Trouble With type 4 engine oil pressure.

[raygreenwood]

I just write it up what have been happened in last few weeks.
Engine came down and to parts again because I really wasn´t pleased with that pressure ans sloppy pump fitment. It just made clocking noise when you heat the oil to 90c and let it idle, when it was near 1000 or lower rpm. It blinked betweeb 0.3-0.4 bar (near 5psi)
I regrinded the crank and ordered new bearings. Also replaced all gaskets. Made oil pump to tight fit.
Result is strange. Little improvement on low RPMs but insane peak on 4k (starts at 3.5k already)
compared to last time it was like that:

difference:
5 -> 7 PSI@ 1000
17 -> 19 PSI @ 2000
29 -> 33 PSI @ 3000
43 -> 68 PSI @ 4000

This pressure now looks pretty good. As Piledriver noted, that 5-7 psi at idle is normal.

Why is this? Because....of that small oil pressure control valve over under cylinder #1. It actually never closes all the way. So when you are at low rpm with the oil pump only putting out minimum volume...and the oil control valve near #1 bleeding off minimum volume at the same time.....you will never get high oil pressures at idle.
I am sure the oil pressure relief valve also has some effect on this "bleed off".

The other thing...why are the pressures that much better in the higher rpm ranges?

Yes, making the oil pump fit tighter is part of the answer but also....tell us what your original main bearing to crankshaft tolerances were....compared to what they are now that you had the crank reground and new bearings installed.

If your bearing to main journal tolerance was originally on the high side of specifcation.....AND ESPECIALLY if your rod side clearance is in the upper 3/4 of the maximum specification.....this combination loses a LOT of oil pressure at all rpm. Ray

[Piledriver]

With a stock pump I would not like to see 70psi at 4k, that will bypass the oil cooler until the pressure comes down, regardless of how hot it is.

I would be concerned a bit of something was stuck in the sump return passage at the bottom of the relief bore.
..of course if you are still running 50 grade oil, that will do same.

Great way to see 260f oil temps.

5w-30s with reasonable amounts of ZDDP for your flat tappet lifters exist these days.

[joosep]

Absolutely bearing clearance makes effect.
Now I´m pleased with oil pressure for tuning it on dyno.
With 10w60 @ 90c (194F)
0.6bar (9PSI) @ 1000 rpm
1.4bar (20PSI) @2000 rpm
2.5bar (36PSI) @3000 rpm
5.0bar (72PSI @4000 rpm

My biggest question is about the pressure boost what comes before 4k. It seems like it closes cooling port and goes directly to crank so there must be really bad 90 degree angles that doesn´t flow that good and pressure drops when it goes to cooler. But now I´m confused about that valve acting when you get that extra pressure from high revs and come back to 2k rpm there is a lot of more pressure when rising rpm from idle to 2k. it acts weird to me.
Dont look high pressure, its caused about not warm oil (78c 172F) but you can see what I mean when you look pressure @ 2bar
Anybody has any clue how much revs the type 4 crank and rods can take? is 6k safe? If I´m not mistaken I used to push stock type 1 safely to 5500 and type 4 to 6k when I raced with them 12 years ago.
https://www.youtube.com/shorts/e89Dq3nj3MI

[Piledriver]

re: rpm...
It depends on your valve springs... (and boost... dual valve springs required with any significant boost)
I ran my 1.7 in my 914 to 5600 rpm on ~every upshift... Eventually became a 1.8 with 2l heads and a web73, dual springs, ran it to ~6k on every upshift.(web 73 stopped making power even with 44 idfs and 2l heads around 6k)

They ran the super-vees to 6800 rpm, which were at least allegedly 100% completely stock ish t4s.(think destroked to 1600cc)
Typically the stock cam and valve springs conspire to keep you from getting much past 5500...(pointless anyway)
the 914 2.0 had bigger runners and valves/ports even the heads were Porsche-only with different castings, chambers and plug angles and intake ports. They also crack easier and should not be used on busses.

You don't want to push it too hard unless you have at least replaced your valve springs with HD singles, fit the keepers properly, and have good quality SS exhaust valves made in this century. A good balance job, upgraded rod bolts, dual springs will keep it together well past 7.5K if headflow and cam allows it, upgrade to H beam rods for more and more reliability.

If you are pushing a bus the high RPM stuff is mostly theoretical, but better rod bolts, regular HD single springs and SS ex valve replacement ...and a good balance job is always a great idea, will run cooler, smoother and longer.

The exhaust valve guides actually only wear a little. the hot hot hot ex valves stems STRETCH and get skinnier... a freshen up every 50-70 K miles will probably only need valves, the side play will be in spec with new valves at least once, probably more.

With boost I would probably pull it down/inspect annually if you drive it much and are equipped to do so.

[joosep]

Thank you again.
Then I´ll try to keep it under 6 but will see how the graph will look.
We ordered cam and springs 3 years ago and this project has been going such a long time because I´ve broken my back 2 times in that 3 years and owners plans have changed also. So it is now turbo engine with quite wide cam and low vacuum. I`ve tuned even 300+ degree cam turbo engines before but this time we have quite little turbo compared to them, I´m abit worried about BP it has hx30 holset with 6" turbine. but will see, maybe I put it on dyno this week. I´m not sure but I quess there is webcam 163 because I looked somethind not too wide and for single HD springs.
You told me smtng about head flow vs revs, Turbo this time unfortunately expands cam. Mostly atleast 1000rpm but sometimes 1500rpm. Thats what I don't like at this setup at the moment because I dont like graphs where max HP will bee after rpm limter. As NA it should work good between 1500-5500 so with turbo it pulls hart atleast to 6.5k if not to 7. I`m also a bit worried about knock because I don`t know where could be the place I can detect it with sensor. With pump fuel and no IC and wide cam its a real fear.
You also asked about making pump tight. I just cutted and drilled a part from beer can and put that betveen the case when closed the engine. I was able to hold it in place with drill pit and check free passage to pump on both side. It can´t move there and its tight enough when I cant pull the pump off. It changed the time when it pulls up the oil. (tightens both sides)

[Piledriver]

Knock... What are you using for ignition? EFI or carbs?

The fellow who makes the J&S Safeguard knock systems is back in business,(he retired for awhile...for good reason)

I'm buying one or two this spring, Any of them can be used in passive mode using the knock detect out signal as an analog knock input on MS2 systems that lack internal detect but have knock inputs. (have knock LED and audio outs, so make for great tuning aids) MS2/MS3 can add fuel and/or pull timing in a programmed manner, or the J&S units can retard for you.

http://www.jandssafeguard.com/safeguard.html
Cheap insurance.

Web163 requires dual springs per Webcam.
Doubly so with boost. may act as rev limiter with boost, esp with big valves.
Web119 or 163... Aggressive ramps. Web86 (a,b,c) based on Chevy corvette factory profile, also needs duals.
Web 494... Aggressive ramps, less lift.. duals still strongly suggested.

Stock 2l rods ok well past 6500 for bursts if the bolts have been upgraded to ARP, assuming balanced.
I picked up some 3/8" ARP2000 for a Chevy 396, need to ream the rod bolt holes a little...
I _THINK_ you can use T1 rod bolts. Carrillo may still sell the 9mm rod bolts for the T1 rods.

T4 cranks do not require counterweights, they don't have the T1s torsional flex/vibration issues.
(might be prudent on a welded stroker with 2L rods etc)

Huge turbo at least wont spool too fast...
you are at 103x71, web1i63@112?
CR?

[joosep]

I have two different ways for detecting knok, my problem was with finding good spot for sensor. Not sure its heard in case, I quess head is better place but there are some noise because of solid lifters.
Its all EFI, sometimes you just make really safe ignition map by based on your 500+ earlyer tune but still there can be some issues why that engine won´t take it. I had such a chance 2 weeks ago with one SR20 engine. I´ve tuned them when built correctly but this time the quench was too tight and it knocked insane. It would be broken if I just had go with map I thaught is safe.
I quess we have this cam: https://vwparts.aircooled.net/Web-Cam-T ... 00-432.htm
It doesn´t say it needs dual springs but baybe you are right. Valves are stock size.
Its not 103x71. its with stock 94mm pistons. CR abit under 9
I´m quite sure it will make needed power with really low boost. I quess it makes 100kw with 0.5bar and 150kw with 1bar but will see. Don´t remember a lot but I used to charge all type1 and type4 engined I used to have 10 years ago 150kw came out quite easy on these days with stock engines.
I think that hx30 is actually not big for that engine. Yes it can make 400hp but aircooled engines mostly ask abit larger hot side for good comprimise between BP / ignitin / knok and power.

[Piledriver]

108LC or 112?
On a 2L that cam should easily pull past 7K with decent heads ,NA
(5500 maybe with 2.4L motor)
A tight deck should have the opposite effect, assuming the pistons aren't smacking the head.
(should resist knock better, if CR is same vs wider gap, you may have "fixed it' with reduced CR)

HX30 is reasonable, depends on exhaust side.
The J&S units can be permanently installed or used as tuning boxes.

Assuming forged pistons of course...

[joosep]

stock lobe (108)
I´ve never been thinking like cam should be choosed by displacement because I´ve been working with regular engines mostly where you just cant make such a difference but I quess there is some point in your opinion. I just think that every engine needs correct port and valve size and how long valves are open should affect quite same then. Tight quench is main reason for turbo cars knock, I´ve seen it hundreds of hours in dyno. For example opel XE engines has really tight quench (near 0.6mm in stock) and once my customer came with freshly built engine that knocked with 3 degrees of ignition angle. Had never seen smtng like that before. But 2 differen devices and pipe listening told me its knock. We tested and checked everithing and owner was so pissed off that he told me to just add ignition for a try. It blowed head gasket in next pull with 6 degrees. (he had resurfaced block and it was near 0.3 only) after rising it to 1.7mm it took 16 degrees under 2bar of boost and after going to 2.0 quench it asks 20deg on 2bar and 17 on 2.8bar of boost and makes 520kw and 800nm from hubs (2L engine) When drag engine then 3mm is mostly enough where you can make MBT tune and its mostly near what it asks as naturally aspirated atleast to 3bar of boost. One another my cliend has 1.8L engine with grinded quench areas and 2.8bar of boost makes 511kw from hubs but it takes 24 degrees of ignition under max boost and zero knock.
For my own drag engine I choosed 284 intake 251exhaust cam. its also inline 4 but 90x90 (2.3L) and I´m going to push it to 8k for a start and my target is 1000hp, it should come before 3bar of boost. My turbo is hx52Pro Billet, it has same turbine size as hx55 and larger billet compressor than Hx60
This summer I was able to help one drag team with LS turbo engine with my tune. it has 308degrees cam and we pushed it to 2bar of boost, its 7 second car. but ths large turbo helps to stay together.

[Piledriver]

.060 is not remotely tight quench on any bore, particularly an 86mm one.
The only reason to run that much deck is if you are worried about valve<>piston contact or running aluminum rods.

.060" is in the "no" quench zone for on small bore motors.
.040-045 max. at up to ~100mm, less is better.
.065 maybe ok on BBC size bores.

Tight quench prevents knock.

If over that you need .080"-.100"+ and have to rely on good turbulence/mixing from the intake/ports and chamber design, if 4V staggered intake valve opening helps.

2 valve heads inherently have reasonable swirl as long as the chamber design doesn't interfere.