For years our car was hampered by this damn break up beyond 6k rpms. We thought it was the crank/cam triggers. They were revised and on the money. Then we thought it was the ignition signal wires from the Autronic to the M&W ignition box. I rerouted these wires through the wiper cowl and they had a good twist to prevent EMI. Still this problem persisted.

The break up sounded like a retarded firing or mis fire all together, sort of like an anti lag. The best we could run with the car acting like this was 11.0 @ 130mph. After some research and talks with Darrell *** and Aaron we determined it was the lifters seeing too much oil pressure and hanging the valves open. There goes our compression!!!

I am taking a spare set of lifters to the machine shop to mill off .005" off the bottoms. We are also putting a restrictor in the head to reduce oil pressure to 40psi max @ 8500 redline.

Finally I might be able to get somewhere with this car. After so much time and heart-ache spent on this car, I hope there is a huge pay off.


Modified by Blitzkrieg at 1:31 PM 9/15/2006

 

Intresting. That has to be a huge relief, what times are you expecting now?

 

There is no reason that this car can't run well into the 9s and trap over 150mph

 

Cool deal man...i hope this works out for you! A friend of mine(drewsrt on here) had Darrell do headwork on his srt. They put an oil restritor in there and it ran fine for a while. After a month or so it started ticking alot on initial start up...it would go away after it warmed up though. We checked everything over like 10 times and couldnt figure it out(ive done like 8 srt heads myself so im fairly familiar with them), so it was pretty frustrating. The ONLY thing we could think of that would be causing the problem was that restrictor. Since the oil wasnt warm(and still really thick), we assumed that it wasnt getting adequate oiling until the engine warmed up and the oil thinned a little. I also read another thead on srtforums that said the same thing. That guy sad that he ran a thinner oil and the ticking wasnt near as bad.

As i said...this is all an assumption. We never took the retrictor out to see if the ticking stopped. I just thought id give you a heads up. Darrell is a really good guy and hes ALWAYS willing to help people out. We were gonna take the head off and take it to dcr to see if that was the problem...but he sold the car before we got the chance.

Good luck man. I hope this works out for you

 

So when you say finally are you sure its the lifters?

I sure hope so because you guys have a really nice car. Hope it works!

 

actually i had one of darrell ***'s motors on my dyno the other day.

w/ a gt40, it was having problems dropping off power too soon.

They (darrell ***) told the owner the same thing, that they are thinking the lifters are the problem.

We werent having issues w/ misfire. granted this was only at the 400 whp level and on pump gas, we didnt turn the boost up past 15 psi.

 

It is funny because in the GM build book for Ecotec page 81 they recommend cutting .005 off the bottom of the lifter as well.
http://www.gm.com/company/gmtu...k.pdf

 

I Highly think so. The ignition is in fact firing, but it sounds like it is retarded when it is not. The valves in a sense are floating, but due to the lifter height and not spring tension. Not to mention there are alot more SRTs going stand alone and they all have this problem. Knowing this lead us to seek other issues other than the Autronic config/tuning.

 

what boost level/power level are you starting to experience misfire?

This car i tuned was running aem, and we had no problem what so ever as far as misfire concerns, just the power dropping off prematurely. but again we are at low boost levels right now


interesting find about GM recommending them cut off .005.

Does anyone make solid lifters for these motors?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mase &raquo;</TD></TR><TR><TD CLASS="quote">what boost level/power level are you starting to experience misfire?

This car i tuned was running aem, and we had no problem what so ever as far as misfire concerns, just the power dropping off prematurely. but again we are at low boost levels right now


interesting find about GM recommending them cut off .005.

Does anyone make solid lifters for these motors?</TD></TR></TABLE>

Big Len does!!!
they neva float 111!!!!

 

I am running a T72 with a ceramic turbine. Anything over 18psi would really get bad. This was 425whp through a 3 speed auto tranny.

 

car has an awsome setup!! i remeber NOPI 05 right nexyt to you Anothony.
good luck and hope your problems get resolved!!
Darren

 

Very interesting find. its nice to see problems diagnosed and the information shared like that.

just wondering, what rpm does darrell feel the hydraulic lifters are good for after the modifications?

 

I have .010 off mine....

Steve

 

Glad to hear you guys may have found out the problem. I would be kinda worried about an oil restrictor up there in the head, valve springs create a lot of heat and need the oil to cool them down.

Quick question. Did your valve stem pads have any abnormal wear on them?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by RacerStev &raquo;</TD></TR><TR><TD CLASS="quote">I have .010 off mine....

Steve</TD></TR></TABLE>

DOH!!!!!

 

The GM book says to use solid lifters with 0.005" lash, not shave off the bottoms of hydraulic lifters.

Kevin

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Mase &raquo;</TD></TR><TR><TD CLASS="quote">what boost level/power level are you starting to experience misfire?

This car i tuned was running aem, and we had no problem what so ever as far as misfire concerns, just the power dropping off prematurely. but again we are at low boost levels right now


interesting find about GM recommending them cut off .005.

Does anyone make solid lifters for these motors?</TD></TR></TABLE>

hey focker, i have all the GM material from their build book to their class material if you want it(there's a lot of good stuff in there you can carry over to any 4 cylinder motor)
bring me over one of those phillips highway hotties and you got yourself a deal

does anyone know of anyone else other than BLE that makes the lifters for the SRT-4?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by kiggly &raquo;</TD></TR><TR><TD CLASS="quote">The GM book says to use solid lifters with 0.005" lash, not shave off the bottoms of hydraulic lifters.

Kevin</TD></TR></TABLE>

Actually that is for the 1000+ builtd up. For the 600-1000 they suggest milling the factory units. Page 81

 

Why/how does shaving the bottom of the hydraulic lifters help?

 

It is actually a lash adjustor rather than a lifter. By shaving the bottom I am increasing the valve lash or gap between the rocker and valve. This will prevent the lash adjustor from pumping up and holding opent the valves.

 

Honestly I feel you have other issues as well,like valve float.Usually the way the lifter is pumping up is if it has that room to pump up to begin with.You might want to take a look at your springs.BTW I have a custom drop in spring/retainer deal that doubles the stock spring rates for Neons/SRT's for those interested.