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  • 1979 - 1995 (Fox, SN95.0, & 2.3L) -General/Talk-
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another problem weird noise at 5k

  • Thread starter Thread starter 1994Vib.RedGT
  • Start date Start date Aug 20, 2006

1994Vib.RedGT

Member
Aug 19, 2004
585
0
16
Denver, CO
Aug 20, 2006
#1
  • Aug 20, 2006
  • #1
I just got the new valve springs put on the car and got it running a week ago. Ive noticed kind of a wierd vibration, and tonight I hit it on the on-ramp and in 2nd at 5k it made a weird noise and fell on its face, it almost felt like hitting a rev limiter, just with some awful noise, I pulled it into the garage and reved it up to ~5500 a few times and no noise, no vibration. I took it out and hit second again and bam, problems. Could this be my tranny taking a **** on me?
 
R

rockin_rick

Member
Oct 9, 2003
968
1
17
Aug 21, 2006
#2
  • Aug 21, 2006
  • #2
Perhaps your valve springs were not shimmed properly and don't have enough seat pressure and are allowing the valves to float when you hit 5K. If so, that weird noise may have been the valves hitting the pistons. Hope I'm wrong...

Rick
 

1994Vib.RedGT

Member
Aug 19, 2004
585
0
16
Denver, CO
Aug 21, 2006
#3
  • Aug 21, 2006
  • #3
how would I check this kind of thing, and why would it only happen when Im moving if it was valve float?
 

1994Vib.RedGT

Member
Aug 19, 2004
585
0
16
Denver, CO
Aug 22, 2006
#4
  • Aug 22, 2006
  • #4
bump
 

1994Vib.RedGT

Member
Aug 19, 2004
585
0
16
Denver, CO
Aug 23, 2006
#5
  • Aug 23, 2006
  • #5
bump again
 
R

rockin_rick

Member
Oct 9, 2003
968
1
17
Aug 23, 2006
#6
  • Aug 23, 2006
  • #6
While I'm no expert, I don't know why it would only happen while moving. Assuming it is valve float, I'd guess that it isn't that you are moving, but rather under heavy load. Perhaps you don't notice it at light load? While it is falling on it's face, since their is such light load you can't tell?

This was just my initial reaction to your post, perhaps I'm wrong. I don't see why the car would fall on its face at 5000 due to the trans. So I sorta ruled out the trans as a potential problem. AND since you just had valve springs put on, that seems to be where the main suspicion lies.

Who installed these? What valve springs are they? What is their installed height? How much seat pressure does your cam require? IMO- If you're not sure that they are installed to the correct seat pressure, then I'd suggest taking it easy until you are certain. If these were professionally installed, then perhaps it would ease your mind some, but if some buddy did it for you, then you better be finding out for sure before you destroy something.

While it's possible that swapping springs without checking the shims may provide the correct installed height, most likely it will not. I swapped AFR springs for some beehives and had to reshim a lot. The retainers and keepers sat at a different level on the valve than the AFR spring's retainer and keepers.

I used one of these to check the installed height:

http://store.summitracing.com/partd...CCA-4928&N=700+400114+304425+115&autoview=sku

Perhaps someone else can shed some light on this...

Rick
 

1994Vib.RedGT

Member
Aug 19, 2004
585
0
16
Denver, CO
Aug 24, 2006
#7
  • Aug 24, 2006
  • #7
http://store.summitracing.com/partdetail.asp?autofilter=1&part=CRN-44308-1&N=700+115&autoview=sku

these are the springs, they are crane cams springs for cast iron heads with an upgraded cam.

specs are:
Installed Height (in) 1.940 in.
Seat Pressure at Installed Height (lbs) 120 lbs.
Open Height (in) 1.380 in.
Open Pressure (lbs) 375 lbs.

and Im running the steeda 19 cam. Everything looked to match up

and I had a shop that we take our stuff to for big repairs because he knows what he is doing.
 
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