School me: changes to grey motor engine front cover plates

[Harv]

I pulled down the EJ block last weekend, and put all the odds and ends to one side, ready for consideration for the meth monster project. One item that caught my attention was the engine front cover plate. I have half a dozen of these, and could vaguely remember that they changed over the years. I seem to recall there is a difference in where the engine mounts bolt on, which raises the height of the motor significantly.

Some digging through the MasterParts shows that there are four type of engine front cover plate:
a) FX/FJ (7412004),
b) FE-FB (7412006),
c) EK (7418742), and
d) EJ (7416374).

I know that the early Holden oiling design was changed with the FB, adding the slinger ring to the crank and some modified drain holes. The info below (from the FE/FC workshop manual) shows this change:

Engine plate changes.png (1.26 MiB) Viewed 1491 times

From the drawing, the "1st Type" is the FX/FJ engine front cover plate(7412004), whilst the "2nd type" is the FE-FB engine front cover plate (7412006). The vent hole (or it's absence) makes them easy to identify.

What was the change made for the EK, and the later change made for the EJ?

Cheers,
Harv

[BS]

From memory i think there is an extra hole in the j block compared to the b block which accomodates the extra bolt in the front main cap.

Below is a b block front main cap compared to a j block front main cap showing the extra bolt I am talking about.

Apart from this I am not sure what the other differences are.






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[ardiesse]

Harv,

"Some digging through the MasterParts shows that there are four type of engine front cover plate:
a) FX/FJ (7412004),
b) FE-FB (7412006),
c) EK (7418742), and
d) EJ (7416374)."

@BS: Your "B-block" front main bearing cap is in fact from a pre-L313838 motor (FX-J-early FE) - the oil drain holes are in the "old" position. Did this engine leak oil out between the front engine mount plate and the front main bearing cap?

7412004 is the "backward compatibility" front engine mount plate for earlies, to suit the later style of front main bearing cap with repositioned oil drain holes. In the earlies, the pad for the front engine mount points backwards, whereas in anything FE onwards, the return for the front engine mount points forwards. This plate would be used if you were fitting a late FE - EJ motor into an early. But to the best of my knowledge, the 7412004 does not have provision for the extra bolt that the J-motors have.

7412006 will be the "normal" front engine mount plate for late FE-FB to suit the later style of front main bearing cap. The captive nuts for the front engine mount will be 5/16" UNF.

Somewhere along the way, the bolt sizes for the timing cover were revised . . . I think at least one 1/4-20 screw was changed to 5/16. This may be why the EK front engine mount plate has a different part number. The captive nuts for the front engine mount are still 5/16" UNF on EKs. At what stage did the studs on the front engine mount go from 5/16" UNF to 3/8" UNF? EK, I think. But this would not affect the front engine mount plate. I also reckon the extra bolt in the front main bearing cap was an engineering change part-way through EK production. This may be why there's a separate part number 7418742 for EK front engine mount plates.

7416374 (EJ) is drilled to suit the extra bolt in the front main bearing cap. Also, the captive nuts for the front engine mount are enlarged to 3/8" UNF. Everybody who puts a J-motor into an FE-EK drills out the FE-EK front engine mount to suit the larger bolts. The EJ front engine mount is a compression-only mount, whereas before EJ, it was a compression/shear mount.

And you also say, "From the drawing, the "1st Type" is the FX/FJ engine front cover plate(7412004), whilst the "2nd type" is the FE-FB engine front cover plate (7412006). The vent hole (or it's absence) makes them easy to identify." Not quite. Second type, yes, late FE-FB. First type is the early FE front engine mount plate. It will have a different part number again. And the original production FX-FJ front engine mount plate will also have a 740- part number.

Rob

[ardiesse]

. . . and also, if you look at BS's photo of the two front main bearing caps, you'll notice that the "bolt hole" on the right side of the photo/ left side of the crank axis is not threaded, while its counterpart on the J-block front main bearing cap is tapped 5/16" UNC. This is the revised timing cover bolt size thing I was talking about.

All FE-EJ front engine mount plates have the same height from engine mount pad to crank centreline. But it's quite different from FX-FJ.

Rob

[BS]

Great info!

The "b block" that main cap came off was a spare block and i never had it running but i beleive it was pulled out of a humpy so maybe had a fair bit of bastardization going on.


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[ardiesse]

And also -

Front engine mount plates for the earlies are wider than for FE-EJ: the webbing extends a lot further out the left side of the block, to include the front bolt hole for the generator.

My 1957 master parts catalog has 7412004 as the front engine mount plate for the earlies; but the parts history index lists its predecessor as 7402435. And it has 7412006 as the front engine mount plate for FE, but the parts replacement index lists its predecessor as 7409879.

Could be that the front main bearing caps had already been revised by the publication date of my 1957 parts catalog.

Rob

[Harv]

Many, many thanks gents - appreciated.

Cheers,
Harv

[FbSTDwagon]

Thanks for the info guys.

I have a j block at Southcotts getting dipped and crack tested at the moment.

Seems the J motor will drop straight onto my FB front end as long as I drill the front end one mount out to 3/8.

I didn’t know this earlier so thank you

[ardiesse]

Drew,

That's right: drill the holes in the front engine mount out to 3/8" (10 mm would be better). The front engine mount studs were enlarged from 5/16" to 3/8", probably when the FB came out, so trial-fit your new front mount in the crossmember. Drill the holes out if the studs are too big.

Rob

[Harv]

B89C539C-7C7D-4DC4-819E-1B3FFEE6E8B6.jpeg (3.4 MiB) Viewed 955 times

Cheers,
Harv