Most modern VVT engines will be using a closed-loop system. It will not be an open-loop, X% duty cycle = some fixed cam phasing. The PWM controlled valve meters oil to the mechanical actuators and things like oil temp, oil pressure, oil viscosity, engine speed etc. all play a role in the final cam phasing. The ECU will have a baseline PWM starting point for a giving operating point and desired cam phasing, but will compare the cam and crank sensor signals to adjust the PWM accordingly. Any aftermarket ECU will need to be able to handle this closed loop operation to properly and accurately control the cam phasing. Just being able to drive a PWM output won't be enough.
So I have had to put my plans on hold over the last few months as I was laid off due to economic down turn. In this time I have had to bring my swap plans into scope. I am going to go for a budget swap situation to increase power and reliability. I still want to go with the LZ9, I plan to use stock ECM from donor, I would like to use the donor's instrument cluster, which means possibly needing to bring the BCM from the donor as well. I have been thinking about the transmission. I was originally thinking about doing a swap on the trans to the 4T65E and bringing the TCM from the donor over as well. However to keep the swap simple I was wondering about keeping the TH125C that is in it now. My thoughts are if I keep the original trans it will mount the same and also simplify the axle situation. Saving money and complications.... maybe...
My new questions:
If I keep the old trans, what would need to be done to have it shift correctly? I know doing this will mean issues on using the donor instrument cluster for the Speedo.
Is the 125 all hydraulic or are there electronics to worry about? Vacuum?
Can the 125 handle the aprox 250 hp?
The bolt pattern should be the same GM Metric correct? will the flywheel / flexplate work still? which would I use the Fiero or donor?
Or would it still be easier and more economical to use the donor's 4 speed and deal with mounts and axle issues?
[This message has been edited by ChuckR (edited 07-22-2020).]
250 hp, not a problem. 250 lb-ft, or close to it and your 2-3 shift will be slipping in no time. That was my experience with it behind a boosted iron head 3.4L and that was after I rebuilt the transmission prior to install. It might help some to have one of the high strung 3 speeds with the 3.33 final drive to shift more of the torque loads to the axles. It's a pretty simple transmission otherwise, you will only need to rig up a torque converter clutch lockup signal for better economy, 12volts. The 4 cyl cars were most likely to have the 3.33 final drive as well as a higher stall torque converter, which I discovered upon swapping a 2.8L into a base 4 cyl car. It made a huge difference in performance. I posted some rebuild manual pages that contained gear ratios and torque converter stall speeds on the forum several years ago, that will be helpful for the 125 and 440 transmissions if you can find them.
I have done a couple of larger displacement V6's. One 3100 GM 60* engine swap and the power was MUCH better than a stock 2.8 Fiero engine. I then swapped out the automatic for a 5 speed manual and it got even better. I have also helped another PFF member do a 3800 SC 5 speed swap and that thing was a monster. BUT they did not sound as good as the new GM high feature twin cam v6. Just listen to the sound clips of the new Camaro v6. AMAZING sound and outstanding power. I would LOVE to do this swap in a Fiero.
[This message has been edited by Rickady88GT (edited 07-22-2020).]
I have done a couple of larger displacement V6's. One 3100 GM 60* engine swap and the power was MUCH better than a stock 2.8 Fiero engine. I then swapped out the automatic for a 5 speed manual and it got even better. I have also helped another PFF member do a 3800 SC 5 speed swap and that thing was a monster. BUT they did not sound as good as the new GM high feature twin cam v6. Just listen to the sound clips of the new Camaro v6. AMAZING sound and outstanding power. I would LOVE to do this swap in a Fiero.
I'm just starting an install of the 2.8t 'high feature' twin cam in the UK (88 formula - currently has an archie sbc kit fitted). I know BMWGuru on here has one fitted and I've looked through his thread a few times for inspiration. I've been in touch with Dave though and unfortunately his isn't quite finished yet, mainly electronics problems I believe. I'll be running a hybrid turbo with charge cooling and a stand-alone ECU on the engine with full closed loop mapping capabilities, aiming for around 400hp. mated to a F40 6 speed with quaife LSD fitted. I know people with this motor/trans combo in other cars running 450-500hp without issue (other than torque steer!)
If I keep the old trans, what would need to be done to have it shift correctly? I know doing this will mean issues on using the donor instrument cluster for the Speedo.
As long as you get the TV cable hooked up correctly, the transmission will shift "correctly", meaning as it's calibrated to do. Whether this matches the engine or not is another matter.
quote
Originally posted by ChuckR: Is the 125 all hydraulic or are there electronics to worry about? Vacuum?
The shifted gears are hydraulic, but the TCC is electrical. Your expected control system will not be able to operate that correctly.
quote
Originally posted by ChuckR: Can the 125 handle the aprox 250 hp?
No way. Even the "built" ones are hit/miss and the builds are expensive.
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Originally posted by ChuckR: The bolt pattern should be the same GM Metric correct? will the flywheel / flexplate work still? which would I use the Fiero or donor?
This is the one thing that would be easy... I *think* it would bolt right up to the LZ9.
quote
Originally posted by ChuckR: Or would it still be easier and more economical to use the donor's 4 speed and deal with mounts and axle issues?
I think using a manual transmission would make the most sense, but after that the original 4 speed auto would be best.
I think using a manual transmission would make the most sense, but after that the original 4 speed auto would be best.
Will and Joseph thank you for the input, it was just an idea i was kicking around. Using a manual could be easier, but then I would have to add the costs of locating the transmission, the parts for shift cables, hydraulics for clutch, and other parts to make an Auto into a manual, thus project creep. Working with a trans from a donor or the original trans would limit costs and creep. I think with this information that the best route for me is still the 4T65E. Now all I need to do is get new employment so I can figure my budget again. I have had interviews get cancelled since they are not opening their offices yet. They still want to meet with me but they do not know when their offices will reopen... So until I have a proper income I am on penny pinching mode and this is just research. I did however get my Fiero running again on the stock motor! At least I can enjoy driving her as she is.
<snip> I consider the L44 thru stock exhaust the best sounding V6...My Father, who was into sports cars back in the 50s and 60s said the only sixes he ever heard that sounded better than my Fiero were the Jag straight six in the E-type and the Maserati sixes. <snip>.
Often wondered if the aluminum headed versions of the L44 sound as good through the Fiero exhaust as the L44. Never liked the sound of the earlier versions in GM cars. Or is the sound particular to the iron heads?
[This message has been edited by MarkS (edited 07-23-2020).]
Originally posted by MarkS: Often wondered if the aluminum headed versions of the L44 sound as good through the Fiero exhaust as the L44. Never liked the sound of the earlier versions in GM cars. Or is the sound particular to the iron heads?
Should be the same. Exhaust systems are like musical instruments, change the length, diameter, or baffling and you'll change the sound.
cvxjet...is 300lb for the LV3 an estimate or has somebody verified the weight? I would have estimated 340-350lb.
the lightest v6 with at least 3.0L I have heard of is the 60 degree Bowtie at around 270lb. The aluminum block part number is 10051141. I saw one on eBay about a year ago. I've heard that block has larger Gen III 2.25" journals so it could be used with an LW9 80mm forged crank. Together with common 89mm pistons, displacement is 3.0L. Gen III aluminium heads from the L82/LG8/LA1 are supposed to fit.
cvxjet...is 300lb for the LV3 an estimate or has somebody verified the weight? I would have estimated 340-350lb.
the lightest v6 with at least 3.0L I have heard of is the 60 degree Bowtie at around 270lb. The aluminum block part number is 10051141. I saw one on eBay about a year ago. I've heard that block has larger Gen III 2.25" journals so it could be used with an LW9 80mm forged crank. Together with common 89mm pistons, displacement is 3.0L. Gen III aluminium heads from the L82/LG8/LA1 are supposed to fit.
You can go bigger on the bore, probably dependent on how much boost you want to run. The heads flow plenty to run the 84mm stroke from an LX9. Some of those crankshafts are forged.
cvxjet...is 300lb for the LV3 an estimate or has somebody verified the weight? I would have estimated 340-350lb.
the lightest v6 with at least 3.0L I have heard of is the 60 degree Bowtie at around 270lb. The aluminum block part number is 10051141. I saw one on eBay about a year ago. I've heard that block has larger Gen III 2.25" journals so it could be used with an LW9 80mm forged crank. Together with common 89mm pistons, displacement is 3.0L. Gen III aluminium heads from the L82/LG8/LA1 are supposed to fit.
I have read that in a few places on the net...But nothing really official. I just did a calculation......Chevy 5.7 (550 lbs) vs LS V8 (Aluminum)(400) which gives a ratio of 1.375 to 1, so a Iron 4.3 weighs 425 (Approx') and that gives you 309 lbs for the LV3. (Remember, they eliminated the Distributor but they added VVT....Also, they are really trying to make the engine lighter so eliminating extraneous crap)
I'm currently looking at LZ9's for my car's next engine. FWIW, the Buick Lucerne LZ9 has the alternator mounted high, and forward, near the hinge box, which may fit in the car better than the other applications, which mount it near the dogbone.
------------------ "I am not what you so glibly call to be a civilized man. I have broken with society for reasons which I alone am able to appreciate. I am therefore not subject to it's stupid laws, and I ask you to never allude to them in my presence again."
Originally posted by 82-T/A [At Work]: This reads like my story as well.
Rebuilt my 2.8 into a 3.1 w/ crank and rods, and a .040 overbore. Went with an inexpensive (but recommended) cam and lifter kit. Wiped a lobe almost immediately. I set the valve lash pretty low so it wouldn't be aggressive to the cam during break-in. Babied the car, didn't make a difference.
I'm determined to stick with the 3.1 I've built because it's the original motor, and I'm past the point of making this car something it isn't. I just want to keep it as I remember it since it was my first car.
But, if I had no history with this car, and it was new to me... I would ABSOLUTELY be doing the 3.9 V6/60 w/ 6-Speed manual swap... all... day... long.
Maybe you are using the wrong oil for break-in and change intervals and wrong and lifters. I've never wiped a cam lobe and I'm using WAY more spring pressures than anyone on these motors. Synthetic oil doesn't mean is good for the flat tappet cam engine if it doesn't have the right additive package. The lifters I use have a .021 pin hole on the face of the lifters that feeds pressurized oil to the cam lobe and lifter face, better than a roller lifter because it is much lighter. But even though with that .021 pin hole supplying oil to the lobe, if you don't have an oil with at least 1100-1400ppm of ZDDP and Moly regarless it is synthetic or regular, you'll be missing not one but several lobes from the cam.
I haven't found a write up with costs. If you wanted to do a straight swap it would be one of the cheaper to do. I would check around on FB groups like 60* V6 and the forums there as well. The engines are cheap in the junkyards as they are not popular. the costs will also be different based on your skill level. Fabrication, welding, and engine tuning will all have a cost. There will be custom brackets, half shafts, engine, and trans mounts.
I am swapping an LZ9 into my Fiero currently, I am building it to make power higher in the RPMs. I have had the rotating assembly blue printed and the crank balanced to within a gram, cleaned up the heads, intake, polished the exhaust, stiffer valve springs and stronger keepers and retainers from an LS motor, cryo treated the biggest timing chain and sprockets I can get for the motor short of a double roller, and beefier custom length pushrods, and just to possibly improve the stock rocker arms (since there is no aftermarket for those) I had the rocker arms cryo treated as well. Oh and it has a cam going in it as well, and cam bearing spacers to accept the cam. The motor is currently going back together, and will soon be mounted on the cradle. I will be making custom headers to mate up to a custom exhaust, and it is being controlled with a Microsquirt ECU which is basically MS2. I have an Aeromotive fuel pressure regulator to deal with the returnless setup, and I will be fabbing custom fuel lines as well as modifying the coolant lines on the Fiero to end up in a more ideal location. I am using the stock Fiero 5 Speed for now with an 88 Fiero flywheel, if that blows up I will swap in an F23. I have been documenting everything and have a big spreadsheet to track all my costs, I am around 6K right now for the swap so far, but I haven't chose to do anything the easy way, and the only items left to procure are exhaust tubing bits. I intend to get this running and driving this summer and I plan to get some dyno numbers for it. The DOHC 60* V6 motors are cool, but I want to be able to work on my motor easily in the engine bay, and have a simpler, cheaper, lighter and more readily available motor. I am still figuring out my alternator mounting, but other than that I have most things sorted mechanically. The wiring and tuning will be new for me but it is pretty straight forwards, and there is a ton of documentation for Megasquirt, so I look forwards to figuring it all out. I don't have all the answers but I have quite a few now.
[This message has been edited by zkhennings (edited 06-10-2021).]
Here is a question going through my head, has anyone looked at works best on this engine to increase compression ratio? By modern standards 9.8:1 that is stock on this engine is pretty low.
Can you deck the heads? if so how much before you need new pistons with reliefs?
Is there a domed piston that would work on this engine?
are there thinner gaskets?
This engine is designed for 87 octane, but running premium 93 pump gas in my area, 91 for some or E85 gives a lot of room for a high CR and avoiding det.
Aftermarket LS1 pistons can be found in varying compression heights, and with various dishes and domes, they are the same OD as the stock pistons. An aftermarket LS1 rod or SBC rod can be found to work with this setup in varying lengths, but the crank will need to have the rod journals resized as they are slightly smaller in the LS and slightly smaller than that in the SBC. This does give you the opportunity to slightly stroke or destroke the motor if you offset how the journal is resized. It will take some research to find the correct combination that you are looking for. Seems as though the aftermarket rods and pistons will use a 0.927" floating wrist pin setup which is slightly smaller than stock. You would most likely need to cut valve reliefs in the pistons, take that into account when calculating dish/dome. I have an SBC rod and LS1 rod I bought for checking this all out, I will measure the width of the big end of the rods when I get to the garage later to confirm that they need no modification in width to work with the LZ9 crank.
Here is a stock LS1 piston in the LZ9 for fitment, no dome nor dish.
[This message has been edited by zkhennings (edited 06-15-2021).]
The LZ4 & LZ9 use 2.250" rod journals. That's the same size as 4.3litre V6 journals. 4.3 V6 rods can be narrowed at the big end for use in LZ4/LZ9 engines, just like small journal Chevy V8 rods could be narrowed for use in the older V6/60 engines.
The LZ4 & LZ9 use 2.250" rod journals. That's the same size as 4.3litre V6 journals. 4.3 V6 rods can be narrowed at the big end for use in LZ4/LZ9 engines, just like small journal Chevy V8 rods could be narrowed for use in the older V6/60 engines.
Thanks for the info, I went digging for aftermarket rods with the correct journal size and did not find any, are forged aftermarket versions available?
To add to that the LS1 journals are 2.1" and the SBC journals are 2.0"
Thanks for the info, I went digging for aftermarket rods with the correct journal size and did not find any, are forged aftermarket versions available?
To add to that the LS1 journals are 2.1" and the SBC journals are 2.0"
This list actually shows "big end bore diameters" of 2.125, 2.250 & 2.375... I'm not sure if they actually mean bore diameter or if they mean design journal size. Here's the list:
Here is a question going through my head, has anyone looked at works best on this engine to increase compression ratio? By modern standards 9.8:1 that is stock on this engine is pretty low.
Can you deck the heads? if so how much before you need new pistons with reliefs?
Is there a domed piston that would work on this engine?
are there thinner gaskets?
This engine is designed for 87 octane, but running premium 93 pump gas in my area, 91 for some or E85 gives a lot of room for a high CR and avoiding det.
It has the same bore as an LS1 and the 0.943 pin size, right?
I have read that the bore is the same. I have to take your word on the pin size. You guys have shared some good info on the pistons. This is great to know, but what about the other side of the question? Can the heads be decked and by how much before there is a clearance issue with the valves? This seems like the most effective way to gain a few points of compression in the least invasive manner. That is assuming there is room to do so without having valve clearance issues.
Do you have a good reference on the 3.9 that lists the details of the engine like pin size? Also do you not also have to worry about how tall a piston is and its location of the pin? Not just diameter and pin size?
Maybe I need to read some engine building books to better understand the question I am asking.
It has the same bore as an LS1 and the 0.943 pin size, right?
Yes that is correct.
Aftermarket LS1 pistons come in varying compression heights, which is essentially the distance from piston pin axis to the top of the piston. You could also get 4.3 V6 rods if they sell a slightly longer rod, that also has the correct 0.943 floating wrist pin and get the rods narrowed. However the quick search I did on Summit showed only 5.7" long rods (vs stock is 5.9" according to manual) and they all had the 0.927" floating wrist pin small end. But more research could be done.
I do not know how far you can deck the heads until you have valve clearance issues to the pistons, you may run into clearance issues with the valve seat first. It is pretty simple to cut deeper valve reliefs in the pistons though, you can make a cutter from an old valve. Check the youtubes for tutorials.
You may want to deck the block instead of the heads if you do go down that route. Heads warp a lot more than blocks do, I wouldn't want to remove too much material from the aluminum heads.
I bought a factory service manual pdf for Impala/Monte Carlo off Ebay and it has a lot of detailed information on the motor specs, it was like $9.
[This message has been edited by zkhennings (edited 06-21-2021).]
I have read that the bore is the same. I have to take your word on the pin size. You guys have shared some good info on the pistons. This is great to know, but what about the other side of the question? Can the heads be decked and by how much before there is a clearance issue with the valves? This seems like the most effective way to gain a few points of compression in the least invasive manner. That is assuming there is room to do so without having valve clearance issues.
Do you have a good reference on the 3.9 that lists the details of the engine like pin size? Also do you not also have to worry about how tall a piston is and its location of the pin? Not just diameter and pin size?
Maybe I need to read some engine building books to better understand the question I am asking.
I think google will have all the numbers you need, one way or another.
Decking the head makes the intake manifold not fit right, which requires cutting the intake at weird angles on all three mating surfaces... You're probably better off with drop-in pistons. Replace the rod bolts if they're torque-to-yield, though.
EDIT: as noted above, get a service manual covering this engine if you're going to start tearing into it that far.
[This message has been edited by Will (edited 06-22-2021).]
I plan to get the service manual once I purchase the car, but until I know the donor I don't want to get just any manual for a car with this motor. I may end up getting the flex fuel version etc. Thanks for the info.
If you dont mind forking out the money for forged pistons you can order a set from WOT and choose from 9 10 or 11 CR. I hadnt checked their page in a while and I dont think this was there the last time I looked.
I have read that the bore is the same. I have to take your word on the pin size. You guys have shared some good info on the pistons. This is great to know, but what about the other side of the question? Can the heads be decked and by how much before there is a clearance issue with the valves? This seems like the most effective way to gain a few points of compression in the least invasive manner. That is assuming there is room to do so without having valve clearance issues.
Do you have a good reference on the 3.9 that lists the details of the engine like pin size? Also do you not also have to worry about how tall a piston is and its location of the pin? Not just diameter and pin size?
Maybe I need to read some engine building books to better understand the question I am asking.
Valve clearance shouldn't be a problem, it's a VVT motor so it has extra in addition to about .1xx piston to head clearance. As mentioned, it is more practical to purchase pistons in the compression range you are aiming for. When I built my motor, there was a lot I did not take into consideration on the metrics side, that I would now. Ebay is probably the best place to search for LS1 pistons and is where I found my production Mahle forged options remarkably cheap. I recall many options to choose from with the range enhanced by small over bores. The listings were very informative by posting all of the important measurements and all options available in the listing.
Be careful with the 4.3L rods, I recall mention of some being offset in a discussion on this topic some years back. If you're interested in stroking the motor, you may want to check with phoenixbeginning on the forum. He has my first offset ground forged crank which was machined to the wrong stroke of about 3.41". The crank was radiused and was a nice piece without a purpose at the time.
[This message has been edited by Joseph Upson (edited 07-01-2021).]
