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fastback wrote:intresting reading ,as i have had the similar problem on one of my wbx engines.
fresh bearings,
i have 4,5- 5 bar at cold engine @ idle
when oiltemp reaches around 60 celsius the pressure seems to fall at more rapid rate and at hot engine/oil around 80-90 ceslius the oilpressure is only ~0.5 bar pr 1000rpm.and i have tried different oils, sanded the pump,swapped bypassvalve. and double checked readings with mechanical gauge.also tried differnet oilfilters
i uses the stock watercooled oilcooler
please post what u find out about the accusump and what hardware is needed, regarding valves etc. as im considering this soulution against the CB drysump setup (have started modified the pump)

thx

I'm actually finally stuffing a T4 in the 73 Square, I almost went with the 2L I have DS prepped, but couldn't "see" a satisfactory place to put the DS tank. (plus I wanted to use the factory oil cooler setup/Vanagon housing)

Current plan is either using a low mileage stock T4 pump or a 28mm Melling I dual oringed and pressure balanced.

If you have any tank location ideas, I'm still working on it...

I run my tank up against the rear luggage carrier with the bottom setting under the bottom of the luagge carrier about 1/3. So, 2/3 s of the tank is above the horizontal surface of the luggae carrier. Then I built a box from aluminum with zues fasteners etc.

Here is the best info on tuning e85 I have found



Fuel AFRst FARst Equivalence Lambda---- ----- ----- Ratio -----=======================--====================================
Gasoline stoich 14.7 0.068 1 1
Gasoline Max power rich 12.5 0.08 1.176 0.8503
Gasoline Max power lean 13.23 0.0755 1.111 0.900=======================--====================================
E85 stoich 9.765 0.01235 1 1
E85 Max power rich 6.975 0.1434 1.40 0.7143
E85 Max power lean 8.4687 0.118 1.153 0.8673


I am running E85 and .8mm idle jets. The window gives me 12 AFR with one turn. I had tried .7mm idle jets and a 2.00mm main. There was noticably less power of the line and the top end sucked whne the stochiometric was 13 to 1 ( Gas calibrated meter) I am looking for 11 to 1 for best power on E85. The 2.00mm jets were on the lean side. I drilled it to 2.37 mm or 12 thou bigger. Once I get 11 to 11.5 in the window it will be good. As it is I may add a quart of 60 weight oil and set the idle at 2000 rpm. Its to bad that CB pump cant be modded some more. . Weld the internal pickup galley closed and tap the outside of the case for the feed line, then full flow the case for external oil filter and regulator. Use the 21mm stage for sucking out the case and returning to the sump.


naah the bottom line is the inlet needs to be a 3/4 inch line with a 3/4 inch inlet. Then we will see what the oil pressure does. I think this is the next step............

I also bumped the timing to 35 degrees at full throttle. If it slows down, I will just back it off by feel.

I am ready for Woodburn.

If you take 14.7 to 1 and divide it by 1.35 you get about 10.88888 to 1 stochiometric on E85. 1.30 nets 11.3 and so on. 13 to 1 in the window doesnt even put me in the lean power category.

14.7 divided by 1.12 for about 13 to 1 on the meter. At a minimum for jet sizes, I had to make up 1.12 to 1.35

so a 200mm main was about 13 to 1 on e85

I could ratio and proportion , but I think 2.35mm main will work to span the gap between 1.12 and 1.30 or so......

I advanced the timing gear 10 degrees and have small carbs so the bottom end is hard and the sixty foot time are getting into the 1.40

I will watch the gage and see what the value is at WOT........................

Who are you...........and when do you sleep

Here is 3literboy serving an 11.50

One guy talking a lot of BS.

Have to love the line about the century $300 crap crank. Real cranks cost $1250.00 and up no matter if you put it in a WBX block or a T-1 case.

pocketrocket wrote:Have to love the line about the century $300 crap crank. Real cranks cost $1250.00 and up no matter if you put it in a WBX block or a T-1 case.

Read the whole thread, Rocky

I think he got past the "venting" stage, and we all worked out some possible solutions to the issues he was seeing.

I don't do Twitter etc, but he seems to have a decent setup.

(DPR and DMS make a pretty reasonable welded crank... for not much more than the Elcheapo.)

When you look at the NEW DRD case its looks nice but can you buy one right now. And if so what is the real cost? Building race engines is not cheap. If going 11.50 is your goal then a T-1 engine is some what cheap to build. But as the times get faster the cost go's up. All engines are started on a piece of paper. But in the real world it takes $$ to build them. That's all I have to say. Thanks Rocky

After all this I forgot to mention the #1 most likely reason oil pressure goes way down hot.
(I was reminded as I was fitting an oil pump...)

This is particularly annoying as I identified this issue ~5 years ago, and I bitch incessantly to all that will listen.
(This isn't remotely a new issue)

This may NOT be YOUR problem, as the dry sump pump inner stage is scavenge, but read on, esp if you are considering going wet sump later.

Aftermarket pumps OD "fit" the opening in the case just about perfectly.
Unfortunately this is the WRONG SIZE.

They SHOULDN"T "FIT" they should be a ~.003" interference fit (at least)

In other words, a medium press fit in an untorqued case, and "it `aint movin" when the case is all torqued down.

The factory pumps are .003"+ larger than the aftermarket pumps in every instance I have measured, some are .005' larger.

It SEEMS like this would be no big deal, but when it all heats up, you start sucking air around the pump body and leaking oil pressure out the other side with the incorrectly sized aftermarket pump bodies.
This is actually FAR worse for the Mellings (iron body) as they don't expand with heat like the aluminum case.

An oringed pump can HELP this a lot (with some PITA assembly differences), but the only CORRECT fix is a pump made correctly.

Jake Raby is getting some billet pumps to his specs to solve this (wet sump pumps, 30mm) but I guarantee they will cost what you would expect a billet pump to cost. (plus... I'm not sure if they are available yet)

The Schadeck pumps (including the CB drypump I have, as well as about a dozen others from various vintages) as well as the Mellings are all basically exactly the size of the hole, case torqued.

The Schadeck pumps might "feel" right, but sometimes the pumps stud holes aren't quite drilled right, so they drag.

I have never measured the "maxi' models of CB pumps.

good tip regarding o-ring Pile.
i'll try it to add a o-ring to my pump in my "little bit lower oil pressure than normal engine".

fastback wrote:good tip regarding o-ring Pile.
i'll try it to add a o-ring to my pump in my "little bit lower oil pressure than normal engine".

The case has to be prepped just right for an oringed pump to slide in an assembled case... and even then you risk ending up with a cut oring chunk the oil system.
It's best to install an oringed pump with the case "on the halfshell" and install all the pump studs ( or bolts) after the case is together.

The above rants are true for T1/T4 and WBX cases, and probably just as true for aftermarket cases, if not moreso.
(Have never measured one)

I have been o-ringing all the pumps in the engines that I build for the last 15 years. You can go to my web site to see how its done ( www.rockyjennings.com go to machine work, then to oil pumps. And yes i take out the studs & use oil pump bolts on the 1-2 side so I can fit the 1-2 side down on the 3-4 side so the pump won't have to side in and have the chance of cutting the 0-ring. then install the bolts through the pump cover. Thanks Rocky

thx!

pocketrocket wrote:I have been o-ringing all the pumps in the engines that I build for the last 15 years. You can go to my web site to see how its done ( http://www.rockyjennings.com go to machine work, then to oil pumps. And yes i take out the studs & use oil pump bolts on the 1-2 side so I can fit the 1-2 side down on the 3-4 side so the pump won't have to side in and have the chance of cutting the 0-ring. then install the bolts through the pump cover. Thanks Rocky

So like the song asks "...How long has this been going on?..."
Re:the undersized pump ODs.

Before ~5 years ago, I was just occasionally building throw together stock T4s and would reuse OG T1 pumps in good shape (clearanced/blueprinted), and had a few OE stock T4 pumps, so I never ran into this issue.

I know Berg has been doing oringed pumps for ages, so perhaps it's been going on since dirt was new.

Is there a stash of OG T1 oil pumps out there?