Big Problems with New 408 +PICS

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dust

dust

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  • Cylinder 7 Intake lifter will not pump up and making noise.
  • Carbon/Oil deposits on valves of Cylinder 7
  • Thick ridge on Cylinder 7 compared to others
  • Smoke coming from left tail pipe at midrange RPM. Or when after high RPM and let off gas, we were unable to tell which or if the white smoke had blue in it

So, the lifter is bad and needs rebuild/cleaning or replace but why? And is that related to the ridge on the same cylinder? I'm worried it may be a valve or Edelbrock machining problem...

Specs: 408 Eddy heads, 650 Mighty Demon, Racer Brown .470/232 and lifters, HV oil pump, CC Pro Mag rocker arms. 4 speed. At most 200 miles on engine and 2 runs.

Ideas?
 
What exactly was done to the block? Be specific. The hone pattern looks rough to me. It should be much smoother. What was the end gap set to on #7? Were the heads checked and corrected or run out of the box? Were the heads re-torqued? What does the #7 intake lobe on the cam and base of the lifter look like? When exactly did it start to smoke? Has it always done that? Or did it start abruptly one time while driving? Any signs of coolant seaping out between the heads and block on either side? What do the other chambers look like?
 
Call me crazy or just blind, but I don't see ANY cross-hatch at all. Looks like your burning oil from the cylinder. Either the rings didn't seat from a poor hone job or the oil control rings were installed improperly.

Or....you have a tight valve caused by incorrect valve train geometry, too long of a pushrod, incorrect adjustment, etc. This would cause this cyl not to fire and wash the walls down with fuel, as well as the lifter problem you mention.
 
I would have been nice if you took a comp test before you took it apart and a leak down test, Post a picture with the piston farther down in that cylinder and maybe 1 or 2 others. What rings did you use? Cast rings seat fast but eat a cylinder up ASAP. I agree with the above statement, need to check for valve being held open.
 
More info:
-All lobes are fine, measured and at spec. Lifters all fine.
-Pushrods are straight, all checked for unique signs of wear, nothing noticed.
-Smoke only started after second run on strip, about 150 miles on engine. Only on strip is seems.
-Head are out of box, not re-torqued but checked before disassembly, OK.
-I reviewed the video I have from the car on the dyno and on the strip, seems that the smoke comes from the exhaust after he let off the gas.

One thing that I did find out:
Oiling rocker arm shafts were installed upside down, so the oil feed hole on my Comp Pro Magnums were facing down instead of up and toward the intake.
 
dust said:
More info:
-All lobes are fine, measured and at spec. Lifters all fine.
-Pushrods are straight, all checked for unique signs of wear, nothing noticed.
-Smoke only started after second run on strip, about 150 miles on engine. Only on strip is seems.
-Head are out of box, not re-torqued but checked before disassembly, OK.
-I reviewed the video I have from the car on the dyno and on the strip, seems that the smoke comes from the exhaust after he let off the gas.

One thing that I did find out:
Oiling rocker arm shafts were installed upside down, so the oil feed hole on my Comp Pro Magnums were facing down instead of up and toward the intake.
Click to expand...
From the look of the cylinder, I would be pulling the block and checking that piston. I have had a couple of small blocks that have had this problem due to ring flutter. At high RPM the oil ring had come out of its Land and cocked sideways in the cylinder. Rings could have been damaged during installation or improperly installed, or even the wrong rings.
kenny b
 
Does that mean you dont know the end gap? Does your builder? The oil on the heads is typical of a cylinder that has problems. I wouldnt sweat the heads, but again, I totally disassemble them and check seat runout and valve stem clearances. I have seem OOTB seats .010 out of round, but those would seal..Just not very well...lol. If I had to guess, I'd say a combo of things. The honing pattern is odd. But that may just be the pictures too. Take a clearaer pic of a bore with the pistosn down 1/2 way. But I dont think that would cause it to pop a gasket. My money's on the lack of retorque, or surface contamination of the deck or gasket that didnt allow it to bite well. Sealing aluminum and iron together is not easy. Permatorques can do this, but if there was a weaker area because of torquing, it would pop during the pass pumping gasses into the cooling system, and when the throttle was slammed shut, the vaccum level draws coolant into the cylinder. At least it didnt hydraulic and really break something.
 
Do you torque spec for the Small Block ARP head studs?

I checked them all at 70lbs before disassembly, forgot what the spec was...
 
I don't know about the torque spec on eddy heads, but 70 lbs don't sound like enough to me. I'm like moper...Retorque on alum. heads is critical for the alum. will swell and contract more. This definetely could cause a blown head gasket which mopars are noted for anyway...I always torque my heads on mopars 10 lbs more than it calls for...Just my 2 cents and that aint worth much..LOL...Good luck on gettin it fixed !
 
Well, I got more specs... alot more specs...

The oil concern with the lifter has been resolved, the shop who built my shortblock forgot to re-install the rear oil gallery plug... Yet another one to add to my list of SpeedOMotive f*ckups...

I was hoping someone could give me a more precise idea as to what caused this ridge on my number 7 cylinder. Too tight of piston ring? Rich condition caused fuel to wash oil off cylinder?

Or is this not far from normal? :scratch:

I measured my cylinder #7 bore, which feels obviously like it has a larger ridge by hand. I included cylinder #3 since it’s what all the other cylinders on that side looks like.

Engine info: 408 from 360 block, about 200 miles, 2 quarter mile runs and one dyno pull.

Cylinder 7 Bore Measurements:
*Note this is oddball, much larger ridge by hand*

Left to Right bore:
4.026 (at the ridge)
4.034 (just below ridge)
4.035 (middle of cylinder)
4.030 (bottom, against piston)

Top to Bottom:
4.028 (ridge)
4.033
4.035
4.035

Cylinder 3 Bore Measurements:
*Note, this is what all the others look like*

Left to Right bore:
4.027 (ridge)
4.026
4.029
4.031
4.029

Top to Bottom:
4.024 (ridge)
4.031
4.035
4.030
4.031

Also, here are the compression test numbers:
Cylinder, Dry, Wet
1, 175, 210 ***most compression and biggest difference dry/wet***
3, 160, 175
5, 145, 175
7, 145, 155 ***the ridge***
2, 165
4, 155, 165
6, 160
8, 160, 170

Thanks :icescrea:
 
An engine that has been bored and honed oversize with only a few hundred miles on it shouldn't have any ridge. Are you sure the ridge isn't just carbon?

That cylinder would appear to be a little larger but that shouldn't have been a problem if the cylinder finish and ring end gaps were proper. My opinion would be poor ring seating. This may have even gotten better the more miles you put on it. But now that you've taken it apart I'd suggest having it honed at a performance machine shop and if the other rings are OK install new top rings and gap them properly for the type of pistons you have.
 
If I had to guess, I would say the rings in that hole butted and wore the block away. Did you get a sheet with the measurements for the ring gaps? Look a the ends of the rings (where they were filed in the gap) and see if there are any marks that looks like they hit and rubbed on each other. The good holes should show no signs of contact, that one should be pretty obvious. Shiney spots are what you'd see, as opposed to the gritty marks the grinder leaves. Another way to check is put the work rings in the bore and measure the end gap. With the hole .005-.008 larger bore, those gaps should be like .035-.040. If it's tighter than that, they were probably much too tight when fresh.
 
moper said:
If I had to guess, I would say the rings in that hole butted and wore the block away. Did you get a sheet with the measurements for the ring gaps? Look a the ends of the rings (where they were filed in the gap) and see if there are any marks that looks like they hit and rubbed on each other. The good holes should show no signs of contact, that one should be pretty obvious. Shiney spots are what you'd see, as opposed to the gritty marks the grinder leaves. Another way to check is put the work rings in the bore and measure the end gap. With the hole .005-.008 larger bore, those gaps should be like .035-.040. If it's tighter than that, they were probably much too tight when fresh.
Click to expand...


I agree with most of that post but .035-.040 is huge for ring end gap. You should have about .004 per 1 inch of bore thus a 4.030 bore should use about .016-.017 on the top ring. There's less heat in the second ring so you can get away with less, but I don't recommend it. The second ring is really only along for the ride. Many Stock and Super Stock racers put very undersize rings in the second groove because the rules state it has to be there, it doesn't have to drag on the cylinder wall.

Anyway, I'm getting ahead of myself. If you are using the hypereutectic pistons then you need to consult with the piston manufacturer for ring end gap specs. And they must be followed or you'll end up with hyperexplosives instead.
 
I didnt write that clearly enough I guess. I meant that if the rings were removed from that cylinder's piston, and placed back int he bore and the gaps checked now, the end gap should be .035 to .040. Because the extra .007-.008 of bore will cause the gaps to grow by a lot. I would think the assembler would have noted what the ring gaps were in that hole, and the others. If they set it at .018, it was probably too tight for the intended use. Depending on the ring manufacturer and piston type, I would probably go .019 on the top, and .022 on the 2nd on a 4.03 bore that was going to be raced. If I read right on the other site this was posted, you don't have a dial bore gage. You should if you want to properly measure this stuff.
 
Guitar Jones said:
I agree with most of that post but .035-.040 is huge for ring end gap. You should have about .004 per 1 inch of bore thus a 4.030 bore should use about .016-.017 on the top ring. There's less heat in the second ring so you can get away with less, but I don't recommend it. The second ring is really only along for the ride. Many Stock and Super Stock racers put very undersize rings in the second groove because the rules state it has to be there, it doesn't have to drag on the cylinder wall.

Anyway, I'm getting ahead of myself. If you are using the hypereutectic pistons then you need to consult with the piston manufacturer for ring end gap specs. And they must be followed or you'll end up with hyperexplosives instead.
Click to expand...

Ring end gaps on the top ring are very wide on the KBs, since the ring land is high. Second ring is normal gap. A .030" gap would not be too much when using KB hyper's. If the top ring was not enough, then wear, would be present, as the picture indicates. My .002.
 
Dug up the reciept: They are JE piston rings #s100s84030-5 and SRS? pistons #13744-030, I think those are Probe?

'Been awhile since I read up on these parts, I'll research them later. Time to go to work... sucks....
 
lenweiler said:
Ring end gaps on the top ring are very wide on the KBs, since the ring land is high. Second ring is normal gap. A .030" gap would not be too much when using KB hyper's. If the top ring was not enough, then wear, would be present, as the picture indicates. My .002.
Click to expand...

That's why I qualified my statement with "If you are using the hypereutectic pistons then you need to consult with the piston manufacturer for ring end gap specs."

dust never said what pistons were in there.
 
Machine shop (SpeedOMotive) says that it is fuel wash that caused the ridge on the left side... I thought that if the carb was out of tune that it'll effect two cylinders on the left and two on the right?
 
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