Spring recommendation for GN1s

[bison]

after talking with comp cams, they dont recommend running 26120's closer than 050-060. so i think i will try another spring. i attached the comp cam pdf on the 26120's

http://www.compcams.com/WhatsNew/Files/26120 Beehive Spring2.pdf

comp gave me part number 978-16 a dual spring that they think is a better option. i have ordered K motion #750 springs and will try these this weekend and see how they check out.

I've ran the 26120 down close to coil bind. But with hyd lobes and the lift is theoretical because of the bleed down. PAC 1203 has a much higher rate and works well in hyd rollers with lift up around .600

 

[NCTURBOS]

FWIW, I've been using the CompCams 26926 spring, with 885 lifters, and .105" wall pushrods (or thicker) on both iron heads and aluminum heads for a few years now with great success. They're not a drop-in spring for either head though. You'll need to either send them (heads) for some machining, or call Goodson (like I did) and buy a couple tools.

K.

 

[tonysmach]

Good thread. I have to look at my build sheet to see what springs I have on my GN1 heads. I also have DLS 218 cam. Right now the engine breaks ups a little once I get over 5100 rpms at about 23 psi of boost. I get no KR. I need to check my spark plugs.

 

[qws2000]

I just changed my plugs, and they were fine, and I added the power logger and the wideband shouldnt I be able to see the breaking up?

 

[GNDriven]

I'm skeptical that the valve springs are the only suspect in a "breaking up" above a certain RPM issues stated here. I'm not trying to diverge from topic, which is valve springs. The combos and part number given in this thread are good info, however, I had a break up /stumble at higher RPM were the car would lay over and refuse to find any higher rpm. I found it to be a weak/bad coil pack. I changed the coil pack and away I went it went from shaking at 4200 to a clean 6200 in short order. I wished better approaches to diagnosing a breakup, stumble issue at higher RPMs were more clear.

 

[SloGN]

I'm skeptical that the valve springs are the only suspect in a "breaking up" above a certain RPM issues stated here. I'm not trying to diverge from topic, which is valve springs. The combos and part number given in this thread are good info, however, I had a break up /stumble at higher RPM were the car would lay over and refuse to find any higher rpm. I found it to be a weak/bad coil pack. I changed the coil pack and away I went it went from shaking at 4200 to a clean 6200 in short order. I wished better approaches to diagnosing a breakup, stumble issue at higher RPMs were more clear.

The issuse on busa69's car was ruled out. everything under the sun was changed out from my car and it made no difference. John's problem started after the freshened up the motor and changed from a flat tappet cam to this new roller cam. When i mean everything was checked i mean everything. coil/module, scoped the crank and cam sensor, checked all grounds. chip, car pulled like a mofo till 5350-5400 then the KR would nuts with race gas or alky. Used a wideband on the dyno and AFR's perfect. ALso the boost could be anywhere from 18-28 psi and it made no diffrence. The problem would start sooner with the hight boost.

 

[jpwalt1987]

The issuse on busa69's car was ruled out. everything under the sun was changed out from my car and it made no difference. John's problem started after the freshened up the motor and changed from a flat tappet cam to this new roller cam. When i mean everything was checked i mean everything. coil/module, scoped the crank and cam sensor, checked all grounds. chip, car pulled like a mofo till 5350-5400 then the KR would nuts with race gas or alky. Used a wideband on the dyno and AFR's perfect. ALso the boost could be anywhere from 18-28 psi and it made no diffrence. The problem would start sooner with the hight boost.

I may have missed it , but what lifters are you running? I had this problem with some morels. I just put the car back together with some comp 885s and .116 wall pushrods. It's a 218/218 cam. Haven't driven it yet though.

 

[SloGN]

i'm using the comp lifters than dan at dls sent with the cam kit.

 

[tonysmach]

Since this is about valve springs...does anyone know the specs on the upgrade Hyd. Roller Springs that come with the Champion Aluminum Heads. The description states that they are behive springs but no specs. I did not see them mentioned is this thread. Here is a link to FT website.
Springs for Hyd. Roller Cam

 

[turbobusa69]

Since this is about valve springs...does anyone know the specs on the upgrade Hyd. Roller Springs that come with the Champion Aluminum Heads. The description states that they are behive springs but no specs. I did not see them mentioned is this thread. Here is a link to FT website.
Springs for Hyd. Roller Cam

tonysmach, i have the kit from FT, the springs are PAC, mike from FT says the ones i have are about the strongest single beehive available from PAC, there was one a few pounds stronger but isnt one he usually sells. the ones i have are the ones he sells alot of, they came up to 130lbs seat pressure and install height was under 1.72. the open pressure with a 530 lift cam was just about 300lbs. but this set up was with his retainers, the locks he sent which were -.050. so with a zero keepers your seat pressure would be way less due to your install height would be 050 taller.

 

[turbobusa69]

well i have the K motion 750's with standard retainers and +060 locks and thanks to mike D for assembling them. pressures are about the same at seat(130ish) and open 530 lift is now 385 range. will try and finish motor this weekend and hopefully see if its resolved. hopefully richards shop will be available this weekend and sloGN will be done playing with golf balls

 

[turbobusa69]

I may have missed it , but what lifters are you running? I had this problem with some morels. I just put the car back together with some comp 885s and .116 wall pushrods. It's a 218/218 cam. Haven't driven it yet though.

morel lifters

 

[SloGN]

well i have the K motion 750's with standard retainers and +060 locks and thanks to mike D for assembling them. pressures are about the same at seat(130ish) and open 530 lift is now 385 range. will try and finish motor this weekend and hopefully see if its resolved. hopefully richards shop will be available this weekend and sloGN will be done playing with golf balls

going to play a round of golf sat morning. T-time is 10:15

 

[vacuum 6]

I may have missed it , but what lifters are you running? I had this problem with some morels. I just put the car back together with some comp 885s and .116 wall pushrods. It's a 218/218 cam. Haven't driven it yet though.

So Jeremy have you drove the car yet?

 

[jpwalt1987]

I have but I have had some issues with blowing off an intercooler pipe and really haven't gotten to make a clean pull. I'll let you know what I find and how it pulls.

 

[turbobusa69]

well motor is back in and running great. made a pass on the street, 5800+ no issues or banging. i have the morel lifters and the k motion springs and all seems fine now headed to richard clarks dyno asap again to final tune. so for those following this thread, be cautious with the bee hive springs on your roller cam setup. mine didnt like 130lbs seat and 300lbs open pressures they have!!!

 

[jpwalt1987]

well motor is back in and running great. made a pass on the street, 5800+ no issues or banging. i have the morel lifters and the k motion springs and all seems fine now headed to richard clarks dyno asap again to final tune. so for those following this thread, be cautious with the bee hive springs on your roller cam setup. mine didnt like 130lbs seat and 300lbs open pressures they have!!!

Good to know. I will more than likely get a chance to make a couple blasts to see if mine will pull the rpm it should this weekend. I changed to comp 885 lifters. I'll update also.

 

[jpwalt1987]

Well I got a chance to make a couple pulls on the back roads. Disappointed to say the least. My valve train noise has been a lot less with the comp885 lifters and smith brothers pushrods. However at 5500 rpm it goes bat$hit crazy. Knock detector goes off and motor starts to feel erratic. This is on only 20-21 psi of boost and 19* timing and spraying alky !!! I really don't see how it could be real knock showing up either. I have to think that the valves are floating now. The springs should be enough but I still haven't verified pressures. They spec at 141@ 1.80 on the seat and 424@ 1.250. That ought to be plenty of spring. WTF??

I tried to upload another screen shot but it wouldnt do. It was way worse than this one.

 

[jpwalt1987]

Here is the other screenshot.

 

[RmvBfrFlght]

Pull the spark plugs out and check them for signs of detonation. Can see what to look for at this link:

http://dynamicefi.com/SparkPlug.php

Note that the first three pictures that show the peppering are from a SBC. While the last two are from a TB running open loop.

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