I was enjoying the new setup w/ the TR 224 cam and logging some WOT events and on the last run I felt something give. Well I coasted up to the stop sign and noticed it is not idleing and has high number of misfires on 5 and 7 cyl. I got it home...barely. I looked at the log and there is nothing unusual it was running .92 on the O2's and no KR and TM at 27.5...the Ltrims were at +2 to +5, which has never happened they are usually 0 or small negative numbers. This would indicate it was running lean and trying to adjust by adding fuel at WOT...but the O2's were showing slightly rich...wtf <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
Any help with this would be greatly appreciated.
Any similiar experiences?

 

Any noise--like change in your pocket?

Perhaps you lost a valve spring <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />

 

I did not notice any unusual noise, but did notice an odd odor. Actually the same odor I had when I had my leaky headers on...I just installed Macs when I did the cam install. I need somebody to listen to the engine while I try to keep it idling?? Dunno. Thanks for the input.
This sucks. Welcome to the land of mods..huh.

 

What valvesprings are you running??? Sounds like you broke one.....

 

clogged cat .converters?

 

Brand new Comp 918's. I don't think a "clogged" cat would just make only 2 clyinders miss...would it? I did have my RT cats welded in on Wedn. with no problems or weird O2's since install. I thought I was being conservative with my rev limiter too set at 6700, which btw I did not hit but was around 6000 when this happened. Has there been other instances where the Comp springs gave out like this? If it is broken springs, what other possible damage could have occurred? I just started it to see if I could hear any unusual noise and noticed a raw gas smell coming from the 5 and 7 cyl. location...as far as noise i can't really tell.
Thanks for the help...this forum is awesome.

 

ttt...if it is a clogged cat, what damage could occur to the engine...possible gasket problems? I do smell fuel. Any input? Thanks.
BTW, when I had the cats welded in they cut the inlet and outlets back to the cat which exposed the "screen" on each end. I guess they could have disturbed the integrity of the welds holding the screens in place. If I pull the drivers side y out (thank God for the ease of disassembling the Mac y) how do I tell if it is clogged. Will it hurt anything if I run/test with that open header..except my ears.

 

My co-worker had the same problem and it was 2 broken valvesprings. He heard no unusual noise. Just a sudden loss in power..

 

Can you believe it! A broken #5 spring. Just installed this week. I am sure TR will make good on the spring, but what about the rest of them. I did heat-cycle the springs before I opened it up. I did notice a 6690 rpm reading from the ATap log and my limiter is set at 6700. It was between shifts 1/2 w/ this log:

LTFT 1&2 RPM TM TPS O2's 1&2 Cell
--------------------------------------------------
4.7 3.9 6698 27.5 0.4 0.74 0.745 3

I thought I was being conservative on the limiter. I have heard alot of you guys going higher. Has anybody else had a bad "batch" of springs or is this a fluke...\
Mark with Raging MS is coming over tomorrow a.m. to change out the spring(s). NOW THAT IS SERVICE!
Should I have all springs done? I sure did not expect this s#!t happen but I will keep the faith....

 

This may be the first broken 918 I've heard of. U sure it was the beehive style CC918? Which retainers did you use? How much cam lift?

<small>[ June 09, 2002, 07:12 PM: Message edited by: MelloYellow ]</small>

 

918's sent from TR with the titanium retainers...

 

You are the first person i've heard who broke a comp 918 spring? I beat the crap out of my car, and so many others do as-well, and no one has broken one yet, until you came along <img border="0" title="" alt="[Sad]" src="gr_sad.gif" />

 

TR 224/.561/114

 

You sure you installed the springs correctly, so far the 918's have been VERY reliable....

 

How could they be installed incorrectly? <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

 

Incorrect installed height can lead to premature wear and breakage from excessive stress.

Blake

 

How could you have a wrong spring height? They really only go in one way. The spring sets in the spring holder mold and is held on by keys holding them at one height... <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />

 

Stock height, not shimmed? Guess we'll just have to take it as a break.

Good news tho, it happened shortly after install, so could have just been a bad defective spring. Not a spring designed with the wrong metal that breaks after 3-15k miles like Russian Roulette.

It broke shortly after install? How many miles?
i have 2.5k on mine I believe.

 

one day i was going to work and decided to have a little fun on the way. so i slammed on the gas and nothing, the car had no power up top. so i get to work and was listening to the car idle and could barely hear what sounded like something in my exhaust. so i pulled off my mac y-pipe with cats, i had these for about 4 months or so, and on the drivers side converter was broken. i got a hammer and some rebar and punched em out and put everything back together. fixed my whole problem and i found out how bad mac cats suck. now the car sounds better and feels stronger too. just thought i would share.

 

It only had about 50 miles on it....not shimmed. I don't believe the 918's need shimming.