Rookie's Drivetrain Swap? Advice Needed
#1
07-06-2022, 09:36 PM
Rookie's Drivetrain Swap? Advice Needed
Hi all! I fell in love with the look of the XJ-S, and I'll admit that I wanted to experience a V12 engine.
I bought one for next to nothing in with a pretty good body that someone's spouse wanted gone.
It doesn't look like enjoying a V12 is in my future though. Engine is seized. Wiring is redone.... poorly. It honestly
looks the previous owner just spent all his time and money fighting someone else's work.
Which leads me to the possibility of a drive train swap.
My current goal with that would be to have a reliable but aggressive cruiser. I believe this makes the
LS drive train a great candidate. Me and everyone else in the world huh?
Anyway, here are my questions:
I guess that's it for starters. I'm happy to hear any advice not related to my specific questions.
And I apologize if my questions seem pretty noob-ish. My experience working on cars is
almost entirely pre-1940s or post-2010s, so this is a very different world for me.
Anyway, cheers and thanks for any help!
I bought one for next to nothing in with a pretty good body that someone's spouse wanted gone.
It doesn't look like enjoying a V12 is in my future though. Engine is seized. Wiring is redone.... poorly. It honestly
looks the previous owner just spent all his time and money fighting someone else's work.
Which leads me to the possibility of a drive train swap.
My current goal with that would be to have a reliable but aggressive cruiser. I believe this makes the
LS drive train a great candidate. Me and everyone else in the world huh?
Anyway, here are my questions:
- Can I keep the stock transmission without much work using a kit like Jaguar Specialties or some other one? I think my 1989 V12 Coupe has the TH400?
- If the TH400 would be a no go, should I do a manual swap now or go one step at a time? Are there any kits to help with a manual swap?
- Besides rear cage torque issues, spring changes for the front end, upgrade sway bars and bushings, anything else to look out for with a power upgrade?
- I do a VATS bypass since I won't have a BCM right? Is there anything else I need to know about the swap for electronics that a kit won't help with?
- Do I need to take an ECU from a donor car (or some aftermarket thing)? Would that give me OBDII or do I need to put more time in to get to that?
- At first I'd like to get the new drive train in and working, but overtime I'll probably hunt for more power/fun. Are there kits out there for things capable of swallowing more torque like a TKX 5 speed?
I guess that's it for starters. I'm happy to hear any advice not related to my specific questions.
And I apologize if my questions seem pretty noob-ish. My experience working on cars is
almost entirely pre-1940s or post-2010s, so this is a very different world for me.
Anyway, cheers and thanks for any help!
#2
07-06-2022, 11:19 PM
Veteran Member
I can't help much with the swap info, but the car will have a TH400. However, the bolt pattern is unique to Jaguar, it won't bolt to a Chev engine. Jaguar had them built to their specification, the internals are generally heavier duty than anything you'll find in a GM product.
However, V12 engines are generally cheap and not that hard to find, you might find it less work, and certainly less money to find another V12 and repair the wiring, assuming you can do the work yourself. The difficulty with a manual swap is the pedal box, finding a clutch pedal will be difficult. I believe most of the conversions fabricate one.
However, V12 engines are generally cheap and not that hard to find, you might find it less work, and certainly less money to find another V12 and repair the wiring, assuming you can do the work yourself. The difficulty with a manual swap is the pedal box, finding a clutch pedal will be difficult. I believe most of the conversions fabricate one.
#3
07-07-2022, 07:53 AM
Veteran Member
If I were to go this route, I'd do a Connect and Cruise crate engine and transmission that includes the ECM and TCM (if needed).
Even if you go the route of the junk yard LS motor, you're still going to have to do a lot of your own fabrication for engine mounts, exhaust, etc.
Whichever way you go - just acknowledge the fact that you're doing it for fun and the car will be worth less then when you started.
Even if you go the route of the junk yard LS motor, you're still going to have to do a lot of your own fabrication for engine mounts, exhaust, etc.
Whichever way you go - just acknowledge the fact that you're doing it for fun and the car will be worth less then when you started.
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csbush (07-09-2022)
#4
07-07-2022, 10:01 AM
If it’s seized it’s reasonably easy to unfreeze and you may not need to rebuild it.
Give it a try. It’s a whole lot easier that an engine swap.
Here’s what to do.
Pull all 12 spark plugs. Go buy some white vinegar. Regular white vinegar is about 10% acidic. If you can find the commercial cleaning stuff which is 30% acidic. I find it at Home Depot but check hardware stores too.
Fill each cylinder full of white vinegar. If it’s the stronger stuff a day later put a long handled wrench on the crankshaft bolt and try to turn it over.
Brief reason why not to use oil. ( even ATF and acetone which is just real thin oil ). The part that is stuck is the cylinder rings. They stick together when the oil hasn’t been changed in a while and acids build up. The ring both stick to the cylinder walls and the corrosion behind them shove them out into the cylinder walls. You have to remove that corrosion. White vinegar does that.
If it’s really bad you have to drain the oil/ white vinegar ( you don’t want the bearings to soak in the vinegar that slips past the rings). And give it a second soaking. This time leave for a few days.
Once it will turn over freely. Now is when you put the ATF/acetone in each cylinder. About 1/4 cup in each. Things should be turning over freely at this point. Fill the pan & oil filter with oil. Now put 1/4 cup of engine oil in each cylinders. Using a fresh battery spin the engine over until you have oil pressure.
Replace the spark plugs and check the fuel system. That running motor just saved you thousands on rebuild costs. Some rings may still be slightly stuck but they will come free with use. Don’t go more than 100 miles before you change the oil.
Give it a try. It’s a whole lot easier that an engine swap.
Here’s what to do.
Pull all 12 spark plugs. Go buy some white vinegar. Regular white vinegar is about 10% acidic. If you can find the commercial cleaning stuff which is 30% acidic. I find it at Home Depot but check hardware stores too.
Fill each cylinder full of white vinegar. If it’s the stronger stuff a day later put a long handled wrench on the crankshaft bolt and try to turn it over.
Brief reason why not to use oil. ( even ATF and acetone which is just real thin oil ). The part that is stuck is the cylinder rings. They stick together when the oil hasn’t been changed in a while and acids build up. The ring both stick to the cylinder walls and the corrosion behind them shove them out into the cylinder walls. You have to remove that corrosion. White vinegar does that.
If it’s really bad you have to drain the oil/ white vinegar ( you don’t want the bearings to soak in the vinegar that slips past the rings). And give it a second soaking. This time leave for a few days.
Once it will turn over freely. Now is when you put the ATF/acetone in each cylinder. About 1/4 cup in each. Things should be turning over freely at this point. Fill the pan & oil filter with oil. Now put 1/4 cup of engine oil in each cylinders. Using a fresh battery spin the engine over until you have oil pressure.
Replace the spark plugs and check the fuel system. That running motor just saved you thousands on rebuild costs. Some rings may still be slightly stuck but they will come free with use. Don’t go more than 100 miles before you change the oil.
#5
07-07-2022, 07:57 PM
I can't help much with the swap info, but the car will have a TH400. However, the bolt pattern is unique to Jaguar, it won't bolt to a Chev engine. Jaguar had them built to their specification, the internals are generally heavier duty than anything you'll find in a GM product.
However, V12 engines are generally cheap and not that hard to find, you might find it less work, and certainly less money to find another V12 and repair the wiring, assuming you can do the work yourself. The difficulty with a manual swap is the pedal box, finding a clutch pedal will be difficult. I believe most of the conversions fabricate one.
However, V12 engines are generally cheap and not that hard to find, you might find it less work, and certainly less money to find another V12 and repair the wiring, assuming you can do the work yourself. The difficulty with a manual swap is the pedal box, finding a clutch pedal will be difficult. I believe most of the conversions fabricate one.
#6
07-07-2022, 07:58 PM
If I were to go this route, I'd do a Connect and Cruise crate engine and transmission that includes the ECM and TCM (if needed).
Even if you go the route of the junk yard LS motor, you're still going to have to do a lot of your own fabrication for engine mounts, exhaust, etc.
Whichever way you go - just acknowledge the fact that you're doing it for fun and the car will be worth less then when you started.
Even if you go the route of the junk yard LS motor, you're still going to have to do a lot of your own fabrication for engine mounts, exhaust, etc.
Whichever way you go - just acknowledge the fact that you're doing it for fun and the car will be worth less then when you started.
#7
07-07-2022, 08:19 PM
If it’s seized it’s reasonably easy to unfreeze and you may not need to rebuild it.
Give it a try. It’s a whole lot easier that an engine swap.
Here’s what to do.
Pull all 12 spark plugs. Go buy some white vinegar. Regular white vinegar is about 10% acidic. If you can find the commercial cleaning stuff which is 30% acidic. I find it at Home Depot but check hardware stores too.
Fill each cylinder full of white vinegar. If it’s the stronger stuff a day later put a long handled wrench on the crankshaft bolt and try to turn it over.
Brief reason why not to use oil. ( even ATF and acetone which is just real thin oil ). The part that is stuck is the cylinder rings. They stick together when the oil hasn’t been changed in a while and acids build up. The ring both stick to the cylinder walls and the corrosion behind them shove them out into the cylinder walls. You have to remove that corrosion. White vinegar does that.
If it’s really bad you have to drain the oil/ white vinegar ( you don’t want the bearings to soak in the vinegar that slips past the rings). And give it a second soaking. This time leave for a few days.
Once it will turn over freely. Now is when you put the ATF/acetone in each cylinder. About 1/4 cup in each. Things should be turning over freely at this point. Fill the pan & oil filter with oil. Now put 1/4 cup of engine oil in each cylinders. Using a fresh battery spin the engine over until you have oil pressure.
Replace the spark plugs and check the fuel system. That running motor just saved you thousands on rebuild costs. Some rings may still be slightly stuck but they will come free with use. Don’t go more than 100 miles before you change the oil.
Give it a try. It’s a whole lot easier that an engine swap.
Here’s what to do.
Pull all 12 spark plugs. Go buy some white vinegar. Regular white vinegar is about 10% acidic. If you can find the commercial cleaning stuff which is 30% acidic. I find it at Home Depot but check hardware stores too.
Fill each cylinder full of white vinegar. If it’s the stronger stuff a day later put a long handled wrench on the crankshaft bolt and try to turn it over.
Brief reason why not to use oil. ( even ATF and acetone which is just real thin oil ). The part that is stuck is the cylinder rings. They stick together when the oil hasn’t been changed in a while and acids build up. The ring both stick to the cylinder walls and the corrosion behind them shove them out into the cylinder walls. You have to remove that corrosion. White vinegar does that.
If it’s really bad you have to drain the oil/ white vinegar ( you don’t want the bearings to soak in the vinegar that slips past the rings). And give it a second soaking. This time leave for a few days.
Once it will turn over freely. Now is when you put the ATF/acetone in each cylinder. About 1/4 cup in each. Things should be turning over freely at this point. Fill the pan & oil filter with oil. Now put 1/4 cup of engine oil in each cylinders. Using a fresh battery spin the engine over until you have oil pressure.
Replace the spark plugs and check the fuel system. That running motor just saved you thousands on rebuild costs. Some rings may still be slightly stuck but they will come free with use. Don’t go more than 100 miles before you change the oil.
I'm a bit concerned my problem may not be corrosion. The story goes the previous owner had the car running (bought it that way),
then it stopped running, and he just cranked and cranked and cranked with the starter and eventually it stopped and only clicked.
When I looked at the oil, it also seemed brand new (but it could be bad in the cylinders I don't know).
At this point though, I can't trust anything the previous owner has told me except what I can confirm with my own eyes. So I will definitely still try your idea.
My eyes show me that someone left me with monumental issues with wiring and general bad workmanship but if I can get the engine working again,
that'd at least eliminate one issue.
I'm starting to believe that the wiring is probably a total loss, at least in the engine bay. Dozens of loose wires, missing ground cables, exposed copper
in the middle of wires that can rub against unrelated engine bits, what looks like a suspiciously empty relay box, old style plugs I'd expect to have
fuses seem to have solder blobs instead, etc. At least if it were just old wiring that'd be one thing, but this looks like AFTER someone redid it.
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#8
07-07-2022, 08:25 PM
Senior Member
Absolutely do not try to turn the engine over backwards. If it isn’t seized, you’ll break the timing chain tensioner and that’s no fun to change.
When it only clicked, what clicked? The starter? The starter relay? The starter solenoid? They can all go bad and that’s a lot easier to fix than swapping the whole engine.
When it only clicked, what clicked? The starter? The starter relay? The starter solenoid? They can all go bad and that’s a lot easier to fix than swapping the whole engine.
#9
07-07-2022, 08:25 PM
Senior Member
Hi all! I fell in love with the look of the XJ-S, and I'll admit that I wanted to experience a V12 engine.
I guess that's it for starters. I'm happy to hear any advice not related to my specific questions.
And I apologize if my questions seem pretty noob-ish. My experience working on cars is
almost entirely pre-1940s or post-2010s, so this is a very different world for me.
Anyway, cheers and thanks for any help!
I guess that's it for starters. I'm happy to hear any advice not related to my specific questions.
And I apologize if my questions seem pretty noob-ish. My experience working on cars is
almost entirely pre-1940s or post-2010s, so this is a very different world for me.
Anyway, cheers and thanks for any help!
V12 5.3L start up check list
Over on the Jag-lovers forum, which has owners much like this forum, we had somebody with the same problem. He bought an XJ-S at a low price because it had not run for a while and he was trying to get the engine up and going. It took him about 6 months and a zillion posts backwards and forwards before he got it running and sorted out. It looked to me it was done the hard way by not tackling the problem in a systematic way. There are known weak spots with the 5.3L V12 and it is best to investigate those in a systematic way from a check list. Then you can either figure out what to do yourself or ask questions on this forum. That will be about 500% more productive than just jumping into random items to get the engine running. I volunteered to make a check list, which is available in pdf format if you follow the link above on the Jag-lovers XJ-S forumThere are also "sticky notes" at the start of this XJ-S section which have valuable information.
If you spend 2 or 3 hours reading this material and making notes it will easily save you 100 hours if you just dive into it and hope for the best
Like Mguar says, it is quite possible to have that V12 running again with moderate time and money unless you are very unlucky. Then you have a car with an interesting engine that has good resale value. Good luck with your project.
#10
07-07-2022, 09:06 PM
Veteran Member
Rather than resale, I think the biggest problem with an engine swap is that each is unique and orphan. The wiring will be different on each one and nobody who isn't infront of the car can help you.
It's often bandied about that changing to a GM engine "makes it more reliable" but I think the opposite is actually the case - it's all the ancillary things that will cause a car to quite running, very infrequently is it a catastrophic failure of the engine. An engine swapped car becomes essentially unservicable by anyone other than the person who did the swap, and you can only hope that person kept good notes. Otherwise, it's a shot in the dark.
New wiring harnesses ( at least some anyway) are available, it might be easier to rewire the car than do an engine swap. Here is one harness: https://www.autosparks.co.uk/finder/car/jaguar/xjs
It's often bandied about that changing to a GM engine "makes it more reliable" but I think the opposite is actually the case - it's all the ancillary things that will cause a car to quite running, very infrequently is it a catastrophic failure of the engine. An engine swapped car becomes essentially unservicable by anyone other than the person who did the swap, and you can only hope that person kept good notes. Otherwise, it's a shot in the dark.
New wiring harnesses ( at least some anyway) are available, it might be easier to rewire the car than do an engine swap. Here is one harness: https://www.autosparks.co.uk/finder/car/jaguar/xjs
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Mguar (07-11-2022)
#11
07-07-2022, 09:34 PM
Absolutely do not try to turn the engine over backwards. If it isn’t seized, you’ll break the timing chain tensioner and that’s no fun to change.
When it only clicked, what clicked? The starter? The starter relay? The starter solenoid? They can all go bad and that’s a lot easier to fix than swapping the whole engine.
When it only clicked, what clicked? The starter? The starter relay? The starter solenoid? They can all go bad and that’s a lot easier to fix than swapping the whole engine.
#12
07-07-2022, 10:29 PM
Rather than resale, I think the biggest problem with an engine swap is that each is unique and orphan. The wiring will be different on each one and nobody who isn't infront of the car can help you.
It's often bandied about that changing to a GM engine "makes it more reliable" but I think the opposite is actually the case - it's all the ancillary things that will cause a car to quite running, very infrequently is it a catastrophic failure of the engine. An engine swapped car becomes essentially unservicable by anyone other than the person who did the swap, and you can only hope that person kept good notes. Otherwise, it's a shot in the dark.
New wiring harnesses ( at least some anyway) are available, it might be easier to rewire the car than do an engine swap. Here is one harness: https://www.autosparks.co.uk/finder/car/jaguar/xjs
It's often bandied about that changing to a GM engine "makes it more reliable" but I think the opposite is actually the case - it's all the ancillary things that will cause a car to quite running, very infrequently is it a catastrophic failure of the engine. An engine swapped car becomes essentially unservicable by anyone other than the person who did the swap, and you can only hope that person kept good notes. Otherwise, it's a shot in the dark.
New wiring harnesses ( at least some anyway) are available, it might be easier to rewire the car than do an engine swap. Here is one harness: https://www.autosparks.co.uk/finder/car/jaguar/xjs
#13
07-08-2022, 06:25 AM
Veteran Member
I agree with folks who've said to begin trying to fill the cylinders with an agent that will breakdown the corrosion at rings and the potential ring ridges that may have grown over time. And yes, I have heard (only heard) to NEVER turn the engine the wrong way. Never.
If the PO was spinning the engine with a starter as you say,,, the engine was spinning when "parked"... Good evidence (if the PO can be trusted at all) that freeing it up is possible.
I have heard folks talk about just filling the whole damn thing with kerosene or diesel and letting it sit - hitting it with the wrench/breaker once in a while. If you Google anything to do with locked, frozen, seized etc engine, and click videos, you will find an ocean of examples of people coming in a car that hasn't run in decades and the process they go thru to free them up.
I'll say this. As I've slowly gotten my car running better and better, there is NOTHING like the feel of this engine when it's purring along on all 12 doing 70+mph... It makes this uncommon sound, and just feels so nice. I could go on. Save the engine, it doesn't take a lot to bind them up at first.
I would also say hold off on just tearing into and removing electrics in mass... Going in the other direction once your ready could prove a REAL challenge.
If the PO was spinning the engine with a starter as you say,,, the engine was spinning when "parked"... Good evidence (if the PO can be trusted at all) that freeing it up is possible.
I have heard folks talk about just filling the whole damn thing with kerosene or diesel and letting it sit - hitting it with the wrench/breaker once in a while. If you Google anything to do with locked, frozen, seized etc engine, and click videos, you will find an ocean of examples of people coming in a car that hasn't run in decades and the process they go thru to free them up.
I'll say this. As I've slowly gotten my car running better and better, there is NOTHING like the feel of this engine when it's purring along on all 12 doing 70+mph... It makes this uncommon sound, and just feels so nice. I could go on. Save the engine, it doesn't take a lot to bind them up at first.
I would also say hold off on just tearing into and removing electrics in mass... Going in the other direction once your ready could prove a REAL challenge.
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Mkii250 (07-12-2022)
#15
07-08-2022, 11:31 AM
I agree with folks who've said to begin trying to fill the cylinders with an agent that will breakdown the corrosion at rings and the potential ring ridges that may have grown over time. And yes, I have heard (only heard) to NEVER turn the engine the wrong way. Never.
If the PO was spinning the engine with a starter as you say,,, the engine was spinning when "parked"... Good evidence (if the PO can be trusted at all) that freeing it up is possible.
I have heard folks talk about just filling the whole damn thing with kerosene or diesel and letting it sit - hitting it with the wrench/breaker once in a while. If you Google anything to do with locked, frozen, seized etc engine, and click videos, you will find an ocean of examples of people coming in a car that hasn't run in decades and the process they go thru to free them up.
I'll say this. As I've slowly gotten my car running better and better, there is NOTHING like the feel of this engine when it's purring along on all 12 doing 70+mph... It makes this uncommon sound, and just feels so nice. I could go on. Save the engine, it doesn't take a lot to bind them up at first.
I would also say hold off on just tearing into and removing electrics in mass... Going in the other direction once your ready could prove a REAL challenge.
If the PO was spinning the engine with a starter as you say,,, the engine was spinning when "parked"... Good evidence (if the PO can be trusted at all) that freeing it up is possible.
I have heard folks talk about just filling the whole damn thing with kerosene or diesel and letting it sit - hitting it with the wrench/breaker once in a while. If you Google anything to do with locked, frozen, seized etc engine, and click videos, you will find an ocean of examples of people coming in a car that hasn't run in decades and the process they go thru to free them up.
I'll say this. As I've slowly gotten my car running better and better, there is NOTHING like the feel of this engine when it's purring along on all 12 doing 70+mph... It makes this uncommon sound, and just feels so nice. I could go on. Save the engine, it doesn't take a lot to bind them up at first.
I would also say hold off on just tearing into and removing electrics in mass... Going in the other direction once your ready could prove a REAL challenge.
#16
07-08-2022, 12:40 PM
Veteran Member
Yeah I had heard the same things about the feel and sound. I'm going to at least give unfreezing it a shot and go from there. Even if electronics work, I'm going to have to redo a lot of it for the sake of my own sanity. But at least that way it could be more systematic if I start with a vaguely working vehicle instead of a brick or an engine swapped car. So you make a pretty good point there.
All I'm saying is, old engine or new swapped, at least you'll have a road map, even if it's a full out mess, with the OE electricals...
And,,, it will be good for us all, cuz I'm sure you be back, lol 🥴
#18
07-08-2022, 11:10 PM
Update!
I did get the engine to turn following the vinegar advice. I haven't done anything beyond that (ran out of time tonight).
Man this car is a PITA haha. I really see what people mean, like the engine itself doesn't seem too terrible but it seems like every single supporting component is a mess
in terms of unction or design or layout or both. Regardless though, it moves! Thanks all!
I'm sure there's still a host of things wrong so we'll see what the future holds.
I did get the engine to turn following the vinegar advice. I haven't done anything beyond that (ran out of time tonight).
Man this car is a PITA haha. I really see what people mean, like the engine itself doesn't seem too terrible but it seems like every single supporting component is a mess
in terms of unction or design or layout or both. Regardless though, it moves! Thanks all!
I'm sure there's still a host of things wrong so we'll see what the future holds.
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Mkii250 (07-12-2022)
#19
07-10-2022, 09:04 PM
Good to hear that the vinegar treatment worked, Vinegar is also good to dissolve surface rust. Congratulations, you are learning to work WITH your Jag instead of AGAINST it. The best course is to work with what you have and at the car's pace. Unless you get a replacement harness I'd follow each wire and inspect, replace as necessary. Good Luck.