I got it to lean out to 11:1 - 11.5:1. The timing is being ran by the PCM, I took a few data logs. I checked the accuracy with a timing light. Base timing is set to zero at the distributor, with the the PCM out of the equation. Then I verified about 21 degrees advance, at idle, with the PCM back in control. My timing light is adjustable, so with it set to 21 degrees, I am back at zero on my balancer. I am pretty sure my timing is accurate, I have idle timing set to 21 degrees in the tune.

The cam in the old motor was on a 112 LSA, this one is on a 110. I am beginning to think that I have killed this motor by putting this cam in it. Plus I retarded it 2 degrees.

I have an extra 02 sensor bung. I am going to take the plug out of it, drill and tap it, then hook some type of pressure gauge up to check back pressure.

Here are what the plugs look like, pretty much all the same.

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Waiting on a buddy to show up with his compression gauge.

I am more than likely going to swap cams, what would you guys think about a 210/218 .560/.555 113+4 (109 ICL)
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=207&sb=0

 

I think I may have degreed the cam in on the exhaust lobe.....

 

So, I have a better, larger degree wheel. I am going to check for true top dead center and remark my balancer if need be. Also going to check and see how far the cam is off, then I am taking it out and swapping the cam. I have changed my mind, I am going to install a Lunati off the shelf cam 215/224 112/108. Degree it in and run it.

https://www.lunatipower.com/Product.aspx?id=2005&gid=261

 

So I have verified true top dead center, my balancer and timing pointer are perfect, so I know my ignition timing is right. I got the timing cover off and the cam is right where I put it 2 degrees retarded. I checked intake center line and its 108. Cam card says 106, so it is retarded 2 degrees or still advanced 2 degrees, however you want to look at it. Since Comp grinds 4 degrees advance into the cam. Its hard to believe this cam could cause it to run like that, but maybe it is.

I did do a compression check before taking it apart and I was getting around 175-180 pounds on all cylinders.

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I still don't think its the cam.... plenty are making good power with cams all over the board. Lobe sep from 110-122, big duration splits, they all tend to make decent power with a decent turbo selection.

 

Hmmm...well I don't know what else it could be.

Unless its the heads somehow, I don't know.

 

I wish I had an answer, but just hard to believe its the cam. Forcefed86 had a similar problem with his ls based engine, and I think it was a cam timing issue, but I believe he was quite a ways out, and you have degreed yours, so should rule that out. Wouldn't hurt to look at his posts though.

 

You've down a compression test, but have you done a leak down test?

 

no, have not done that yet. May try and do that today.

 

I ended up pulling the motor out, I had some head studs leaking water so instead of leaning over the thing and pulling the studs one at a time, I went on and pulled it out. So far I have not found anything wrong. I pulled the intake, the gasket is compressed all the way across the heads and is sealing. I think the reason I was getting water out of some of the head studs was because I installed the studs one day, then the next day put the heads on. While torquing the heads a few of the studs spun and broke the silicon in the threads lose.

I decided to cc my heads, supposed to be 180 cc intake runners and 72 cc combustion chambers. I came up with 195 cc intake runners, and 65 cc combustion chambers....I did 2 chambers and 2 runners and the were pretty much the same. To me the chambers looked small compared to the 76 cc heads that came off the truck. Unless these heads are just complete garbage...there is a review on them, on Summit Racing, where a guy said his motor never ran right with these heads.

 

Too high of compression (72 to 65 cc chambers will raise compression almost a point) causing spark knock and the knock sensor is picking it up and retarding timing?......I didnt go back through to read if you are using a factory ecu or not...just a thought

if it is the factory ecu.... your should be able to log knock activity to verify my suspicion.

 

Was not showing any knock counts, I have a bigger cam now show that should help bleed some compression off.

 

Nice build man, love how the truck looks, in that first video seems to be moving hard!

It is weird, that problem you are having, so the chambers ended up being smaller, 1 point in compression... now it should be close to 10:1 comp ratio? could be a problem when boost...

 

Damn....worth a shot.

 

So I have the truck back up and running, it does run better. Seems like by me adding the MAT sensor has cause it to run bad under boost. Something in the tune.

I am also having a problem getting my headers to seal, keep getting exhaust leaks. I did try to drive it a little last night, was a little warmer outside and I was getting some knock. Even though I have the MAT disabled I can still see the temp readings. They are in the 110 - 120 range while under boost. AFR is around 11, timing is about 18 degrees.

I have not pushed on it real hard yet.

I ran my compression numbers, it comes out to 9.8:1 static, dynamic comes out to 8.0 even with the new cam. I am a little pissed about my heads being so far off at what Dart advertises them at. 72cc which is what they are supposed to be. 65cc is a big difference.

When I get my exhaust leaks fixed I can get it out and do some more tuning. I am kind of getting burnt out with it right now.

 

are you sure your IAT's/MAT are that low under boost.....compressor (turbo for that matter) seems small for the combo and your compression is higher than you thought.....both of which make the combo more knock prone.

what style IAT sensor are you using? if its the closed big chuck o' metal type the response time of that sensor is not quick enough (or you arent in boost long enough) to show true IAT....need to use a open element style unit for applications where intake temp changes quickly (IE forced induction).

As a giggle check...throw some race gas in that thing and see if it improves

 

Here is my sensor.#ad


I am going to drive it to work tomorrow, do some data logging. Pretty sure it's right. Maybe I will stick a TC in there somehow to check it.
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Drove it to work yesterday, pretty hot out. Was still getting some knock. I am going to look at my plugs next. I have an accel 414s in there right now. What would be a good cold plug to run? I also ran a compression test last night, my cranking compression did go down with this cam, now its 160 pounds, was 170-180. Worst case I could pull the heads back off and open the chambers up, or convert the thing to run on E85.

 

If you have E85 available, I would do that in a a heart beat. 10:1 is perfect with boost and high octane for the street. It gives great street manners and great power under boost. I am also dealing with tuning issues on a new head combo. I cracked my cheap 440 source ones and had a set of opened up stockers. So far in tuning I have spit out a set of head gaskets. LOL

 

I noticed your target air fuel ratio is 14.7, i think you want a much richer ratio when under boost...