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Stroker Intake Backfire

That sucks man! I built my stroker about 8 years ago and it seemed cams were going flat everywhere in the performance world and some 4.0 guys. I broke my cam in with just regular oil because I didn't know/understand about the ZDDP thing. My first oil change I rolled it over to rottella and just recently went back to conventional 10/30. But damn for a long time if I heard any wierd noise or anything didn't seem perfect I was convinced the cam was going flat lol.

Good luck and keep us posted, if you do tear it down all the way take some pictures of your rod bearings if you could. I want to see if you have had any signs of detonation with the cranking compression bieng so high, thats a little outa pump gas terrirtory especially considering you have a cast iron had. If your getting away with it thats awsome!
 
BlueCuda said:
That sucks man! I built my stroker about 8 years ago and it seemed cams were going flat everywhere in the performance world and some 4.0 guys. I broke my cam in with just regular oil because I didn't know/understand about the ZDDP thing. My first oil change I rolled it over to rottella and just recently went back to conventional 10/30. But damn for a long time if I heard any wierd noise or anything didn't seem perfect I was convinced the cam was going flat lol.

Good luck and keep us posted, if you do tear it down all the way take some pictures of your rod bearings if you could. I want to see if you have had any signs of detonation with the cranking compression bieng so high, thats a little outa pump gas terrirtory especially considering you have a cast iron had. If your getting away with it thats awsome!
Click to expand...

I'm curious about something regarding the knock sensor equipped Renix motors. Maybe he doesn't have detonation because of it.

I'd like to know how much advance the ECU pulls and at what rate, when the signal comes in from the sensor.
I had a supercharged car with a knock sensor and it had a dash display showing when knock started to occur and how many degrees of advance were pulled at each instance. I can see the knock sensor values with the DRB hooked up but I should probably drive with it hooked up to see what happens in real world conditions.
 
I don't know if there is a way to make the renix computer spit that information out is there? I know with a GM product you can hit the intake manifold with a hammer and it will almost die because the knock sensor pulls so much timing.
 
Have you thought about a clogged CAT causing the backfire originally?
 
BlueCuda said:
I don't know if there is a way to make the renix computer spit that information out is there? I know with a GM product you can hit the intake manifold with a hammer and it will almost die because the knock sensor pulls so much timing.
Click to expand...

We used to knock on the intake manifolds with a large wrench of the AMC 258s that had a knock sensor and the idle would drop momentarily.

I'm curious how much total advance it will pull. My J&S knock sensor would pull up to 20*, depending on the severity of the onset of knock.

I'll drive one of my Jeeps with the DRB hooked up sometime and monitor the knock sensor. I have seen a noisy lifter cause the ECU to pull a few degrees before.
 
You can use a DRB on a renix? The others don't have knock sensors
 
IIRC the 91+ HOs do not have a knock sensor, if my 97 does I don't know where it would be.
 
New cam and lifters came in today but I'm still waiting on a head gasket. I have everything stripped down and the head is loose. I wish I had everything I feel like I'm sitting on my ass wasting time.

imgp0256640x480.jpg
 
I'm using a Comp Cams 68-232-4 it only has a one year warranty.
 
Thanks for all the suggestions I'm now back up and running. I had a flat lobe on the cam and a very warn lifter. It took a good full day to get everything torn apart and put back together. It started perfectly on the first try and I was able to get a good break-in. I’ve now switched to conventional oil. The rest of the cam and lifters looked like new almost no wear.

imgp0292x.jpg


imgp0287e.jpg
 
Thats pretty shitty. Hopefully your oil filter was doing its job and cleaning out the metal. After your cam break in you should change the oil and filter, especially if you reused the oil filter, which I hope you didn't.

What oil do you plan on using now?
 
I never saw any metal in the oil it looks like my Wix filter was doing its job. I used a new filter and oil when I put the cam in and another filter and oil after the break-in. I couldn't find any specific ZDDP oil locally. I'm running Castrol GTX 10w30 and some Lucas zinc additive. I still need to research oil more I didn't have time to dig through all the forum posts and articles online.
 
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