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Author Topic: Erioshi's 86 FC / LT1 + ZF6 swap  (Read 3647 times)

Offline erioshi

Erioshi's 86 FC / LT1 + ZF6 swap
« on: March 18, 2014, 02:42:43 AM »
Looks like it's time for to start a build thread.  I haven't been able to find an LT1 + ZF6 swap thread anywhere, and I'm sure I'll have quite a few questions.  I'm also new to the LSx/LT swap process, at least when it comes to an RX-7.  Most of my performance experience has been with imports for a number of years.  This build will probably progress slowly over the summer; bits and pieces will go in as they become available.

The planed use for the car should be mostly street driving with occasional track day and autocross thrown in.  That said, a priority is making the car survive the inevitable track time.  Loosing an engine at a track day would be an unacceptable failure.

The car I'm starting with is an '86 base (no PS, manual windows) with an automatic transmission.  The car is essentially rust free (at least for the local environment), which in MN tends to outweigh trying to find a car with the just right options.  Many of the local FC's seem to have already been parted or crushed, with most survivors being either someone's baby or completely used up.  Finding a good chassis was a bit hard.

Poor quality phone pics of the starting point:
[attach=1]

[attach=2]

The weights on a set of scales:
[attach=3]

[attach=4]

The engine & transmission we have for the swap are an LT1 and ZF6 6-speed out of a '92 Corvette.  Bot came from the same car, and the LT1 looks to have quite a few aftermarket parts.  I may have to ask some of the members here who are more familiar with these engines if they can help me identify the parts on the engine.

Engine, transmission & weights:
[attach=5]

[attach=6]

Engine weight is complete with everything including clutch and flywheel, ECU, all pumps and brackets .. even the emissions pump.  Parts not included in the engine weight are the engine wiring harness and fluids.  I'll be looking to trim some weight, but figure this info may have some use.

*edit - Looks like I'm finally getting the pics to load correctly.
« Last Edit: March 18, 2014, 03:10:57 AM by erioshi »

Offline erioshi

Re: Erioshi's 86 FC / LT1 + ZF6 swap
« Reply #1 on: March 18, 2014, 03:40:46 AM »
Since the car is going to be used mostly as a driver, the goal is to keep the stock interior intact and make the OE gauges play nice with the swap parts.  Being a base model, the car has 4-bolt hubs & smaller brakes.  I've sourced a complete 5-blot swap locally that includes hubs, rotors & 4 pot calipers, etc., so those parts will be replacing the original 4-bolt set-up.  I've also managed to track down a Granny's kit a couple hundred miles away that should help move things along.  Hopefully the kit will be delivered in the next couple of weeks.

At this point, the next serious question for me is fitment of the ZF6 into an automatic transmission car.  I haven't been able to find an example of any swap using a ZF6, and I'm not sure how much starting with an automatic chassis will complicate things.

I'm open to suggestions for recommended maintenance and inspections on the LT1 that should be performed before it's permanently installed into its new home.  This engine looks to be well cared for, but it's supposed to have about 82K on it.  There are quite a few aftermarket goodies already installed, but I'd hate to miss the chance to take care of any engine-out, no-brainers for an LT1.

Offline Dvous

Re: Erioshi's 86 FC / LT1 + ZF6 swap
« Reply #2 on: March 18, 2014, 07:30:49 AM »
As far as the lt1...replace the water pump gaskets and the o- ring on the front cover, I'd also replace the opti-spark if it were me...the pump tends to leak and take out the opti, at only the best times too. Also avoid rain puddles, for the same reason.

'93 fd~black/orange, 5.3l, t56, 7875, HP efi, 4 pt, etc
'63 F250~95' F350 frame, D60, 12valve, zf 5spd, 35's
'51 Willys M38~350/4spd, otherwise all original
'72 FJ40 landcruiser
'03 2500hd duramax~ppe stg 5 trans, efilive tunes, etc, 600hp 1000 ft lbs - daily
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Once you drive a V8 RX7 you'll feel like a friggin Viking that just pillaged a village.
- Speedfab

Offline erioshi

Re: Erioshi's 86 FC / LT1 + ZF6 swap
« Reply #3 on: March 20, 2014, 06:49:44 PM »
The opti-spark is a concern, but we'not sure if we're replacing it or not yet.  Thanks for the other items to take a good look at.

Offline gadzooks

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Re: Erioshi's 86 FC / LT1 + ZF6 swap
« Reply #4 on: March 20, 2014, 10:56:44 PM »
check your main and rod bearings on the engine too, I killed 2 before I learned that lesson, the first was a total loss and second was rebuilt as a 355ci
for cheap insurance I would also get a whole gasket set and some MLS head gaskets and get the heads checked for warpage, might as well throw in a new rear main seal too since they're cheap
1987 Base/Light Weight with '95 Firebird LT1/T5

Offline erioshi

Re: Erioshi's 86 FC / LT1 + ZF6 swap
« Reply #5 on: March 21, 2014, 05:06:23 AM »
We've been debating opening up the engine, but I'd almost prefer to just fire it up in the car first.  I figured the obvious things like the main seals would be replaced, but I'm not as familiar with the general maintenance schedule stuff for these engines.  I've wondered about things like the timing chain, oil pump & water pump.  I guess I'll have to think a bit more about doing a tear-down before installing the engine.

I am really interested the sorting out the types of upgrades that will help the engine live under road-course & time attack conditions.  I figure a baffled sump and accusump are probably good additions, but I'm not sure which aftermarket pans would fit with the swap.

Tracks the car is likely to see include places like Grattan Raceway, Road America and Mid-Ohio, so elevation changes as well as lateral loads could both possibly become issues.

Offline gadzooks

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Re: Erioshi's 86 FC / LT1 + ZF6 swap
« Reply #6 on: March 21, 2014, 05:17:31 PM »
absolutely open up the engine, and if you plan to take it on those tracks I would have an engine builder do a full rebuild, the front straight at RA is no joke! A new timing chain is a good idea, the water pump should be fine, an oil pump is less than $50 new. Make sure you use really good brake fluid and pads too
1987 Base/Light Weight with '95 Firebird LT1/T5

Offline erioshi

Re: Erioshi's 86 FC / LT1 + ZF6 swap
« Reply #7 on: March 22, 2014, 04:03:11 AM »
Doing hard-core track time is a ways off; I'm sure there will be quite a bit of sorting before the car is ready for that kind of abuse.  I guess my thinking was "make it run" then go back and deal with the serious track-prep before major abuse begins.  The engine & transmission come with a start & run guarantee, so I think I'd like to accomplish that before taking on serious engine surgery.

I love Road America, I'm actually kind of meh about Mid-O, but there are lots of events there.  Gratan is blast, but the pavement there just shreds tires.  I love VIR, but it's too far away for me to visit with any kind of consistency.  I have a list of other tracks I'd love to run, but they are all far enough away that I'd have to arrange a min-vacation to run them.  I'm hoping I can hit a least a few of them.

You mentioned brakes, and that's honestly one of the larger question marks I have about building out this platform.  I searched the forums for ideas and suggestions, but I'm not sure I'll find the kind of braking I'm used to without needing to do some trial and error.  I ran Carbotech pads on my modded Evo and really liked the performance & feel, just didn't like the price every time they needed replacement.  I just see brakes as something I'll address once the car is running and I can start to gain experience with the various options available.

Tires are also a bit of struggle.  I'd like to run 275/40-17's, but I should probably be using a 9.5" or 10" wheel for a tire that wide.  That probably means butchering or replacing the front fenders even if I can manage to make the tires work in back.  Narrower wheels & tires would fit better, but I'm not sure the car would have enough grip.  I do have a line on some 17x9.5 wheels that would work & know where to get good quality spacers & hubcentric rings made to fit them properly.  Thoughts?

And of course related to the wheel issue is choosing springs & dampers.  I'd like to go with a decent coilover set-up, but may end up looking for a more more budget friendly solution to start out with.  I haven't really had time to read up on the various suspension options currently available for the FC; I suppose I need to research that as well.