springs they look damn near identical til you look up close. iirc the manta springs are a little taller and have a slightly larger wire size. which would stand to reason for them having the little bit more seat pressure. i did measure them too, they came out at around 70psi at 1.437 i wanna say....

it wouldnt be the first time mantapart claimed to make something they just found on a shelf somewhere for a different engine and made work ill tell you that much.

still not enough seat pressure for HO cams in my book. even though they might work just fine 9 times out of 10. definitely an absolute great idea to run them with secret, straight LO, or similar sized cams, though...

i might still try and find a way to make those new lightweight 33mm lifters that you found work on HO cams though. not only would that make it so you wouldnt need to bother running 2.3 towers or modding the 2.4 towers, it would be a damn nice weight savings on the valve train components. who was it.. jay that found a thread over on Q4F that had someone machining the inner diameter of the 33mm lifters so they would fit the HO spring without binding or cutting into it? the more i think about doing it that way the better it sounds, honestly. great job jeremy!


Edited 1 time(s). Last edited Wednesday, June 12, 2013 6:46 PM


M45/OS crank/2.4 snout. It's nice to be injected but I love being blown!
Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Wednesday, June 12, 2013 7:02 PM
Definetly. Finally maybe we found these springs out after they wont give the specs or part numbers out for them. Would be something in consideration using the HO cams as well for a cheapy way to get by and use the 50 gram weighted 33mm lifters without the 35mm lifters using the quad 4 valve springs since the'll dig into the smaller lifter. Hell these and the Quads Sealed Powers are only 5 lbs different lol nothing for over 7000, but still. the 3.4l does say it has .37 and .39' lift on these springs. lighter valvetrain is always a plus for even quicker revs. The other spring next in line to use is the Crower spring Part Number 68190-16 since this is also ideal for the 2.4 33mm lifter because the springs diameter is smaller... We'll freakin A, need to get my hands on on of these springs and compare!
Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Wednesday, June 12, 2013 7:06 PM
HELL YEAH! YOU GUYS ARE WELCOME!
Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Wednesday, June 12, 2013 7:11 PM
Good info, Thanks



Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Wednesday, June 12, 2013 7:16 PM
So what was Mantapart selling these springs for? They dont have the old site which I believe was a hotmail format or what not... Hell these springs are like 8 bucks at your local dealer. lol
Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Thursday, June 13, 2013 3:10 AM
link isnt working.


I do not see the big deal with running secret cams on stock springs and lifters. I have been doing it for almost a 100k. I know a few others also.

Still could be a good find for different cams.



FU Tuning



Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Thursday, June 13, 2013 10:17 AM
Addicted to meth wrote:

link isnt working.


I do not see the big deal with running secret cams on stock springs and lifters. I have been doing it for almost a 100k. I know a few others also.

Still could be a good find for different cams.


i agree. mine have also been just fine, even with the .375 LO intake cam. and i beat the absolute piss out of my car, so...



M45/OS crank/2.4 snout. It's nice to be injected but I love being blown!
Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Friday, June 14, 2013 8:55 PM
Does this link work...
http://www.fme-cat.com/overlays/part-detail.aspx?brand=SP&PartNumber=VS-1562&pt=Valve Spring&lu=1992 CHEVROLET LUMINA&vin=
Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Friday, June 14, 2013 9:00 PM
VS-1562 Sealed Power, just search it, and go to Federal Moguls site to look up applications. Compare it to the Quad 4 valve spring and Twincam... Its the earlier years of the GM 3.4L dohc. Why they don't show a valve spring for the later years... who knows..
Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Saturday, August 17, 2013 4:27 PM
Well, with 1.4" install height, New HO cams at .0410", gives about a ten thousandths error gap. Factoring in coil bind at 0.982"...

I may try this.


Chris


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08


Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Sunday, August 17, 2014 5:27 PM
Well, it worked.

Cut used LG0 cam, 47/64 drill bit for the hex, ford style oil pick up and a LG0 oil pump, using these springs on a stock LD9 head.



Chris





'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Monday, August 18, 2014 4:17 AM
Chirs anything special with the springs?




PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Monday, August 18, 2014 8:25 PM
yeah. after more testing (long story. lol) LG0 cams are to big, the "bucket" of the lifter hits the spring and binds.

So, now I have modded 2.3 LG0 cams I need to get out and hunt up some LD2 cams.

Sigh, all for a daily driver.


On the plus side I have (have to get it to post it for others) the belt you need with a Over drive crank pulley and the replacement idler pulley.


Chris


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Sunday, August 24, 2014 7:15 AM
22 my last. The 2.3 pump swap and whoever modded the block for Brian...anyway way to much oil PSI in the head, causing the lifters to hang the valves open.

HO cams and 2.4 lifters work great.

Mike, is this pulley smaller then the RaceTec one? I seem to remember the other one hitting a timing cover bolt when It went on.

But, love the hit of 8PSI at 3500. Just need to tune it now.

Chris


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Sunday, August 24, 2014 5:36 PM
Well, right around 10-12 psi... way to much heat though (dont feel like buying water injection for a DD). That OS crank pulley and belt will be in the classifieds soon.

Back on topic.

The valve springs for the 3.4 DOHC work with HO cams, you just need to make the bottom spring guide fit, and can not use the valve rotators.

Chris


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Monday, August 25, 2014 3:42 AM
Taetsch Z-24 wrote:


Mike, is this pulley smaller then the RaceTec one? I seem to remember the other one hitting a timing cover bolt when It went on.

But, love the hit of 8PSI at 3500. Just need to tune it now.

Chris


The pulley is actually larger ever so slightly, but the rear most rib is cut down as much as possible to clear "that" timing cover bolt. When I made my prototype it ran right into that bolt head.






PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Friday, August 29, 2014 3:04 PM
lol chris... you of all people should know the M45 could benefit from WMI on even a stock 2.8" pulley. you say its "just a dd" like you don't care but in reality if you did not, why did you do HO cams, why the 2.3 pump swap, etc?

you can use WMI on a dd, hell I did and it wasn't a big deal.



RIP silver car. You will be missed.
Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Wednesday, September 17, 2014 9:50 AM
I did the block work for the 2.3 swap, just had a welder touch it up to seal it. Same with the other "hybrid" engine I built for Craig.

Not exactly sure how high oil pressure would make the lifter contact/stick with the spring though. Still kinda confused on that one.

Glad you got it going though! Dugan called me Monday to say he talked to you at work and was thinking about buying you DD now. lol.


SPD RCR Z - '02 Z24 420whp
SLO GOAT - '04 GTO 305whp
RACER X - '78 Opel Kadett W41 Swap

Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Monday, September 22, 2014 2:53 AM
HA! SO THESE WORK?????? IM sure as hell thinking these are the Mantapart Sport Springs....
Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Monday, September 22, 2014 3:03 AM
Chris are you sure you cant use the rotators? I just pulled Thomas Thyrons head off to swap a ported one and changed over the valve springs. They were the Mantapart Sport ones. LOOK very identical to the 3.4l.... Now I cant remember if his head had rotators. Believe it did, but the HO cams seem to be working well with the lifters buckets in the towers clearing the bigger lobes. Lifters fine, springs fine. Works well. Revs to 7000...

Re: LD9 2.4L Twincam Valve Springs Secret/LD2 L.O. Camshafts
Saturday, October 18, 2014 9:10 PM
They did not fit, but I also did not grind them to "make" them.

Brian, so the real issue is wayyyy to high of oil PSI in the head. long story but it has around >60 and the lifters pump up, holding the valves open. (donor engine was a 96)
Make a controlled oil leak in the head, put it back to the block and it runs great. Took the blower off and am running a 2.3 intake. 26 mpg and nice low end. it would idle at 20 in/hg with the HO cams. the springs worked great!

Brad, the DD had 176K on it and leaked oil bad, wanted to be proactive and not break down in winter with a rod telling the starter to not stay attached.

Oh Brian, I got the GTO Speed density tuned, hits HARD. VE\LTFT is within 1.2%. LSx rips...hard.

Chris


'02 Z-24 Supercharged
13.7 @102.45 MPH Third Place, 2007 GMSC Bash SOLD AS OF 01MAR08

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