CYLINDER HEAD Face Off - 4AGE vs 4AFE - DETAILED Comparison

In this video we are doing a detailed comparison of two different cylinder heads, a performance cylinder head represented by the high revving Toyota 4AGE and an economy cylinder head represented by its more modest cousin, the 4AFE engine. Both of the engines from which this heads come from share an equal displacement and an almost identical cylinder block design, which means that the key differences between the engines lies in the heads, making this a great example to demonstrate how cylinder head design influences engine character, power, torque, efficiency and more.
Although both our heads are DOHC and have the same number of valves, they differ in the way their camshafts are driven. In our economy head only the exhaust camshaft is directly driven by the belt, but in our performance head both camshafts have their own cam gears and are directly driven by the belt. In stock form this doesn't play a big part but the performance head has a key advantage when it comes to tuning. It gives you the opportunity to install adjustable cam gears on both cams and retard or advance cam timing independently for intake and exhaust.
Both heads feature a shim over bucket valvetrain. A staple of many Toyota engine designs the shim over bucket is easy to maintain, compact, lightweight and low friction but it's limited in the amount of cam lift and duration you can run with it. Too much lift and duration can pop shims off buckets and high rpms. Which explains why Toyota employed a roller rocket based valvetrain on its more modern 2ZZ-GE engine which features very high lift and duration on the aggressive cam lobes of its variable valve timing system. Honda's K20 is similar example.
But our 4AGE and 4AFE are pretty old engine designs. Neither feature any sort of variable valve timing so their camshafts must strike a compromise between high and low rpm operation. When it comes to valve sizes it's interesting to note that the economy cylinder head doesn't fall behind the performance head, largely due to the fact that it's a more modern design. The performance head has thicker and stiffer valve springs to prevent valve float at the higher rpms that it's capable of reaching.
A key difference that defines the character of the two heads is the valve included angle. The included valve angle is the angle of the intake and exhaust valves against the cylinder head's center-line. Our performance head features a wide valve included angle, while our economy head features a more narrow valve included angle.
If you look at other more modern engine designs you will notice that many of them incorporate a more narrow valve included angle. A narrower valve included angle also has the benefit of improving combustion efficiency, because the air comes into the chamber at a steeper angle it tumbles more which promotes better mixing or homogenization of the air fuel mixture improving combustion and helping the engine squeeze more energy out of the air and fuel mixture. Most modern engines are also able to maintain a good scavenging effect despite the narrow valve included because many have variable valve timing and cam phasing.
The combustion chamber is in our performance cylinder head is a typical pent-roof combustion chamber design. It's a staple the design of the vast majority of performance oriented dual overhead cam engines and it is a good design. As you can see when the valve opens the area around the valve is for the most part free and unrestricted allowing the air freely flow, this promotes good airflow and cylinder filling which enables the engine to breath better and perform better, especially at high rpm.
The combustion chamber in our 4AFE cylinder is obviously very different. As you can see almost as much as 50% of the valve area is actually shrouded and the valves are set deep in the combustion chamber. It seems that the goal here again was to tumble the air against the walls of the chamber as much as possible with the same goal of maximizing homogenization for better combustion efficiency. The 4afe engine doesn't rev very high at all which is why high airflow that would be need at high rpms was sacrificed in favor of combustion efficiency or economy.
00:00 Intro and specs
01:04 Basic anatomy
02:57 Shims and buckets
04:17 Variable valve timing
06:55 Valve sizes
09:09 Valve included angle
14:59 Combustion chambers
16:16 Intake ports
18:32 Exhaust ports
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#d4a #cylinderhead #enginebootcamp

[@d4a]

4AG/ 4AF Head Stud kit: amzn.to/36gcPyo Wear the G: amzn.to/2UbEACx Show them gears: amzn.to/32teT59 D4A merch: teespring.com/en-GB/d4a-merch

[@gwanam6319]

Do a video on the gdi mitsi heads best down draft factory port I know of... there is ways of dailing in slave cam cylinder heads reposition dowel /key or make off set dowel/key or remove and weld in at desired or recommend cam angle degree to suit application

[@gwanam6319]

And you are better off going shimless buckets less weight ect

[@m1ndmu5ic24]

The new cylinder head now are wide angle for better tumbling

[@sepg5084]

Overlap happens a few degrees after the intake valve started to open and when the exhaust valve is a few degrees from closing, thus the intake air and exhaust gases will try to move around their respective valves. Wouldn't this be better for scavenging because the valves will be deflecting the air around them and thus the intake and exhaust streams would interact better? Also, it would seem that the proximity of the intake and exhaust valves with each other will affect scavenging effect the most (the closer the better), regardless of valve angle?

[@kusheen5865]

I had a 1993 corolla with the 4A-FE. So much fun driving it at 6000k rpm pedal to the floor on a mountain road. I joined a hill climb race with it once and got 4th over all in my category. I miss that car...

[@bryan10444]

AE101 are underrated

[@kennethstephens8046]

@@bryan10444 all is the AE92. I have a 1991 with the 4afe. Great little car. Once it has coil overs it will be much better than my 2020 corolla se 6mt

[@teme5529]

Cool! Intetesting because mine kicks in @6200 rpm and revs to 8250, its so cool to compare these statements! One revs to 6000, one hits lift after that. Edit: since everyone seems to miss their toyotas, I ain't selling my celica ts ever.

[@hazza2247]

6000k = 6million rpm lol

[@mudzy9820]

@@kennethstephens8046 yeah bro i hope its a liftback, those things lowered can almost be mistaken for ae86

[@NEEL69P]

My dad bought his ae92 4afe corolla brand new from the factory in 1996, it currently has 490 000 kms, just an exhuast, engine has never been opened. Runs like a dream. I love the 4age BUT this video made me love and appreciate the 4afe even more ❤️ UPDATE: car currently has 502 000 kms 😁

[@Zfrk]

AE92 chassis was 88-91, more squared off body. 92 was the next gen which I think was the AE101 with the rounded body and headlights. my car was a 90, buddy had a 92 which was the next body style.

[@NEEL69P]

@@Zfrk I know, it's an ae92, in south africa we still had models of the ae92 on sale till 1996. We get our cars abit late

[@ToreDL87]

Nothing to be ashamed of with the 4afe all things considered. They go surprisingly well too.

[@tomacatipovic7854]

Any updates on kms?

[@abhishekchaudhary9542]

Wow, just wow, I'm amazed by the knowledge and content that this guy creates.

[@maxcactus7]

Who-hoo!! Happy D4A Sunday, everyone! You're smarter and more interesting for having watched this video. Great job, fantastic channel, D4A!

[@NachoCV]

I fell very lucky to have the motor with the best information in KZbin thanks to your chanel! Cheers from Spain!

[@kamarlpringle1392]

Lucky , I have a VW 1.6 FSI with barely any information on it at all . Makes 115 HP at 6000rpm :)

[@samcoote9653]

Iive seen a tonne of car and engine theory vids over the years and dabbled a little bit and you always see examples of tradeoffs in engines, like you want more torque well you trade power etc. But this video really clearly explains how every little thing can affect an engine and its design. Cam timing, cam lift, valve size, valve angle, portsize, port angle. So. Many. Variables!!! But thats why its so awesome to get into cars, you could be like every other guy and drop an LS in a car because its a relatively easy way to get big power for decent money. But you man, you take an economy head and youre going to make it work because youre looking at the design and how the things they did for efficiency can help you make a fun, serious, and probably really unique engine. This is why I love this channel. No sheep doing the same tired old projects. Were breaking new-ish ground!!! So awesome and great job dude so excited for this one!!

[@kusee.]

The content you create is insanely eductional. No other channel makes videos at this level.

[@Neroslk]

I'm an engineer myself (not automotive) and absolutely love your videos! Very knowledgeable, well explained and interesting. Keep up the good work!

[@1ZZFE]

I recently worked on my 1zzfe 1.8L Toyota Engine head. Literally I did my 1st top-overhaul, and it's also my 1st time removing the cylinder head. And yes, I can almost totally relate to what is explained in this very educational video. Great content. Thank you.

[@of_lion22]

Been looking for a video exactly like this to compare both designs. Great work

[@jor8625]

doing the head job on my 5efe right now and this is the best explanation I've seen of how it actually works. Thank you very much!

[@TheMonk98]

God bless your videos. They just saved me tons of time of research with on point info and a clear direction for a technical documentation. Keep up the good work🤘👌

[@jambek2003]

Always like your videos when I want to gain knowledge about engines. Thanks and keep up the marvelous work!

[@JasonLuther1]

Always making well put together and high level of educational content

[@DJrainbizzles]

I love you, you are like 10x more interesting than my university classes right now, thank you.. Keep up the awesome content! (Been planning some things for my car based on some knowledge from your videos :)

[@JazzbLu]

You have so much knowledge of the simplest things of an engine I am amazed and thankful for you sharing your information!

[@terjejohnsen3651]

Love this videos you allways learn something good. Ceep up the good work look forward to next.

[@Vanessinha91Pucca]

Man, i'm in love with your channel, very well done.

[@matinirudolph8420]

Hands down the best channel ever!!

[@ML-rx7tv]

I compared these 2 cylinder heads for a couple years. Wonderful presentation!

[@KaoticPhoenix]

This was an amazing comparison, I was hoping for a comparison between the most modern 4AGE and 4AFE engines as I have owned both. The 4AFE was definitely a strong engine and I wanted to use it more a very lightweight vehicle.

[@alexanderburger3399]

Now you have it! I've bought my first 4A-FE car (a beautiful white 1988 Carina 2 liftback) because of your awesomely detailed videos. ;) Now that's the third 80s Toyota in my little collection and it sits right next to my 1988 3S-FE Camry and my 1987 3S-GE Celica convertible... I'm a happy fanboy... ^_^

[@not12listen]

Thank you so much for being so specific! It is truly wonderful to not only see the physical differences, but an explanation of those differences as well. This does make me want to get another AW11 and turn a wrench on that 4AGE again! :)

[@bobross6677]

I like how you're explanation always goes into the engineering of the engine i dont think anybody else even does that that i know of Thanks

[@pabauza]

One of my favorite channels.

[@TurboHappyCar]

Really good stuff man! Dropping a comment to help out the algorithm.

[@ibrahimqureshi2420]

huge respect man i learn a lot from you

[@iamgerry86]

Another great video! Good job my friend!

[@danchoiordanov6740]

keep doing it bro, i've learnt so much from you

[@TheJohnlyh]

I'm a simple man, i like heads from any model!

[@idriwzrd]

Most men like some head.

[@Bkamron]

Just flippin' brilliant... sub from just one video.

[@fernandoanatomia]

Very interesting video as always. Thank you!

[@WouterB76]

Very educational and clearly explained, thx!

[@michaelsmdk]

one video and I feel a lot smarter already! coool and thank you!

[@marvinhenry1027]

You’re the best bro... Great videos!!!

[@tonimartinovic5552]

Fenomenalan video, pozz iz Zagreba

[@negativeindustrial]

Every single thing covered here is also true of the larger 3S-GE and 3S-GTE and their economy family members the 3S-FE and 5S-FE.

[@claysonwebster1622]

Awesome vid bro was very informative

[@Treston089]

I always love watching these vids because despite all I've learned, there's always more info to be found! Thanks for sharing with us

[@vwoday1872]

Very nice Great job explaining

[@dgsdavid8623]

My congrats for your videos, Very good explanantion and content

[@nochilljay6369]

This is the first video I've found from you (subbed around the 15 minute mark, awesome info) I think another good video if you haven't done it already is the subaru fa20 (brz/frs) compared to the fa20t from subarus other models

[@DejaVu19711]

You made it easier for me... Thank You Sir

[@gennarodellacorte8478]

An other great video! Thanks again!

[@arthurleeki]

Love u man, appreciate this alot.

[@fastinradfordable]

Saw 99 comments. Love you bro. Just wanted to get you into triple digits. 100😎

[@realtlt]

Holy cr... Your videos are sooo goooood!

[@ethanbunch3274]

I had just finished watching your quiz video on the inline 4 and so when I saw this I jumped at the chance to expand my knowledge. I grew up on old school Ford engines primarily the Windsor line so some of this stuff is completely new to me. However the trick with the hammer to get the valve retainers off it's actually a really damn cool trick! Probably wouldn't do something on high performance vehicle but just to pop them out of there that is really awesome!

[@Alex_Miller1980]

I love how you explain that simple, even I know most of the architectures applied to combustion engines, the options to improve one to the other, options and different flavors, I love car engines but I work as motorcycle mechanic, I peel my hands everyday working on different motorcycles and I'll keep doing it until I can't

[@nwpioneer2551]

Fantastic high-cost videos.

[@danpollard4210]

This guy really talks perfect. You can hear ever word clearly he is the best!!

[@MrBlackMysterious]

Good head has its benefits lmao

[@jamiehipperson]

Love these engines and love your information on them. I am smarter now! 😀

[@jakeboniol9550]

Well explained!!

[@ProjectExMachina]

driving 4 answers, I think this is the beginning of a beautiful friendship.

[@Peristeronicify]

Sounds back, thanks!

[@jaziborilistyle5811]

Love this video

[@DeftAnesthetik]

Before I watch gotta say. this is info i have been searching for. building my own hybrid "A" and have always suspected the F would take turbo very well... now to watch and see what you think. =D

[@Samqdf]

I commend you for the quality of the video, given just how much information you give I only have a small amount of additional information / corrections that I wish to add: - You mention different cam profiles and different lift with VVT. But for both times you show the VVT parts on the screen the parts are for variable angle only VVT systems, these still use a fixed cam profile and lift although it would be true for dual cam lobe or constantly variable lift VVT systems. You are however are completely correct with everything you said in regard to their variable phasing and the effect on factors such as the overlap. - When mentioning the later heads having a narrower valve angle on the screen the 20V 4age Blacktop is shown. This has the exact same 50 degree valve angle from the exhaust to the outer intake valves, but to be fair the middle intake valve angle is 37.7 degrees so that still counts as being partially narrower then? - The 2ZZGE and VTEC engines are forced to have rocker arms as having a twin cam lobe system is as far as I know impossible with a traditional bucket and shim system. That aside your point is still completely correct that OEM valvetrain in a 4age would in no way be able to handle the secondary cam profiles as used in the 2ZZ and Honda. - One thing not mentioned with the relation of the port velocity verses flow is that with a more upright port it can sustain a much higher port velocity before reaching the same air choke point. This significantly reduces the trade-off. It's also why modern heads can have a fairly small cross sections for their ports. A good example of this is the 3sge Beams engine, I wouldn't consider the ports to be overly large but flow amazingly well and can support high power without mods. Although you make very good points with how VVT does wonders to mitigate the issues with large CSA ports. - Alright so this one is just being pedantic and I know it's just what the common terminology is- pictured are adjustable cam pulleys, not gears. If it's driven by a belt then it's pulley. I can't fault anyone for using that term that is almost universally used regardless of if it's technically correct or not. Well anyway with that aside this isn't a criticism of your video, you clearly have done careful research here and your explanations for everything are excellent. I just commented in case you wanted some constructive feedback. I am completely open to correction on any of these points also. I thought you might find it interesting that did some mods to a 7afe head a while back and I was surprised to discover it had literally zero overlap between the cams. This isn't just by eye either, I put a dial indicator on that head when it was on the bench and I can confirm that the intake valves would fully close before the exhaust would open. Before this I didn't think any car engine had that. Oddly enough it had a reasonable amount of lift at a measured 8.34mm for the intake, weird.

[@xwliu6074]

rly nice video. Thx

[@sergiykud]

this channel is so dope

[@rileypaterson7117]

I love this thank you ! I have a 97 corolla with the 4afe

[@regeneric928]

My friend has Corolla AE86 with this 4A-GE 16V engine (plus one spare engine for doing fun stuff like turbo, ITB, 20V head etc.) and I was so surprised how felxible this engine is and how fast can that car be with just 1.6 T-VIS heart under the hood. Fantastic piece of engineering.

[@refuge9]

There's some incorrect information on this video. 1) the heads compares are from a earlier Bigport 4A-GE, which was out from 1983 to 1987. The 4A-FE was made from 1987 to 2001. A better comparison would have been between a Smallport 16v 4A-GE and 4A-FE, as they would have been out at the same time. (Also, the smallport 4A-GE was around 10.5:1 compression ratio, meaning it was higher compression than its' FE counterpart, as opposed to lower compression vs the predecessor version of the GE). This would have been a better comparison, since that would allow the heads to be more properly compared. 2) @5:55 - Variable Valve Timing (toyota VVT) does not change the amount of lift, only the timing of the cam. This is confused with Variable Valve Timing with Lift (VVTL-i), which is only available on Toyota's 2ZZ-GE engine. Late models of the 4A-GE 20v had VVT, which would change the timing of the intake cam, based off hydraulic pressure, though it wasn't computer controlled. VVT does not in any way affect the lift or duration of valves, save for what can be done solely through timing. 3) @12:50 - He mentions that the narrow angle is due to better, newer design, however, the later 4A-GE 16v Smallport heads still utilize the wide angle intake ports, but carry more air into the combustion chamber than both the bigport 4A-GEs and the 4A-FE. (Though the smallport angles were lowered to 44 degrees vs the earlier 51 degrees). This is another example of it comparing later models with earlier models of different lines of the engine that work against it. it -is- accurate the more modern engines utilize narrower valve angles thanks to newer designs that help with this, notably: direct injection. However, the efficiency and power benefits from narrow angle valves were just considered at the time these engines were made, and that context in a comparison between the two can't be ignored. These are all relatively minor points in the grand scheme, but should be noted regardless.

[@barryduff5058]

I've only just watched this now (July 2022) and noticed the same regarding variable valve lift being confused with variable valve timing

[@sammyboytv3153]

You made me appreciate my 4afe 😅

[@mikelow4374]

Cool video bud 👍 Damn I miss my 87 AE86 coupe 😥

[@markbarber7839]

Thanks for the video! My 1979 Honda cb750f motorcycle had 9.5k redline, narrow value angle, shims under cam and 10.5:1 compression. I think it made 78hp.

[@nulldua8547]

best channel

[@justRD1]

Before I even seen the title or channel, I could tell by the thumb nail that D4A dropped a video!!!

[@802Garage]

Well, I def learned something about shim over bucket vs shim under bucket! Learned more about valve angles too. Plus more detail on those 4A heads of course. Excellent, excellent video as always.

[@gwanam6319]

Shim under bucket old tech shimless solid buckets are were it's at.... lighter and no Shim issues cause there is none...

[@SvcGlobal]

If I could suggest topics for this channel, one is capacitive discharge ignition and two, how to adjust variable timing cam gear, both intake and exhaust, as you show in this great video. Thank you.

[@d4a]

I did one of those ages ago: kzbin.info/www/bejne/j6eXcqJtjLKgiZo

[@beefcakemonsta]

question: by removing the excess casting on the exhaust ports on the 4afe and also shimming off some of the material on the shroud on the fe, does that promote more air velocity overall? if yes, how much of an improvement you would get thru hp and decrease in torque?

[@anthonyh958]

Fantastic,bloody fantastic

[@sherlonio]

New subscriber over here nice vídeo

[@sethk1429]

I have a 7afe and am looking to do a 4age head swap. Cool vid useful info

[@GlennnD]

I'm driving a Corolla daily witht the 4AFE. It's not a quick car, but the sound it makes is great! Not many people know this or mentioning it.

[@GaurdianAzzar]

Love the video, as always. Is there any chance you might be looking into head modification like porting? I've read about flow benches and wet vs dry testing but I've never actually seen a flow bench or how they work.

[@d4a]

I will be porting this head and there will be a video on it, but without a flow bench sadly. I don't own one, and don't have access to one. It will be a relatively mild port and a bit of combustion chamber reshaping.

[@GaurdianAzzar]

@@d4a Sounds great, looking forward to it!

[@akashssmenon]

Hey can you make a video comparing 2 wheel drive transmissions? I searched a lot for answers but none are satisfying. Also totally love your videos

[@d4a]

What exactly do you mean by 2 wheel drive transmissions? Fwd and rwd?

[@akashssmenon]

@@d4a I mean comparisons between production rear wheel drive transmissions. and how they differ. what's the difference between a Porcshe Dual Clutch Manual and a Dodge A580 DCT. Like how do you decide which is better based on what application?

[@jaybosher6144]

Had a 4afe with a manual, great little peppy engine but the 4age was leagues ahead.

[@UncleTito]

Awesome!!!

[@nicosiano1174]

Oh my god thank you so much! I needed this information for my next mod thank you :D

[@d4a]

You're welcome Kaguya sama 😉

[@sahalin12345]

More, more, more...please make more videos!

[@renattoalcala3472]

I wish this video has spanish subs, I have a Levin AE111 with a 4AFE engine, I love it and your video looks really interesting, congratulations.

[@garethburke7826]

Great video, You should compare the 16v 4age to the 20v 4age blacktop or silvertop,

[@Zfrk]

I built an AE92 Corolla for Lucky Dog Racing League with an unmodified 4A-FE (ok, I baffled the oil pan and built a cold air intake from PVC pipe, but other than that, unmodified). there is jack shit for power above 5800 RPM, where I set the shift light. We held off some odd cars through 3rd gear but waved goodbye to their tail lights once pulling into 4th, and the explanation on valve angle effects kind of explains it. glad I didn't convert to the GE head though.

[@jesserenn3152]

Car nerd bliss 😌

[@erwinschmied]

What exactly is the valve angle on the 20 valve 4AGE?

[@kollolghosh8369]

The background music is good also 😅

[@nootsen5522]

Great video, but I think you switched the cams on the 4age, at least in the beginning. Because you can see the opening for the distributor cap on the right (exhaust side), but the cam with the gear to drive it is on the left (intake side).

[@Ensource]

the only criticism i have (at this moment) would be more clear pronouncing of some words like 'scavenging effect' and 'pent roof'. I had to google for a few minutes before I found what you meant. this video was very well done, and was a superb learning tool about engines. I really enjoyed it. good clear explanations for some key concepts about engines. thanks a lot for showing us! really looking forward to more engaging content, you have a sub, here!!

[@georgegherghinescu]

Would tiny, tiny fin like structures on the valve side facing the intake port (machined on the valve disk in a slight spiral maybe?) help with better mixing of air and fuel in the combustion chamber? Help make the charge enter the cylinder in a mixing helping way :) Love your videos! fun and educational!

[@d4a]

Check out racing 4age valves from manon racing performance, or even many other aftermarket racing and high performance valves. Many have something extremely similar to what you're describing.

[@annienguyen1799]

Thank you! I now understand why my 4ac pulls harder then the 4age at lower rpm.

[@stevenash4408]

Listening to you is like listening to a favorite song😊

[@AdinSLaboy]

Good inf I got the 5efe very similar too for those eng

[@AlexTrull]

Great Video. I've got a 4wd car with the 7AFE and the heads are very similar and this has kind of convinced me that a turbo on the existing head is probably smarter than a GE head :-)

[@AlexTrull]

It's a Toyota Sprinter Carib - AE115G - really popular in russia :D

[@whittysworkshop982]

​@@AlexTrull7a-fe...... everything before the dash is the block, everything after is the head. 7a is the block...... the seventh generation of the A block, 1.8l and a longer stroke than the 4a, so the block is taller. The FE refers to the head, F is the narrow valve angle, E means it's injection. Your 7afe head is the exact same as the 4afe head.

[@TheStraser]

Hi great video. I have a question. Does 3SGE head fit on 4AFE block;

[@StupidBlokeStupidVideos]

0:54 105hp @ 6600rpm Redline 6300rpm 🤔

[@StupidBlokeStupidVideos]

2:48 If you advance the exhaust cam shaft, you’d also be advancing the inlet cam by the same amount, not retarding it by the same amount. Even though they move in opposite directions through the gear drive, they would still advance/retard together.

[@d4a]

Serves me right for copy pasting engine specs... You're right! Because the cams move in opposite direction, "retarding" is actually advancing the intake. If the intake had a 4age adjustable cam gear on it, the gear would show retarding, but because it moves in the other direction the cam gear would be lying. You need to change your usename.

[@d4a]

The direction of the intake cam rotation shouldn't have any significant effect on harmonics or balance, at least in theory.

[@TriXelOne]

@@d4a isnt it like retarding one cam moves both intake and exhaust events in time?

[@LSmiata]

@@d4a Hello @driving 4 answers, Hat's off to you for professionally addressing a trolling comment and accepting/correcting the mistake. Did not plan on leaving a comment and also noticed max RPM vs peak HP discrepancy...but let it slide as I always enjoy watching your videos, so keep them coming! PS: Personal thank you. Several years ago you did a video on rebuilding Toyota brake calipers. I rebuilt on the calipers on my 2001 MR2/S and your video helped! You even responded to my request on where to find the caliper pin dust covers! Thank You! LSmiata/Mr. P

[@iansmith6728]

The Volvo 850R head was very similar to the 4AGE head. Walkinshaw racing modified them for the super tourers by bolting in some additional metal to lift the intake valve angle and straighten the inlet runner. The result was an additional 60hp on that engine. The exhaust runner was left at a similar angle to the 4AGE exhaust because it flowed really well anyway.

[@Samqdf]

If I remember correctly they shaved a wedge out of the the head surface to mount the whole head on a tilt, this made the intake port angle face more upright relative to the cylinder. That and machining the top third or so off the head to completely remake the main valvetrain section. Those engineers were amazingly creative in their way to work within the limits of rules and get around the fundamental limitations they had. My hats off to them for being so clever. As for the 4age 16V head I have seen the intake ports corrected by either machining a big chunk out of it and making the intake manifold reach right in or welding large sections up and machining / die grinding new ports. Both end up at the same goal of running the new ports through were the injectors would normally are located and hence ending up with a fairly modern looking port design.

[@andresgoyenaga1229]

@@Samqdf please share a link showing this mod

[@angelsandoval6493]

Hi my friend. Nice to meet you and greetings from Venezuela. A great and wonderful video. The explanation is perfect. A question: ¿Can i install the 4A-GE head in a 4A-FE engine block?

[@d4a]

You can, but if you leave the 4AFE pistons in there you will have low compression because the 4age combination chamber is larger.

[@angelsandoval6493]

@@d4a Thankful my friend...