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Track Whore
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1,120 Posts
Discussion Starter · #1 ·
OK Folks here is the problem. I have a set of pitted JWT S4 cams on my race car. I want to replace them with JWT S4 high lift cams. We have tried to install the HLS4 cams wice and we keep running into the same problem.

When we put the HLS4 new cams in we get a misfire in cylinder number 1 and the spark plug gets fouled with gas. It only happens in cylinder number one. When we go back to the old S4 cams the problem goes away and the car runs fine.

We tried going with the thinnest shims for the rocker arms but that did not work either. The only possibility left are the Hydraulic Lift Adjusters. What could go wrong with these? Could they get stuck ar a certain level and refuse to adjust to the newer lift on the cams?

What else could be wrong? :confused:
 

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Charlie Brown look alike
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3,825 Posts
Perhaps thet are just old and need to be replaced? I'm not really sure, but I will keep a close eye on this thread because I'm curious to know also.
 

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Track Whore
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1,120 Posts
Discussion Starter · #4 ·
NX$paniard said:
Do the new HLS4 Cams require Cam gears to change dial out overlap or anything like that?

Dumb question, but is it possible you skipped a tooth during install?
Just **** to double check
To my knowledge the HLS4 are plug and play. We double checked and triple checked timing and we are sure that we did not skip a tooth. When we put the HLS4 in the car misfired in number one. When we swap back to regular S4s the car runs fine with the somewhat lopey idle that is normal for an S4.
 

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easy 400WHP
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12,682 Posts
**** it, try swapping out the HVLA's on the #1. Perhaps the extra lift does jam them up. Ho wmany people have ran these HLS4? This is the 1st i hear of them.

Perhaps they need stronger springs?

regualr S4 on a turbo car can gain 2-3 whp w/ stronger springs according to Mr. Miko.

Perhaps its a similar situation. Weird, either way.
 

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Track Whore
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1,120 Posts
Discussion Starter · #6 ·
NX$paniard said:
f-ck it, try swapping out the HVLA's on the #1. Perhaps the extra lift does jam them up. Ho wmany people have ran these HLS4? This is the 1st i hear of them.

Perhaps they need stronger springs?

regualr S4 on a turbo car can gain 2-3 whp w/ stronger springs according to Mr. Miko.

Perhaps its a similar situation. Weird, either way.
We will try and change the two HLA on that cylinder. We will not do it right now, however. We are sick and tired of swapping cams. I hope that new HLAs will do the trick.
 

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Track Whore
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1,120 Posts
Discussion Starter · #8 ·
FastNX said:
You mean the thinnest shims on top of the valve with the theory that the valves were not seating?
Correct. We thought that the valves were staying open because the HLS4 have more lift, so we used thinner shims for the rocker arms. It did not make a lot of difference. I thought that the misfire was less pronounced, but that could be my imagination. Point is the misfire stayed.
 
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