Chevy I6 and Toyota Engines

[fj hunter]

thanks ..

nice report and pics.

i saw those brushes on a vehicle in Phnom Phen, Cambodia. the owner told my translator that it keep rocks from fling into pedestrains, bikes, or motorbikes.

The ones i saw were halfway up the wheel.

 

[kitabel]

2 problems:
1. if there isn't pressure oil to a gallery supplying the tappet body (and I suspect not from your comment, and from the fact that all GMC engines - intended for truck use - are solid lifter) then it cannot pump-up, which requires not only pressure but a fairly high volume to maintain "inflation" against spring tension.
2. if Toyota followed the GM dimensions accurately, the tappet is .990" OD.
The original 1950-62 Chevy hydraulic tappets are fine if you can find them (I've seen many disparaging comments about current repro tappets: leak-down, poor quality control, too soft), but getting pressure to the body port is going to be very tough. If the tappet OD was "metricized" to 25mm etc., of course it's not going to work as a drop-in.

 

[FJ40Jim]

The lifters are still .990, but there is no pressurized oil in that neighborhood of the block.

 

[kitabel]

Well, some brave soul may decide to do exploratory surgery on an F block. The hole must transect each lifter body so that the waisted feed port area is within the hole ID. The hole has to be pretty accurate, but not very pretty (surface finish and exact ID not important). It's blind at one end, but IDT it matters which end. If no useful connection is apparent, you could simply plunge right through the exterior of the block anywhere along the length of the new passage, and use an external hose to the filter, etc.

 

[FJ40Jim]

No time to drag the manual in the house and scan, so here are some bad pics:
1st is the early staggered valve configuration
2nd, the improved inline valves
3rd, the siamese port & manifold

 

[FJ40Jim]

And the improved 12 port head & manifold
staggered valve crossection
and staggered valve guide install details.

Sorry, no pic handy of the chamber, but it looks like the old chevy pictured above.

 

[kitabel]

Thank you, kind sir!

 

[MtnTrucker]

Well, some brave soul may decide to do exploratory surgery on an F block. The hole must transect each lifter body so that the waisted feed port area is within the hole ID. The hole has to be pretty accurate, but not very pretty (surface finish and exact ID not important). It's blind at one end, but IDT it matters which end. If no useful connection is apparent, you could simply plunge right through the exterior of the block anywhere along the length of the new passage, and use an external hose to the filter, etc.

Interesting, drilling and tapping from outside and running a line from the oil filter housing that provided oil to all the lifters......sounds like a challenge that some knowledgeable expert might want to under take. It could be the first really new innovation for F engines in the lasy 20 years.

 

[kitabel]

The biggest problem I can see is that if the original block casting was not made with this provision in mind, there may not be enough metal for a hole of that size to pass right down the length of the tappets. The exact alignment lengthwise is automatic - any tappet exposed will pressurize since the port is annular.
However, for the port to present during the full range of tappet motion the hole should be equal to the lobe height, probably .250-.300". I have no idea of the consequences if the port is masked at either full lift (maximum spring pressure) or zero lift (where inflation is most needed for lash control).
Based on this picture, there's not enough metal right above the cam.
Individual (unconnected) holes could be bored right through the block from the exterior for each tappet and fed from a common external manifold, but it'll look like a Baldwin locomotive after.

 

[joeyg1973]

The biggest problem I can see is that if the original block casting was not made with this provision in mind, there may not be enough metal for a hole of that size to pass right down the length of the tappets. The exact alignment lengthwise is automatic - any tappet exposed will pressurize since the port is annular.
However, for the port to present during the full range of tappet motion the hole should be equal to the lobe height, probably .250-.300". I have no idea of the consequences if the port is masked at either full lift (maximum spring pressure) or zero lift (where inflation is most needed for lash control).
Based on this picture, there's not enough metal right above the cam.
Individual (unconnected) holes could be bored right through the block from the exterior for each tappet and fed from a common external manifold, but it'll look like a Baldwin locomotive after.

Actually an external manifold supplying pressure might be ideal for one reason. The ability for crazy nut jobs like me to be able to control oil flow and shut down cylinders automagically using my Megasquirt to save gas.

Do you have a good diagram or picture of what the block side of what the oil feed to a hydraulic lifter would need to look like in the lifter cylinder?

PS: the second reason for me would be I like the form following function look. Steam locomotives are cool.

 

[joeyg1973]

I got something.

YouTube - hydraulic tappets (hydraulic lifters)

But what the heck kind of cutter or tool would one have to use to get a slot on the inside of the lifter cylinder?

 

[kitabel]

I take it the tappet holes in the block are not vented, viz. if pressurized will not simply leak from some opening not readily apparent?
The first thing to do it find out if original Chevy hydro tappets are available (12 + 2 spares = 14?), unless you want to sleeve your tappet bores down to .842".
Now, is the lifter base radius compatible with your existing cam lobe taper (viz. will it rotate properly, or just tear each other up), and rate of lift? Is a later hydro cam do-able in the older block?
You'll probably need new pushrods both for length and because the tappet receiver cup may not match your existing shape. If you're lucky it will, and the pushrods are too long - remove one end and shorten it.
Next, the height of the waisted annular feed groove above the base determines the vertical position of the hole in the block. IMHO you may find it easier to make 2 smaller holes 1 above the other rather than span the entire lift in a single hole, plus there may not be enough wall thickness for a big thread.
Small, tapered MNPT is probably the easiest to install and seal, or machine thread and a bulkhead fitting for a seal? I would think simply soldering a short length of Bundyweld steel brake line to each, then compression fittings to the manifold would be enough and allow service without taking the whole thing down.

IDT this will work as a method of disabling cylinders, though. The range of inflation of the tappet is much, much less than the lobe height so the valve will open no matter what.

 

[kitabel]

General idea - crudely shown on a 235 engine.

 

[joeyg1973]

IDT this will work as a method of disabling cylinders, though. The range of inflation of the tappet is much, much less than the lobe height so the valve will open no matter what.

I am pretty sure that cutting off the oil supply to the lifters after power cycle to a cylinder so that it acts as a spring is how it is done. I am guessing that those tappets are specially designed for it then right?

 

[kitabel]

Yes, there's a snap ring inside a common tappet that restricts movement and very short plunger travel. To disable, the plunger must have at least lobe height travel distance, or the valve will still open.

Is there a specific engine that has this function (pushrod OHV with remote oil pressure control to tappets), and if so what do the tappets look like?
The oil supply could be shut down (if external) by a simple solenoid in the feed to the main oil, controlled by various switches (high vacuum, low throttle disc angle, high gear only, low RPM, etc.) so that it either can be manually selected only when conditions are favorable, or engaged automatically.

 

[joeyg1973]

Is there a specific engine that has this function (pushrod OHV with remote oil pressure control to tappets), and if so what do the tappets look like?
The oil supply could be shut down (if external) by a simple solenoid in the feed to the main oil, controlled by various switches (high vacuum, low throttle disc angle, high gear only, low RPM, etc.) so that it either can be manually selected only when conditions are favorable, or engaged automatically.

A lot of GM V8s as of late have this ability. They shutdown half the cylinders. The notorius caddy 8-4-2 did this very poorly in the early 80s. It might have been the first engine to do this. It was a grand failure.

I am not interested in automating it just yet... I can run it off a manual switch right now to the MS2.

 

[IDave]

No time to drag the manual in the house and scan, so here are some bad pics:
1st is the early staggered valve configuration

Jim, if I might ask, what year parts manual is that illustration from? That's the first time I've seen a picture of the cup-shaped valve retainers, which are what came with my F135 head. I had wondered if they were even toyota.

 

[shelfboy1]

the 270 in my gmc 6x6 is still running after 67 years and looks just like an old f engine in the garage .some parts even are the same but internally they differ .the old 270 was used in many race cars and even a few dragsters.some even had 671 blowers on them.if clifford inlines is still around they probably have already done all the hopup stuff on these engines .it would be neat to see an old f engine with a 671 on it.dont know how long it would last .years ago i took all the water proof stuff off a military gmc 302 and put it on a 65 fj40 .the thing ran under water ,had to change the coil to 12 v but it pretty much all bolted on.

 

[FJ40Jim]

Jim, if I might ask, what year parts manual is that illustration from? That's the first time I've seen a picture of the cup-shaped valve retainers, which are what came with my F135 head. I had wondered if they were even toyota.

Parts book is 1968, illustration is for the later siamese head, appx 1964-later.
There is also an illustration of the earliest (58-64?) valvetrain that does not have the umbrella retainers.

 

[IDave]

Cool! Thanks! And do the stem seals go above as I have them in the picture, or below the umbrella retainers as they do in other years?


(Don't mean to hijack, but I hope these details are tangentially on topic.)