Vetteracerx
1/2 ton status
I had the same pistons in my big block build they did the same thing! Mine started pushing oil on the dyno. 9.7 to 1 my machinist sent them back they told me too much fuel caused the failure. These pistons are s##t.
CK5
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Rebuilt motor w/ broke pistons UPDATE: 11/13/13 1.5yrs later upgrade time!
- Thread starter dabomb6608
- Start date
Well I didn't order the speed pro ones again so hopefully if they are that bad I won't have a problem again. I still haven't got the pistons in. They said they will be here friday. Hopefully I can get them over to the machine shop so I can pick them up Saturday and start building the motor.
CGT80
1/2 ton status
I went with TRW hyper flat tops for my 406. I have edelbrock heads with lots of porting/flow work done to the heads and intake. My CR is 10:1 or so. The flat tops are better for proper combustion and quench, but the deck height and head volume has to fit as well. My pistons stick out of the cylinder by 0.005" to give me somewhere around 0.035" squish quench. I am still working on my distributor mechanical advance mapping (carb and msd hei dizzy). I had some minor pinging but I back off the timing from in the cab when that happens. With 20k hard miles on my 406 it still runs great. Like others said, I had my 406 built to turn out as much torque as possible out of a small block, while sticking to.........well.......breaking my budget. It was built more like a drag racing engine than a stock engine. The engine builder and head porter both knew it was for a heavy truck that tows up to 9k pounds. I was told by the engine guy that hypers are ok if you stay under 600 tq and 500hp and don't add nitrous or a super charger, and don't abuse the engine. My engine was estimated to make 525tq/420hp on 91 octane. It is limited by the 600 carb right now. I drive it like a hot rod, but I take good care of it and try not to push it to its limit (it stays under 5500 rpms and I don't run it hard if anything seems off).
I think the open headers masked any detonation sounds. I put a gm goodwrench 5.7 in my 88 k5. I had one side of the y pipe disconnected, due to the new exhaust manifold fitting different, when I started to break in the cam. It seemed like the knock sensor may have picked up the open exhaust. It seemed really retarded. Once I got 20-30 minutes on the cam, I checked my initial timing-I had to bump it up a little ways to get to 0 degrees for the ECU. I am not a fan of running open exhaust. The melted starter wires and melted amplifier power wire probably doesn't need any explaining either.
I think the open headers masked any detonation sounds. I put a gm goodwrench 5.7 in my 88 k5. I had one side of the y pipe disconnected, due to the new exhaust manifold fitting different, when I started to break in the cam. It seemed like the knock sensor may have picked up the open exhaust. It seemed really retarded. Once I got 20-30 minutes on the cam, I checked my initial timing-I had to bump it up a little ways to get to 0 degrees for the ECU. I am not a fan of running open exhaust. The melted starter wires and melted amplifier power wire probably doesn't need any explaining either.
Hey guys, got the pistons in and back from the machine shop where they pressed the rods on. Ive got a couple questions regarding the piston rings.
The new rings didnt have any directions in the box. So I cant really tell for sure which ones are the top comp rings and which ones are the second comp rings. I snapped some pictures of the differences between them. One set has a little dot on the one side by the gap. The other set doesnt have any markings and the sides are shinier on them. The set with the dot also has a beveled? inside edge opposite of the dot, so another words if the dot was facing up, the beveled edge would be inside facing down. I think thats the best way to describe that.
The one with the dot:
The one without dot and shiny edge:
Picture showing edge color:
And pistons/rods:
The new rings didnt have any directions in the box. So I cant really tell for sure which ones are the top comp rings and which ones are the second comp rings. I snapped some pictures of the differences between them. One set has a little dot on the one side by the gap. The other set doesnt have any markings and the sides are shinier on them. The set with the dot also has a beveled? inside edge opposite of the dot, so another words if the dot was facing up, the beveled edge would be inside facing down. I think thats the best way to describe that.
The one with the dot:
The one without dot and shiny edge:
Picture showing edge color:
And pistons/rods:
Dot goes up.
Martin
Martin
Well I feel dumb. The box the rings came in had the little flaps where it opens labeled for which one was top comp and sec comp ring. Got them all in with the help of a buddy of mine.
I made sure the gap was right at where the sheet that came with the pistons said they should be and clocked the gaps at about 4 and 6. Dot facing up on the rings with the dot.
I made sure the gap was right at where the sheet that came with the pistons said they should be and clocked the gaps at about 4 and 6. Dot facing up on the rings with the dot.
what kind of gap did you have on the comp rings?
the comp. gaps ideally should be about 90* apart, your a little under that with 4 and 6....
I run Forged TRW's in my Vette motor with 10.1 static c.r. and beat the snot out of it...this is after about 300-350 full throttle runs with at least up to a high gear shift point (80mph) and some street driving on it too... holding up great.
the comp. gaps ideally should be about 90* apart, your a little under that with 4 and 6....
I run Forged TRW's in my Vette motor with 10.1 static c.r. and beat the snot out of it...this is after about 300-350 full throttle runs with at least up to a high gear shift point (80mph) and some street driving on it too... holding up great.
Going by what the paper said, they shouldve been at 0.027. Which was right where they were. The werent file fit rings but I wanted to check them to know for sure they were where the paper said for the KB pistons
Well got the motor almost ready to be dropped in the car. Heads are on and torqued down, as well as the lower intake manifold and the runners. Got the rods all torqued and oil pan on too. Still need to get the rockers set and valve covers put on. Since I am off tomorrow night i should have it in tomorrow night and hopefully running by Tuesday
Well got the motor almost ready to be dropped in the car. Heads are on and torqued down, as well as the lower intake manifold and the runners. Got the rods all torqued and oil pan on too. Still need to get the rockers set and valve covers put on. Since I am off tomorrow night i should have it in tomorrow night and hopefully running by Tuesday
Cool hopefully all runs great and no more broken pistons.
what did you do with the timing/computer programming...wasn't that the issue to begin with?
those ring gaps seem to large unless you plan on boosting it, which wouldn't be a good idea with hypre pistons.
those ring gaps seem to large unless you plan on boosting it, which wouldn't be a good idea with hypre pistons.
There shouldnt be anything wrong with the programming considering im running the stock tune that came in the 5.0L Fbodys with the TPI. Other then me adding fuel to make up for the car being a 400ci and me changing the constants for the bigger fuel injection. Went from 19lbs to 22lbs injectors. The timing wasnt even touched other then telling the motor it had 6degrees of base timing.
The rings were right at where the directions sheet said they should be that came with the pistons. This is taken from the description for the pistons on summits site: To complete the install, the Keith Black hypereutectic piston and ring kits feature OE-quality piston rings manufactured from ductile iron, and the compression rings have moly facings for extra durability. They'll seal mild to high-compression engines, help to protect against oil blowby, and feature standard ring end gaps for an easy installation.
The motor is now ready to be fired up. Im on the phone right now with summit because im having issues with the y-pipe fitting. Im going to end up having to cut the flange off and make some changes to a section of the ypipe. The ypipe I bought is the only one flowtech makes for the 82-92 Camaro/Firebirds and ive got flowtech headers that are for the same cars but yet this one doesnt fit.
Heres a picture of the motor in the car.
I do have one question really quick before I start her up. How should I run it for the break in? I was thinking to just start it up let it idle while I check leaks/oil pressure/etc. then bring it up to about 2k rpm for 5-10mins then vary the rpms from 1500-3500 for another 10mins. Then take it for a drive doing some lowish rpm/high load pulls and maybe some engine breaking? What do you guys think/suggest?
Heres a picture of the motor in the car.
I do have one question really quick before I start her up. How should I run it for the break in? I was thinking to just start it up let it idle while I check leaks/oil pressure/etc. then bring it up to about 2k rpm for 5-10mins then vary the rpms from 1500-3500 for another 10mins. Then take it for a drive doing some lowish rpm/high load pulls and maybe some engine breaking? What do you guys think/suggest?
CGT80
1/2 ton status
On my engines I started them up and varied the speed between 1200 and 3000 rpm for 15-20 minutes. I was told that the idea is to splash oil in every place possible. I was told to try not to run the thing full throttle until the rings had time to seat (500-1500 miles). I think you want the parts to gradually break in.
Are you running a flat tappet cam? Did you add ZDDP or a zink additive to your engine oil? Modern oils are missing the zink and can cause quickly worn cams and other surfaces. The new cars run roller cams and are built to use the new oils. Break in oils and additives may have the necessary ZDDP also. I add one bottle of ZDDPlus to my oil every time I change it. My engine builder swears by it.
Are you running a flat tappet cam? Did you add ZDDP or a zink additive to your engine oil? Modern oils are missing the zink and can cause quickly worn cams and other surfaces. The new cars run roller cams and are built to use the new oils. Break in oils and additives may have the necessary ZDDP also. I add one bottle of ZDDPlus to my oil every time I change it. My engine builder swears by it.
I'm not breaking in a new cam, it's the same cam that's been in the motor. Only parts getting "broke in" are the rod bearings and rings.
I think your top rings were a moly faced...those should seat quick on a freshly bored/new cylinder...if the cylinder is not perfect, it could take a while, but anything below 3500 rpm for about 500 mi. should be good. No heavy loads, or full throttle stuff unless the cylinder is in perfect shape.
Well I got the y pipe tack welded together and good enough to run it. Started right up with no issues and sounded pretty decent with the exhaust system thats on the car. It still has exhaust leaks due to the y pipe being tack welded and not completely sealed though. I had my dad checking for stuff outside of the car while I was in it keeping the rpms around 2k for around 10mins. No problems there so I pulled it outve the garage and set the base timing. Then took it for a spin after putting the hood back on. Ran pretty good other then my tranny mount breaking(No i didnt romp on it, it literally happened as I was pulling onto the highway haha). Replaced that with a poly mount and she was back up and running.
Now I need to start looking at my tune, its having a little bit of a loping idle issue. Other then that it ran great! During this process I installed a new knock sensor just to be on the safe side. Havent heard it pinging at all.
Now I need to start looking at my tune, its having a little bit of a loping idle issue. Other then that it ran great! During this process I installed a new knock sensor just to be on the safe side. Havent heard it pinging at all.
You really need to take things a little slower. What was the water temperature and what was the oil pressure? You need to make sure those things all get to where they are supposed to be before you even think about driving that thing. I would not tune that motor with a leaking exhaust either. Your tune will be completely different.
Anyway congrats on getting it running and with 8.5:1 compression now hopefully you wont break any more pistons.
Good luck with the tuning in can test your patience at times. You wont always "hear" a ping you need to get it connected to a computer and read the sensor.
Anyway congrats on getting it running and with 8.5:1 compression now hopefully you wont break any more pistons.
Good luck with the tuning in can test your patience at times. You wont always "hear" a ping you need to get it connected to a computer and read the sensor.
That post wasn't the exact steps I took before I decided to drive it. It got up to temp and the fan kicked on right when the ECM told it to, it held at about 200-210. Oil pressure was the main gauge I was watching as soon as it started up. It hold right about 30psi at idle when it is up to temp. And rises with the rpms.
All the exhaust leaks are after the o2 sensor, they still might effect it some but not as much as it would if it was leaking at the head. I have to wait till I can use my friends mig welder so I can get it sealed completely.
And every time I drive it I have the laptop hooked up so I can watch my "WUD" what's up display. It shows me data from basically every sensor on the motor.
CGT80
1/2 ton status
congrats on getting it going. The oil additive is used all the time, as the new oils are missing what is necessary to make a cam last. Some people run diesel oil or off road/racing oil as it sometimes has the ZDDP chemicals in it. Others, like me, add the stuff to standard oil, and some don't bother at all. I'll buy the insurance. YMMV.
I hope your tuning goes well.
