- Joined
- Jun 18, 2001
I've detonated my fair share of 109 motors and if I remember correctly the HG's seemed to blow WAY before knocking holes in pistons. Especially a custom forging which should be able to take considerable abuse without failing.
Broken Diamond Piston. Pics why????
- Thread starter 87we410877
- Start date
Well in my 1 afternoon with John Wilde and a PT70, and 1 pump fail and no significant follow up tuning on the DFI
I'll see if I still have the piston. But we pretty much have the SAME result. Melted the top crown which cause significant blowby into the crankcase. I used 2 Big Bosch pumps from a Bently, bolted on a PT70 turbo (upgraded from a TE-44) and NO access to a wide band gauge. This was back in the day when dynos were few and far between.
We went WOT to 15 psi and power felt great but I noticed it backfired/broke up and let off. Limped it back home to find it barely idling. When a took the heads off, the gaskets were fine but the #5 or #6piston was shot. Quick lean spike and goodbye piston!
Chris remember the 87 White Limited with NO motor with 27k on it .. That had a burned piston and the headgasket was fine
well don't start out balls to the wall !! just creep up on it. What were ya running for plugs ???? what did they look like?
DailyDrifter
The Slow and the Curious
- Joined
- Dec 5, 2007
Good question, the plugs will tell you the story.
Also another good point made about the actual timing vs. FAST timing. Before my 1000 mile engine took a chit I forgot to verify the timing. My combo is in my sig, kinda along the same lines as you.......But my ultimate failure was a "block boring cam". My new combo however never ran "right", and was a real dog from day 1. I still kick myself in the ass for not checking the timing
. When you get the new engine built, make sure you verify the timing.Totally agree.
87we410877
Well-Known Member
- Joined
- Apr 5, 2005
No i never verified the timing. Plugs are autolite 103's and look fine. I'll take pics of the heads and post them up.
I will probably go with a stock ECU, MAF translator, some kinda AFR monitor and a turbo tweek chip.
I will probably go with a stock ECU, MAF translator, some kinda AFR monitor and a turbo tweek chip.
- Joined
- Jun 18, 2001
Chris remember the 87 White Limited with NO motor with 27k on it .. That had a burned piston and the headgasket was fine
Was that a stock cast piston or a custom forging?
I agree with Dan and Lonnie above.
I think that failure came from knock. I'm betting the knock sensor is unplugged or has a issue in the wiring. In the fast B2B i beleive that if you set the timing attack rate to zero. when knock occurs and it doesn't pull any timing it will show no knock.
Also verfing the timing is a very important thing to do on the aftermarket ecm's. I have found a few gn's that the timing was off as much as 5 degrees.
One other thing you might want to consider is have the Wideband checked.
on a another side note if ya run alky and pump gass run it a tad richer say 10.8 -11.0 any leaner than that is asking for trouble IMO
If this failure just happened for know reason it's got me bumed as i just purchased a stroker set-up from mike licht before Xmas.
Also verfing the timing is a very important thing to do on the aftermarket ecm's. I have found a few gn's that the timing was off as much as 5 degrees.
One other thing you might want to consider is have the Wideband checked.
on a another side note if ya run alky and pump gass run it a tad richer say 10.8 -11.0 any leaner than that is asking for trouble IMO
If this failure just happened for know reason it's got me bumed as i just purchased a stroker set-up from mike licht before Xmas.
87we410877
Well-Known Member
- Joined
- Apr 5, 2005
Yea i guess everythings going to have to be checked on the new motor set up and checked again. I took alky out its for sale in the for sale section
why ??? it's the greatest thing for a street car to run some boost
sorry alky didn't do this damage.- Joined
- Feb 18, 2006
Yup, typical for an offcenter engine, and yes, shows signs of heavy detonation.
- Joined
- Jun 18, 2001
These pistons are NOT from my motor that pic's coming later. This piston is very similar to the one we are discussing.
This pic is a comparison of Diamond v.s. a Ross that was HEAVILY abused and detonated but did not fail (Notice the ring placement)
Detonation or not there is a design issue with that piston IMO.
This pic is a comparison of Diamond v.s. a Ross that was HEAVILY abused and detonated but did not fail (Notice the ring placement)
Detonation or not there is a design issue with that piston IMO.
BEATAV8
The Engine Whisperer
- Joined
- Feb 14, 2002
Should the top ring be positioned lower? Thanks in advance.. looking to learn from you!
interesting piston pics... I def see what your sayin.. Good thing we run only "TSM" boost (24#s)
ok ... back to the original post .. maybe keep the FAST and go see Otto for tuning ??!!! He has a dyno there and has messed with Buicks and Fast for a long time.. that is whenever ya get your motor back.....
NO WAY WOULD I THROW THE ALKY OUT .. BUT it's your car
)ok ... back to the original post .. maybe keep the FAST and go see Otto for tuning ??!!! He has a dyno there and has messed with Buicks and Fast for a long time
.. that is whenever ya get your motor back.....NO WAY WOULD I THROW THE ALKY OUT .. BUT it's your car
- Joined
- Jun 18, 2001
Is the original post about why his piston failed or how he should have Otto tune his car
Is the original post about why his piston failed or how he should have Otto tune his car
piston failing !! AND detonation.. I just said Ottos name because he also has a dyno. Maybe would have seen something more. I don't have a Fast or want a Fast.. Know NOTHING about them either. I am a old CHIP man
Has anyone considered the engine was just run hard and the piston failed?
1) As Dan pointed out Ring land is too close to the piston top.
2) Picture shows the relief cut left next to no material in that area Supports Dans observation
3) Bearing looks like side loading typical off set rod more wear than normal.
4) The rods look like they were not clearanced on the small end could also add to side loading if touching the pin area of the piston.
5) the Skirt on the piston in question is killed IMO could also add to abnormal bearing wear
6) The other pistons in pic look fine.
Based on the info he has provided. I see no reason to replace engine management, Throw away the alky system, put 3 fuel pumps on the car, do scientific knock sensor research or Do the hokie pokey and turn yourself around.
We are not curing cancer here guys. Its racing. Fix the engine and get back to burning some rubber.
1) As Dan pointed out Ring land is too close to the piston top.
2) Picture shows the relief cut left next to no material in that area Supports Dans observation
3) Bearing looks like side loading typical off set rod more wear than normal.
4) The rods look like they were not clearanced on the small end could also add to side loading if touching the pin area of the piston.
5) the Skirt on the piston in question is killed IMO could also add to abnormal bearing wear
6) The other pistons in pic look fine.
Based on the info he has provided. I see no reason to replace engine management, Throw away the alky system, put 3 fuel pumps on the car, do scientific knock sensor research or Do the hokie pokey and turn yourself around.
We are not curing cancer here guys. Its racing. Fix the engine and get back to burning some rubber.
Lonnie ya hit it right there .. Life in the big city so to speak ! They are all goin to break sooner or later! BUT...ya always a BUT.. Melissa's motor has 15k on it with Diamonds in it. We took that motor from my Buick RX7.. Had stock headgaskets on it so we took the heads off to swap in the Cometics. I looked at the pistons and commented to Russ about the "thin spots on the edge". Scatched my head for a minute and said.. Lets throw it in the car an see what it does. Melissa, Russ and I beat the living hell out of it.. DRIVE IT LIKE YA STOLE IT !! Like ya said get out and have fun with it! Blows up tomorrow ??? so what ... look at the beating it took .. Oh ya.. If ours did blow we would have been running long before this thread will end !
....I still go back to detonation for doin the damage BUT Dan knows a lot more than me:biggrin: Also have to remember how much power to most of the Buick guys run ??? Maybe 400/550?? Dan has BIG POWERED cars out there !! Nothing small like most of us run
OH... DAMMIT LEAVE THE ALKY SYSTEM IN IT
It's a street car .. No fun running around with 15#s of boost!!