The Stovebolt Site Forums The Shop Area Engine Shop Dipstick length?

1963 GMC 305e motor. Ive been running for afew years now. Ivè always put 7qts with filter when changing oil. But why im asking about the dipstick length is because the dipstick has a welded repair towards the top, but below the tube. And it just seems to run better when its about a quart short, which would be 6. Not to mention, everything i find is saying 6 quarts with filter. Ive been putting 7 to hit the full mark. Any insight on the right lenght would be appreciated. Thanks

glenns towing I took care of a whole fleet of those in the 70's from 305 up to 401 pretty sure it would be 6 quarts. Once bought a new 401 from springfield illinois, installed it went out in the dark shed for oil,broke it in on hydraulic oil. Discovered my mistake changed it ...it never hurt it ran a long time.

Yes I didn't think I hurt it. More oil is better than not enough, I guess. I was hoping for the right length to mark it instead of just putting in 6, then marking it. Thanks for the insight tho.

More is not necessarily better.

If the oil level is too high, the bottom of the connecting rods and crank weights splash into the pool of oil churning it up into a froth. The oil pump can't pump foam so you can lose lubrication to the rest of the engine.

Fill it with the amount specified by the maker.

As for your dipstick, as long as your oil pan isn't an aftermarket deep sump unit, put in the 6 quarts specified in the manual, then put your dipstick in and etch a new "full" mark on your dipstick. The dipstick you're using probably came from some other engine.

Well I don't know if the pan is a deep sump type. But the chassis it is in, is a 63 gmc 2500 one ton, that lived it whole life as a fire truck water carrier. When I got the chassis, it only had 11k on it. The repaired or modified dipstick takes 7 qts to the full mark with a filter. Add mark is exactly 1\2 quart short. So is it off exactly 1quart or just coinsadence? Hmmm. Any way to identify a deep sump pan compared to a regular one? Dipstick length would help I think? Maybe it was modified for the deeper pan?

glenns towing,

I did a bit of part# researching using GMpartswiki and results indicate only 1 part number for the oil pan being used for the GMC 305e (and 305a/305d) (see screenshots below). There are different part#s for the pans needed for 305b/305c/351/401/478 and a 3rd number for the 702.

The parts book also notes the dipstick (Oil Level Indicator) part is the same for all 305/351/401/478 engines with the exception of on Model N5000 series trucks. Thinking that indicates there is not a "deep sump" pan or dipstick for your particular engine and 1 Ton truck model.

The only odd thing that may negate some of this would be that your truck being a "fire truck water carrier" could indicate some changes/modifications may have been done for that special vehicle application.

Perhaps some of our resident "GMC" experts can chime in with more info???

Anyone with a GMC "305e" that can take some pictures with measurements of their existing dipsticks and oil pans to help figure this out???

Hope this may be of some help.

Dan

Thanks Gdads51 for the time and effort. The fire truck application is the only pan issue, if there was an optional pan. But with the info you've found im leaning towards probably not? If someone could give me some oil dipstick measurements, to the stop, and overall, would be great. I would probably be content at that point, I think.

Wow guys. If I'd ask how many bolts are involved in a frame off restoration and the torque spec of each one, everyone would of been all over it. Lol. I guess measly info about a dipstick length is like pulling teeth around here.

By "top of dipstick", do you mean the stop that rests on the dipstick tube?

Also, the length of the dipstick tube itself must be known.

Without all these measurements, an accurate assessment of any dipstick's usefulness for a particular engine are impossible.

But, the OP has a GMC 305. Any dipstick measurements for a different engine are useless unless they share the same GM part number.

I replied to the post without carefully reading what was asked. If I new how, I would delete it. Will be more careful in the future. Apples to apples.

EDIT BY MODERATOR: Deleted your two previous posts as you wished!
Here's how to change or delete a post. (see the pic below)

Ok. Let me clarify. The engine is a 1963 GMC 305e. All I'm to hoping to find out is the dipstick length. Overall length? And length from bottom tip to stop that hits the top of of the tube? Thanks to all who are trying to help.

Sorry can’t help with the dipstick measurements. My 1963 305 V6 in a 1963 GMC Carryall took exactly 6 quarts of oil including the filter. Haven’t had the truck in 50 years so I can’t measure the dipstick for you.

Wonder if posting in the 60 - 66 Forum may help some.

Any chance someone can pull up a drawing to help actually mark what Glenn is looking for.

1946-1961 dip stick lengths/etc

Maybe someone has a similar chart for newer engines?

Added later: the tube length and the oil pan depth are other factors that affect the necessary dip-stick length/markings.

Now, THAT'S the kind of picture I was thinking about.

Well according to Gdads51 I have the right dipstick, "2389607" see pic. And I measured and came up with, 29â…ž overall which came out to 23â…œ from tip to stop and 6½ from stop to top. I didn't think to measure from the "full" or "add" mark. But hopefully this will help verify weather it's right or wrong. Thanks again to all.
I do realize also tube length and pan play a factor, but at this point, I'm assuming they are factory and unmolested, or swapped?