Itinerant Air-Cooled

asiab3 wrote:

Amskeptic wrote: [we interrupt this program for the following Type 4 Control Valve bulletin . . .
Type 4 control valves were NOT used in hydraulic lifter engines for the simple reason that the lifters happily utilized cold oil pressure to pump themselves up if and as necessary. Hydraulic lifters are continually bleeding themselves in operation at every down ramp off the cam lobes. I speculate that if you revert to solid lifters in a hydraulic non-control valve crankcase, the relief valve might spend too much time towards the bottom of its bore, playing "high rpm control valve", diverting oil that should be making a dedicated loop through the oil cooler]

I read on the internet, so it must be true, that Jake Raby only uses solid lifters in his T4 builds. Does anyone know his thoughts on the cases which lack control valves? Has anyone seen if his engines have the valves or not?

Robbie

IIRC Jake usually puts a steel rod in the control relief so it keeps as much oil in the mains. 75-76 914 cases have no oil control valves either and if you do the oil notch in the rods I would think this is a good thing as you need as much oil as you can get to the crank/rods with the rods spraying the bottom of the pistons/cylinders for cooling and oiling. On cases he has preferred the "W" and "EA" cases in the past as they are stronger with more meat in key areas so the mains don't pound out nor do the cylinder registers collapse.
He only will use solid lifters as the provide the best longitivtiy and hp vs hydraulics.

So with oil-pressure guage attached..how does one verify that oil-pressure relief gizmos are functioning ??

Man, this thread has some legs. Colin will be in South Florida this week (I think), and should be messing about with possibly two new Headflow Adrian builds. Just stay tuned.

dingo wrote:So with oil-pressure guage attached..how does one verify that oil-pressure relief gizmos are functioning ??

From my observations, you won't be able to tell when the relief piston has changed position. On a semi-cold idling engine, at lets say, 30psi, you can slowly accelerate and watch the pressure cap at around 50-60psi. This is the control valve opening and allowing excess pressure to drain back into the case. This happens (regardless of temperature) around that pressure on my gauge. (This means it can happen at low speeds with cold oil or high speeds with warm oil. My hot oil never gets that high in pressure.) How do you feel yours compares?

I dunno..dont have much driving data. All i know is that these german cases are old and the oil relief bores are grungy and out of shape. I clean as best i can, grease it up and shove it all back. I read the entire thread and the esoterica of oil-pressure is intrigueing but the reality is that at some point you have to get on the road without being at the mercy of some janky 50 nyr old spring

dingo wrote:…the reality is that at some point you have to get on the road without being at the mercy of some janky 50 year old spring

What reality are you living in? In my reality, I put explicit faith in 50-year-old parts. If they've gone this long, they'll work just fine for my grandkids' grandkids. As long as the springs measure up to the specification for your case setup, there is NO reason not to trust them.

I think about my oil cooler, date stamped 1971… I think of my valve seats on cylinder heads that I pulled from a crate full of dirt and bug parts… I think of my crank that I dusted off of a machinists floor… I trust them all FAR more than any new parts.

So, in a way, I AM at the mercy of the parts.

And that's ok.
Robbie

In some cases, thats a very valid point...then theres the bucket full of german 34picts...none of which will idle

asiab3 wrote:

dingo wrote:…the reality is that at some point you have to get on the road without being at the mercy of some janky 50 year old spring

What reality are you living in? In my reality, I put explicit faith in 50-year-old parts. If they've gone this long, they'll work just fine for my grandkids' grandkids. As long as the springs measure up to the specification for your case setup, there is NO reason not to trust them.

I think about my oil cooler, date stamped 1971… I think of my valve seats on cylinder heads that I pulled from a crate full of dirt and bug parts… I think of my crank that I dusted off of a machinists floor… I trust them all FAR more than any new parts.

So, in a way, I AM at the mercy of the parts.

And that's ok.
Robbie

Robbie,

I wish I'd learned as quickly as you have that the original, German made VW parts are SSOO much better than most new parts sold today. So many people on this site and on The Samba see "new" parts in shiny packages and get fooled into thinking "new" is better than old. We only have to look at Volksbiz's thriving business in refurbishing original German Solex carbs as a great illustration. I'd take his refurbed carbs over ANY POS currently being made and sold today. My 69 bug engine is running ALL it's original VW parts. I've refurbished the original distributor, generator, carb and it has an NOS Pierburg pump. The internals are all original, refreshed VW parts. It purrs like a kitten and I'm sure it will continue to do so long after I'm gone.

I've been "enjoying" beating out my original, thick metal front bumper on my bus for the past several days. I have over 15 hours in it. It had taken a solid impact in it's life and was horrifically repaired. I've had to dolly it, shrink it, reshape it, de-rust it and it's finally at the stage of laying some epoxy primer on it to start the painting process. Would I have loved to buy a "new" bumper and save all those hours? Hell yea but.. I didn't want a flimsy, thin metal, poor fitting POS going back on the bus..

We should all be grateful for the hoarders and remaining VW salvage yards for our ability to still buy original VW parts to refurbish that fit, last and support our VWs.

asiab3 wrote: I believe the grooved piston AND dual relief setup would begin to show low pressure at hot idle

I do not understand how this conclusion was reached. The groove in the relief plunger, in a dual relief case, really has no function at all, since it
was meant to work with the upper "dump" port in the relief valve bore that does not exist in dual-relief cases. However, since the grooved plunger is
significantly longer than the stock plunger, using one would pretty much have exactly the same effect as using a much stronger relief spring. AFAICT, most
vendors who include, inappropriately, a grooved plunger in their kits also provide a spring for it that is, at least approximately, intended for use with the
plain plunger in a dual relief case. The stock relief plunger in a d.r. case doesn't even begin to move until the oil pressure is well over 40 psi. Substituting
a grooved plunger will of course raise that figure quite a bit. Thus, regardless of temperature, the relief valve in a d.r. case does pretty much nothing, with or
without a groove in the plunger, at normal or low oil pressures.

Bleyseng wrote:Jake usually puts a steel rod in the control relief so it keeps as much oil in the mains.

Control relief is right lifter gallery. Mains wouldn't know the difference.

75-76 914 cases have no oil control valves either and if you do the oil notch in the rods I would think this is a good thing as you need as much oil as you can get to the crank/rods with the rods spraying the bottom of the pistons/cylinders for cooling and oiling.

On cases he has preferred the "W" and "EA" cases in the past as they are stronger with more meat in key areas so the mains don't pound out nor do the cylinder registers collapse.
He only will use solid lifters as the provide the best longitivtiy and hp vs hydraulics.

Do you have any documentation as to this "more meat"? The only modification in the case that I know of is the recirculation port from the relief over to the pump inlet. There is no indication I know of of meat to prevent "cylinder register collapse".

Amskeptic wrote:

Bleyseng wrote:Jake usually puts a steel rod in the control relief so it keeps as much oil in the mains.

Control relief is right lifter gallery. Mains wouldn't know the difference.

75-76 914 cases have no oil control valves either and if you do the oil notch in the rods I would think this is a good thing as you need as much oil as you can get to the crank/rods with the rods spraying the bottom of the pistons/cylinders for cooling and oiling.

On cases he has preferred the "W" and "EA" cases in the past as they are stronger with more meat in key areas so the mains don't pound out nor do the cylinder registers collapse.
He only will use solid lifters as the provide the best longitivtiy and hp vs hydraulics.

Do you have any documentation as to this "more meat"? The only modification in the case that I know of is the recirculation port from the relief over to the pump inlet. There is no indication I know of of meat to prevent "cylinder register collapse".

When I started on my engine, Jake told me to use the 1.7 case rather than the 2.0 case due to the 1.7 having more metal in the area of piston #3. Later cases don't have this. We compared my 2.0 to the 1.7 and I could see the difference.

That is a pretty interesting observation.

dingo wrote:In some cases, thats a very valid point...then theres the bucket full of german 34picts...none of which will idle

I will get them all to idle.
ColinWillTOO

Hobug wrote:

Amskeptic wrote:

Bleyseng wrote:Jake usually puts a steel rod in the control relief so it keeps as much oil in the mains.

Control relief is right lifter gallery. Mains wouldn't know the difference.

75-76 914 cases have no oil control valves either and if you do the oil notch in the rods I would think this is a good thing as you need as much oil as you can get to the crank/rods with the rods spraying the bottom of the pistons/cylinders for cooling and oiling.

On cases he has preferred the "W" and "EA" cases in the past as they are stronger with more meat in key areas so the mains don't pound out nor do the cylinder registers collapse.
He only will use solid lifters as the provide the best longitivtiy and hp vs hydraulics.

Do you have any documentation as to this "more meat"? The only modification in the case that I know of is the recirculation port from the relief over to the pump inlet. There is no indication I know of of meat to prevent "cylinder register collapse".

When I started on my engine, Jake told me to use the 1.7 case rather than the 2.0 case due to the 1.7 having more metal in the area of piston #3. Later cases don't have this. We compared my 2.0 to the 1.7 and I could see the difference.

Now that is in opposition to Bleyseng's observations. Can you be more specific? As far as I know, the Type 4 castings are pretty much identical, save for that excellent improved oil dump passage, but the *machining* to clearance the 71mm stroke might very well make for a skinnier cross-section across the rod throw areas.

Type 1 cases did indeed have added metal to '73+ cases at the #3 spigot to reduce cracking. Later, the Mexican / Brazilian cases got rid of that same metal because of improvements in metallurgy.
Colin

No, the early cases are the stronger ones. Years ago there was a thread where cases were cut to show the differences.