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Username Post: oil tube and dipstick length        (Topic#364880)
ktgraf 
Newbie
Posts: 2

Reg: 04-09-21
04-11-21 08:57 AM - Post#2817852    

hello all

joined this site specifically to ask these questions:

got a boat with a vortec 350 motor (block) in it. this engine block came out of a tahoe (gm 5.7 lg sgi 10243880) and i was told the spinning parts were from a different motor. not sure if the oil pan came w block or is from somewhere else. the previous owner (we’ll call him sparky) installed the engine. he had to reduce the length of dipstick tube so it would clear under the engine cover. he said he cut equal lengths off the tube and dipstick (handle end). he re-flared tube. yellow handle was apparently removed from dipstick, metal dipstick was cut and handle reinstalled with cotter pin.

so, after my first time in water with it, i notice oil on the bottom of the boat on the right side of motor. it appears the dipstick worked its way out a bit and oil came out the end of the dipstick tube.

i checked the o ring on yellow handle and it was bad so replaced it. as im pushing the dipstick into the tube i hear what seems like the dipstick end scraping/sliding against oil pan. this occurs last 2-3 inches of travel before it seats. it doesnt seat well into tube either and at this point i cant tell if its due to the o ring being too big or maybe the dipstick bottoming out and preventing full insertion. sparky said he added 5 qts of oil to motor and level lined up w full mark on the dipstick.

q#1 - can anyone verify the dipstick is not supposed to hit the oil pan (or anything else for that matter)?

there is a pcv valve where the bottom of the valve sits in a rubber holder which is inserted into top of valve cover. this pcv valve appears to be just a ball check valve which lets air out but not in. there is a hose that goes from top of pcv valve to the height of the air cleaner (spark arrester) and terminates with the open end of the hose pointing at the spark arrester (about an inch from it).

q#2 - does this pcv set up sound right? isnt there supposed to be vacuum involved? could this set up be contributing to the oil coming out dipstick tube?

thank in advance to anyone who wants to tackle this







 


Mr. Sinister 
Contributor
Posts: 593
Mr. Sinister
Age: 43
Loc: Fair Hill, MD
Reg: 05-18-09
04-12-21 06:37 AM - Post#2817897    
    In response to ktgraf

I run a Vortec block as well, and the dipstick is indeed different from a traditional SBC. I ended up getting a Spectre universal SBC setup, filling the pan with 5 quarts, then waiting an hour and making my own full and fill marks and cutting off the excess dipstick length. The stock style SBC dipstick will be too long on a Vortec setup, it will need to be cut down to work properly. Dipstick should slide in and out with a little resistance (so it doesn't easily blow out) and it shouldn't be hitting the pan. I wouldn't trust the other guy's work, make your own so you know it's right.

As for your PCV, that sounds like an incorrectly installed fixed orifice valve. GM started using those on applications that were prone to oil consumption issues (so I've read) and I believe the Vortec 350 was one of them they used it on. They also work well on high performance applications with big cams where idle vacuum is not great. I've had issues with finding a traditional PCV that works well with my combo, so I'll be trying a fixed orifice unit soon myself. I'll let you know how it works.

It does sound like you've got some crankcase ventilation issues if the dipstick is getting blown out. Make sure you've got a good clean breather on the opposite valve cover to the PCV. It can either have its own filter media or can be run to a port on the air cleaner lid, it should never be open to unfiltered air. Without a breather, a PCV valve is useless. The PCV also need to be connected to a manifold vacuum source, like on your carb base. It receives no vacuum when tied into the air cleaner base. It's OK to plumb a breather to the air cleaner base, but not the PCV.

It could also be if the engine has been hotted up, the PCV is not correct for the application. Would need more info before diving into that, like cam specs and idle vacuum in gear.

Bill -
1955 Chevy D/Gas Tribute
Gassholes HRC



Edited by Mr. Sinister on 04-12-21 06:40 AM. Reason for edit: No reason given.

 
ktgraf 
Newbie
Posts: 2

Reg: 04-09-21
04-12-21 08:14 AM - Post#2817902    
    In response to Mr. Sinister

thx sin.

one valve cover has the check valve in it. the other valve cover has a rubber plug. there are no vacuum lines on the motor.

i just watched some video on pcv..

at this point, i can see that, if the check valve were to be connected to intake vacuum, there would be no where to draw fresh air into the system (engine crankcase) so i would need a small filter in place of the rubber plug.

my question now is, if the pcv system is designed to draw air in through the valve cover filter, down through the crankcase, back up to the pvc valve in the other valve cover and then into the intake manifold, why does there need to be a check valve in the system? is there ever positive pressure in a na engine intake manifold..?







 
Mr. Sinister 
Contributor
Posts: 593
Mr. Sinister
Age: 43
Loc: Fair Hill, MD
Reg: 05-18-09
04-12-21 09:01 AM - Post#2817905    
    In response to ktgraf

The check valve is there to prevent positive pressure from blowing back through the PCV like during a backfire or if you are boosted.
Pretty much any time the PCV system is not operating correctly, you will have positive crankcase pressure. This is why you end up blowing gaskets and in your case, pushing the dipstick out.

Bill -
1955 Chevy D/Gas Tribute
Gassholes HRC



Edited by Mr. Sinister on 04-12-21 10:19 AM. Reason for edit: No reason given.

 
1983G20Van 
Super Senior Member
Posts: 3872

Loc: Bedford, Texas, USA
Reg: 11-13-02
05-03-21 06:36 PM - Post#2819230    
    In response to Mr. Sinister

  • Mr. Sinister Said:
I run a Vortec block as well, and the dipstick is indeed different from a traditional SBC. I ended up getting a Spectre universal SBC setup, filling the pan with 5 quarts, then waiting an hour and making my own full and fill marks and cutting off the excess dipstick length. The stock style SBC dipstick will be too long on a Vortec setup, it will need to be cut down to work properly. Dipstick should slide in and out with a little resistance (so it doesn't easily blow out) and it shouldn't be hitting the pan. I wouldn't trust the other guy's work, make your own so you know it's right.

As for your PCV, that sounds like an incorrectly installed fixed orifice valve. GM started using those on applications that were prone to oil consumption issues (so I've read) and I believe the Vortec 350 was one of them they used it on. They also work well on high performance applications with big cams where idle vacuum is not great. I've had issues with finding a traditional PCV that works well with my combo, so I'll be trying a fixed orifice unit soon myself. I'll let you know how it works.

It does sound like you've got some crankcase ventilation issues if the dipstick is getting blown out. Make sure you've got a good clean breather on the opposite valve cover to the PCV. It can either have its own filter media or can be run to a port on the air cleaner lid, it should never be open to unfiltered air. Without a breather, a PCV valve is useless. The PCV also need to be connected to a manifold vacuum source, like on your carb base. It receives no vacuum when tied into the air cleaner base. It's OK to plumb a breather to the air cleaner base, but not the PCV.

It could also be if the engine has been hotted up, the PCV is not correct for the application. Would need more info before diving into that, like cam specs and idle vacuum in gear.



ALL RH dipstick small blocks can use the same dipstick, regardless if it is a vortec or not. I used the stock 1983 305 dipstick and tube for my 880 "Vortec" block in my 83 G20. 350 Vortec had a 5 qt pan plus the filter. 7 qts put it exactly to the full mark running the 2 qt truck filter (S373 equivalent). It is possible the end of the dipstick is colliding with the windage tray if it was not installed correctly or the dipstick tube inside the block was somehow bent out of its correct location.

1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals


Edited by 1983G20Van on 05-03-21 06:37 PM. Reason for edit: No reason given.

 
Mr. Sinister 
Contributor
Posts: 593
Mr. Sinister
Age: 43
Loc: Fair Hill, MD
Reg: 05-18-09
05-04-21 10:48 AM - Post#2819267    
    In response to 1983G20Van

Right. The point was it seems as if he had the incorrect dipstick that was unsuccessfully modified by the previous owner.

If you go to the parts store and get an old school LH SBC dipstick from the parts aisle to run with a Vortec, which is probably what this guy did (all conjecture at this point), it's not going to drop in and work correctly on any RH dipstick block. I found that out the hard way when I installed my engine.

Bill -
1955 Chevy D/Gas Tribute
Gassholes HRC



 
1983G20Van 
Super Senior Member
Posts: 3872

Loc: Bedford, Texas, USA
Reg: 11-13-02
05-04-21 07:07 PM - Post#2819283    
    In response to Mr. Sinister

My point was that he could get a new RH dipstick tube and stick and actuall fix the problem.

1983 G20 Van, 350 TPI, Ported 906 Vortecs, Edelbrock 3817 Base, ASM oversize runners. Reed Custom Roller cam, 700r4, 12 bolt with 3.08 gears, Doug Thorley Tri-Y headers, true duals


 


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