Spring recommendation for GN1s

[jpwalt1987]

I need a spring recommendation for some GN1 heads. The cam is a DLS 218/218 hydraulic roller with morrell lifters and T&D rockers. The cam has .545 lift on the intake and .512 lift on the exhaust. I am not sure what springs Dan used but the engine doesn't seem to want to RPM like I thought it should. It won't pull past 5500. I had a solid roller a while back that would pull 6500 all day long. I have yet to pull a spring and check the pressure but I will as soon as I can. Whenever I make a pull the motor goes to about 5300-5500 rpm and stays there as the car accelerates. Not sure what the max rpm is on this cam but i figured it would be more than 5500 Thanks.

 

[jpwalt1987]

Here is a screen shot. You can see the flat rpm curve(non curve ).

 

[SHADOWII]

I (did) run a mild 212/212 and it spun to 6250 no problem, 23#s of boost. Not sure of the seat pressure. Did you experience any valve float? Doesn't look like it from the graph. how about the fueling and timing?

 

[jpwalt1987]

No valve float. AFR is about 10.2-10.4:1. Timing is 18* verified. This is an SD chip from Eric. I am picking up some knock on the PL but the plugs are clean and with the alky on position 8 and the AFR that I am running I dont believe it is real knock. The valve train has some noise to it. Not sure if it is from the lifters or rockers or what.

 

[jpwalt1987]

The knock shows up at about 5500 rpm too

 

[Quik Six]

I need a spring recommendation for some GN1 heads. The cam is a DLS 218/218 hydraulic roller with morrell lifters and T&D rockers. The cam has .545 lift on the intake and .512 lift on the exhaust. I am not sure what springs Dan used but the engine doesn't seem to want to RPM like I thought it should. It won't pull past 5500. I had a solid roller a while back that would pull 6500 all day long. I have yet to pull a spring and check the pressure but I will as soon as I can. Whenever I make a pull the motor goes to about 5300-5500 rpm and stays there as the car accelerates. Not sure what the max rpm is on this cam but i figured it would be more than 5500 Thanks.

I have 218/218 cam, etc from DLS on iron heads and it has no problems going to 6500+ without float. Can't find my cam card but don't believe it has same lift specs you posted, more like .512/.512. Springs are CC941-1-R according to my invoice.

 

[bison]

With a 218/218 the engine shouldn't be over 6000 rpm unless it has enough power to pull that high in 3rd. I run 200lbs on the seat and over 500lbs over the nose with the 218
In my black car. You either need an 885 comp lifter or a solid lifter if you want to run higher spring pressures. If the car is accelerating as it should then the converter is what's preventing the rpm. Throw more power at it and give it a few seconds.

 

[jpwalt1987]

With a 218/218 the engine shouldn't be over 6000 rpm unless it has enough power to pull that high in 3rd. I run 200lbs on the seat and over 500lbs over the nose with the 218
In my black car. You either need an 885 comp lifter or a solid lifter if you want to run higher spring pressures. If the car is accelerating as it should then the converter is what's preventing the rpm. Throw more power at it and give it a few seconds.

I am going to pull the plugs to inspect for any signs of
Detonation then I will slowly creep the boost up toward 27-28 and then creep the timing up to 21-22*. The problem with giving it a few more
Seconds is that I was already going 111mph at the end of that pull. I believe that was just a third gear pull from about 45 mph with no down shift. Th400 with a RMVB.

Brian, do you think that the Morrell lifters are not up to the task of going higher on the rpm? For a lifter that was touted as being quiet , they sure are loud. Lash is set 1/2 turn past zero.

 

[bison]

Ive only run 885 lifters in any application where the engine made power over 5500. I use 885 lifters in everything I've done. They always act the same.

 

[jpwalt1987]

http://m.summitracing.com/parts/CCA-26926-1

These are the springs that are being used right now.

 

[bison]

http://m.summitracing.com/parts/CCA-26926-1

These are the springs that are being used right now.

I wouldn't run anything but an 885 with those. That's a lot of spring for a hyd type lifter.

 

[jpwalt1987]

Guess its time to buy some lifters then. Damn. Do you know if the pushrods would be the same length?

 

[toomanymodz]

I'm running Morel lifters with PAC springs. RPM is limited to about 5400. If you change anything, please post your findings. Perhaps your gremlin is also my gremlin. Thanks

 

[SloGN]

I have been working on a car for the last couple of weekends and has this same issue. The car just dies @5450 rpms

We have been running it on the dyno at richard clarks place to try and find it!

The engine info is what was told to me from owner

Stock crank,rods,pistons
GN1 iron heads
GN1 R intake
Roller cam 215/220 Full throttle unit
Morel Roller lifters
T&D roller rockers 1.55 lash was set @ 1/4-3/8 turn from zero lash. He did this i didn't verify.
Cloyes T-chain
70 turbo
60lb inj
Razor alky
The valve springs are the bee hive type. The one we removed and checked it was in the 145lb area on the seat and open was over 300.

Like i stated above the car just dies 5400-5500 rpms no matter where the boost is set at. 18-28 psi. The AFR on the dyno ranges from 10.8-11.1 depending on boost and amount of alky spraying.

The thing has stupid knock having when the car started sounding flat to the tune of 20 degrees. When the boost is lowered the knock lowers to by just a few degrees.

We have used to ecms and 2 different chips, another known good coil/module. Richard even scoped the crank sensor and the injector and we found nothing. I'm leaning towards the morel lifters just can't cut it!


so i hope there are some thoughts

 

[bison]

I have been working on a car for the last couple of weekends and has this same issue. The car just dies @5450 rpms

We have been running it on the dyno at richard clarks place to try and find it!

The engine info i as follows from the guys that owns it!

Stock crank,rods,pistons
GN1 iron heads
GN1 R intake
Roller cam 215/220 Full throttle unit
Morel Roller lifters
T&D roller rockers 1.55 lash was set @ 1/4-3/8 tu from zero lash. He did this i didn't verify.
Cloyes T-chain
70 turbo
60lb inj
Razor alky
The valve springs are the bee hive type. The one we removed and checked it was in the 145lb area on the seat and open was over 300.

Like i stated above the car just dies 5400-5500 rpms no matter where the boost is set at. 18-28 psi. The AFR on the dyno ranges from 10.8-11.1 depending on boost and amount of alky spraying.

The thing has stupid knock having when the car started sounding flat to the tune of 20 degrees. When the boost is lowered the knock lowers to by just a few degrees.

We have used to ecms and 2 different chips, another known goocoil/module. Richards even scoped the crank sensor and the injector and we found nothing. I'm leaning towards the morel lifters just can't cut it!

so i hope there are some thoughts

Not enough spring. I run PAC 1203's with any hyd application with a fast ramp/high lift that will be over 5500. I run zero lash/zero preload on 885 lifters. Some of the slower ramp profiles could use a solid lifter with a tight cold lash around .006 and make a little more power. Your engine should be hitting peak power at 25-30psi around 5500-5600. Not laying over there. It should carry it within 10% all the way to about 6100 too. So if you had 650whp@5500/27psi it should still have about 590whp@6100. I personally would never run a cam that peaks that late with a stock crank/rods. 212/212 will peak around 5100 and you can play with tire height if you have a good coupling converter and run 136-137@ less than 5800rpm. With the 218 intake lobe you need a flash stall of at least 5300 to really throw it in the power band. Anything that will get it close to 5500 as long as possible will make it quicker once you get the problems sorted out

 

[bison]

I have 218/218 cam, etc from DLS on iron heads and it has no problems going to 6500+ without float. Can't find my cam card but don't believe it has same lift specs you posted, more like .512/.512. Springs are CC941-1-R according to my invoice.

I ran a 212 lobe with similar lift last year and it was fine up to 5800/136mph with 941's with more lift and more ramp 941's wouldn't cut it.

 

[jpwalt1987]

I believe that my knock shows up because of rpm and valve train noise. My tune is real safe. 10.2 AFR 18* timing and alky maxed out. Plugs told the story of no knock. I had a solid roller cam before that would pull to 6500rpm all day long and didn't cause any noise induced knock retard.

 

[bison]

Guess its time to buy some lifters then. Damn. Do you know if the pushrods would be the same length?

It's not likely they would be the same.

 

[jpwalt1987]

It's not likely they would be the same.

Not suprised. I hate to pull the manifold off and do this job, motor has about 1000 miles in it. But it isn't going to fix itself. How are the 885s as far as noise?

 

[bison]

The noise is determined by the lobe. I have noise in my black car and very little noise in the blue car. Same lifter. The cam is a small .330 lobe lift on the blue car. The black car has about .600 total lift and I'm using considerably more spring to control it. If you want it quiet put in a cam with no more than .290 lobe lift/.450 net and run a spring with 120 on the seat and 350 over the nose. I've never heard any ohv v6 engine that made 2.5hp/ci or more with a quiet valve train.