Cam shaft thrust plates

[up2nogood]

Hi guys,
Just putting a 4.6 together with all the bits off my 3.9.
Trying to source the right cam to use but have ended up in a bit of a fix.

The 4.6 was running an old model cam, with no thrust plate. The dual row timing set was wearing on the timing case. Presumably because:
* Dual row is bigger
* There's some small amount of end float on the unretained cam

I know 4.6's with the THOR ign system no longer have the oil pump/distributor drive so no big surprise that no thrust plate was fitted.

The 3.9 I have (which was a virgin, so is the same as it left the factory) is SUPPOSED to have a half thrust plate. But it doesn't have one at all. It's a 1993 3.9 (late D1, before the update dash).

4.6 engines are SUPPOSED to have a full thrust plate.

The questions:
* Which cam do I use
* Should I dig around for a half thrust plate to match the 1993 specs, even though my 1993 doesn't have one?
* Why does my 1993 not have one, is this unusual?

Thanks!

[PhilipA]

I think your problem would be to get a cam machined for the thrustplate WITH a distributor drive.

So the best /cheapest solution IMHO would be to get an older cam with distributor drive .

if you see a problem with cam endfloat you can fit a teflon button, although the lobes are angled to spin the followers and hold the cam back.

I understood from replies to your previous post that you should have relieved the timing case, and that was the reason for the contact by the dual row chain.

Regard sPhilip A

[up2nogood]

Teflon button's a good idea!

Although if not needed, then might not bother and just go older cam. But that begs the question, why did the 3.9's use one?
But then my 3.9 doesn't have one anyway...........


Hey, I don't recall positng about timing case/cam chain wear, did I?

[PhilipA]

Sorry , I just assumed you were the same poster who had exactly the same problem about a week or two ago after years of nobody mentioning this issue.

They must come in clusters , or it's aliens.

Do a search and you will find the earlier discussion.
Regard sPhilip A

[up2nogood]

Aliens, or too much cordial.....

[Lucus]

When i built my 4.6 I installed a 3.9 style dizzy drive cam.(although i am running coil pack, the remains of the dizzy drives the oil pump) The cam i purchased ( a heatseeker) had provisions for the Thrust plate. I installed it as per specs for the 4.6. Im also running a dual row timing chaind (rollermaster) and havent had any issues with it making love to the timing case. I did measure and check though.


Luke

[Traco]

So which engines have the thrust plate fitted? Those without a distributor
(4.0/4.6), or all 1994-98 serpentine engines i.e 300 series 3.9 Discos with the so-called "Interim" distributor front housing.

[up2nogood]

According to the workshop manual, my 1993 3.9 is supposed to have a half thrust plate.
But there are no bolt holes to bolt it with, so I am going to guess only the dissy-less cars? D2's, P38's and later Defenders?

Stuffed if I know.......

[RoverP6B]

Engines fitted with camshaft thrust plates are the 4.0 and 4.6 (block casting HRC 2411) both of which are distributorless, and the 3.9 and 4.2 litre interim engines (block casting HRC 2493) built from 1994 onwards, both of which retained a distributor.

The 3.9 litre engines built up until December 1993 were not drilled and tapped to accept a camshaft thrust plate, and as such none were fitted.

Ron.