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Author
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Topic: valve spring & lifter help
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thirty5window
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Member # 7041
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posted
 
 
I ordered a custom cam from Brian at HiTech for the combo below. I'll also ask him these questions more specifically when I can get ahold of him again, but I wanted those with experince with his cams to weigh in also.
What spring pressure's do you recommend? 180+ seat pressure?
Will new stock lifters hold up?
Also, have any of you used Probe flat top pistons (part #1066) and a 240 duration cam? Did you have to notch the pistons?
Here is the combo:
custom cam: 240/236 duration, 574/555 lift, 110 lsa
342 stroker
Probe 10666 pistons ~ 11:1 compression
Victor Jr. heads w/ mild clean-up. milled to 57cc chamber
1.6 roller rockers & girdle
Victor EFI intake
Accufab 80mm TB
1-3/4 longtubes
5 speed, aluminum flywheel
3.55 gears
90 Mustang LX coupe ~3100#
I am shooting for 420-430 rwhp with a flat torque curve, planning to shift ~6500rpm. The car is my daily driver that will see 60 miles per day of mostly highway & country road driving with some stop and go.
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04 Cobra
90 LX - 347 in the works
Posts: 11 | From: Colorado | Registered: Sep 2006
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93PONY
Mr. Valve Events
Member # 60
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posted
My wife's 347 uses Probe flat-tops. No piston to valve issues with the 248/245 camshaft.....but it's always a good idea to check P2V.
As for valvespring you're going to need something 'special'.
I've found that in order to stave-off valvetrain issues with XE lobes you need over 400lbs of spring pressure on the nose...preferably 425+. We run 500lbs in the wife's car with Modified hydrualic roller lifters, but there are plenty of stangs out there with stockers & 450lbs on the nose. So, here is what I'd recomend:
Compcams:
953 valvesprings setup at 1.900" install height (stock VicJr) 157lbs @1.900, 429lbs @.550 lift
732 or 721 Titanium retainers
611-16 Super locks
Custom .125 wall thickness 5/16th pushrods, or Custom 3/8th pushrods (.080 wall will work with 3/8th). You'll also need 3/8th guide plates if you run 3/8th pushrods, compcams also sells these for VicJr's.
This will get the job done safely for under 6800rpm shiftpoints.
Brian will probably tell you the springs are overkill, but since all the springs are the same price, might as well error on the side of safety & get a bit heavier spring. Typically Brian recomends 914's for his cams....these are a bit weak for the XE lobes IMO. We've had issues with them in the past using XE lobes. Valvefloat can lead to piston to valve contact....which can lead to valve failure & ultimately destruction of the motor.
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www.advancedenginedevelopment.com
SCT dealer
Dynotuning
(916)715-7569
Posts: 4266 | From: Fair Oaks, CA | Registered: Nov 2000
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thirty5window
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Member # 7041
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posted
quote:
I've found that in order to stave-off valvetrain issues with XE lobes you need over 400lbs of spring pressure on the nose...preferably 425+. We run 500lbs in the wife's car with Modified hydrualic roller lifters, but there are plenty of stangs out there with stockers & 450lbs on the nose.
Brian will probably tell you the springs are overkill, but since all the springs are the same price, might as well error on the side of safety & get a bit heavier spring. Typically Brian recomends 914's for his cams....these are a bit weak for the XE lobes IMO. [/QB]
Actually, I think he made the comment that a spring with a minimum of 180 seat pressure was needed. That sounded excessive to me... but I don't know the specifics of the cam profile either. That made me question whether stock lifters would hold up to long-term use. Would Sherman modified lifters be the way to go? For mostly street useage?
I would like to err on the stiffer side to avoid broken pieces from floating the valves, but don't want to break other pieces with a 180-200# seat & 550# max lift pressure. Are titanium retainers needed at this level or would the Comp steel retainers I already have work?
The block is zero decked, the heads have been milled, and I am planning to use a thin head gasket to bump the compression a bit. All of these things reduce the PTV clearance to the point that I will likely have to fly cut the pistons. I'll know when it gets mocked up and checked. I just wondered others experience was with Probe pistons.
Thanks for all you help.
Posts: 11 | From: Colorado | Registered: Sep 2006
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93PONY
Mr. Valve Events
Member # 60
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posted
Your camshaft uses these lobes:
Intake: Comp #3636
289 @.006, 240 @.050, 162 @.200
Exhaust: Comp #3196F
288 @.006, 236 @.050, 162 @.200
Overlap = 18 degrees @.050
This will have no issues clearing the flycuts in the probe pistons.
My wife's cam has 24.5 degrees of overlap .050. with a .030" Quench, zero decked & heads shaved .006". (VicJr's) Although she is using 331 pistons with 5.315" rods.
Your combo is very similar to hers & Yellow94GT's.
For head gasket don't go too thin. Ideally you want the quench (distance between piston & head) to be between .030 - .045". Any less & you risk hitting the head with the pistons, any more & you lose the benefits of quench.
The shermans are what we run on the wife's 347. They are GREAT as long as you set them up correctly. Yellow94GT also runs these lifters. They can take a LOT of spring pressure....but stock replacements can take 425-450lbs which is all you need with this camshaft if you use Titanium retainers, strong pushrods, & keep RPM's below 7000.
Both of these motors use Comp 917 valvesprings with ~150lbs seat & 500+lbs open. With Titanium retainers & super 7 locks. Both have run into pushrod issues (deflection) at high RPM. Yellow94GT recently converted over to 3/8th pushrods/guideplates & was able to finally rev cleanly past 6500 (he runs 1.72 rockers with XE lobes). I just ordered custom 5/16th (thicker wall) pushrods for my wife's GT for the same reason as she runs into deflection around 6900rpm (1.6 rockers with an XE intake & Magnum exhaust lobe). Both of these cars have run 10.80's or better & 126mph at 3200lbs+ on motor.
180lbs seat is overkill unless you're boosted. My boosted car has 180lbs seat pressure....that's because of the intake air pressure on the back of the intake valve (& exhaust since it's a turbo setup) that pushes on the valves when they are closed. Otherwise there would be no need for that high of seat pressure with these hydrualic roller camshafts. It's the inverted flank of the XE lobes that require more open pressure to keep the lifters from flying off the camshaft at RPM.
With that high of spring pressure, Titanium retainers are not 'needed', but it's always a good idea to remove weight from the valvetrain. I'd advise using titanium retainers & less spring. 917's are overkill, but they get the job done nicely & are proven with the XE lobes on VicJr heads.
[ February 24, 2007, 12:05 PM: Message edited by: 93PONY ]
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www.advancedenginedevelopment.com
SCT dealer
Dynotuning
(916)715-7569
Posts: 4266 | From: Fair Oaks, CA | Registered: Nov 2000
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thirty5window
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Member # 7041
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posted
The combo is very similiar to your wife's and Drew's on purpose. Your results are very impressive.
It sounds like I am using the same pistons as your wife's car. 5.135 rod in mine also. I bought the heads used so I don't know exactly how much they were shaved, but here are some measurements from the valve to the head surface; the very edge of the valve sticks out past the head surface 0.047 on the intake and 0.018 on the exhaust. It would be great to not need to cut the pistons... but I'll definately check the clearance anyway.
Thanks for the spring recommendation. Brian seems to be a pretty hard guy to get in touch with. I'll go your route and probably the titanium retainers unless they are ridiculously expensive. With the milder lobes, less spring pressure, and a little less rpm as the other 2 cars you mentioned, should I still get thicker wall pushrods? Who do you order them from?
Do you think this cam will reach my performance goals? It looks quite a bit more tame than yours or Yellow94GT's. I am sure Brian designed it that way since it will see a lot of street duty. I guess we will see soon enough if it will make the desired power. ![[Smile]](smile.gif)
[ February 24, 2007, 02:46 PM: Message edited by: thirty5window ]
Posts: 11 | From: Colorado | Registered: Sep 2006
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93PONY
Mr. Valve Events
Member # 60
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posted
Pushrod strength is needed when using the 917's. The only reason my wife's 347 doesn't hit deflection sooner is the pushrods are actually touching the heads which stablizes them somewhat (long story).
Her cam is also tamer than Drew's simply because of the 1.6 rockers vs his 1.72's. All XE lobes are super aggressive....doesn't matter the size of the lobe. In fact, one of the most aggressive XE lobes is the 224 lobe used on an XE274HR. It too needs a LOT of spring when run at high RPM.
Lots of places can do custom pushrods...even Summit racing I believe. HiTech can get them for ya....as well as a lot of machine shops. I ordered mine from MotorMachine (local speed/machine shop).
Your heads are definately milled more than the wife's or Drews, so you'll need to check P2V, but again, we run more overlap & that is what affects P2V more than anything. You can run less P2V with Sherman lifters since they aren't preloaded as much as stockers...so keep that in mind if you're 'close' to minimum specs.
Titanium retainers are around $239 these days. But IMO if you're going to spend the money anywhere, it's best to spend it on the valvetrain. 90% of all engine failures are valvetrain related.
You should have no problems topping 400/400RWHP. More than that really depends on the little details of the setup. BTW I'd recomend re-working the upper intake. It's quite restrictive. In fact, talk to Brian about the upper plenum plate I sent him....should be worth at least 20hp. I got tired of messing with it & sent it off to him for testing/finishing.
The wife's GT can be driven daily without issues. It still has A/C, PS, PB, full interior, all power, etc. The only things we removed were: smog pump, spare tire/jack, front sway bar, & the moose-nuts on the rear end. Her motor will idle all day long in traffic at 700rpm....although I have it set ~850-900 to give a little more brake pedal. (low vacuum = stiff brake pedal) A properly designed camshaft will have more low-end than others.....which equates to a more stable idle among other things.
BTW, the 331 piston/5.315 rod combo will sit IN the 'hole' .010" vs a 347/5.400 rod combo. Some machine shops will 'zero' deck the block to 8.200", others to the piston/rod/crank height.
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www.advancedenginedevelopment.com
SCT dealer
Dynotuning
(916)715-7569
Posts: 4266 | From: Fair Oaks, CA | Registered: Nov 2000
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thirty5window
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Member # 7041
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posted
I can't tell you how appreciative I am of you help. ![[Cool]](cool.gif)
2 last questions:
What is the difference between the 732 or 721 retainers?
To reduce weight further are Comp stainless rockers worth the money to upgrade from the aluminum rockers I already have?
[ February 25, 2007, 10:30 AM: Message edited by: thirty5window ]
Posts: 11 | From: Colorado | Registered: Sep 2006
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93PONY
Mr. Valve Events
Member # 60
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posted
Comp makes 2 Titanium retainers. One standard weight & one lightweight (both are FAR lighter than steel retainers). You don't need the lightweight & they are more expensive, but I threw them out there just in case.
Aluminum rockers deflect too much. The only rockers I use on these setups are the Comp ProMagnums & HiTech stainless. The HiTechs are nicer & more expensive, but again not neccessary. I'd advise staying with 1.6's. 1.72's will be harder on the valvetrain, although they will make more power.
[ February 25, 2007, 02:24 PM: Message edited by: 93PONY ]
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www.advancedenginedevelopment.com
SCT dealer
Dynotuning
(916)715-7569
Posts: 4266 | From: Fair Oaks, CA | Registered: Nov 2000
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thirty5window
¯
Member # 7041
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posted
Alright
I talked to Brian. He recommends at least 180# at the seat and to use the 933 springs. He assured me that the stock lifters will live. Here are my choices using my 732 retainers calculated using a 1.900 installed height and .575 maximum lift:
953 - 148# at seat. 420# max
933 - 194# at seat. 476# max - Brian's recommendation
939 - 161# at seat. 430# max - Comprimise
What do you think? Will the stock lifters live with 476# at max lift?
Posts: 11 | From: Colorado | Registered: Sep 2006
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93PONY
Mr. Valve Events
Member # 60
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posted
Odd why he's recomending such high seat pressure.
He just sent Drew (Yellow94GT) some 26120 springs from Comp which are 150lbs @1.900 @ 377lbs @.620 lift. Of course, these are beehive springs & use a much smaller/lighter retainer. However, Drew decided to run the 917's which seem to get the job done.
If I were using stock lifters I'd run the 953's & keep the shiftpoints below 6500rpm. If you want more pressure, run .060 shims under the seats. That will bring it up to just under 180lbs seat & 450+ open. Or, .030 or .045 shims to get the spring pressures right where you want them.
I have seen issues with stock lifters & over 165lbs seat pressure (once)....however, I'm running 180lbs seat on my Crane/Ford link-bar lifters without any issues.
Of course, if you go with the Sherman modified lifters (extra $200) you won't need to worry about seat or open pressures being too high.
--------------------
www.advancedenginedevelopment.com
SCT dealer
Dynotuning
(916)715-7569
Posts: 4266 | From: Fair Oaks, CA | Registered: Nov 2000
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