Jamesbond2509

iTrader: (1)

Recently Ive been misfiring on Cylinder 7. I checked the compression on cylinder 7 and found that it was down to 60 compared to 150 across the rest of the cylinders. Seeing that the plug was fouled and that there was lots of blowby in the catch can, it appears that this is 90% rings. ouch! (any thoughts) Part of the problem is that the KB mail order tune. that came with the SC didnt catch all the unique characteristics of the Engine and SC. I saw atleast 7lbs boost. Looking Back, I should have done some custom tuning after the fact.

So as an everyday driver I need your advice.

1) Have the pistons and rings upgraded as a 5.3 and continue with the Kenne Bell SC. I think this would be the lowest cost option and try to hit 10PSI boost with an intercooled install and dyno tuning. Would be nice to try out & report!

2)Go for the 408 stroker that has been discussed in several threads. (What is the history of the 408) At that time I dont think my SC would be as effective as aTurbo since the losses at 10PSI are around 50HP. If that's correct then Im headed towards getting an STS in the long term.

3) Also how long can I last with #7 cylinder down before the engine self destructs.(there is no smoke yet, konck on wood. I use M1 oil religiously and now watching my boost) If im to go with option 2, I need to last until at least spring before I can afford to do this.

Inspector12

iTrader: (29)

Just a friendly piece of advice I had a 5.3 with a Whipple and couldn't figure out my missfire issues well did a check same thing #7 had like 65lbs and all other were like 150ish. I found out that the radiator was leaking the trans fliud and the coolant were not seperated (GM had a recall) the trans was pushing in to the coolant causing it to puke when I shut it off and then when I would check my trans fluid it was alwasy low so I kept adding fluid and I finally figured it out when I was draining the coolant and ny brother made the comment that it looked like trany fluid. The light went on and I found out the trans fluid had caused my head gasket to fail on #& and the coolant washed the rings etc and you see it went down hill from there. I know it is off subject just wanted to let you know because of the simularity of your problem(Same cyclinder). Not saying it is your pboblem just thought I give you more things to check LOL! So just check your radiator if you have ever had any issues with the truck pukling at all. Sorry to here about your issue. Oh and by the way you will be able to go a long time with the dead hole from experience if you have cats though it will ruin them after a little while.

Jamesbond2509

iTrader: (1)

Thanks I will definitely check that out. What did you do with the engine afterwards? It looks like many on this forum had cylinder 7 problems. That must be the first cylinder to go due to leanout.