Not another smoking LB7...

Cakes

Cakes

Member
Mar 14, 2014
54
2
8
Vegas
Need some thoughts/input.

Truck went down for injectors about a month ago. Bought some used 50s from a member on here and had them tested by Exergy. They aren't Exergy's but they said the injectors tested pretty good. Sent them back nice and clean with spec sheet.

Got everything buttoned/running and it sounds real damn good but it smokes heavy at idle, well always now, grey/dark. Not white/blue like the og stocks I just replaced. Those were pretty bad. It's one hell of a smokey pig driving around.

ATP says tuning is good after sending them data. I just finished tearing into it to double check valve tolerances, all took slight turns to get them set at .012. Ran compression test.

Compression:
1. 400
2. 400
3. 380
4. 375
5. 400
6. 350
7. 400
8. 350

I don't have balance rates for op temp but I do know that #6 is around -6.6 or so. With the rest of them being 0. something to 1.6 or so

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Cakes

Cakes

Member
Mar 14, 2014
54
2
8
Vegas
Umm, not sure really. No track time but a few good launches with the stocks. And some cruising fun here and there.

230k on the clock though, so this has already had me thinking that some valve train components, rings, maybe the rods, are tired by now or hurting.

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Cakes

Cakes

Member
Mar 14, 2014
54
2
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Vegas
IOWA LLY said:
Rods 6 and 8 are short.....

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Click to expand...
Yeah I saw that they were right on the cusp of in spec by 50psi.

That's a bummer if that's the case but not shocking I suppose.

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DAVe3283

DAVe3283

Heavy & Slow
Sep 3, 2009
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Boise, ID, USA
Those compression numbers don't look great, but odds are your "new" injectors are toast.

I did the exact same thing as you. Bought a used set of injectors, had Exergy test them. Came back "good", with a flow sheet. Smoked gray CONSTANTLY. I couldn't clean it up, so I paid Rob @ ATP. He couldn't clean them up either.

Broke down and bought new 75% over injectors, back to my tuning, and boom, crystal clean.

In your situation, I might be more worried about the compression, though, sorry to say. That much variance is not normal / good.
 
Cakes

Cakes

Member
Mar 14, 2014
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It's just got me stumped seeing that this is the state of it right after putting everything together.

It didn't run like this with the old injectors, they were just badly worn. I guess it's totally possible the damage was already done by the previous ones and I just never noticed it.

I have some vids to show how it's running but it won't let me load them from my phone. Like I said it runs great, smooth and quiet. Doesn't present the signs that something worn/broken/bent.

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Cakes

Cakes

Member
Mar 14, 2014
54
2
8
Vegas
DAVe3283 said:
Those compression numbers don't look great, but odds are your "new" injectors are toast.

I did the exact same thing as you. Bought a used set of injectors, had Exergy test them. Came back "good", with a flow sheet. Smoked gray CONSTANTLY. I couldn't clean it up, so I paid Rob @ ATP. He couldn't clean them up either.

Broke down and bought new 75% over injectors, back to my tuning, and boom, crystal clean.

In your situation, I might be more worried about the compression, though, sorry to say. That much variance is not normal / good.
Click to expand...
Yup, same situation almost.

A lot has crossed my mind in trying to figure this out and the possibility of having bum injectors was one of them.

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DAVe3283

DAVe3283

Heavy & Slow
Sep 3, 2009
3,724
292
83
Boise, ID, USA
Glad it's running right now. And sorry you had to go through having a bad "new" set, I know how that sucks.

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