Oil pan bolt length (the odd one)

E-Type
1

Hi Everyone,

When removing the oil pan, I found that all the bolts were the same length (3/4"). They are 5/16", fine thread.

The manual says that one of them is supposed to be shorter than the rest.I believe I know which hole requires the shorter bolt.

Q1) What length is the shorter one supposed to be?

Given the PO, or someone, used bolts all the same length, plugging the flow at the point were the short bolt is supposed to be, I am supposing this means something was being denied its oil rights.

Q2) What may have suffered oil deprivation?

Thanks…

It’s a beautiful day here in S.E. PA and rain due tomorrow. Why am I working on the E today? Because swmbo has declared that when she gets home tomorrow these many months waiting for me to change the bearings and oil seal in situ MUST end. I thought my issue was OIL pressure, but what did I know?

2

The short one goes to the right front, next to the timing cover. Don’t know its length.

3

And it is shorter so it does not bottom out on the threads of the timing cover cross bolt.

4

The odd (short) bolt is not a standard bolt according to the Parts Lists. It has part number C.14170. The other 25 bolts are standard parts UFS.131/6R which means they are 5/16" UNF threaded and 3/4" long. The fact that the shorter bolt has a “special” part number would imply that it is probably not just 1/8" or 1/4" shorter than the rest. That said, since the only reason for it to be shorter as far as I know is to avoid clashing with the timing cover bolt, I’d be inclined to just (a) screw a bolt into the corresponding timing cover hole and have it bottom out, and then (b) screw one of the 26 3/4" bolts into the corner sump hole by hand and see where it runs into the timing cover bolt. You will then be able to measure how much shorter it needs to be. An angle grinder with a cutoff disk will complete the operation…

-David

1 Like
5

Thanks for the replies. I was mainly concerned to not block oil flow.

6

The tapped portion of a bolt is constant irrespective of length, so a longer bolt will have a greater unthreaded length than a shorter one. I have found that grinding/cutting off the end of a longer bolt sometimes allows the modified bolt to bottom on the unthreaded shank. This can make you mistakenly think it’s tight when it’s just seated on the unthreaded part of the modified bolt. Worth checking.

7

That’s why in this instance you should use what the Brits refer to as a set screw- basically a bolt threaded all the way to the head with no shank.

8

Or it one is unavailable break out the tap and die set and cut additional threads.

9

Learn something new every day!

Rod