Wow that's an insane crack. Just wondering are those heads worked or stock? I'm not savy with the v6's so I can't tell if those valves are oversized or not. Any damage to the deck surface of the block?
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93 LX 2.3 to 5.0 conversion. 60% of the time it works every time.
VTEC - All the lag of a turbo............None of the boost
If its Fast and reliable, it ain't cheap.
If its Cheap and reliable, it ain't fast.
If its Fast and cheap, it ain't reliable.
Wow that's an insane crack. Just wondering are those heads worked or stock? I'm not savy with the v6's so I can't tell if those valves are oversized or not. Any damage to the deck surface of the block?
About the only thing stock on that car is the alternator and water pump. We really can't see any damage to the block, and the pistons look great, so we're guessing "no" at this point. The #6 exhaust valve looks a little ashy, so we're going to send the injectors off to get flow tested and cleaned......
We are thinking it is the fast ramp up/fall of the cam, the spring combo, or the solid roller lifters, or a combination of all three. This was an experimental set of heads, and has proven to be a failure for right now. If you look at the pics that Jr took, it shows the cracks are right along the valve line. If those valves, were opening and slamming shut at a faster than normal rate, it might weaken the area to make is succeptable to cracking. (It's like slamming a door shut. It will break the door frame eventually) The springs/lifter combo has not been tested in this particular combo before. We needed solid rollers for the spring rate, and it might have contributed to the cracking.
We are thinking it is the fast ramp up/fall of the cam, the spring combo, or the solid roller lifters, or a combination of all three. This was an experimental set of heads, and has proven to be a failure for right now. If you look at the pics that Jr took, it shows the cracks are right along the valve line. If those valves, were opening and slamming shut at a faster than normal rate, it might weaken the area to make is succeptable to cracking. (It's like slamming a door shut. It will break the door frame eventually) The springs/lifter combo has not been tested in this particular combo before. We needed solid rollers for the spring rate, and it might have contributed to the cracking.
That's our story at this point........
Could too high of spring pressure play a role in this? Extreme seat pressure with like you say slamming the valves shut?
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Building it right from the beginning is always better than starting over to build it better because it was temporary.
93' LX hatch, 460 with mods, TH400 trans, 9" w/ 3.89 spool. Best (so far!) of 10.18 @ 131 mph with 1.39 60'
Could too high of spring pressure play a role in this? Extreme seat pressure with like you say slamming the valves shut?
Not necessarily..... You can have a high seat pressure. The higher pressure was for a higher revving motor, like a turbo car, to reduce valve float and accomodate the lift of the cam and to avoid coilbind. The solid lifters were to support the open pressure of the springs. Hydraulic rollers could not be used in this application because the open pressure was too high and would have eaten them up. The ramp up/down of the cam was too quick and the "slamming door" effect came into play-especially at 6.8k+ rpms......
We are going to send them off to one of our friends to do some further investigation.....
Well, the car is back together, and we're headed to Beech Bend tomorrow. Got a little things to take care of besides tweaking the tune, but she'll be ready to run Open Comp. Go or blow, we'll take videos......
. Sorry to see this. Like they say for the Cubs, There's always next year!
