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PostPosted: Wed Dec 04, 2019 10:02 am 
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Those loads might be just fine but since you'll be running a solid lifter you might as well either stack the spring tighter or go with some that have a higher rate. The springs that you have right now will gain about 21lbs if you stack them .060 tighter.


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PostPosted: Wed Dec 04, 2019 4:25 pm 
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The recommended springs for mine were light to, 118 seat @1.880 and 355 open @1.200 with 348 rate.
Went bit overboard with 430 or so open in the end with a pac 1207x, the morel street roller lifters reckon 380 max and 6400 rpm, probably same as yours, they might be stressing out a bit :lol:
Brent's new cam and spring package arrived cpl weeks ago so that's a job for the new year...


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PostPosted: Thu Dec 05, 2019 6:31 am 
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Joined: Fri Mar 01, 2013 9:58 pm
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I’m running a set of isky ez roll solids on a comp cams hydro roller in one of my cars.
Motor is a fairly basic 351 , aftermarket crank with scat 6 inch rods and a set of SRP slugs.
Heads are a set of closed chambered 2Vs that have had a bit of work done to them.
Heads are set up with a set of 99893 crane springs. Seems to work ok .
In the future I’d like to upgrade the whole top end of the motor with a nice set of CHI’s .


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PostPosted: Thu Dec 05, 2019 9:40 am 
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XA, whatever Brent sends you is going to be good for sure. I run Howards Race Max in the dragster on one of Brents cams using PAC springs. Close to 600 over the nose on those, around 280 on the seat. 6800 shift, could go higher but just haven't put in a bigger shift pill LOL.

Yes, the cam is "noisy", it's decently stout. Makes good launch torque at 2300 and pulls good. It'd be better with a Brent spec solid, that will come later.

Thanks for the tip Dave on the shims. That could be a interim step. Easy enough to toss a .060 shim under the springs.

Trying to put together a budget for next year, this might have to wait. Just tires, water pump, new starter for the car is over $1000. Methanol compatible pump, regulator and filter is another $460. Dragster needs about $600, all but having the heads cut is just license and re-certifications. I spent $300 at Jegs yesterday because all their fittings and Pro-Flo hose that is methanol compatible was 50~60% off. Buying same in January would have been $280 more. Wife gets it but ain't too happy this close to Christmas. My "sell" is that having both cars running on the same fuel will save $$$ in the long run. 55 gallon drum of VP 110 is $440, same size Sunoco methanol is $160.

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http://raceabilene.com/kelly/hotrod
"Owner built, owner abused."


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PostPosted: Thu Dec 05, 2019 10:24 am 
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Shimming the springs tighter would probably be helpful but you just need to know how much room you have to work with on the springs with your cam. The catalog spring data can be WAY different than the actual measured springs because this all varies from one batch of springs to the next.

I have a spring tester from Peformance Trends where I pull every one of the springs to coil bind. After this I know the loads at any reasonable height. Also I know the rate and the actual coil bind height on each spring. There can be some surprises:

The coil bind height can vary a lot within a set of springs. I've seen it vary by more than .070 in a set before. This testing has saved me from myself and also allowed me to run some springs loaded way differently than what's shown in the catalog data.


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PostPosted: Thu Dec 05, 2019 1:51 pm 
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If I was a good builder boy, I'll have notes on that, specifically P2V clearance notes, installed height and such. Hah! Maybe, I'm as bad a note taker as I was in school. If I don't then I'll have to test for clearance on the engine and see what the baseline is before changing anything. .060 is a spring cup, so that part is easy enough. The .611 does have me worried a bit - Installed minus bind is .725 (per the specs), less .060 safety margin leaves .665, minus another 60 is less than the exhaust lift spec on the cam by .006. That's cutting things close but is within the lash spec, so there is a bit of wiggle room.

I use a home made spring tester for the same - making sure the installed height doesn't put things into a bind, installed and open pressure and such. You make an excellent point about variation in rates in a set - I have not specifically looked for that, but as an old QC guy I do run several springs - or all - from a set to check pressure at installed and max lift. On the dragster motor, I remember running all across the tester because that was my first time dealing with pressures in that range. I did not note any large variation.

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http://raceabilene.com/kelly/hotrod
"Owner built, owner abused."


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PostPosted: Fri Dec 06, 2019 10:15 am 
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Most of the time I put the springs with the highest rates in the set on the intake valves if I'm using the same spring across the board. With that said its not the rates that can vary all that much it is the height were the springs coil bind.

Looking at a typical set PBM 3000 springs singles with damper 1.250OD that I use for a hydraulic roller in a 383 small Chevy in a jet boat: The cam has .525 lift at the valve. Looking at 16 springs the average rate is 418.7lbs/in. Average open force 327, seated force of 107.9 bind ht 1.03. Looking at the averages doesn't tell the whole story. The spreads between highest and lowest is more interesting: the rates vary by 15.3, not much. The open loads only vary by 13.8, seated loads by 6.9lbs but the bind height varies by .041! That's a lot of variation and that puts me at a minimum of .071 and a maximum of .112 before coil bind in my installation.

If I made an assumption that I could get away with a shim based on the spring that was .112 I might be in a jam on the spring that's only .071 away from going solid.

These numbers are fairly typical for a set of springs.


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PostPosted: Fri Dec 06, 2019 10:24 am 
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Good news - I have notes LOL

Cam dial -
Intake open 8 BTDC / Close 46 ABDC
Exhaust open 52 BBDC / Close 8 ATDC

I did not go with the Howards spring. Crane 96870. installed 1.880~1.885 Spec: 134 @ 1.900/424 @ 1.250 - Rate 448 - Max Lift .686 - Bind @ 1.154 They are sitting in .060 cups with additional shims as required.

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http://raceabilene.com/kelly/hotrod
"Owner built, owner abused."


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