TORQUE PLATE - WHAT, WHY, HOW? Do you NEED one and how to MAKE one - PROJECT UNDERDOG #7

In this episode of Project Underdog we are talking about torque plates. What they are, why you might want one and how to make the most of them. We also take a look at my DIY torque plate made from a junk cylinder head that I believe is not only more cost effective but also better than a traditional torque plate.
Torque plates come into play when you need to bore and hone your cylinder block. When you want to rebuild your engine and install oversized pistons you need to overbore your block. In most cases a block is bored as a bare block, with nothing attached to it, and this leads to our issue.
Ideally you would want to bore and hone the block with the cylinder head attached to it. Why? Because when you install and torque down a cylinder head your bores get distorted. They get distorted because they are hollow cylindrical shapes that get exposed to very significant clamping and other forces generated when you torque down the head. You want to bore the block in this distorted shape because this is the shape in which it will be running. This is why boring the block in the distorted shape results in better ring seal and thus better compression, more power and possibly even less oil consumption due to reduced blow-by.
Of course boring and honing the block with the head attached is impossible because the boring and honing machine would no longer have access to the bore. This is where a torque plate comes in. A torque plate is essentially a thick piece of metal, usually aluminum, that mimics your cylinder head. It has large holes that match the size and spacing of your bores and it has holes that match your cylinder head bolt holes on your block. You bolt it down and torque it down just like you would an actual head and then you bore and hone your engine block. The result is that you're boring and honing in the distorted shape as is optimal.
But torque plates are expensive and if the machine shop that's doing your build doesn't have the right torque plate for your engine your options are to either buy one or have one custom made. Both options are usually very pricey, the custom route usually more so.
When facing this same scenario in my engine build I asked myself: "why not mimic a cylinder head with an actual cylinder head?" And in the end that's exactly what I ended up doing. I took my old junk 4AGE cylinder head which head irreparable damage (totally busted cam journals) and turned it into a torque plate. I took it to a machine shop and asked the shop to drill holes straight through the head. The center of the hole is the center of the spark plug hole, because that's also the center of the combustion chamber and thus the bore. I asked them to drill holes with 83.5 mm of diameter. I went larger than my 81.5 mm of final bore diameter to leave some room for error in case the center of the spark plug hole isn't the perfect center of the bore.
The end result is what you can see in the video. It's cheaper because old junk heads are usually 50-100$. Chances are you or a fellow enthusiast probably has some laying around that are just begging to be turned into torque plates so you might get one free too. The only other cost is the cost of machining which will of course vary depending on where you live and what kind of head you bore through. But it likely won't be over 150$ for an inline four which means you're getting a torque plate at a fraction of the price of a ready made one.
The other benefit is that this torque plate is better because it not only uses the same alloy as the actual head it also better mimics the shape of a cylinder head because it used to be an actual cylinder head. This means that the distortion created should be even more accurate than that of a conventional torque plate.
A few other important notes for using torque plates in general. Always use them together with head gaskets of the same brand and kind that you will be using in your final assembly and together with the head bolts or head studs you will actually be using. This is because the head gaskets and bolts are an important factor in the overall distortion generated. MLS head gaskets can be reused as long as you don't heat cycle them. Also bore and hone with main caps or any main cap girdles installed as well.
A special thank you to my patrons:
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[@freddyrosenberg9288]

Good idea, but once you drill those huge holes the head loses it's rigidity and you are not clamping on the block the same as with a complete "full strength" head casting. With this partial (hollowed out) head, the block will distort the head and not the other way around, which is what you want. The plate is the best solution.

[@atlasintegrations4114]

Had this done to my Procharged 4.3L V6 Vortec. The machine shop used the 350 V8 torque plate which matched the deck perfectly. Creativity at its best.

[@GoldenGrenadier]

Not surprising. The 4.3 is, after all, a 350 with 2 cylinders cut off and cast in aluminum.

[@atlasintegrations4114]

@@GoldenGrenadier Most 4.3s are cast iron blocks. However, aluminum was available in the Bow Tie aftermarket stuff.

[@santtilagmailcom]

Make sure to measure the roundness after the honing with and without the makeshift torque plate. It’d be interesting to see what’s the difference.

[@d4a]

Will do!

[@santtilagmailcom]

@@d4a take the measurements from the piston ring levels at TDC and BDC. I don’t know, but it would seem logical, that if there’s difference with and without the plate, that it would be higher at TDC (near the plate and bolts).

[@minkodima]

On a kzbin.info/door/QsclMBXdxYS1VR6nr2gEsA channel there were a video with torque plates, unfortunately I'm not able to find it, and unfortunately channel is on russian, thus even if info is useful it's useless for those who don't know russian language. (

[@rustypunkclassics1960]

there will be no difference at all probably. i would only use a torque plate with an open deck block. the key word here is vibration. there are no vibration problems during boring a closed deck block.

[@minkodima]

There it is kzbin.info/www/bejne/hKPIlmqKgNlrbcU

[@nagyandras8857]

indeed, when my girlfriends scooter got rebuilt, even tho its just a single cyl 50ccm engine bored to 80 ccm, we had the boring done without a plate. then out of fun, the old head was drilled, and torqued down and the bore machine sent over it again. the results where quite far more than we first expected, supposedly the rings can take that up, but we went on with this and ever since any engine rebuild we do use this solution. it was allso fun to put the engine block into hot water, wait till it heats up and then run the bore machine over it. oddly enough even that made a huge difference, so the original block got scrapped as it is. we sourced a new block, and done the bore with the plate installed, and the thing heated up to near 100 celsius. got a better carb and a few things, and we are extremely statified with the results. it was a kinda expensive job for a scooter we got for free. it was the test bed to see the effects of heat, and head tourqed down properly. it is a great experience, and that little scooter does indeed goes like a real little rocket. final gear reducer was worn so it got exchanged for one that has lower ratio, it does nomore than 55 km/hr with far higher revs than stock, and the added more than 50% displacment shines a lot too. what can i say? it can pull a wheelee anytime you twist the throttle. its realy realy fun. so ever since this rebuild, when a rebuild a must have, i do my best to use a plate , and i do like to get bores done on hot material. it has quite an expense attached to it, as the machine shop is kinda.... you know that wierd dude is comming again, i wounder what stupidity he has came up with now kinda look over me. but if you gotta rebuild an engine for your self, and you are not in a rush, these little details add up quite a lot. not just performance wise. but it ensures longetivity of the engine, and for a rebuild you do for your self, making it lasting long is a factor. at least for me it is. i like it.

[@amirkarimi6496]

Nobody uses torque plates in Iran and as a sensitive mechanic I had no Idea what to do about it and I saw your video and you're brilliant. Once I have the costume made torque plate in my hands, I'll stick your logo on it.

[@d4a]

I have a better idea, put YOUR logo on it 😊

[@amirkarimi6496]

@@d4a I owe this to you and that's the least I can do😊 And also I don't have a logo and I live in Iran and KZbin has removed Iran from its list so I can't be a KZbinr unless I leave Iran.

[@flyonbyya]

Brilliant idea ! I would have never thought of that !

[@funnydubby6401]

Thing is tho, if it’s cracked, when u torque it down, it’ll defiantly not stay the same size...

[@vikassm]

Yep. Could've bored out those holes in 2" Alu plate with nothing more than a cheap drill press and a couple of hours of work!! Dunno why they're expensive because most machining jobs I see are way more complex (injection molding dies)

[@DM-wp9vq]

Drrrrrrp

[@dieselscience]

Defiantly?

[@redlinecardiff7651]

@@DM-wp9vq H

[@rimmersbryggeri]

@@vikassm Is expensive because they can and also material can be pretty expensive when it gets up to size. If you quote a none motorsport machine shop it's probably much cheaper. Especially if you can do the modeling yourself. As you said it's only straight holes so the only real limits are the machine strokes and power but since you don't need to bore it in one go if you are smart most shops will have sufficient machines. (You can use much smaller endmills in circular toolpaths if it its just a 2" plate).

[@terjejohnsen3651]

Interesting as allways nice to learn this in a understandeble mather. Happy new year to you and your family to.

[@DM-wp9vq]

You didn't sound as bad as you think you do. I easily understood everything you were teaching us fledgling engine builders/mechanics in training/DIY home mechanics. I really appreciate your videos because they help me wrap my head around the many complex (and often overwhelming) functions of the internal combustion engine. Thank you so very much! I hope you (and all of us) have a happy & great new year as well & that we can finally kick this plague to the evolutionary curb.

[@Lv1_Capanga]

it kinda looks like a two stroke cylinder. a heavily ported one

[@gazzafloss]

Great idea, many of us who play with engines have a spare cylinder head or two that are u/s sitting under a bench waiting to go for scrap metal. Recycling is a great way to go.

[@mainerockflour3462]

Brilliant reuse of an old head. Especially, when it's nuts to butts time.

[@janveit2226]

It is an interesting idea, however, when you bore an old head, you alternate its mechanical properties and therefor its behavior under the "torqueing load".

[@olimpiomesser2041]

Yeah, of course, but since it's literally impossible to perfectly represent behavior under Torque Load while honing, I'd be willing to bet his set up is just about as accurate as an aftermarket Torque Plate. So whatever mechanical properties he alters by boring the head would just make it more alike a actual torque plate but not much worse if, at all.

[@deusexaethera]

@@olimpiomesser2041: An intact cylinder head, with just a few millimeters of clearance machined-out of the tops of the combustion chamber, would be more accurate. It would require honing the cylinder bores from the underside instead of the top side, but who cares about that? That just requires mounting the block in the stand upside-down, which is not difficult.

[@kusee.]

Awesome video as expected. Happy new year!

[@nerd1000ify]

it's cool to see the cooling passages in your bored head. Rare to get a glimpse of them normally.

[@TheChzoronzon]

Finding this channel has been a gift, I love how you present the info and how un-american you make it, not poochied up at all, tnx mate

[@1crazypj]

Don't know how I missed this video ? That's an inspired use of an old cylinder head, something I've never seen or heard of before

[@SupraSav]

Ah, these are the kinds of youtube videos I look forward to on a Sunday morning. Especially since I can't work on my car during these dreary Canadian winters.

[@yerrakrishna1699]

Amazing and thank you. Your point will save many people

[@kaner5873]

Love the videos! Definitely furthering my desire to turbo my own 7Afe 😉

[@alejandro52612]

Super exited for this project!!

[@sking2173]

Simply excellent !!

[@ryanmalin]

Im sitting at home with COVID and I sound just like you! Get well soon buddy! I am very interested in engine girdles recently! I see why the little 4cyl turbo engines can take so much abuse after seeing the design differences compared to pushrod or OHC V8's

[@blkdna748]

Learning more from D4A. Keep going.👍

[@iuse9646]

Thank you for covering a very important topic

[@oliverkromann1902]

very nice video displaying upcycling and "uncommon" knowledge about "over" boring a cylinder on an engine, also profit cause cheaper

[@PapotsGarage]

Great stuff as usual !

[@Folderq]

Very usefull material, thanks ! :D

[@jozsefizsak]

Much appreciated. To the critics, while we can say that drilling big holes in a head will weaken it and thus not mimic a normal head precisely, I would imagine that it will still be distorting the block in a manner similar to its final state even if to a somewhat lesser extent. A solid block is unlikely to be better unless tests are undertaken to compare it to a normal head. I don't see this happening, even for $750.

[@dieselscience]

Exactly. We're not talking about an F1 engine with clearances so tight the pistons are SEIZED in the bores at room temperature. I think the block distortion is close to the same also. There are ZERO clamping forces in (later) holed out combustion chambers... this is a very creative solution.

[@georgegherghinescu]

Awesome ideea, makes a lot of sense! Having a small budget heps to find great diy solutions :-D

[@o.c.garagejapan9737]

Very good information!

[@64maxpower]

Great idea !

[@killerdinamo08]

As soon as you've mentioned a torque plate is expensive it sprouted up in my head 'use the old junky head...' 😅. Nicely done 😉.

[@gideonbasson5982]

Wel I learned something new...Cool!

[@77ronghosh]

Superb video.

[@jonahreyes1165]

I work as a machinist and we had a customer bring in an F20C Honda engine to be bored and honed. This is exactly what we did to make a torque plate for his block. We actually used a junk K series head so that we didn't have to desecrate a much harder to find F20C head

[@GaurdianAzzar]

Loved this video, I have zero experience or knowledge with machining so this was incredibly informative. A couple of questions on this video. At what point is it best to overbore the block vs rehoning it? Why with hypereutectic pistons would you need to overbore the block a bit more, don't they expand much less than forged pistons? Will the cracks I see in your bored out head create issues once it is torqued down to your block? That is to say, won't those cracks allow your "torque plate" to distort in an unpredictable way?

[@Lambros_Stefaneas]

very interesting video Thanks.

[@bluewanderer9903]

Interesting idea.

[@ivanvago2011]

Love the content btw🙏🙏🙏🔥🔥🔥

[@DerExperiminator]

Nice video as always, thanks. I actually heard from an other reason for a Torque Plate. For this, the plate also has it's own name, so i'm not sure, if it is exactly the same and i'm also not sure how to translate to english, perhapps something like "hone-glasses". The "hone-glasses" have the role of supporting the honing tool, since the honing tool is moving in and out of the cylinder and temporarily peeks out of the cylinder, so that the contact pressure of the grinding stones now acts on a smaller area of the cylinder. This causes the cylinder to become larger towards the top, and the honing glasses are used to prevent this. But in this case, the bore-holes of the "hone-glasses" has to have the exact size of the finished cylinder, this of course is not posible with your suggested solution of using an old cylinder head.

[@endeavour2127]

Very interesting video!👍

[@sahalin12345]

Holy cow your videos are good!

[@madcat4563]

Today I learned something new. And my Dad that was a diesel mechanic in the 90s and early 2000s was like WTF? , when I showed it to him. He did a lot of honning, boring and sleeving on inline 6 truck engines and nobody ever thought about torque plates. He told me that's very high level stuff as well as being very accurate. So glad I found D4A. But yep, this isn't your run of the mill engine mod project this is high end stuff. So every bit helps.

[@gidovoskos1437]

Allright, as I'm working to a machine shop and I am facing similar problems of roundness in our parts, you gave me the idea of making some "torque heads" for some of our products to eliminate this issue. In addition, what's is an acceptable roundness in an engine cylinder? About 0.01 - 0.02mm i guess??

[@w140]

That’s exactly the type of content I expected from this great channel! Thank you very much and keep up the good work

[@w140]

And get well soon too, brother!👍👍👍

[@TheFakeFatLegitimate]

I work in a machine shop and regularly hone bores, and got curious to the surface finish of bores, and google said about 0.20 Ra (microns), did you specify a surface finish requirement? Just curious, love your channel and style of explanations so much! Thanks

[@chestnut01111]

They don't do this in any of the engine production factories as far as I'm aware? Even with the recent highly turbocharged engines giving upwards of 150 bhp per litre. What level of benefit is there?

[@SupraSav]

Peace of mind for those with OCD? Unless you are running a high HP/ extreme setup the benefits are typically negligible. At the best your pistons rings/cylinder walls would last longer and seal better/burn a little less oil.

[@GW2_Live]

@@SupraSav ya, it's for those either running extreme builds or who just want something that is done as well as possible at each step

[@bluewanderer9903]

Chris Wade I think engine manufacturers similate torque fastening when building their engines, they may not use torque plates as we know it but they do have some sort of jig on their assembly lines that does this. Also you are comparing new blocks made with new techologies at 150 hp per liter, vs old blocks producing 200 and often a lot more hp per liter. And, new vs already used, heated etc material. Dont know about usa oem, but most, if not all, well known american engine builders will use and advocate torque plates.

[@billshiff2060]

Many engines now use free standing cylinders with no connection at the top to the bolt areas. Cylinder sealing is critical for top performance when the last 1% makes or breaks it so this gets you that 1%. A test with a good leak down tester will confirm your benefit. Deck plates will improve leak down from 4%ish to 1%.

[@Roarman57]

Happy new year!

[@kencohagen4967]

I hope allot is is a cold brother. I like your videos, and don’t want to see you get anything worse than a cold. That goes for all the other viewers too. Be careful, be safe, stay healthy and wear your mask!

[@felixar90]

Lol that purple anodized aluminium torque plate. How do we justify the huge price tag on this big rectangle of metal with straight holes? Let's make it look super fancy.

[@jamsbong]

I'm watching this channel eventhough I have no plans to ever rebuilt an engine.

[@questy44]

Great vid. Are you planning on using new headbolts just for this process?

[@itzluizzz1159]

I will never get bored watching his videos! Always interesting , nice and entertaining.

[@tsiawdspyder]

Was thinking and researching this exact thing because my block is at machine shop currently and torque plate is pricey. I work at a factory and have easy access to run a Bridgeport and have several spare cyl heads just laying around.

[@rolandocrisostomo2003]

The fact that the torque plate is a solid piece is what makes it effective. That head is no longer solid because you milled the center out loosing its rigidity.

[@slowvag8v]

exactly

[@MRCATWRENCH]

Thank you, I totally agree with using torque plates. Could you please give your opinion on break in and seating rings on a rebuilt engine. Seems like if the cylinders are finished true, the need for following strict break in guidelines wouldn’t be necessary?

[@PinkGuy120]

Hey dude, I've been watching the videos for Project Underdog since I was planning to do the same thing. I'm keen on porting a 4A-FE like you did, since as you've seen, the combustion chamber is too small for boosting. Thank you for the videos on the engine so far and I'm hyped to watch the rest of it. I have one suggestion for you, but it might have some drawbacks. Get a 7A-FE bottom end. You get more displacement (only difference, according to my research is that the block's a little taller, 7A belt should still work) for the extra gains, it's not much, but should help with the torque at least and the crankshaft is a bit beefier from what I've looked up too. Drawback, not that many aftermarket options for conrods, which should be one of the biggest concerns adding boost anyway. I've read that the 7A can take 16psi on stock internals, but obviously that would reduce the lifespan of the engine, but is a nice reference to have. Hope this helps and keep the videos coming our way, they're very informative :D

[@Wrenchen-with-Darren]

Good video

[@andretsang7337]

Won't boring out the old head change the properties of it? Why not just bore it out just big enough to stick the shaft of the machine through, then install the head and get to work?

[@daleoldfield7961]

Makes perfect sense

[@richardcaldwell6159]

Interesting. I was on the "it will be too compromised" side (and I'm not 100% convinced yet), but you're there and I'm not. I await your testing.

[@ethanengland7268]

Hey, @driving4answers I am building a budget 1.8T VW engine. The block is in really good condition and cylinders look awesome. The entire short block has NEW spec measurements and I am wanting to run forged pistons of stock bore with ARP head bolts. Do I need a torque plate? I am short on some money for them and not sure if I need one

[@Manuqtix.Manuqtix]

What if you're installing new sleeves, do you need a torque plates to make things better? Also if you choose to install sleeves is it cheaper and better than getting a torque plate?

[@rogerking7258]

It depends on the block, but it is quite often possible to see honed and unhoned areas in the same bore when you hone with a dummy head - which is why you need to bore sufficiently undersize to hone all of the bore surface. However, even this isn't perfect because the block will change shape with heat, and also with the stresses and strains it undergoes when running. It's probably best described as the "least worst option".

[@BradBo1140]

Just learned something. Did not realize these existed.

[@captaincrazy3444]

I can't see how this is much cheaper than making one from aluminum or steel stock.

[@felixar90]

Why use good stock when you have a piece of scrap that would work? A big slab of steel in that size would be pretty expensive, and aluminium even more.

[@aizazashraf5024]

Please make a video about choosing the right engine oil.

[@LeZturbo]

Great !!!

[@daveyjones-sx6ym]

interesting, thanks

[@mixedboi]

4th Commemt and of course, amazing explanation.

[@vladulescuadrian6080]

Nice video, but since you already have that cylinder head can you bolt it on and do some measurements ? I mean, I like and get the theory, but I would like to see some numbers and the real world impact that this has.

[@BG.108]

The 4A-FE is a great engine! Which car are you putting it in and how are you building it to get 300hp? I had a 1993 Corolla with 308,000kms on it. It wasn't idling the best. I basically would run it easy until operating temperature then rag on it most chances I got. It very quickly started running way better. Over the course of the next couple of years, I made mistakes and overheated it a couple of times, and at one point it went over 20,000kms without an oil change. I continued driving it for another 35,000kms after that without engine issues. I only got rid of it because the car needed a bunch of wear items and there were other cars with fewer kilometers on the clock for cheaper than that maintenance was going to cost. What would your favourite Toyota engine, besides the A series, be to build?

[@radishtrader5591]

to be honest if your going to use a torque plate, ypu might aswell heat up the block to operation temperature to account.

[@lebaillidessavoies3889]

and installing the boring machine on a vibrating plate to simulate the actual vibrations of the engine when running :) this all torking plate story is a joke ....

[@radishtrader5591]

@@lebaillidessavoies3889 🤣

[@billshiff2060]

Been tried. With Minimal/none success. You'd have to get the upper cylinder hotter than the bottom and hotter on the exhaust side. Heating the whole block just makes the whole thing bigger with zero benefit and HUGE problems measuring.

[@UkuKelder]

That piston clearance cant be right. Forged pistons use 0.07-0.09mm clearance for that bore size usually. Stock pistons use 0.03-0.05mm. Torque plates are good if you use them properly, first you have to install main caps and torque them, then torque plate, same order as you assembly your engine. Also if there are gearbox bolts near the 4th cylinder you need to make a plate and torque them too. Torque plates have to be in place when machining and measuring ring end gaps too.

[@kencohagen4967]

What would be the trick thing is a torque plate that is tapered and set up for the oversize that matches the size of your cylinder after it’s is bored oversized. That way you not only get the right size torque plate, being tapered you can also use it to instal the piston and ring assembly when your building the engine after everything is machined.

[@JeffReeves]

Didn't know about torque plates. The theory behind it seems really solid, and I like the upcycling you've done with your old head. I'm curious if the clearances on a machine shop boring your pistons would run into any issues due to the head being attached? Like would the programmed movements of the bore arm hit the head while moving to the next cylinder? Or does each cylinder get set up for boring independently so there's no risk of the machine hitting anything in a pre-programmed path?

[@dissapointingsoup4893]

^^^ i would like to know the answer to this as well lol

[@ignacioanaya3403]

Do car manufacturers do that when making new blocks? don't heat distorts more metals than tension bolts?

[@eddiekururangi7503]

Can you use a cast iron head for a torque plate?

[@aleksandarridzovsky9211]

Bwak... I love you dude... You made mu day 🤣🤣🤣

[@sagifern4444]

I think that after you bore the engine head it looses its structual rigidity and distort much more when torquing it compared to its original cobdition and also compared to a torque plate

[@michaelstellitano2810]

Would removing that much material from the head now change the clamping forces from the studs/bolts compared to a solid torque plate?

[@d4a]

Not really I tested it, heads are a lot tougher and stiffer than everyone seems to think.

[@michaelstellitano2810]

@@d4a Excellent.

[@ThisRandomUsername]

Very interesting. Why wouldn't you be able to bore it from underneath? That would let you mostly leave the head in-tact. Would it be difficult to align and centre the holes?

[@ok9k572]

Depending on the block you may not have space on the inside. iv tryed to push a piston thoght a block and the bain journels would touch the skirt after a few mm in

[@ThisRandomUsername]

@@ok9k572 Ah that makes sense. I completely forgot the bearing structure would be in the way. You could probably do this on single-cylinder bikes that have a base gasket, but bigger engines tend to have a solid block. Maybe you could somehow fit the tooling in there sideways, but seems like much more missions now that I think about it.

[@isaiahpalo2797]

In an event that I want to rebore my engine but no torque plates available. Can I bore my sohc head? Wilk it mimic the dohc head that I will put on my engine for final assembly?

[@d4a]

If the head fits you can drill it out, a head is still similar to a head, sohc or dohc.

[@alexkinnane5831]

Smart booiiii!

[@flyingpeter]

would be possible to bolt the block upside down to the mill table and bore the cylinders from the bottom to archive the same effect?

[@d4a]

Nope, many blocks can't be bored from the underside as there's a lip that prevents the piston from coming out that way. In many V engines there's also no access to the underside of the bore.

[@AmirPomen]

Thinking out of box.. interesting.. But i think when drilling massive hole on the head, it becomes weaking because its missing big chunk of original cylinder head webbing... Hence the pulling of torqued surface might be a little different than actual head... Anyway i still think it is better than bore/honing without any torque plate at all... And dont forget to resurface the head-plate before using them as torque plate

[@benoitgamache3845]

one problem torque to yield head bold cannot be reused so if you use some for a torque plate you will need to replace them for your final build

[@gaspererjavec7108]

""cold"" now we know why your statistics are so good :D

[@deusexaethera]

Wouldn't it be even better to mount an _intact_ junk cylinder head onto the block and then machine the bores _from the underside?_ That way you don't have to deal with changes to the cylinder head's material strength, and thus changes to the way it compresses and deforms the engine block, caused by drilling enormous holes through the middle of the cylinder head. I realize the honing tool needs to be able to reach slightly past the end of the cylinder bore to complete its job, but that could be accommodated by machining-out just the tops of the combustion chambers in the cylinder head to provide a few millimeters of clearance for the honing tool, rather than drilling all the way through the cylinder head.

[@tititite]

Great video ! Where do you guy come from ?

[@ericohman]

4AGE is super rare in Sweden. Can I use a 4AFE head to make a torque plate for my 4AGE build? :)

[@Shabbe02]

Do more videos about engine balance

[@tcollogan]

um mate some f1 motors have the head cast into the block to stop head lift, you can do it from the bottom

[@syedminhazuddinrizvi3068]

okay.. so I got this very confusing thing going on in my head. project underdog is a 4afe engine, if whether or not you're keeping the stock cam or upgrading to 4age cam has this any relation to the fuel injection ? I mean what kind of fuel injection system you're going with and what effect it has on the cam variation. looking forward to this build. love from bangladesh. we got lot of these laying around and your videos are helpful.

[@michaelgunning347]

You have taken so much structure out of the head and seriously reduced structure at the gasket surface are , while better than nothing but will still not distribute loading now the same as a head

[@TonyRule]

I agree. There's too much material removed. You'd have to go considerably smaller with the access hole to be of any real benefit - just enough for the boring bar then install the cutter to it from below. Or an undersized toothed cutter working on CNC in a planetary fashion.

[@GmPeter62]

The down side that I think is that a torq plate done that way don't have the same rigidity as an operating cylinder head, so some distortion is absorbed by the drilled cylinder head, but got to be good enough

[@genesfel]

Could one, if in a pinch for some reason, just bolt down the screws in the block as usual without anything else attached to it, to at least replicate the basic force they apply to the block? (Like in a "its better than nothing"-scenario^^)

[@macmaniacal]

I hoped that you provided data on how much distortion. Maybe even demonstrate..

[@MrTench8]

If you are going to this extent to obtain a perfect bore then should the block and head (torque plate) also be heated to 90 degrees C?

[@d4a]

The block doesn't distort when heated it just expands

[@MrTench8]

@@d4a no expansion of an irregular shape will be be completely uniform.

[@billshiff2060]

@@MrTench8 Yes it will be uniform, only in transient changes with local hot spots does it distort but how are you going to do that in a honing tank?