0-60 time is even slower??
Thread Starter
Teching In
Joined: Aug 2016
Posts: 12
Likes: 0
From: Arkansas
0-60 time is even slower?? I recently built an LQ4 6.0 in a 2002 Silverado. My 0-60 time is 2 seconds slower and the quarter mile is 4 seconds slower. I don't understand how I can completely rebuild an engine and beef it up and it run slower. I think I made the mistake of installing a stock stall. The website said that cam didn't require one but I think I'm going to get a 2800 or 3000 stall. And yes the truck has been tuned. By a reputable tuner at that. He also did my previous tune. This weekend a valve stuck the day after I got it tuned and the piston came up and bent it. Also broke the pushrod. I took the heads back to the machine shop and they said all the intake valves weren't given the right clearance. Could that be my performance problem??? Truck idled and ran great. Even got good gas mileage. The performance just wasn't good.
214/222 cam .585 lift 155 LSA
7.375 pushrods
Dual valve springs
Stainless steel valves
Heads milled .020
28lb injectors
Bored .030 over flat top pistons
Tuned
Longtube headers
Stock stall (probably part of my problem)
P.S. cam company said the pushrods shouldn't be too long even with the heads milled.
Any advice would be great!
214/222 cam .585 lift 155 LSA
7.375 pushrods
Dual valve springs
Stainless steel valves
Heads milled .020
28lb injectors
Bored .030 over flat top pistons
Tuned
Longtube headers
Stock stall (probably part of my problem)
P.S. cam company said the pushrods shouldn't be too long even with the heads milled.
Any advice would be great!
Thread Starter
Teching In
Joined: Aug 2016
Posts: 12
Likes: 0
From: Arkansas
Okay that's what I originally thought. But alot of people said just because it didn't require one doesn't mean it wouldn't like to have one. But do you think the sticking valves hindered my performance that bad? They didn't give them enough clearance. I don't get how you can build something up and it be slower than stock. It's running 10 second 0-60. Was running 8.0 with a 300k mile engine with only injectors and a tune
TECH Fanatic
Joined: May 2016
Posts: 1,292
Likes: 436
From: St. Louis
Any cam will benefit from a looser converter, even a stock one. Still, my car went .5 tenths faster with a mild cam still running the stock converter. Something is still wrong with the engine or the tuning. I wouldn't touch the trans until you've got it running as good or better than before. Have you had it on a dyno?
Thread Starter
Teching In
Joined: Aug 2016
Posts: 12
Likes: 0
From: Arkansas
Any cam will benefit from a looser converter, even a stock one. Still, my car went .5 tenths faster with a mild cam still running the stock converter. Something is still wrong with the engine or the tuning. I wouldn't touch the trans until you've got it running as good or better than before. Have you had it on a dyno?
Trending Topics
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Thread Starter
Teching In
Joined: Aug 2016
Posts: 12
Likes: 0
From: Arkansas
Some cheapie brand X Pistons move the wrist pin which pulls the piston down creating huge quench numbers on an Undecked block. Lower than desired compression ratio and perhaps a cruddy timing chain (retarded cam) with a stock converter can all lead to weak acceleration in a heavy vehicle
Thread Starter
Teching In
Joined: Aug 2016
Posts: 12
Likes: 0
From: Arkansas
Some cheapie brand X Pistons move the wrist pin which pulls the piston down creating huge quench numbers on an Undecked block. Lower than desired compression ratio and perhaps a cruddy timing chain (retarded cam) with a stock converter can all lead to weak acceleration in a heavy vehicle
Thread Starter
Teching In
Joined: Aug 2016
Posts: 12
Likes: 0
From: Arkansas
One of them got smacked last weekend and bent. But when I took the heads back to the machine shop they said all the intake valves were tight and not given enough clearance. But I had been driving it and letting it run for a little while and never had a problem of them touching until last weekend. That's how I know they were sticking in the first place. So would them sticking and not seating properly cause me to lose that much performance?
Rare that it would be an intake valve. That usually points to an oiling/seal issue. Most times the exhaust valve will gal/stick cuz it operates so much hotter and expands more
Thread Starter
Teching In
Joined: Aug 2016
Posts: 12
Likes: 0
From: Arkansas
See that was the thing. They gave a little more clearance for the exhaust for that specific reason but didn't touch the intake valves. And the intake valve on cylinder one was the one that stuck and got bent. And they also admitted to all the intake valves not being given enough clearance. So that's my only lead on my performance problem because I can't find any abnormalities wrong with the motor. Cam is timed properly too. I can't find anything as to why this motor is slower than it was before the rebuild. Could it also be a possible this engine is still pretty fresh and not loosened up yet?