hi i just have a question about the ls6 swap i search and i just dont found if you need absolutely to cut your cradle or chassis to fit this engine. does anyone salke a kit that can bolt on the cradle without cutting the cradle or the chassis ???? many thanks all
V8Archie is the only vendor selling an installation kit for the LS6 and it requires a frame notch on the passenger frame rail and welding in a new front crossmember on the cradle.
thanks fieroguru and i have a last question i search but i speek french and it sometimes hard for me to understand your build thread lolol about the other ls engine did have a model that can fit without cutting the cradle or frame rail ????? im searching a v8 that can fit without cutting the cradle or the frame rail many thanks
The LS4 will fit between the frame rails without any cutting (depending on how you mount the alternator), but the oil filter will require a notch to the cradle frame rail. Installing the LS4 with anything but the 4T65e-hd that comes with it will require more custom machined parts. My personal swap is an LS4/F40 6 speed manual... but it has required extensive fabrication and custom machined parts.
In another thread, fieroking put together a LS4/4T65e-hd kit for another member:
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Originally posted by F355spider: Joe put together a kit for me for the ls4 swap.
V8Archie is the only vendor selling an installation kit for the LS6 and it requires a frame notch on the passenger frame rail and welding in a new front crossmember on the cradle.
why you have to cut the frame rail ????? ( because of the water pump ) ???? and where i can find info about this swap i search and i dont find info except to v8archie did you saw a buid thread ??????? many thanks fieroguru
Originally posted by fierogtx: why you have to cut the frame rail ????? ( because of the water pump ) ???? and where i can find info about this swap i search and i dont find info except to v8archie did you saw a buid thread ??????? many thanks fieroguru
The frame notch is required for overall engine/transmission length with the two largest factors being the thickness of the adapter plate (about 1 1/2" to clear the 168 flywheel) and the use a the corvette balancer that is a double serpentine setup. In this picture you can barely see the outer serpentine pulley on the balancer. As you can see, this pulley is well into the frame rail on the passenger side.
For comparison, here is the balancer clearance on the LS4 (different balancer pulley and shorter crankshaft snout):
Here is the thread with the very first LS1 running in a fiero. It was a DIY project and has several pictures and some commentary to the particular challenges of an LS(x) swap. //www.fiero.nl/forum/A...040710-2-027739.html
[This message has been edited by fieroguru (edited 08-15-2012).]
The frame notch is required for overall engine/transmission length with the two largest factors being the thickness of the adapter plate (about 1 1/2" to clear the 168 flywheel) and the use a the corvette balancer that is a double serpentine setup. In this picture you can barely see the outer serpentine pulley on the balancer. As you can see, this pulley is well into the frame rail on the passenger side.
For comparison, here is the balancer clearance on the LS4 (different balancer pulley and shorter crankshaft snout):
many thanks fieroguru it is a dream to have a ls6 but i dont want to cut my frame on my fiero i will keep my 3800 sc many thanks for your help your very professional
Here is the thread with the very first LS1 running in a fiero. It was a DIY project and has several pictures and some commentary to the particular challenges of an LS(x) swap. //www.fiero.nl/forum/A...040710-2-027739.html
The frame notch is required for overall engine/transmission length with the two largest factors being the thickness of the adapter plate (about 1 1/2" to clear the 168 flywheel) and the use a the corvette balancer that is a double serpentine setup. In this picture you can barely see the outer serpentine pulley on the balancer. As you can see, this pulley is well into the frame rail on the passenger side.
For comparison, here is the balancer clearance on the LS4 (different balancer pulley and shorter crankshaft snout):
If you shortened an LSx crank and used an LS4 balancer pulley would an LSx fit in the same space as a an LS4 or would there be other changes as well? Thanks, -Paul
------------------ 1988 Fiero Formula 25k miles, garaged since 1988
Originally posted by Paul.S: If you shortened an LSx crank and used an LS4 balancer pulley would an LSx fit in the same space as a an LS4 or would there be other changes as well? Thanks, -Paul
You can install the LS4 balancer on a RWD LS(x) engine w/o shortening the end of the crankshaft, you just need a large washer. The LS(x) Porsche kits do it all the time.
The next part of your question gets complicated... The LS(x) engines will require an adapter plate to bolt to a Fiero transmission. If you use Archie's adapter plate, it is around 1 1/2" thick, so that is extra thickness that the LS4 engine just doesn't have. He shifts the placement of the transmission to the drivers side to make room for the 1 1/2" adapter plate and notches the DS frame rail for clearance. If you put the LS4 balancer on one of his swaps, you could likely avoid the PS frame notch for the balancer, but then you have to rework all the accessory mounts to line up with the LS4 balancer.
Now, the LS(x) blocks are physically about 3/16" SHORTER than the LS4 block. The difference is at the rear where the Metric pattern is raised from the SBC type pattern to clear the bolt heads on the rear cover plate. If you put a flat edge across the bellhousing surface on a RWD block, the heads on the cover plate will interfere. Do the same on the LS4 block and they will not. Here is also a picture showing that the Metric pattern is raised from the RWD pattern. The large hole across from the starter cutout on the transmission is the RWD dowel pin location and bellhousing face:
So with the LS4 block being about 3/16" longer than the LS(x) blocks, you could use a 3/16" adapter plate and create a LS(x)/F40 combo that is the same overall length as the LS4/F40 combo. The flywheel will need to be different (a few mm thinner) than my LS4/F40 one due the LS(x) crankshafts being longer.
[This message has been edited by fieroguru (edited 12-21-2014).]
The LS(x) engines will require an adapter plate to bolt to a Fiero transmission. If you use Archie's adapter plate, it is around 1 1/2" thick, so that is extra thickness that the LS4 engine just doesn't have.
Thanks for your quick response.
Are you saying that an LS4 doesn't need an adapter plate?
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If you put the LS4 balancer on one of his swaps, you could likely avoid the PS frame notch for the balancer, but then you have to rework all the accessory mounts to line up with the LS4 balancer.
Could you just use the accessory mount from an LS4 or would you have to get creative with those too? -Paul
Originally posted by Paul.S: Are you saying that an LS4 doesn't need an adapter plate?
Correct. The LS4 comes from the factory connected to the 4T65E-HD, so it has the GM Metric bellhousing pattern and will bolt to most common fiero transmissions. The issue with the LS4 is that it does not have an engine mounted starter mount and there is limited room on the engine side for a starter with the 142 tooth flywheel… so most continue to mount the starter on the transmission.
Here is a picture of the LS4 with the GM Metric bellhousing:
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Originally posted by Paul.S: Could you just use the accessory mount from an LS4 or would you have to get creative with those too? -Paul
Yes, but the LS4 water pump requires some tweaking (idler relocation) and other work for the coolant fill (moving/modifying the decklid hinge box or cutting the stock fill off, welding it shut and adding another coolant fill). You will also need an alternator bracket as the stock LS4 alternator mount places the alternator well into the strut tower. If you low mount the alternator in the rear (most common method), you are back to notching the PS frame rail for alternator clearance.
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Originally posted by Paul.S: Is there a manual trans that would be easier to use? Thanks, -Paul
That is a tough question… Easiest is likely the 92-94 HTOB Getrag. Stock axles, shifter, cables, transmission mounts, etc… just need Rodneys shifter bracket, a custom flywheel, starter mount, and re-flare the clutch line connector. Downside is it will likely break due to torque and fuel economy won’t be as good.
Next would be the F23, but in addition to the flywheel & starter mount, now you add custom shifter bracket, modified shifter levers at the transmission, 1 custom shift cable, transmission mounts, and HTOB coupler. So you can retain the shift shifter, stock Getrag Select Cable, and the axles... everything else is custom. The transmission is strong, but the ratios are worse than the 92-94 HTOB unless you buy 2 and swap bellhousings.
F40 – You need everything the F23 needs, plus a reverse lockout and different axles. So for a little more work, you get a good 6th gear to improve highway mileage… If you follow my F40 install method, you retain the stock 5 speed shifter, stock Getrag Select cable, and stock Isuzu shift cable... everything else is custom. Having driven two 400hp V8 fieros, one with a F23 and one with an F40, my opinion is that the F40 is worth the extra cost/work.
[This message has been edited by fieroguru (edited 12-21-2014).]
The toughest thing for me to figure out in a LS4 swap is where to put the trans and motor mounts. Is there just one obvious place for the motor mounts or does it vary depending on the trans and car? If it varies, could I do a mockup with a scrap HTOB with stock trans mounts to get the motor mounts right, and then do the trans mounts for a better transmission? Archie's LSx motor mounts look like a bargain:
When doing the 6 speed swap to a LSx engine, you will also need these parts: LSx Forward Right Engine Mount LSx Right Rear Engine Mount The price for these LSx specific parts is $235.00.
Would they work for a LS4 swap? With the F23? Thanks, -Paul
------------------ 1988 Fiero Formula 25k miles, garaged since 1988
Originally posted by Paul.S: The toughest thing for me to figure out in a LS4 swap is where to put the trans and motor mounts. Is there just one obvious place for the motor mounts or does it vary depending on the trans and car? If it varies, could I do a mockup with a scrap HTOB with stock trans mounts to get the motor mounts right, and then do the trans mounts for a better transmission? Archie's LSx motor mounts look like a bargain:
When doing the 6 speed swap to a LSx engine, you will also need these parts: LSx Forward Right Engine Mount LSx Right Rear Engine Mount The price for these LSx specific parts is $235.00.
Would they work for a LS4 swap? With the F23? Thanks, -Paul
The mount positions on the trans and block side of the mounts should be fairly obvious. Archie's mounts are solid mounts, and are designed for his LSx kit that uses the adapter plate, so the instructions also include positioning for that setup. You could use them for an LS4 and they should work with either the F40 or F23, but you will need to adjust positioning for that yourself, to get the best fit. And why will be solid mounts, in case what you want is poly or rubber mounts.
Like said above, his mounts are solid mounted and weld into place. Here are a couple of pics of them welded into place on an 88 cradle from qwikgta's LS3 swap. If you look at the front one with the 4 holes... the LS4 block only has 3 of those 4 holes (lower DS one is missing): //www.fiero.nl/forum/F...1/HTML/083204-2.html
When he did Lady Lisa's LS4 swap, he used different mounts to retain poly. It also looks like his normal LS(x) rear engine mount would preclude the alternator from being lower mounted in the rear, so you would have to cantilever it on the top, go remote electrical water pump to mount it up front or do some major fab work like I did to the pump to make room for it. Lots of pictures of the accessory drive and engine mounts on this page: //www.fiero.nl/forum/F.../HTML/000134-10.html
[This message has been edited by fieroguru (edited 12-24-2014).]
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