Starter replacement V12 Etype

e-type
(Larry Carbol) #1

Just about to change starter in my 71 Etype V12. Read the previous posts but still confused. My Repair Owners Manual says to remove battery, left hand under shield, blank off clutch slave cylinder, remove two bolts securing to bell housing, and then withdraw starter forward to clear pinion and remove rearwards through battery location.
Nothing mentioned of a third bolt accessed through cockpit bulkhead or vacuum tank. .?? Maybe instructions are for Right hand drive?

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(baxtor) #2

Confused, I have never worked on an E type but all the V12’s l have worked on have starter R/H side and 2 bolts only retaining. Left or right hand drive will have no bearing other than steering pinion getting in the way or not.

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(John M Holmes) #3

Hi Larry, I have a 1973 SIII XKE , and yes the ROM instructions are for RHD, so the instructions ( ROM 86.60.01 ) are “sort of” incomplete. !!The ROM mentions 6 steps and I will quote to you the notes I took and recorded in pencil in my ROM.Step2 …not aplicable , 3) also na…my notes show…? 4, OK : 5a)The bolts are at 1 and 6 oclock when viewed from the rhs of the transmission bolt heads.1/2 inch…use universal joint and 2 extension rods to get to the bolt. Note with hand reaching up in the space by the bell housing …3 bolts can be felt…the 2 lower ones are for the bell housing 5b) remove emissions canister 6) remove starter motor from its "bay ". SS heat shield needs to be held outwards to enable sm removal. I then went on to service the solenoid, which involves de-soldering the connections, removal of phillips screws, and prying off the head.
So these are my notes, on a project done a few years ago, so I can’t recall any more details!!! Hope this helps, John H.

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(Larry Carbol) #4

Thanks John for the information. I will be replacing with a new starter that is much smaller and turns the engine over faster.

Regards, Larry

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(JimD in Alabama) #5

haven’t done this, but since I have a V12 XJS i read a number of posts in the past. IIRC they all stressed that the top bolt is a 12-point head - -get a 12 point socket to go on it

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(Larry Carbol) #6

Hi Jim, thanks for the tip! Much appreciated.

Larry

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(Paul M. Novak) #7

Larry,
I successfully removed and replaced the starter in my wife’s left hand drive 1990 XJ-S convertible (5.3L V12) several years ago. I had heard that this was a difficult job but it wasn’t too bad. I replaced it with a rebuilt original starter. The starters were a bit heavy, but not too bad.
I found some helpful information in the Jag-Lovers archives, the XJ-S Repair Operations Manual (ROM), and in Kirby Palm’s book before I started. I recall the info in the ROM was just for right hand drive cars and that it was easier for the left hand drive cars than what was described in the ROM. Also I needed to use some extensions on my socket set to reach that top bolt. I had a 12 point socket in my tool box already so no issues there.

Paul

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(Philip Lochner) #8

This is a misconception. The reduction gear starter does NOT turn the engine faster than OEM starter in optimal conditions. (I saw this with my EFI conversions) It only SOUNDS like its turning faster because the electrical motor in the starter DOES turn faster - much faster - than the OEM starter.

The reduction gear starter is a better solution than OEM because it draws less current than OEM therefore it copes better with poor wires, and poor battery and is likely to turn the engine faster (than OEM) under those conditions.

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(Kirbert - author of the Book, former owner of an '83 XJ-S H.E.) #9

Actually, we’ve heard that it actually pulls more current than the earlier non-geared starter as well.

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(Mark Eaton) #10

Philip, I wonder whether the alternate ECU’s actually fire the engine faster than the Jag ECU? I wonder how many revs of the engine is required from the factory ECU before it gets its act together and fires the engine correctly? I suspect this is an area that modern (reduction gear) starters win. Not only are than MUCH lighter, but probably the OEM ecu is capable of firing the correct plug very soon after motion is detected.

In one system I was looking at, they have a strategy that fires multiple plugs while they are waiting for an index mark. Once they sync on the cam, they revert to normal fire.

Mark

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(Philip Lochner) #11

To measure is to know. I have not measured either but if it did draw more current, I would expect typical GR starters to have THICKER cables than non-geared.

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(Ed Sowell) #12

When I put in a GR starter years ago I was surprised at how much faster it cranked. That being the case, it would have to drag more current.

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(Bernard Embden) #13

I might be wrong on this, but my understanding is that the gear reduction starter actually uses less current that it’s direct drive equivalent. Smaller motor turning faster verus big motor turning slower?

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(Mark Eaton) #14

The available wisdom says:

The motor in a GR starter is typically turning at 4 times the speed of a direct drive starter. Current draw of an electric motor is max at stall speed. Therefore a GR motor is operating closer to its sweet spot. A GR should, in theory draw about 40% less current (and weigh 1/2 to 1/4) … and cost about 30% more, and use smaller cables. Efficiency is up (Power losses are proportion Current Squared). Also engagement of the teeth should be more gentle so there is less wear.

GR starters may turn the flywheel slower than a direct driver, but will typically be cranking the motor faster near TDC where compression is max. More importantly, the rest of the electrics will have higher available voltage due to the reduced demand on the battery. And critically, you are pulling less amps out of your battery, so your battery will not only have an easier life, but will deliver more cranking before running flat and leaving your hot V12 stranded.

GR use bearings. A direct drive will use bushings. Once the bushings are stuffed, the starter will turn ever slower, pulling even more current. Thus a GR should last longer with less maintenance.

Standard Jag starter is 11.5kg (25.35lbs) Rated at 900A
Tilton Standard GR Starter 4.99kg (11lbs) 2.8 kg.m Peak Power at pinion 2.2kW 450A
Tilton Xtra Light 3.18kg (7lbs) 2.4 kg.m Peak Power at pinion 1.2kW at 300A

Hope that helps. None of that is actually measured on the car, just from the datasheets.

Cheers

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