Help!!!!!!!!!!Procharger destroyed LT-1!!!!
Thread Starter
Instructor
Joined: Jul 2005
Posts: 101
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From: Astrakhan city no
Help!!!!!!!!!!Procharger destroyed LT-1!!!!
Hello.I put D1 sc procharger with intercooler with 15 psi on my LT-1
engine.I lowered compression to 9.2 & install Clivete 77 P series main bearings & rods H series bearings.All other parts are stock.
What happend after 5 tuning passes?????No main bearings at all,rod bearings look like after 100 K miles & two broken pistons.....Help please.What parts I need to use?I am far from you.I am in Russia....
engine.I lowered compression to 9.2 & install Clivete 77 P series main bearings & rods H series bearings.All other parts are stock.
What happend after 5 tuning passes?????No main bearings at all,rod bearings look like after 100 K miles & two broken pistons.....Help please.What parts I need to use?I am far from you.I am in Russia....
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
Ummm, stock pistons won't do it. You need some kind of heavy duty after market. For 15 psi I would say that you need to lower the compression do below 9:1, 8.5:1 or lower would be ideal.
What did you do for tuning? The stock timing would destroy an engine. What are using for adjusting that. Also what are you using for adjusting fuel? Also what injectors, fuel pump and what not.
Are your pistons pitted? My guess is detonation killed the engine.
What did you do for tuning? The stock timing would destroy an engine. What are using for adjusting that. Also what are you using for adjusting fuel? Also what injectors, fuel pump and what not.
Are your pistons pitted? My guess is detonation killed the engine.
Melting Slicks
Joined: Jun 1999
Posts: 2,872
Likes: 3
From: Wilmington NC
did you check the clearance of the bearing journals on the crank to the rods and main block line? this is important to make sure you have the correct sized bearing in there. also did you change pistons? if so did you balance the assembly? give us some more information as Mnvette stated.. it will help to pinpoint where you went wrong and help to advise on a correction.
Chris
Chris
Thread Starter
Instructor
Joined: Jul 2005
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From: Astrakhan city no
first ,I installed 42 lb injectors & changed fuel capasity in the tunerpro programm.Than I changed timing on full throttle from 36 to 20 degrees.No other changes .I understand that pistons problems are the detonation .Maybe it is better to buy adjustments from somebody ,if you now such place,please tell me.But I dont understand what finished life of bearings?My engine is 37 K miles.Last year I used 200 hp Nitrous on it on stock engine.I opened it but everything was o kay exept rod bearings,But now !!!!Main bearings were destroyed after two days of driving.May be I need another oil pump?I didn t changed my pistons,I only made the dish on them without balancing.The dish is 1.2mm from the top of the piston.
Last edited by alx; Jun 11, 2006 at 01:22 AM.
Instructor
Joined: Apr 2006
Posts: 194
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From: edmonton alberta
to much timing advance
a stock engine with 15 lbs of boost will live for a while as long as you are not detonating ,i would say you haven't put some kind of timing retard ,even a engine with forged pistons will blow if you get into bad detonation ,under hi boost and you pound out the engine bearings at the same time .a engine can take a lot of boost as long as you got the right timing and fuel delivery, even a bone stock lt1
Melting Slicks
Joined: Jan 2002
Posts: 3,293
Likes: 79
From: Jackson MI
Originally Posted by alx
Than I changed timing on full throttle from 36 to 20 degrees.No other changes .
Remember you'll have to change all of the lower rpm as well with the same formula depending on how much boost you make at a given rpm.
Also how are you monitoring your air/fuel ratio? Do you have a wideband setup on the car? If not I'd pick one up, they are only $300 or so.
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Pro
Joined: Dec 2002
Posts: 704
Likes: 16
From: Dallas Texas
Originally Posted by alx
Can you tell me,were is the better place to buy performance rotating assembly for my needs?
www.speedomotive.com
PS--how did you get 15 psi of boost out of your setup? are you running a cog or 8-rib setup?
Racer
Joined: Jul 2002
Posts: 313
Likes: 1
From: Dallas Tx
Originally Posted by mn_vette
Remember you'll have to change all of the lower rpm as well with the same formula depending on how much boost you make at a given rpm.
Also, for ALX, when you say that you adjusted the fuel flow for the higher injectors, I assume you mean you did more than just change the fuel injector constant. I don't have the tunercat program on this computer, but I think that they have a table to adjust the fuel pulse time based on RPM and TPS%/MAP (or something along those lines).
Let me know guys.
Melting Slicks
Joined: Jun 1999
Posts: 2,872
Likes: 3
From: Wilmington NC
Yes.. he is most likely discussing the timing tables.. which once into 100kpa as mentioned will need to be adjusted vs rpm while under boost because you have effectively lost one input for engine data (MAP). same as the other table kown as the power enrichment table.. this is the offset for fueling which adds pulse width under WOT per RPM range.. it is fairly simple to tune with if the base program is already running smooth and you have access to a dyno. and can trim your fueling from reading the data on the dyno print out. which should give you a good bit of insight as to where your fuel needs to be fattened and also if ther eis timing being pulled out. simply pull some timing until you rid the knock retard.
Chris
Chris
Racer
Joined: Jul 2002
Posts: 313
Likes: 1
From: Dallas Tx
Originally Posted by lcvette
Yes.. he is most likely discussing the timing tables.. which once into 100kpa as mentioned will need to be adjusted vs rpm while under boost because you have effectively lost one input for engine data (MAP). same as the other table kown as the power enrichment table.. this is the offset for fueling which adds pulse width under WOT per RPM range.. it is fairly simple to tune with if the base program is already running smooth and you have access to a dyno. and can trim your fueling from reading the data on the dyno print out. which should give you a good bit of insight as to where your fuel needs to be fattened and also if ther eis timing being pulled out. simply pull some timing until you rid the knock retard.
Chris
Chris
Thanks,
Scott
EDITED FOR SPELLING/GRAMMAR
Last edited by Scott94C4; Jun 13, 2006 at 09:13 PM.
Drifting
Joined: Apr 2000
Posts: 1,390
Likes: 35
From: INDIANA
Originally Posted by AKS Racing
That is the way I understood it as well. I have seen people "eyebrow" the pistons, but never "dishing" a piston.
Racer
Joined: Jul 2002
Posts: 313
Likes: 1
From: Dallas Tx
Originally Posted by LT1GMC
Dishing can work well with a forged piston, like the Powerforged 2256 flattop, but factory cast pistons do not have near enough material to do this.
I guess that is new to me. I am not from the "old school." I would rather have a machine and mold to do that for me...
That shay-tree mechanic stuff scares me. Especially on modern fuel injected vehicles.