BadAss SRT-Z - 2.4L / A568 - Update!!!

[turboshad]

.0025? Whats that? The difference between the two rotors was .0045 and I didnt measure the cavity they set in to see what the clearance is... prolly would have to use plastigage and clamp it up?

Whoops, bad math

Page 1051 says the oil pump rotor minimum thickness is 0.421 so it seems like it was way under spec.

http://www.carbide-red.com/service_m...ice_manual.pdf

[Aries_Turbo]

was it supposed to be a little loose cause the new material expands more when hot?

mill the cover except where the oil pump gear is?

[BadAssPerformance]

might just need to spin a tad faster to get going, as long as youve got the pump sealed and its not sucking air in. I feel it should just work.

did you prime your last 2.4 this way?

The last 2.4l primed "dry" with no issues with both stock pumps...

Whoops, bad math

Page 1051 says the oil pump rotor minimum thickness is 0.421 so it seems like it was way under spec.

http://www.carbide-red.com/service_m...ice_manual.pdf

Thanks for the spec DJ!

was it supposed to be a little loose cause the new material expands more when hot?

mill the cover except where the oil pump gear is?

I was wondering that but steel is steel so not sure how much less PM steel would expand than billet...

Didnt mess with it today, maybe later

[Directconnection]

At work, we have the simple, yet effective way of priming an engine. It's simply one of those little portable airtanks modded with a regulator and air fitting, and an area to dump a few quarts of oil into. Screwing it into the oil filter fitting makes priming work everytime. You can see the lifters getting oil... which is scary... as sometimes it takes a few minutes for them to bleed the air out and prime with oil.

Works everytime!

[BadAssPerformance]

Neat idea!

[Warren Stramer]

JT, something OTHER than a .0045 thinner rotor is your problem. I cant believe that small amount of extra clearance could cause a no prime.

What viscosity oil are you starting with? Try 5W20 weight. Or even 10W to prime

could you show side by side pics of the two rotors?
I like Steves idea for priming, would be easy to set up, and once you have it running with pressure it should stay primed. you could feed the oil in a galley plug with the filter on.

Also, You could plug your crankcase venting and rig up regulated shop air (1.5 or so psi) to your dipstick tube to create a slight crankcase pressure differential.
attach battery charger when cranking for max rpm, with spark plugs removed.
of course you probably already tried that.

[BadAssPerformance]

Had the billet rotot in, entire pump and pick up tube filled with assembly lube... pan full of 10w40, oil filter filled with 10w40... could not get anything event to the filter ... using starter with plugs out... didnt have the battery on a box but it was 12.5V

Pics... Stock left, Billet right.

The stock rotor is fairly loose (thicknesswise) already so the billet piece was even looser... and under spec from what DJ posted.

[Aries_Turbo]

wait, you had the pickup tube filled with assy lube? isnt that going to draw up the tube much harder than oil?

try some of the other trick and see if you can get it to prime before giving up on the stronger gears.

brian

[BadAssPerformance]

I forget who suggested that when I was trying to prime the first broken OP before I knew it was broken... I think the packing it all with something is to help create suction and make sure no air pockets in it...

Ya know I REALLY am starting to to miss the OP driven of the I-shaft like the 2.2L

[Aries_Turbo]

yeah i understand the theory, i just think it may be too thick to pull up the tube.

yeah no kidding. hit that i shaft with a drill with the timing belt off and oil pressure galore!

i was thinking with all the oil pump issues with the 2.4L, maybe it would be a good idea to mod the balance shaft assembly to house an old school td oil pump and drive it with a chain off of the crank.

Brian

[Mike M]

Aw sorry to hear about your luck JT. On the same note, yes, I do love my intermediate shaft... I was priming my system this afternoon to feed me new turbocharger, wouldn't pick up a prime with the starter, so within moments had the belt off and duck taped a 18mm 3/8 socket to my wobbly 1/4 extension (couldn't get anything else to work) - hit the shaft with the drill, as soon as it primed my duck tape broke and I knew I was ready to go, lol

[bakes]

I told you to go dry sump!! lol
is the a difference in pans ports on the 2 blocks?

[Warren Stramer]

wait, you had the pickup tube filled with assy lube? isnt that going to draw up the tube much harder than oil?

try some of the other trick and see if you can get it to prime before giving up on the stronger gears.

brian

X2, What sort of assembly lube are you using?? Get rid of the 40W oil!, Fill pump with STP/10w30 mix, fill pan with 5w20, remove assbly grease from pick-up tube, attach batt.charger set to boost (15-16Volts), and crank away. those rotor gears are fine.
If you are racing with 10w40 you are overloading that pump, PM gears will break. Lower the viscosity and go faster. I race with 0w20 Mobil 1. bearings are fine.

[BadAssPerformance]

X2, What sort of assembly lube are you using?? Get rid of the 40W oil!, Fill pump with STP/10w30 mix, fill pan with 5w20, remove assbly grease from pick-up tube, attach batt.charger set to boost (15-16Volts), and crank away. those rotor gears are fine.
If you are racing with 10w40 you are overloading that pump, PM gears will break. Lower the viscosity and go faster. I race with 0w20 Mobil 1. bearings are fine.

Just general engine assm lube...

Interesting on overloading the pump... I was planning to start it on 10w40 and then switch to 5w30 this year, but have run 10w40 in it before... do you think that may have been a cause of breaking the previous pumps?

I measured .4175 on the billet rotor... thermal expansion of steel (7 micro-in/in/°F) and even at 300°F it is only .41911 If the min thick on the stock part is .4210... I think it will have significantly lower oil pressure then?

Maybe the housing is out of spec or on the large side? I could not find specs for that, but with the billet rotor in there it was "ringing the dinner bell" so to speak with a visibly large clearance between the rotor and backing plate...

[dodgeshadowchik]

Interesting thoughts...

I know that the newer cars have been using the lighter weight oils for some time now due to tighter clearances. But from reading through some stuff on SRTforums, these people seem to be all over the board as to what they use. But looks like *most* seem to stay with a 5w30, or a 0w40.

Thought this was interesting... of course this is the internet, so it might not be true. But its interesting to think about since it seems hit and miss on people with pump problems.
"the manual states either 5w30 or 10w30 but one of the main guys from the srt development team has recommended 0w40. in terms of switching over most are switching over at 2-3k and I've been using synthetic for a few oil changes now without any consumption issues."

Ninja Edit: 0w40 Mobil 1 Synthetic is what they are using when going with a 40 weight. Appaprently it is a thinner 40w for some reason. Perhaps because its a Synthetic? But from everything I've read thus far they do not recommend a 40W oil at all. So the post above about getting rid of the 40W is good advice. +1 on that Warren!

[Warren Stramer]

Just general engine assm lube...

Interesting on overloading the pump... I was planning to start it on 10w40 and then switch to 5w30 this year, but have run 10w40 in it before... do you think that may have been a cause of breaking the previous pumps?

I measured .4175 on the billet rotor... thermal expansion of steel (7 micro-in/in/°F) and even at 300°F it is only .41911 If the min thick on the stock part is .4210... I think it will have significantly lower oil pressure then?

Maybe the housing is out of spec or on the large side? I could not find specs for that, but with the billet rotor in there it was "ringing the dinner bell" so to speak with a visibly large clearance between the rotor and backing plate...

JT, could you quantify what you mean by "visibly large clearance" I was under the assumption there was only .0045 difference between the two rotor gears.

[BadAssPerformance]

JT, could you quantify what you mean by "visibly large clearance" I was under the assumption there was only .0045 difference between the two rotor gears.

The .0045 is between the two rotors, I have not tried to measure rotor to housing clearance with either one... not sure how I would do that, plastigage maybe?

What I was refering to with clearance...

With the OE rotor in the housing, with the cover bolted down, it easily slides around but you can only barely move it side-to-side (direction of rotor axis) in the housing.

With the billet rotor in the housing, with the cover bolted down, there is a visible gap between the rotor and housing and when you move it side to side it in the housing it moves far enough it goes "tink tink" like ringing the dinner bell.

So what is a normal oil pump clearance? I am guessing the billet pump is somewhere on the big end of normal plus .0045?

[Shadow]

Just an FYI; AMS recommends running 20/50 in they're 2.4 1000WHP capable mtrs. So are they purposfully building them "looser"? Haven't heard of one failing yet.

[Warren Stramer]

OK, found what I was looking for in the FSM. 2.4l-clearance over rotors-.004 Max. If you remove the pump cover with the rotor gears still in the pump, and layed a straight edge over the rotor gears bridged on both ends of the straight edge by the pump housing, what size feeler gauge can you fit between the straight edge and gears? More than .004 and the book says its too much.
It would have lower oil pressure, but I'm surprised it will not prime.
I believe you could get it to prime but if you can hear it clinking when you move the assembled pump then dont waste your time.
And I still cannot think of one good reason to run heavy viscosity oil in a drag or street car.

[turboshad]

When I was looking for my gears I remember reading that part of the DCR design was more clearance but I don't know how much or where that clearance was added. I assumed it was between the inner and outer rotor, not the case and rotor but I have nothing to back that up. I would have to agree with Warren that it still seems odd it won't even prime. Don't be offended by this question, but you did remember the o-ring on the pickup tube right? Is your assembly oil more of a lube or grease? I've only ever packed the pump just to get suction and not the whole tube. If it is a higher viscosity grease I could see that making it harder to prime with the pickup full of it. If it wasn't such a PITA I would pull mine off and take some measurements for you. Being you are so good at it now you are more than welcome to come over and take a shot. Here are some pics of mine though I don't know if they will help any.