valvetrain question
04-02-2007, 01:23 AM
#1
Supreme Member
Thread Starter
iTrader: (2)
Join Date: Jul 2005
Location: currently Jacksonville NC
Posts: 1,079
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91 z28
Engine: 383 sbc, 88mm turbo a2w IC, CSU 750
Transmission: th-400 PTC 4000 stall
Axle/Gears: ford 9" 3.55 gear
valvetrain question
Im running the afr 210 heads and they came with hyd roller springs. Im running a hyd flat tappet cam specs: 241/249 dur @.050 .525/.546 lift 110 lsa, I was wondering what springs you would recommend for this cam? Im not to keen on springs and such. Also, what would necessetate longer or shorter pushrods? Im going to get a pushrod length checker anyways but i was just wondering what kind of things i know for a fact would change the needed length of a pushrod. thanks for the help
04-02-2007, 06:24 AM
#2
Supreme Member
iTrader: (1)
Join Date: Sep 2005
Posts: 26,123
Received 1,688 Likes
on
1,283 Posts
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: valvetrain question
Those springs should be fine for that cam.
There are about a hundred different things that affect how long your push rods need to be. It would be very tedious to list every one and tell why. Generally though, since in order to make a cam "bigger" what you actaully do is make the back side of the lobe SMALLER, meaning that the lifter drops farther down into the block at zero lift, a "bigger" cam tends to require longer push rods. But with aftermarket heads, no telling what block work, whatever rockers, AND an aftermarket cam, it's anybody's guess what length you'll need.
Get an adjustable push rod and measure your setup for what you need, it's THE ONLY WAY to be sure of getting it right.
There are about a hundred different things that affect how long your push rods need to be. It would be very tedious to list every one and tell why. Generally though, since in order to make a cam "bigger" what you actaully do is make the back side of the lobe SMALLER, meaning that the lifter drops farther down into the block at zero lift, a "bigger" cam tends to require longer push rods. But with aftermarket heads, no telling what block work, whatever rockers, AND an aftermarket cam, it's anybody's guess what length you'll need.
Get an adjustable push rod and measure your setup for what you need, it's THE ONLY WAY to be sure of getting it right.
04-02-2007, 08:11 AM
#3
Supreme Member
Thread Starter
iTrader: (2)
Join Date: Jul 2005
Location: currently Jacksonville NC
Posts: 1,079
Likes: 0
Received 0 Likes
on
0 Posts
Car: 91 z28
Engine: 383 sbc, 88mm turbo a2w IC, CSU 750
Transmission: th-400 PTC 4000 stall
Axle/Gears: ford 9" 3.55 gear
Re: valvetrain question
so you're saying i can use the roller springs with a flat tappet cam? I was almost positive that you weren't supposed to, maybe i read wrong... Well that saves be about $100 since these springs are good to .600 lift. Also, when checking for pushrod length, should i use the "mock" vavle spring, kinda like the ones used for checking piston-to-valve clearance? i would want to use a solid lifter as well i'm assuming? thanks for all you're help!
04-02-2007, 08:24 AM
#4
Supreme Member
iTrader: (1)
Join Date: Sep 2005
Posts: 26,123
Received 1,688 Likes
on
1,283 Posts
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
Re: valvetrain question
The springs for hyd roller aren't particularly different from others, except that they're able to withstand higher lift. Seat & open pressures are about the same. Which is quite different from springs that would be used with a solid roller. As long as they give about 125 on the seat and 350ish open, they'll be fine. Check w AFR and see if they're in that range.
Yes, you can use "check" springs; and yes, it works better with a solid lifter.
Yes, you can use "check" springs; and yes, it works better with a solid lifter.
Thread
Thread Starter
Forum
Replies
Last Post