Just received the new F40 to replace the ailing one in the car now. Below are the two links that will cover what happened with the forged build. After more time to think about it and investigating, the engine wound up with a combination of burnt rings in at least one cylinder and possibly a burnt valve as a result of the oil ingestion as can be seen as a hot spot on a few of the intake valves. I thought the reground camshaft didn't have enough duration but considering it has at least 16+ degrees more than the stock cam at 9.8:1 compression it's probably fine for 11.5:1.
I found the real culprit was not just an improper PE AFR but some extremely lean points under boost that I didn't have the datalog table setup to display and didn't catch on the gauge out the corner of my eye given the car ran so aggressively under boost I had to keep my eyes on the road. I was careless and I paid for it. I can't attribute the rod bearing wear to the compression ratio considering my timing was probably still too far advanced, my bearing clearance was on the tight side at around .0018 instead of .0024" and at some point my oil squirters were damaged and after an experiment with 5W20 synthetic I suddenly started having problems with idle oil pressure dropping low enough to trip the light.
The plan is to refresh the engine, install optimum clearance rod bearings, replace the valves and maybe go with a little more duration on the cam. My reluctance with the cam has to do with the fact that even with a weak cylinder and damaged rings the motor still cranked out 33 mpg on the hwy suggesting a fresh motor might have reached as high as 38 mpg considering I under estimated the actual economy over 150 miles to arrive at 33 mpg according to my receipts and the mileage posted on the odometer to make sure I errored on the low side.
The bad knock sensor complicated things also. Hopefully the swap will be completed in January.
I just wanted to thank you for posting up your entire process of failure and success, I gotta hand it to you alot of people would have gave up already. I read every entire page of your swap last night as Im considering purchasing UND_Sioux's 3900 engine swap stuff to put into my Diablo replica. If decide to go with his 3900 it will be turbo'ed like yours, but xmas is getting in the way of making a decision right now...
Looking foward to see your finished project!
Nevermind on the 3900 swap, I see its already sold....
[This message has been edited by diabloroadster (edited 12-15-2011).]
Originally posted by fierocarparts: Pulling my 2.8L out but install of 3900 VVT won't happen for a while. Enjoying life. But I look forward to your posts and your advice.
Definitely take your time and plan. It will be at least another month before I have a chance to get to the dyno. I got side tracked taking care of deficiencies and missed the dyno window but it was worth it in the end as a result of the improvements. When I finally make it to the rollers hopefully the numbers will justify the effort.
are you still running the variable plenum? I've heard the LZ4 non variable plenum performs much better overall then the variable LZ9.
Yes, and I've heard it mentioned but with the only legitimate SAE dyno results I've seen being provided by GM and to my knowledge the highest output 3900 having the variable intake I'll have to believe GM. 227/237 for the LZ4 intake, 240/240 for the variable.
Yes, and I've heard it mentioned but with the only legitimate SAE dyno results I've seen being provided by GM and to my knowledge the highest output 3900 having the variable intake I'll have to believe GM. 227/237 for the LZ4 intake, 240/240 for the variable.
its a quick swap when you take it to the dyno, maybe take a LZ4 manifold with you?
Originally posted by ericjon262: its a quick swap when you take it to the dyno, maybe take a LZ4 manifold with you?
That's too much work eric, besides I trust GM's certified numbers on this one over what I believe are someones assumptions based on some flow bench numbers. GM has used and is still using a variable intake so it would be a stretch to think that they were doing so in error for all these years. I may try to get a pull with the valve open and closed but I'm pretty confident GM didn't put all that work into it and fail to test its performance. On the other hand for overall average performance it could possibly prove to be a happy medium since I have no active variable function.
It's hardly a quick swap for my setup with all the bolts involved in addition OE hardware.
[This message has been edited by Joseph Upson (edited 04-10-2013).]
Working on the spark blowout issue and just changed the module and coil assembly to an OE backup this morning and so far noticed improvement in performance but have to push it a little more to see if the problem is resolved. That's the only thing keeping me from going up the street to the dyno right now.
Did a 'quick' read through, and I gotta say this is awesome I just discovered the 3900 a couple days ago and started searching for info. A 3900, possibly turbo is now on my future swap list.
I'm hoping the dyno numbers make it worth it. I should definitely have it tested this month. I'll be switching to code59 tomorrow in order to measure boost being made in excess of 15psi having gone as high as 18 psi by the gauge so far. 8F code mask from the Turbo Grand Prix only goes up to 14.7 psi. The plan is to take it to have it tested next week. I'm going to check the cylinder compression tomorrow if the weather permits to make sure everything is still in order.
Also... is the variable cam timing and intake an on/off thing, or is it something the computer adjusts variably? If I go with something like this, I plan on running an EBL, it has an RPM window that's designed for N2O, but it also has TPS and MPH variables.
Originally posted by Doober: Also... is the variable cam timing and intake an on/off thing, or is it something the computer adjusts variably? If I go with something like this, I plan on running an EBL, it has an RPM window that's designed for N2O, but it also has TPS and MPH variables.
I have the intake valve open for top end and during the rebuild I did not set up the VVT for on/off operation instead opting to degree the cam in place. The OE PCM varies the cam but I don't care what anyone says con wise about using a VVT motor with a non VVT PCM/ECM, it's not worth the added wiring hassle, tuning software/hardware expense and loss of total control to me. My mom has the 3.6 DOHC in her car and if you drive it like a race car you'll note the PCM can't always keep up. Her car has the 6 spd auto and my car still gets better mpg with more displacement so, so much for VVT. An electric throttlebody is like having to ask permission to go.
When the engine is running, the generator turn-on signal is sent to the generator from the engine control module (ECM), turning on the regulator. The generator's voltage regulator controls current to the rotor, thereby controlling the output voltage. The rotor current is proportional to the electrical pulse width supplied by the regulator. When the engine is started, the regulator senses generator rotation by detecting AC voltage at the stator through an internal wire. Once the engine is running, the regulator varies the field current by controlling the pulse width. This regulates the generator output voltage for proper battery charging and electrical system operation. The generator F terminal is connected internally to the voltage regulator and externally to the ECM. When the voltage regulator detects a charging system problem, it grounds this circuit to signal the ECM that a problem exists. The ECM monitors the generator field duty cycle signal circuit.
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2007 Chevrolet Uplander
Engine Control Module (ECM) The ECM directly controls the generator field control circuit input to the generator. It monitors the generator's generator field duty cycle signal circuit and sends the information to the BCM. The ECM will override the BCM control of the generator when one of the following conditions is met: The engine control module (ECM) controls the generator through the generator field control circuit. It monitors the generator performance through the generator field duty cycle signal circuit. The signal is a pulse width modulated (PWM) signal of 128 Hz with a duty cycle of 0-100 percent. Normal duty cycle is between 5-95 percent. Between 0-5 percent and 95-100 percent are for diagnostic purposes. The following table shows the commanded duty cycle and output voltage of the generator:
Commanded Duty Cycle.... Generator Output Voltage
10%..................................11 V
20%..................................11.56 V
30%................................. 12.12 V
40%..................................12.68 V
50%................................. 13.25 V
60%..................................13.81 V
70%................................. 14.37 V
80%..................................14.94 V
90%................................. 15.5 V
The generator provides a feedback signal of the generator voltage output through the generator field duty cycle signal circuit to the PCM/ECM, this information is sent to the body control module (BCM). The signal is a PWM signal of 128 Hz with a duty cycle of 0-100 percent. Normal duty cycle is between 5-99 percent. Between 0-5 percent and 100 percent are for diagnostic purposes.
It's a 60 degree motor and bolts in with no more effort than what it would take for the smaller cube fwd motors: 3500,3400 and 3100 using the 85-87 Fiero V6 front engine bracket. The only reason I needed to place a small notch in the edge of the trunk wall is because I was to tired and far along to do a little trimming on the exhaust manifold flange. If it had been bolted to a Fiero tranny it probably would have cleared without a problem. merlot has completed the 3500 which is little to no different except for cosmetics externally than the 3400.
Ahh... I was wondering if I'd missed discussion of engine mounts.
Has anyone done a 3900 into '88 Fiero? The '88 Fiero engine mount bracket is different. It's more like a saddle. It uses the two bolts that the early bracket uses PLUS these two bolts on the forward/left side of the block.
Ahh... I was wondering if I'd missed discussion of engine mounts.
Has anyone done a 3900 into '88 Fiero? The '88 Fiero engine mount bracket is different. It's more like a saddle. It uses the two bolts that the early bracket uses PLUS these two bolts on the forward/left side of the block.
Are these bosses still present on a 3900?
Unfortunately no and even if they were, I don't think the U bracket would clear the aluminum oil pan if the first design mount needing to be trimmed is any indication. Just stopped by to see what was new and saw the thread.
I just discovered the 3900 a couple days ago and started searching for info. A 3900, possibly turbo is now on my future swap list.
