What is the purpose of the tube portion that goes into the block of the dip stick assembly? Does it protect the dip stick from rotating parts? What happens if your tube is broken and pretty much cut about 0.5” below the seating flange on the top of the block? So I don’t have the tube inserted in the block. I just have the raised portion bolted. Is my dip stick going to interfere with anything rotating? is the tube used to protect the dip stick from hitting anything? I know some dip sticks (shorter) just sit in the block and don’t have that tube extension inside the block and don’t have the raising it up portion to get it around the master cylinder. Remainder if tube shown below. just have raised portion
If I remember right, the dipstick passes right next to #4 main cap, so unless it's got a funky twist going on, it'll clear the crankshaft counterweights and the rest of the reciprocating assembly. Why the tube to begin with? We didn't have one on the 400/430 engines, the stick simply bottomed on the block deck thanks to a captive washer. The tube may have been added later for ergonomics, raising the top end of the longer stick a bit, making it an easier reach on a hot engine. Just a guess. And realize, tube or not, the end of the stick protrudes the same amount into the crankcase...that's the only way to read what five quarts w/filter change looks like. With tube, the stick is just a bit longer on the top side, that's all. The only concern I can think of is that the early sticks (no tube) are pretty robust compared to the skinny later versions w/tube. That may be why engineering had the tube protrude into the crankcase a bit, to stabilize the stick. Valid concern, hope others can offer input. Devon
The tube made it easier to get the stick in, especially with power brakes. You can try a stick from a non-tube big block, after oil change and adding correct oil, running the car a few minutes, then shut it off and give it 5 minutes. See if the level is on full, and if not, you can make a new mark with a scribe or dimple with a punch. But your existing dipstick is going to be too long to use without the tube. If you have the tube and it is flush to the opening on the block, you might be OK, just verify the level in case the tube length is + or - from where it broke. Does the tube slip in .5 inch into the block and contact the remainder of the tube?
I currently have the dip stick that sits flush in the block. I’m good with that. I know the levels and that’s what’s been there for a while. I was looking to get the correct assembly for a 70 GS455 which is the tube from what I understand. However the tube was damaged so I cut it off just below the part that it seats on the block. It’s a brand new aftermarket dip stick so no crazy curves in it. so my main concern was hitting something. The dip stick without tube seems thicker and sturdier.
Thanks for the clarification. Edited above as to why the later sticks may have had so much tube support...if I remember right the sticks with tube are more flimsy than the earlier version, so maybe there is more danger of stick movement in the crankcase when unsupported - especially at higher rpm. Not sure. Devon
Ah. Gotcha. You can get an OEM tube and stick, I see them for sale once in a while. and also Repops are available.
@DaWildcat that’s what I was thinking but wasn’t sure. @TrunkMonkey yeah, I was worried about trying to jam home a the tube while motor in car and get stuck half way in and or not being able to get it back out. So I cut the tube off. (All that is open for jokes and sarcasm lol ) So as I drink a beer or two I stare at the two dip sticks and ponder lol what to do. I can always take the top portion off and go back to my normal.
There is NOT supposed to be an o-ring where the tube inserts in the block, correct? When I removed the dipstick tube upon disassembly, there was an o-ring. It probably leaked at some point and someone thought it was a good idea. Does anyone put any sealant on the tube when installing just as a precaution?
@tubecatgs no o ring on mine. I’ve had the dip stick in the block for 20 years with no issues. No leaks. Mines recently restored so trying to get it correct for 70 hence the tube questions. But it didn’t have an o ring either.
The tubeless style works well with stock manifolds and gaskets but If you’re running headers and/or aftermarket one piece gaskets they will interfere when installing or removing the dipstick due to disk shaped stop towards the top.
This'll likely be the same for any off-the-shelf headers that have a common flange for all four tubes on that side. I had to do some dipstick clearance grinding because of that captive washer on my first headers, modded Kenne-Bells. I think some folks have trouble even with the later stick with tube setup due to that left side header flange too. My current headers have independent flanges, so plenty of room for the old stick w/o tube. Devon
