Go Back   Ford Mustang Forums > Mustang > 5.0 Mustang > 5.0L Tech

Welcome to our Mustang forums where Mustangers come together to hang out, discuss and enjoy their favorite Mustang hobby with fellow Mustang enthusiasts. We invite everyone to read, post, and enjoy our Mustang forum as well as the many other sections of our site.

You are currently viewing our forums as a guest. By joining our community you gain access to post topics, communicate with members, upload your photos and access many other special features. Registration is fast, simple and free so why wait, join our Mustang community today! If you have any problems with registration or your account login, please contact support.

5.0 Mustangs Tech Forum

5.0L Talk | 5.0L Tech | 94-95 Tech | 1979-1993   1994   1995   Upload Pictures | Timeslips | Power Adders | Mustang Tech 


Reply   Post New Thread
Unread 02-03-2013   #1 (permalink)
Primedlx is offline Apprentice

5.0L Member


Joined: Apr 2008
Posts: 93 Threads: 17
 Primedlx's Country Flag
Ft Worth   Texas
Primedlx is on a distinguished road
Default 89 Mustang Pushrod length question

Ok so I have a comp cam p/n 249-35-351-8, gt40x turbo swirl heads, crane 1.72 roller rockers and I need to know if the stock push rods are too long? The lift is .512" intake and exhaust, duration 270/276, with a 114 degree lobe seperation. I think the push rods are too long because the valves are not closing all the way to build proper compression. With 1.6 rockers there are no problems. Has anyone else ran into this problem before? If so, what size push rods are you using?

Thank you in advance.
Primedlx is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Sponsored Links
Advertisement
 
Unread 02-03-2013   #2 (permalink)
Rascal is offline PONY Member

5.0L Member


Joined: Oct 2010
Posts: 474 Threads: 17
 Rascal's Country Flag
Third Planet From The Sun   Pennsylvania
Rascal is on a distinguished road
Default Pushrod Length, Question answered.

Many factors come into play here. It all depends on if the block was resurfaced the heads were resurfaced, head gasket thickness. ETC. I would buy or borrow a pushrod checker that way no mather what is going on in your engine you can dial in the correct pushrod length and get the most power out of the engine.
Call Comp Cams (1-800-999-0853 Cam Help) and tell them exactly what you have they may have an off the shelf pushrod to get the job done. Too many times a guy will put an engine together using a mis/mash of parts and the clearances are all over the place. This is one area you want to be right on so that the valve train stays together. Hope this suggestion works for you. Good Luck.
Rascal is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Unread 02-03-2013   #3 (permalink)
YLDPONY is offline SHELBY GT 350 Member

5.0L Member


Joined: Nov 2009
Posts: 8,798 Threads: 46
 YLDPONY's Country Flag  View YLDPONY's 29 photos
Thornville   Michigan
YLDPONY is on a distinguished road
Default

You need a pushrod length checker (and a 8 in. calipers to accurately measure what it determines):

Trick Flow® Adjustable Pushrod Length Checkers TFS-9000 - SummitRacing.com
__________________
'94 Laser red 'vert. Still a 5-oh... for now
YLDPONY is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Unread 02-03-2013   #4 (permalink)
Primedlx is offline Apprentice

5.0L Member


Joined: Apr 2008
Posts: 93 Threads: 17
 Primedlx's Country Flag
Ft Worth   Texas
Primedlx is on a distinguished road
Default

The block is stock, I used fel pro gasket set for a stock 302. I was doing some research and I think since there rockers are pedistal mount, I may have tightened the bolt too tight? I was reading turn 1/4 to 1/2 turn past zero lash. I will try to properly tighten the hold down bolts first and if that doesn't work, I will buy or borrow a pushrod length checker. Thanks fellas.
Primedlx is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Unread 02-03-2013   #5 (permalink)
cindys_sn95 is offline Banned


Joined: Nov 2007
Posts: 7,991 Threads: 25
 cindys_sn95's Country Flag  View cindys_sn95's 7 photos
Gulfport   Mississippi
cindys_sn95 is on a distinguished road
Default

how would you tighten the bolts too tight? they torque to 24fp....YOU NEED TO MEASURE!
cindys_sn95 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Unread 02-03-2013   #6 (permalink)
Primedlx is offline Apprentice

5.0L Member


Joined: Apr 2008
Posts: 93 Threads: 17
 Primedlx's Country Flag
Ft Worth   Texas
Primedlx is on a distinguished road
Default

I tightened the p### out of them. With the cam set up and 1.72 rockers there is very little clearance on the valve springs from keeping the valvs open. I think they are just too tight keeping just enough tension on the valve springs to keep the valve open. I hear air out of the headers on the exhaust side, but when I put my finger over the spark plug hole no air comes out.
Primedlx is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Unread 02-03-2013   #7 (permalink)
YLDPONY is offline SHELBY GT 350 Member

5.0L Member


Joined: Nov 2009
Posts: 8,798 Threads: 46
 YLDPONY's Country Flag  View YLDPONY's 29 photos
Thornville   Michigan
YLDPONY is on a distinguished road
Default

Quote:
Originally Posted by cindys_sn95 View Post
how would you tighten the bolts too tight? they torque to 24fp....YOU NEED TO MEASURE!
+1, you want to tighten the bolts to ~20 ft. lb.; nothing more, nothing less. The 1/2 to 1-1/4 turn equates to 0.020-0.060 in. of preload on the lifters, which is what you want.
__________________
'94 Laser red 'vert. Still a 5-oh... for now
YLDPONY is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Unread 02-03-2013   #8 (permalink)
ryan7662 is offline PONY Member


Joined: Jul 2009
Posts: 477 Threads: 103
 ryan7662's Country Flag
Angleton   Texas
ryan7662 is on a distinguished road
Default

Quote:
Originally Posted by YLDPONY View Post
+1, you want to tighten the bolts to ~20 ft. lb.; nothing more, nothing less. The 1/2 to 1-1/4 turn equates to 0.020-0.060 in. of preload on the lifters, which is what you want.
Don't mean to hijack here but I don't want to needlessly start a new thread since we're already on this topic. My trickflow pushrod length checker has little white dashs on it. The instructions say that every time they line up while you're unscrewing the checker is equal to .050". Couldn't I get close enough using that method combined with checking the contact pattern on the valve stem? I'm using scorpion 1.6 pedestal mounted roller rockers now so I should be able to see the pattern better then with the factory stamped rockers. I don't have a set of 8" calipers so that's why I'm asking.
ryan7662 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Unread 02-03-2013   #9 (permalink)
cindys_sn95 is offline Banned


Joined: Nov 2007
Posts: 7,991 Threads: 25
 cindys_sn95's Country Flag  View cindys_sn95's 7 photos
Gulfport   Mississippi
cindys_sn95 is on a distinguished road
Default

that would do it.
cindys_sn95 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Unread 02-03-2013   #10 (permalink)
ryan7662 is offline PONY Member


Joined: Jul 2009
Posts: 477 Threads: 103
 ryan7662's Country Flag
Angleton   Texas
ryan7662 is on a distinguished road
Default

Quote:
Originally Posted by cindys_sn95 View Post
that would do it.
Cool beans thanks
ryan7662 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Unread 02-03-2013   #11 (permalink)
YLDPONY is offline SHELBY GT 350 Member

5.0L Member


Joined: Nov 2009
Posts: 8,798 Threads: 46
 YLDPONY's Country Flag  View YLDPONY's 29 photos
Thornville   Michigan
YLDPONY is on a distinguished road
Default

+1, I'd probably trust Trick Flow's denoted measurements. Just be sure you know where you're starting (if you're starting at 5.950 in. or 6.000 in. etc.).

With pedestal mount rockers the contact pattern is second hand, and you don't have a lot of room to adjust it. At least the way I see it, it's almost fixed (correct me if I'm wrong). Pedestal rockers usually have a few shims you can change the height they're mounted at, but they are small measurements (0.090 in. max for my case) and that's it.

If you have a pushrod length that gives you 0.020-0.060 in. of preload on the lifter while using no shims, one shim, or maybe even two shims under the pedestal your contact pattern better be good.

I say this for two reasons:
  1. In the instructions that came with my Crane 1.7:1 roller rockers they didn't not say anything about checking the contact pattern
  2. Given the adjustability (when compared to stud mount rockers) it makes perfect sense to me
__________________
'94 Laser red 'vert. Still a 5-oh... for now
YLDPONY is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Unread 02-04-2013   #12 (permalink)
Primedlx is offline Apprentice

5.0L Member


Joined: Apr 2008
Posts: 93 Threads: 17
 Primedlx's Country Flag
Ft Worth   Texas
Primedlx is on a distinguished road
Default

Ok so further checking, I loosened them and retourqued to proper spec, it fired off but ran like crap. It turns out that I am experiencing coil bind. I am going to just sell the 1.72's and get some 1.6's. It's cheaper to replace rockers than the springs, pushrods, etc.
Primedlx is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Unread 02-04-2013   #13 (permalink)
Smurf stang is offline SHELBY GT 500 Member

5.0L Member


Joined: Apr 2009
Posts: 14,199 Threads: 67
 Smurf stang's Country Flag
Miami   Florida
Smurf stang is on a distinguished road
Default

Well I had to reread this all over.....so how do you know that the 1.6 rockers will work?

The problem is the pushrods not the springs.
__________________
2014 V6 Deep Impact Blue Mustang, Borla Type S, 2.73 (Uughh need 3.73)
1989 Sonic Blue Mustang LX Coupe, 349 ci,
392 rwhp 424 rwtq....Mustang Dyno
"There are three kinds of men. The one that learns by reading. The few who learn by observation. The rest of them have to pee on the electric fence for themselves." -Will Rogers-
Smurf stang is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Unread 02-04-2013   #14 (permalink)
YLDPONY is offline SHELBY GT 350 Member

5.0L Member


Joined: Nov 2009
Posts: 8,798 Threads: 46
 YLDPONY's Country Flag  View YLDPONY's 29 photos
Thornville   Michigan
YLDPONY is on a distinguished road
Default

Somehow, I have a very bad feeling about these proceedings...

Quote:
Originally Posted by Smurf stang View Post
how do you know that the 1.6 rockers will work?
302/351W "X-HEAD" ALUMINUM ASSEMBLED 58CC

According to FRPP, even with 1.72:1 roller rockers (0.552 in. net lift) the springs that the heads come with should be good.
__________________
'94 Laser red 'vert. Still a 5-oh... for now
YLDPONY is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Unread 02-04-2013   #15 (permalink)
Smurf stang is offline SHELBY GT 500 Member

5.0L Member


Joined: Apr 2009
Posts: 14,199 Threads: 67
 Smurf stang's Country Flag
Miami   Florida
Smurf stang is on a distinguished road
Default

I am more concerned about pushrod length.

Plus using stock pushrods is another recipe for disaster.
__________________
2014 V6 Deep Impact Blue Mustang, Borla Type S, 2.73 (Uughh need 3.73)
1989 Sonic Blue Mustang LX Coupe, 349 ci,
392 rwhp 424 rwtq....Mustang Dyno
"There are three kinds of men. The one that learns by reading. The few who learn by observation. The rest of them have to pee on the electric fence for themselves." -Will Rogers-
Smurf stang is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiTweet this Post!
Reply With Quote
Sponsored Links
Advertisement
 
Reply   Post New Thread



Thread Tools



Mustang Photos
Mustang Links    Top Sites    RSS    Link To Us    Add to Favorites    Archive    Terms of Use    Site Rules    Privacy    Contact    Sponsors    Advertise   
AllFordMustangs is not affiliated with or endorsed by Ford Motor Company. ©Copyright 2002-2011 All Auto Enthusiasts Network

Search Engine Friendly URLs by vBSEO 3.5.2

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172