massive blow-by and clean plugs??? - Team Camaro Tech
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post #1 of 8 (permalink) Old Apr 14th, 04, 03:17 PM Thread Starter
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I spent part of today finishing up getting the 305 ready to yank out of my 3/4 ton. The engine had massive amounts of blow-by...so bad I had to plug off the pcv port on the carb and just ran the pcv hole in the valve cover open. It would make so much smoke that it was nauseating sitting at a stop or at low speeds, and it left a nasty oil film all over the valve cover. Anyway, when I yanked the plugs (approx 5K miles on them) they looked almost perfect I expected to see at least some crud buildup on them. The truck has a LOT of miles on it, and supposedly the engine was rebuilt sometime in the last 5 years (I don't believe it...too much crud buildup on the outside and inside of the engine). It always starts super easy even with no choke hooked up, and purrs like a kitten at idle, but has absolutely no power above about 65mph. It also smoked when it was started (bad guides I'm sure). How could an engine have so much blow-by and still have good looking plugs?

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post #2 of 8 (permalink) Old Apr 14th, 04, 05:53 PM
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Worn rings and poor valve sealing will create little vaccum to suck oil up into the cylinders but will blow a heck of a lot of combustion gases past the rings.

Dave
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68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI
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post #3 of 8 (permalink) Old Apr 14th, 04, 05:57 PM
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I bet you find broken compression rings but good oil rings.I have seen several low buck rebuilds with alot of cylinder wall taper break the top two rings. Compression leaks by but the bottom oil ring keeps it from fouling plugs.

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post #4 of 8 (permalink) Old Apr 15th, 04, 09:33 PM
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agree with plum buddy,when it rains it pours huh?
so when ya gonna put those vortec heads on the 388? is that all it needs?man i wish i lived closer to ya,id lend a hand!hey at least you'd have wheels,besides i know you'd rather be driving the nova right?
best wishes
Eric

86 camaro,383,topline vortecs,scat crank,wiseco forged 9.5:1,6"scat rods,comp xs282s,performer rpm,750 proform vac sec,msd in cap, hooker coated 1 5/8"headers,3"flowmaster,700r4,2800 stall,3.42 10 bolt posi,hotchkiss lca's,aje tube k member & a-arms
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post #5 of 8 (permalink) Old Apr 16th, 04, 04:56 AM
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Does the lifter valley area look dry? Maybe just doesn't look right. I had an engine that would blow smoke & oil from every seam whenever I had the pedal down more then cruise position.

Ended up being the intake manifold gasket was burned through at the exhaust crossover.

Yep, exhaust gases were being forced into the lifter valley. I wondered why there was so much sludge in the oil every time I changed it, lol.

Bob.
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post #6 of 8 (permalink) Old Apr 16th, 04, 03:26 PM Thread Starter
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The lifter valley, valvetrain, intake and exhaust ports, etc was suprisingly clean. The truck has almost 200K miles on it...and I bet the engine is original. Looks like the oil was changed fairly regularly.

Eric, wheels isn't really a problem. My daily driver lumina is still kicking right along, as is my '78 1/2 ton. The engine I am dropping into the 3/4 ton is the engine that came with the nova when I bought it. All I have done to it is gaskets and a cam swap. The cam that was in there I felt was a bit too big for the truck with its 3.23 gears and 700r4. One of the trucks is going up for sale...I just can't decide which one I'll be finishing up the engine install in the 3/4 ton tomorrow, then will begin putting the 388 back together tomorrow evening or sunday. Vortecs, performer rpm, and different cam (maybe...haven't completely decided yet. Looks like the pro-topline heads wasn't the problem...this time). Good thing I don't have a job getting in the way of all this work

[ 04-16-2004, 09:37 PM: Message edited by: travis ]

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post #7 of 8 (permalink) Old Apr 16th, 04, 09:31 PM
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glad to hear you have a daily scooter!
i don't remember if your 388 was a roller motor or not?or the cam you were using(dunno if it's old age or beer [img]graemlins/beers.gif[/img] !anyway i'd love to hear what cam you finally decide on.i thought you said you had 11 bad guides in the toplines?
if not,what was the problem?really interested to know how the vortecs stand up against the 200 toplines.also the piston dish cc,and head gasket thickness(i know you posted it here somewhere but i can't find it right now .as for which truck to keep,my vote goes to the one with the trailer hitch!lol"Tailgating me will NOT make the person in front of me go any faster"
i would add "but passing them at 140 WILL make them look smaller in a hurry"
you can use that
peace!
Eric
p.s.love your motto...

86 camaro,383,topline vortecs,scat crank,wiseco forged 9.5:1,6"scat rods,comp xs282s,performer rpm,750 proform vac sec,msd in cap, hooker coated 1 5/8"headers,3"flowmaster,700r4,2800 stall,3.42 10 bolt posi,hotchkiss lca's,aje tube k member & a-arms
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post #8 of 8 (permalink) Old Apr 17th, 04, 07:53 PM Thread Starter
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My pro-toplines had 11 bad guides...I got them all replaced, along with a light surface cut just to make absolutely sure they was flat (they was), fresh valve job and seals, and re-sealed the screw in studs. The only place that is still iffy is around a few of the intake ports. I had to take quite a bit of metal off the outsides of the intake ports for pushrod clearance. I didn't grind thru anywhere, but its pretty thin in a few places. But anyway, I am going to use them on something else I have planned for the future, and will be using the vortecs this time around. I will cc them in the next few days after I finish tweaking the chambers a bit more. The plan at this moment is to use the new gm -140 solid I bought a while back to help bleed the compression down. The pistons are wiseco pro-true's with 4.3cc vr's (2vr flat tops), and I am using fel-pro .041x4.166 head gaskets. The cam is 257/[email protected], .493/.512 lift, 112lsa with a 108ica, and I will be using 1.6 intake/1.52 exhaust roller rockers. This is all stuff I have accumulated over the last few years. I may be making a mistake switching to the smaller heads and larger cam...plus, I will probably put the 1 5/8" headers back on it. I am torn both ways...put it back the way it was with the 294s comp cams solid (that is already broken in) or go this new route. I wanted to use my isky 247/254 solid but it is a small base circle cam, so I would need even longer pushrods (and I already have +.300's in there now). Too many decisions to make. I am just worried that the vortecs/-140 cam is going to be too much cam and not enough head.

Yeah, I like that motto too I come up with all kinds of good ones while driving with all the other idiots around here. I just can't post some of them

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