Morning all. The starter in my '89 XJS V12 recently failed. I purchased the popular aftermarket gear reduction starter to replace the original starter (I realize that different people have different opinions about whether to stick with the original type of starter or move to gear reduction, but I am resolved to go this route now).
My question relates to adapting the gear reduction starter to fit. I am currently changing the screw connector to a spade connector on the starter relay wire. Do I need to extend the wires from the battery, alternator, and starter relay to compensate for the different locations of connection on the new starter? Some people seems to say it’s necessary while other have just pulled/bent their wires around to fit. It’s of course hard to see but I think I have slack on the wire to connect them without extensions but it might make life much easier to extend. If I do extend, what gauge wire? I was thinking 4 gauge for the battery and about 14 gauge for the starter relay (as that is what I believe the current wires are).
Old starter is already out btw. Benched tested and got the solenoid working again after cleaning it up. But I don’t trust it. So to the backup parts it goes.
Hi Douglas-
I installed a gear reduction starter about 8 years ago. I used the extenders, if memory serves they came with the starter. The gauges you mention sound correct. The starter is a huge improvement over the stock Marelli starter which was always anemic.
Regards
Bob
Thanks for the replies! My new starter sadly did not come with any extender wires. However, I managed to fit the new starter with the existing wires without too much trouble. There was quite a bit more slack on them then it initially appeared.
Because of the location of the terminals on the new starter, I found it easier to insert it 180 degrees reversed to bolts the wires on then rotate it in the cavity into position. This maneuver was difficult but possible given how much smaller the replacement gear reduction starter is as compared to the original one.
On my new starter, the bottom bolt hole is not threaded so I had to source a new 3/18 - 16 bolt that was a bit longer and could thus receive a nut on the other end. A 4 inch long bolt did the trick for me.
Haven’t tried putting the old top bolt back in yet but I believe I will be able to reuse the original 12 point 7/16th bolt as the top hole of my new starter is threaded and the mounting plate is the same thickness.
Here’s hoping I will hear the v12 cranking to life again soon!
It should be a big improvement. I dreaded the chug, chug start of my old XJ12 - seemed like it was taunting me, will I start today? The geared starter on the XJR-S is a joy in comparison.
Dumb question time … I have heard that the 5.3s use a “gear reduction” starter, but never knew what that meant. Is this as opposed to the common-place Bendix type starter? Is the G.R. why the 5.3 sounds so cool while starting?
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
9
Please remember that wires from the chassis to the starter must have enough slack to deal with the engine moving around on its mounts. And the engine moves on its mounts a lot during hole shots.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
10
The gear reduction starter was introduced somewhere along the line, I think it was pretty late. Everyone, everyone who has to replace a starter for any reason is advised to upgrade to the gear reduction model, so by now there’s probably quite a few of all years. The earlier starter looks and sounds like any ol’ starter. The gear reduction starter has a whine to it, like a turbine starting up.
They both use a Bendix gear and a solenoid that throws the Bendix gear into engagement with the flywheel ring gear.
Wow, just pulled the starter, that thing is HUGE and heavy! I’ve never seen a starter that big. I am now for sure going to put smaller gear reduction in there.
Getting top bolt out is a hope and a prayer before breaking that torque. Scary. Thankfully I got my 12 point socket on there best I could and turned.
Call me paranoid, but I’m ordering a new 12 point star bolt. Current one looks a bit scratchy and corroded. I would hate to strip it putting it back. Anybody know the part #, I’d appreciate it!
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
13
You can use a socket head alloy bolt. That should be a bit easier to find.
What do you mean? Socket head alloy? If you mean Allen head bolt, no way, I’ve stripped those so easily in the past.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
15
A bolt that requires an Allen wrench. And made of alloy steel, which is stronger than Grade 8. Typically black finish.
The only problem there is with the difficulty of even seeing that bolt head when you’re looking to remove the starter. The experienced Jag mech will be trying to get a 12-point socket in there. Gotta remember to use the Allen wrench instead.
I did a search for 12 point starter bolt, a lot of SS ones for Ford and Chevy, maybe one will work.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
17
Hah! Jaguar wasn’t alone in that particular bodge!
I knew a guy who bought a brand new GM truck of some sort, 90’s sometime. Within just a coupla months the starter crapped out. Come to find out it required a special starter because it was a snug fit, and the engine had to be loosened from its mounts and jacked to get it in. And of course he had to wait a few weeks to even get the starter, had to be special ordered.
FYI. When I R/R my transmission last year, I thought I would use something other than the twelve-point bolt.I found an Allen head capscrew the right length, but did not possess an appropriate tool to tighten it.Just too awkward. Went back to the original bolt, with never-seize.
How much torque is required on that bolt? Perhaps I can reuse if it’s not too much (37 ft lbs?), and use anti seize of course.
Kirbert
(Author of the Book, former owner of an '83 XJ-S H.E.)
20
There are Allen wrenches that fit onto 3/8" drive ratchets or extensions. I would think one of those would work well, but you’d have to find one. Call your neighborhood Snap-On or Matco dealer?
