Stripped Engine Details

[Guest]

As I have been asked for some pictures of the inlet manifold off my stripped FA20 engine, I suggested starting a new thread where you guys could all ask for pics you'd like to see of the production engine's internals and ancillaries.

 

So, please just ask here for anything you need regarding this lovely little engine. Your questions will be answered to the best of my ability and pics will be uploaded at your request.

 

 

[Guest]

A little while ago Sideways asked for pics of the inlet manifold, which led to this thread being created..

So, here are the pics as requested...

Note the manifold is made of two plastic shells glued together. I fear this will perhaps split in a heavily boosted application? Obviously Adrian hasn't seen any issues yet, but when he gets his stage 4 set up, who knows?? The GPRM cars have beautifully cast Mag alloy manifolds.

Looking down from the top, we can see the locations for the port injectors. The rectangular slots locate the black steel covers that you see on your engines.

And, the ports from the inside. Note the groove which locates the one piece inlet manifold seal.

Finally we have a shot of the purge valve. This connects into the inlet manifold via the pipe you see going left here. The pipe in the top right corner connects via a steel pipe to the fuel tank evap system above your rear diff. This valve basically switches opens and closes the pipe as required by the ECU and "sucks" vapour from the fuel tank. I wonder how this will cope with a boosted application?

So, there we have the first of the pics. If you would like to see any more, just shout..

[Lee 82]

Inlet and exhaust ports of the head?

Rockers / valve springs / cams?

[Guest]

Here you go Lee....

 

Inlet ports.. all shots are of the left hand head, or bank 2 as it's known in the manual, cylinders 2 and 4.

A closer look down the ports. I often wonder why they are so massive with ne real taper to speak of???

From the combustion chamber, note the nice three angle valve seats.... There's a little clean up required in my opinion, but not too much.

On to the exhaust ports... Note how one port is straight, the other is shooting off to one side. Basically, the ports are unequal in length.

The straight one.

Off to one side...

From the chamber, more clean up required here.

You may have also noticed all the sharp edges in the combustion chamber. These will also need to be polished off as they can promote detonation. Don't ask me why, I just know they do.

And so, we move on to the valvetrain..

Here is one valves bits. Retainer, spring, collets, post, shim and rocker. The post sits in an oil gallery in the head, so one can only assume the oil rushing up through the bore damps the rocker and reduces rattling?? GTNige???

The underside of the rocker.. Note the pad which presses on the valve.

As most of you will know, the valve components need to be kept in order, I normally use boxes but thought this is going to be apart for a while, so I'd better get something a little more substantial. I found these boxes as Homebase.

After drilling a couple of holes, they make great storage boxes for any 16V engine, or just one box for an eight valve.

Here are the cams from the left head. Note the upper, Inlet, cam has the tri-lobe at the front for the HP fuel pump. The cams on this engine are press fitted together. The shaft is manufactured then the lobes are pressed on. From what I can see here, the grooves aid lobe location.

Note also the front of the inlet cam has been friction welded to the shaft. The weld is the dark area just in front of the tri-lobe.

Subaru have been very thoughtful in the manufacture of this engine, marking most parts for ease of reassembly. Here is the cam marking, LE = Left Exhaust. Note the scoring on the bearing, which will need to be polished out.

Here is an exhaust cam lobe profile. This is a very soft profile, but I could well be wrong considering it has VVT??

So, there you have it, the valve train and inlet ports as requested...

[Jamie_GRMN 177]

The posts you mention are hydraulic lash adjusters for the exact reason you mention please make sure you keep them upright when storing or the oil inside will drain and you'll have valve opening issues when you rebuild, we inject oil into them after they're fitted into the head.

I'm quite surprised this engine is still using the parallel springs and thick rocker tbh, thought they would've switched to beehive for this engine as we are currently...

Interesting looking at the retainers, collets and rockers they look identical to the ones used in the ZR engine, at least I'll be sorted if I ever need replacements, good old Toyota commonisation for cost reduction

[Guest]

The posts you mention are hydraulic lash adjusters for the exact reason you mention please make sure you keep them upright when storing or the oil inside will drain and you'll have valve opening issues when you rebuild, we inject oil into them after they're fitted into the head.

They are not like the normal hydraulic tappets I've seen before Jamie, like the type you keep submerged in oil to prevent drain down. They are actually just a solid piece of metal, bored out into a small hole at the ball end. They are hollow.

[Lee 82]

Excellent Nige - thanks.

Nice little detail on the inlet port I never knew about with the 'bump' before the valve stem 

[Guest]

The little bump is there because the tappet post is there. In other words, if it were to be removed, the oil gallery would be exposed.

[Jamie_GRMN 177]

They aren't a solid piece of metal, they're actually a two piece design with a tiny ceramic ball valve in the base of the inner

[Lauren 2259]

Looks like quite a bit of duration on the cam profile. Do we have the stock cam specs for duration and lift? 

[Guest]

They aren't a solid piece of metal, they're actually a two piece design with a tiny ceramic ball valve in the base of the inner the hole in the top is to inject oil in at the assembly process.

Edit: although now I've actually looked at the image in a bit more detail, they do seem to be single piece, my bad, from the quick glance earlier they looked like a shorter version of the ones we use. Sorry for the confusion, my hungover eyes aren't to good

Sorry I should have explained, I'm the assembly (including all sub assemblies) quality engineer at the Toyota engine plant in Deeside, North Wales. Almost at the end of a year long project regarding the valve train in the ZR engines we build so I know the parts like the back of my hand I would love to be able to post the drawing for the lash adjuster as its a lot more complex than it looks but I think that may break confidentiality a tad

No worries.

 

I know exactly what you mean, and have never seen this type of design before. This engine is actually shimmed for valve clearance.

 

I really cant see the point in having these in an oil gallery, unless, as i said earlier, the oil squirts up through the hole, but that would mean the post would have to lift, than hammer back down on the ali head?

 

I'm sure someone, like GT Nige will come on and tell us exactly how they work?

 

Lauren,

 

Thats exactly what I was thinking, but with the VVT, doesnt everything change? I'm not sure how fast the VVT can react?

 

As I said earlier, the profile looks to be very gentle on the valvetrain?

[Jamie_GRMN 177]

The lash adjusters sit in an oil gallery to keep the pressure on the cam. Looking at the image its not a shim as your referring to, just looks like a stem cap; these aren't sized to allow adjustment, thats with the oil pressure behind the lash adjuster is for. The cap is there as a bridge between the hard valve and roller rocker surface.

[Guest]

The lash adjusters sit in an oil gallery to keep the pressure on the cam. Looking at the image its not a shim as your referring to, just looks like a stem cap; these aren't sized to allow adjustment, thats with the oil pressure behind the lash adjuster is for. The cap is there as a bridge between the hard valve and roller rocker surface.

 

I'm sorry, but you're incorrect here Jamie.

 

The "Lash adjusters" as you call them cannot lift the rocker arm. I've worked it out, the oil inside the post will pass through the hole in the ball end, so it will not be possible to build pressure inside the post unless the rocker is under load, but at this point the post will be pressed hard down on its bottom end, which stops the oil getting in.

 

The cap on the valve stem is a valve clearance adjustment shim. Inlet clearance 0.1 to 0.16, exhaust is set at 0.21 to 0.27mm.

[Jamie_GRMN 177]

Then this really is an oddly designed engine, the whole point of using the roller rocker is to reduce friction and wear as its in constant contact with cam, not requiring a shimmed clearance. I shall get on the Toyota techdocs system at somepoint and have a look and get back to you because I don't agree

[Jamie_GRMN 177]

Ooo and the "top" of the head in which the valve train sits

[Guest]

No worries Jamie, I'll get more pics up for you tomorrow. As for not agreeing with me.. well, I have the engine apart, in front of me, and also have the workshop manual.

 

In my opinion, they steered away from hydraulics on this valvetrain due to the high revving nature of it.

 

Most high perfmance single cam V8's use rollers on the cam and dont have hydraulic tappets. We must also not forget, this is not a Toyota engine.

 

 

[Guest]

As promised, here are the pics of the rocker arm pivot post, cam carrier with one bearing fitted and the top of the head.

Note, the post is hollow

The little black bits adjacent to each inlet rocker post hole is a spray jet for the cam / rocker. The exhaust posts have a cut out at the side of the bore.

[Guest]

It's all gone a bit quiet here???
 

[rob275 1817]

I dont know car bits, im just gawping at it all. So continue posting shiney things. Lol..

[Guest]

Not strictly engine parts here, but gearbox parts..

I just thought I'd try and give a brief description on how our gear boxes work. They're no different to 99% of all boxes out there in reality, but most people get their minds blown away by what is essentially a fairly simple mechanism.

In the picture below we can see the main upper shaft and counter shaft at the bottom. The power comes in from the right into the input shaft and goes out through the output shaft on the left upper.

In this next picture we can see how second gear is selected and driven. Ignore the positions of the selectors for this exercise, just concentrate on the arrows...

If we follow the yellow arrows, we can see the power coming into the input shaft, transferring down to the counter shaft, along the countershaft, back up into the output shaft and out to the prop shaft. This is enabled by the selector being moved to the right to engage the second gear hub with the second gear. The power is actually driving through the hub, the gear is free to spin on the shaft unless engaged with the hub.

In the next picture, we can see how fourth gear works..

Again, follow the yellow arrows to see the power transferring from shaft to shaft. The orange arrow shows the selector being moved into position to engage 4th gear but this time it's the counter shaft being driven as the 4th gear is cast as part of the output shaft.

Notice that the input shaft gear is doing all the work in every gear except 5th, also notice how all gears are in mesh at all times. Nothing drives until a hub is engaged. When you crunch a gear, it's not the gear teeth crunching, it's the tiny little teeth which interlock and engage the gear with the shaft.(Red Arrow)

Finally, we can see how 5th gear works. It's a direct one to one drive with no gearing, so the prop shaft is turning at the same RPM as the crank.

I hope this gives a brief insight to those who ever wondered what was going on inside the 'box. None of this explains the issue with a cold second gear though??

[Guest]

Here are all the gears and shafts.

[GT86Jay 202]

I understand the 2nd gear issue to be more of the selector issue than the actual box itself? 

 

Also why the gearbox dismantle? Are you changing ratios? I've often fancied changing the final drive then fitting the Cusco 1st and 2nd gears... To expensive though. 

[Guest]

The selector mechanism is very notchy on my brand new 'box Jay, as it is covered in sharp edges. I will be dressing all the sharp edges off to see if things improve.

I stripped the 'box as I was concerned about the amount of debris in there at 100 miles, then even more debris at 50 miles!! Sure enough, there are some very sharp edges in there which will all be softened when the parts are super-finished.

I have seen that Cusco kit as well, it does seem an awful lot of money for what it is, especially when we consider I may well break this 'box and need to uprate/upgrade it?? From what I can gather these gearboxes will take 400 odd HP, as long as you don't totally abuse it?

[Pitman 188]

I think that the ultimate strength of the gearbox, and the amount of torque it can take before it gives up is very dependent on how you use it.  With their love of drag racing, I would suspect that those in the USA that have had gearbox failure have been doing full power shifts, with very sticky tires on the drag strip.  What are you ultimate plans for your car, Nige (apart from taking lovely pictures of all the component parts?  )?

[Guest]

Hi Dave,

Ultimate plans.. tinker, tune, cut, weld, remove, replace, sit back and look at it, remove and replace more, oh, and perhaps drive it as well