blow-by
Banned
Joined: Dec 2011
Posts: 104
From: Duchesne
Ive seen this before 
the blow by is caused by the renewed heads sealing up tight and the older bottem end unable to hold up. either that or like others have said new rings on egg shaped cylinders no bueno! mic the cylinders that will tell
the blow by is caused by the renewed heads sealing up tight and the older bottem end unable to hold up. either that or like others have said new rings on egg shaped cylinders no bueno! mic the cylinders that will tell
Fourth Generation Moderator
October 2009 ROTM
October 2009 ROTM
iTrader: (1)
Joined: Nov 2007
Posts: 10,560
From: Eastern PA,
ROTM Winner's Club
Thanks for the feedback. As far as having the valve guides done, there isn't smoke out the exhaust, it's out the crankcase.
The motor has 140k on it, and there isn't a spec of carbon build up ANYWHERE. Something is fishy.
I can't get my engine stand peices all in one spot so I haven't pulled the pistons yet, but the walls are silky smooth. I know the heads have been off, it had new FelPro gaskets, (and I can tell where they scraped off the old gasket).
What's the best way to tell if the cylinders are out of round? Is it possible they didn't hone the cylinders at all and the new rings didn't seat (if in fact they did attempt to re-ring it?). Will it cause this amount of blow-by if the rings weren't properly seated or broke in?
Personally I just can't get over how clean everything is for supposedly having 140k miles on it. There is literally no carbon buildup anywhere, not even the exhaust valves, and the valve springs look almost new. It's unlike any higher mileage engine I've ever tore down.
I'm trying real hard not to have to send the block off to the machine shop, I plan on selling the car once i get it running right again, but after machining I'd be lucky to get out of it what I have in it.
The motor has 140k on it, and there isn't a spec of carbon build up ANYWHERE. Something is fishy.
I can't get my engine stand peices all in one spot so I haven't pulled the pistons yet, but the walls are silky smooth. I know the heads have been off, it had new FelPro gaskets, (and I can tell where they scraped off the old gasket).
What's the best way to tell if the cylinders are out of round? Is it possible they didn't hone the cylinders at all and the new rings didn't seat (if in fact they did attempt to re-ring it?). Will it cause this amount of blow-by if the rings weren't properly seated or broke in?
Personally I just can't get over how clean everything is for supposedly having 140k miles on it. There is literally no carbon buildup anywhere, not even the exhaust valves, and the valve springs look almost new. It's unlike any higher mileage engine I've ever tore down.
I'm trying real hard not to have to send the block off to the machine shop, I plan on selling the car once i get it running right again, but after machining I'd be lucky to get out of it what I have in it.
Also if they did re-ring the motor I would guess they cleaned it. Cost wise it is not worth rebuilding a 140K LT1 find a low miles used motor and just reseal the outter gaskets.
Thread Starter
|
In the Staging Lanes
Joined: Jun 2012
Posts: 60
I'm guessing this has something to do with my blow-by issue. This was just the first (and only) piston I pulled tonight, at random. Not even sure how a failure like this occurs.
Last edited by Ecidemon; Aug 28, 2012 at 12:54 PM.
Thread Starter
|
In the Staging Lanes
Joined: Jun 2012
Posts: 60
It was all still held in the piston and fell out after I removed it, the piston walls are smooth with no scratches or gouges. After I saw that I thougth the same thing as you, but it appears as though it stayed roughly intact; at least, intact enough not to damage the walls or have any parts in the pan.
I'll know how the rest look after work this evening.
I'll know how the rest look after work this evening.
Fourth Generation Moderator
October 2009 ROTM
October 2009 ROTM
iTrader: (1)
Joined: Nov 2007
Posts: 10,560
From: Eastern PA,
ROTM Winner's Club
There is no way those cylinders are round enough for a rebuild without boring. If you try to re-ring this engine your going to be right back at square one.To me it looks like hvy wear on the bottom of the piston edge. The same force that broke this piston also cause the piston to **** in the bore, that what causes the out of round. Cylinders wearing out of round on a V style motor is perfectly normal. It is expected not some random event that might happen. Even with a normal use engine I would expect .005-.008" out of round at 50,000 miles.
If you trying to flip this car just replace the motor with a used one. Most of the time when a piston fails like that is because the car was beat on and beat hard. Its hard to see in the pic but if the rings look like they are pitted on the edges like it had rust but was cleaned off then your looking at a motor that had No2 on it at one point.
If you trying to flip this car just replace the motor with a used one. Most of the time when a piston fails like that is because the car was beat on and beat hard. Its hard to see in the pic but if the rings look like they are pitted on the edges like it had rust but was cleaned off then your looking at a motor that had No2 on it at one point.
Thread Starter
|
In the Staging Lanes
Joined: Jun 2012
Posts: 60
would a long block from a 96 Impala SS be the same as my 94? LT1's with decent meilage are hard to come by around here, but I found one for $450 that the guy claims he was told by the dealership he bought it from had 24k on it, but it's been in a crate for a few years
