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Fixing my burned valve...


xtremerevolution
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Yeah buddy, this baby better SCREAM once she's put back together. I'm curious to see if the exhaust note will have changed as a result of the different exhaust port size.

 

assuming the exhaust manifolds can flow it and there aren't any more ridiculous restrictions, yeah, it may sound a bit different, but the performance bump should be "noticeble" to say the least...

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From that point forward, the exhuast is pretty free and the manifolds are decently sized. There's a cat, no resonator, and a magnaflow wide open muffler. I'm pretty excited about this.

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I looked them over quickly and I didn't notice anything that stood out. The exhaust valves were all white, but I didn't pull them all to check the sealing surfaces. I did pull one, and it was pretty bady pitted.

Edited by xtremerevolution
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Well unfortunately I didn't get the car finished today. I did manage to get the exhaust manifolds bolted back up, bolted the exhaust flange together (which took most of the time), installed the rockers on the rear head, got the valve covers back on, LIM, steering pump, coil, and the accessory brackets. I'd give it another 30 minutes to finish putting it together, after which I'll refill the cooling system and go out for a drive. All I really have left is the alternator, UIM, fuel rail, and all of the wiring. Shouldn't take too much longer.

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Well the car is done. Had a LOT of smoke coming out from the engine bay the first 15 minutes from all the crap that was around the exhaust manifolds. After a 10 minute drive though, it all went away.

 

The car still has a light clanking noise that I had heard before I replaced the heads, so I'm assuming it could be a stuck lifter or something of the sort. I didn't bother to pull and inspect all the lifters while I was down there, unfortunately. I'll dump an entire bottle of seafoam in there and run it like that for a week or so and then change the oil to see if that makes a difference.

 

As for power, I really can't tell yet. The PCM still has to re-learn the car, and I haven't driven the car in quite a long time. I've been driving the Bonneville, which is a N* on 3.73 gears, so I've forgotten how the Regal used to drive. One thing I did notice is that there's a nice surge of power between 3500 and 5000 rpm that wasn't there before.

 

I'll give you guys an update once I've driven the car a while and the PCM gets used to the modifications.

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I drove the car to work today. Funny thing compared to the old heads is that the car used to feel rough while accelerating in higher RPMs. Now, its a more rough idle vibration and a much smoother acceleration. Unlike before, the idle doesn't bounce around like it used to. Its very steady at around 800 rpm, but it vibrates more than it used to. I wonder if this is because I messed around with the upper intake insert and now the runner lengths might not be 100% the same. I'll probably try to get a replacement insert and see if that does anything. Otherwise, all the smoke is gone, and the car drives fine.

 

The engine also makes a shuffling noise now. Not sure how else I can describe it, but its repetitive and louder on cold starts. I'm hoping a bottle of seafoam will cure that too.

 

Any thoughts?

Edited by xtremerevolution
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still datalogging it every once in a while? if so, and you have a baseline WOT run, you could compare MAF readings to see how much gain there was to have an estimate of how much power you potentially picked up...

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still datalogging it every once in a while? if so, and you have a baseline WOT run, you could compare MAF readings to see how much gain there was to have an estimate of how much power you potentially picked up...

 

Haven't datalogged anything unfortunately. All I have is the butt dyno, which at this point shows a noticeable increase in power.

 

Any thoughts on the noises coming out of that engine?

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not quite sure what "shuffling" means, but the vibration is more likely to be caused by the larger exhaust ports than the modified intake insert thingy(though in all honesty, they could both be contributing to it(nothing is free, especially power))... was there a lot of difference in the ports of the heads you took off?

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I posted the same situation over on the bonneville forums, and Danthurs agrees it could be a stuck lifter, and a couple of oil changes and a seafoam should do the trick. Also, he mentions I'm getting the rough idle because my LTFT's are way off and its likely that I need a tune. I should send you that chip, lol.

 

Yes, there was a huge difference in the exhauast ports, which you can also see in the photos. It was mainly at the exit of the port on the manifold side. I didn't take much off the intakes ports; mostly just smoothing the casting imperfections.

Edited by xtremerevolution
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I posted the same situation over on the bonneville forums, and Danthurs agrees it could be a stuck lifter, and a couple of oil changes and a seafoam should do the trick. Also, he mentions I'm getting the rough idle because my LTFT's are way off and its likely that I need a tune. I should send you that chip, lol.

 

i don't see the LTFTs getting that far off... at least not from this alone. this is one of the situations where a MAF is actually useful in that it should be reading the increased flow correctly. spark will also be a bit different as well since the engine is likely flowing more air with less throttle, so the spark table(which is calibrated in LV8) should be acting at a lower load(which most of the times means more advance).

 

EDIT: regardless, a good thorough datalog could determine if that is the case...

 

and i meant how consistent were the original ports on the original heads.

Edited by RobertISaar
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and me doing some funny math:

 

stock L27 should be making 170HP at 4800RPM with ~126 grams/sec of air.

so it makes 1.35HP per gram/sec of air at peak HP.

at 255 grams/sec, the MAF should be out of range at ~344HP due to the BSFC of .47 assuming BSFC remains the same(though it definitely won't)

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i don't see the LTFTs getting that far off... at least not from this alone. this is one of the situations where a MAF is actually useful in that it should be reading the increased flow correctly. spark will also be a bit different as well since the engine is likely flowing more air with less throttle, so the spark table(which is calibrated in LV8) should be acting at a lower load(which most of the times means more advance).

 

EDIT: regardless, a good thorough datalog could determine if that is the case...

 

and i meant how consistent were the original ports on the original heads.

 

They were consistent, and constently horrible. I attempted to the best of my abilities to make them identical in shape, size, and amount of material removed. Its only the idle thats' rough. The needle sticks solid at 800 rpm and doesn't move, but I can fee the vibration in the car. I'll keep thinking. Maybe that seafoam will fix a lot of problems.

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Here's a video for those interested in how the car runs now. The L27 usually has a pretty weak top end, but you'll notice the RPM's surge nicely between 3500 and 5000.

 

[video=youtube;SzmehXfRbIw]

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