Dead Cylinder,1100 Miles on Rebuilt 3VZE
02-19-2014, 10:10 AM
#42
Registered User
Different manifold design.
The 3.0 3vze sends all exhaust from passenger side bank to drivers side, past number 6 cylinder before dropping basically at #4 -- all of that heat and all of that pressure creating issues on driver side bank. I also think there's issues with undersized exhaust diameter/lack of ideal flow streams here too recognizing all of the exhaust dumping into driver manifold and how exhaust has to change direction in passenger and #6 flow stream greater than 90* to evacuate, so constantly higher pressure on drivers side than ideal (especially #6) that's further exacerbated and causes issues when you have a plugged cat or other downstream malfunctions... (Passenger top, driver bottom.)
The 3.4 5vzfe doesn't send exhaust back through the manifold. It does crossover, but both its manifolds are similar design to 3vze passenger -- so the exhaust streams join in the down pipe away from the engine, not in the manifolds connected to the block (pressure is predominantly limited just to its own bank and heat is moved away from the block ASAP -- crossovers aren't ideal, but are much better than crossing over and then sending all that crossed over exhaust back through a manifold...):
And then here's its crossover (dumps out passenger side):
The 3.0 3vze sends all exhaust from passenger side bank to drivers side, past number 6 cylinder before dropping basically at #4 -- all of that heat and all of that pressure creating issues on driver side bank. I also think there's issues with undersized exhaust diameter/lack of ideal flow streams here too recognizing all of the exhaust dumping into driver manifold and how exhaust has to change direction in passenger and #6 flow stream greater than 90* to evacuate, so constantly higher pressure on drivers side than ideal (especially #6) that's further exacerbated and causes issues when you have a plugged cat or other downstream malfunctions... (Passenger top, driver bottom.)
The 3.4 5vzfe doesn't send exhaust back through the manifold. It does crossover, but both its manifolds are similar design to 3vze passenger -- so the exhaust streams join in the down pipe away from the engine, not in the manifolds connected to the block (pressure is predominantly limited just to its own bank and heat is moved away from the block ASAP -- crossovers aren't ideal, but are much better than crossing over and then sending all that crossed over exhaust back through a manifold...):
And then here's its crossover (dumps out passenger side):
Last edited by RSR; 02-19-2014 at 10:19 AM.
02-20-2014, 02:20 PM
#44
Registered User
Yeah, in regards to the HG issue from the crossover, probably the best way to describe it is that the driver's manifold receives so much heat that it basically turns your block into a heat sink, instead of removing the exhaust and heat from the engine to the exhaust system as exhaust systems are intended to work...
The cast iron block and aluminum heads at very different temp points and swell rates due to that heat, combined w/ uneven heating created the HG issues.
The pressure issues are secondary, but when combined w/ above it's usually more than the HG can take...
The cast iron block and aluminum heads at very different temp points and swell rates due to that heat, combined w/ uneven heating created the HG issues.
The pressure issues are secondary, but when combined w/ above it's usually more than the HG can take...
Last edited by RSR; 02-20-2014 at 02:35 PM.
02-26-2014, 10:50 AM
#45
Registered User
Thread Starter
Join Date: Jul 2013
Location: Big Bear Lake, Cali
Posts: 294
Likes: 0
Received 0 Likes
on
0 Posts
Machine shop called, heads are ready to be picked up, besides the broken valve in #6 (replaced with DNJ valve) they found the intake valve in #2 was leaking.
Right head no problems, valve lash fine through out, surfaces good, micro-flux says no cracks.
$123
Right head no problems, valve lash fine through out, surfaces good, micro-flux says no cracks.
$123
Thread
Thread Starter
Forum
Replies
Last Post
Poncho0206
95.5-2004 Tacomas & 96-2002 4Runners
3
07-10-2015 06:21 PM
