revisions to timing gear cover?

[ardiesse]

Hi all,

I'm doing a trial assembly of a disassembled EJ motor I picked up recently to see whether I have a complete complement of bolts -

I'm guessing, based on the parts I have to hand, that the EJ timing covers take five round-head 1/4-20 x 5/16" screws and spring washers, one hex-head 1/4-20 x 7/16" bolt and spring washer, and seven hex-head 5/16-18 x 7/8" bolts and spring washers.  Three of the 5/16" bolts go through the reinforcement at the bottom of the timing cover, and the remaining four 5/16" bolts take thick plain washers, the same thickness as the reinforcement.

My 1957 master parts catalog tells a different story:
1/4-20 x 5/16" round-head screw plus lockwasher assy., 5 off
1/4-20 x 7/16" hex-head bolt, 2 off
1/4" spring washer, 2 off
5/16-18 x 3/4" hex-head bolt, 4 off
5/16-18 x 7/8" hex head bolt, 2 off
5/16" spring washer, 6 off
The reinforcement is welded to the timing cover.

So I took a close look at my "other" grey motors.  Some time between early 1960 and late 1961 the reinforcement was revised from two 1/4" bolts and two 5/16" bolts, to one 1/4" bolt and three 5/16" bolts, along with matching changes to the timing cover and the front main bearing cap.  My late 1961 B-series motor still doesn't have the four thick 5/16" flat washers though.

Is there someone with a 1963 or later master parts catalog, and a good set of Service Bulletins (Ken?), who might be able to tell me when the timing cover and reinforcement were revised, and when the thick 5/16" flat washers were introduced?

And here I thought that all grey motor timing covers were the same . . .

Rob

[RET]

"The First Twenty Years" parts book is no help. It doesn't suggest any change at all.

[ardiesse]

Richard,

"The First Twenty Years" parts book is actually a great help.  It just needs a close reading -

Cover, 7418790, and reinforcement, 7418792, are late EK or EJ part numbers.  The 1957 parts catalogue has Cover Assembly, 7401338. (Until 1957, and possibly later, the reinforcement was welded onto the cover, hence "assembly").  The later timing cover will fit the early engines, because it has one larger hole.  That's why it's listed for all grey motors in your catalogue.  But, of course, the early cover will only fit a late engine if you enlarge one hole.

The 5/16" bolt, SP1480, is a tad longer than 7/8", and supersedes 5/16" bolts in two lengths, 3/4 and 7/8".
The 1/4-20 x 1/2" bolt, 120706, replaces a 7/16" bolt.  The A.R. means "as required".  Which means that when fitting a 7418790, you need to choose quantities of 5/16" and 1/4" bolts, determined by the age of the engine you're fitting the cover to.

No mention of a thick 5/16" flat washer, though.

Thanks for finding the catalogue reference.

Rob

[mcl1959]

I'll add some confusion.
First is the FX to FB book



Then the FX To EJ book



So there were at least 4 different versions

Ken

[ardiesse]

Ken,

Confusion is good. From your FX-EJ catalogue, one of the 1/4" bolts was changed to 5/16" at the FB to EK changeover, and the cover and reinforcement changed to suit.

I have a reinforcement which takes two 5/16" bolts and two 1/4" bolts - this must be the 7401127 reinforcement - and at least one spare which takes three 5/16" bolts and one 1/4" bolt: 7418792.

Still no reference to the thick 5/16" flat washer.  Ken: do the master parts catalogues allow you to do a "reverse part number search"?  If so, could you look up 7418791 and see what it is?

Thanks,

Rob

[zulu]

Rob

In my EJ cattledog it misses the part # 7418791
but there is a hand written note about a superceeded cover and reinforcment as per images




Gary

[RET]

You always learn something rummaging around in these old books. To answer your question Rob, not only do they have a part-number to group "reverse lookup", they also have a "Parts History" section.

In the 48-HR book, we find:

7401127 was replaced by 7416140
7416140 was replaced by 7418792
7418792 appears as "current" in group 0.206

Unfortunately there's no reverse look-up of replacement parts, so you can't see what a particular part replaced, only if it was replaced. And when a part was replaced is also unknown from this catalogue. However, I had a look at the 48-FB MPC, and it does not show 7401127 in the Parts History, but as a current part, so 7416140 must be after publication of that tome, which accords with previous comments. I could find no trace of 7418791 though. That doesn't come as a surprise - consecutive numbers tend to be "pairs", representing a left-hand and right-hand version of a particular part.

Hope that's some help, from a fellow Holden nerd

[ardiesse]

Richard, Gary, Ken,

OK then.  The timing cover went through two revisions after the original design.
Oops. I overlooked the reference to the flat washer: SP1482.  It was introduced at the same time as 7418792.
Or perhaps later. Engine B253155, "L301", has the 7418792 cover, only one hex-head 1/4" bolt, but yet does not have the SP1482 washers.
They might be an EJ thing.

Now I know how many SP1482s this disassembled EJ motor should take.

Thanks all for your research.

Rob

[DougT]

Hello Brains Trust, I was looking for information on timing covers and came across this post which answered some of my questions; however, I have a couple more I hope you can help me with. I have what I am assuming is a later EJ cover as it has only the one 1/4 inch hex head bolt hole but it is different to all my other covers in that it has a cross pressing, my question is did Holden change the timing cover pressing when they enlarged the hole? Secondly I have two different timing cover seals, both Holden part numbers 7412742 which is a single lip seal that sits fairly flush with the cover and 7426199 which has the additional felt seal, my question which engines had which seals? Thanks Doug

[mcl1959]

1st question - probably. It makes it easier on the production line if the new part has something easy to identify it as different to the part it is replacing, rather than just the size of a bolt hole.
2nd question - the felt seal is most likely older than the other seal, but with no part number change, it’s difficult to tell when they were introduced.

Ken

[DougT]

Hi Rob, I have been trolling through the Accelerator mags and found the answer to the washers. Check out Vol 17 No5 (Jun 1960) page 14.

Regards Doug