Engine Build × 4BT Cummins Discovery #11 [Land Rover Build]
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- čas přidán 22. 08. 2024
- Finally, the powertrain build is nearly complete! Big turbo & manifold, 5-speed HD trans & clutch, fuel & timing mods, new seals & lines & paint. All ready to meet a new set of Land Rover frame rails.
~ PART#11 in a project dubbed "Nanuuq" to swap out my lifted Land Rover Discovery 2's blown 4.0L V8 & boring ZF auto for a Cummins 4BT 3.9L turbo (Holset Super HX30W) diesel 4-cylinder engine (Bosch P7100 pump) with an NV4500 5-speed manual transmission. The AWD 4x4 will remain with the LT230 transfer case divorced behind it all, & plenty of Dodge 6BT parts too. Another big phase of my custom DIY build to create a do-just-about-anything off-road / overland rig. Did I mention it's a camper too?
~ BUILD THREAD: (Entire build) www.overlandbo...
~ BUILD THREAD: (4BT specific) www.4btswaps.c...
~ SONG: Hot Rod by Ian Cubitt
~ DISCLAIMER: Please do not do/repeat/imitate/recreate anything I do in my videos. JUST DON'T! It can be very harmful to bystanders, your person, your wallet, & your psyche. Don't risk the only "meat vehicle" you get!
![First Start! × 4BT Cummins Discovery #35 [Land Rover Build]](http://i.ytimg.com/vi/nQ5-0PbNupY/mqdefault.jpg)
NOTE: I started the engine before this & it was smoooooth. No smoke or blow-by, & great oil pressure 👍 Oh & that grungy alternator was just a placeholder for the high output Rover alt. Can't wait to hear it sing with all the new parts & mods!!!
Tinker get you a 12 valve or a 8.1 balancer and put on your 4bt smooths them out keeps em from being a rattle machine like they are with the stock pot metal balancer
What bail housing an tranny did you used????
@@matthewlarsen1573 That's an "Advance Adapters" bellhousing with a hybrid Dodge & Chevy 5-speed manual NV4500.
Seems pretty simple but still a lot of shit to put on and together
That's for sure! Simple as far as engines go, but still no shortage of work to be done fitting such a non-standard powerplant.
This build is going to be rad, super clean job!
Thanks!
i enjoy your detail work and you don't have all the fancy equipment this build is a real credit to and you mates.
Thanks! And I'll make sure to pass that on :)
Oddly satisfying to watch. Definitely going to check out the rest of your videos. I've always wanted a 4BT in my jeep excited to see your project.
Glad to hear they're interesting to watch, because that's always the battle with stuff like this... want to keep the audience awake haha!
Great! - One of the best diesel engines you can buy...!
Agreed! So simple & tough 💪
man!! this is my dream biuld Disco2 cummins, manual transmission!!
Me too! Been a long time pondering on it.
How satisfying, and it shows at the end. Great moment
I should've included a before shot with that final clip, such a big transformation.
great engine build. perfect job
Thanks!
Hi everybody. Wonderful job congratulations 👍👏
Thanks :)
The new engine is very beautiful
They do look quite good when they are clean :)
I got one going in my 1992 S-10, 4x4. Modifying the pan now so I can keep the 4x4. Was going to rub😮
Nice! I miss my old ZR2 S10 project. Good choice, might need to modify mine too... it's pretty close at full flex.
Thank you very much for Sharing this video. I would love to be able to do something like this one day!
It was a fun build :)
I'm new to this channel what is this engine off from?
@@omarr6875 You can see where I found this in video #1 of the series. In my case a drilling pump. But normally the easiest source to find them are in "step vans" like what we use in the USA for delivering larger mail packages & bulk food. They can be found in all sorts of industrial, commercial, & power generation equipment... but that I'd less common.
Nice! Nice! Also like the color.
It doesn't have the most inspiring name, Cummins Beige, but I quite like it too & I'm glad I stuck with it for the build.
Thank you I learned a lot from you
Glad to hear it was useful! I wish I had a video like this when I started mine... so easy to lose track of how things went together haha
beautiful work!!! so clean!!!
Thanks!
ok, that alternater needs a little more paint, you forget that ;)
Oh that was just a temporary alternator, as it now has a big shiny Rover alternator
Well done, good job.
Thanks!
Thumbs up right back to you brother. Solid work.
Thanks!
I'm dropping one in a 1969 IH Scout 800.
One of the best transplant options for those in my opinion!
Nice, I was lucky enough to compete in the camel trophy we used discos with the LR diesel it was a good combo, but I'm betting the 4BT will be better. I'm looking for one to put in my 79 F250 4x4
Oooo badass! I love the sound of those old Rover diesels. I think so too, future me will greatly appreciate all the work I'm putting into making it fit & doing it right. Best deals I've seen have been complete step-vans, if you've got the time for the tear down & cutting the aluminum shell up for scrap to recover the initial cost.
I'll bring my Toyota over tomorrow so you can put that motor in for me. Thanks for doing it for free. Lol
If I fell into a pile of money it would be so fun to buy a dozen of them & just start handing out swaps 😎
Great vid. My son and I want to build a 4 runner with the 3.9.
Ooo that could be a good platform for it, especially with a solid front axle too! Which generation you thinking for your swap?
@@Tinker1837 a 1990s 4 runner.
I want one! That looks like a beautiful little engine that I could use In a small pickup. (If I could ever find a tyranny for it.)
I feel you there! I've wanted one for years now, so glad I finally got into it :)
Be warned, the 4BT is pretty heavy (like 700 pounds - more than a big block gasoline V8) so if you put it in a small pickup like a Mazda B1600, an old Toyota Hi-Lux or a Datsun pickup, the nose will drag on the ground. You said small pickup so I figured that's what size you meant
and a TALL engine
i was a little salty when you put that old grimy alternator on that clean AF 4bt, nice work though
It was only a placeholder! It now has my big Land Rover alternator mounted.
Good work 👍👍👍
that pump is just as big as the motor lol
It's like a little engine of its own too! Has it's own crankshaft, pistons, valves, etc
Ahhh my kind of therapy
Now you've got me thinking how I could create a 4BT ASMR video... hmmm...
Tinker your welcome for that idea lol
TheCattlekings I'll make sure you get a cut of the residuals if it takes off ;)
Tinker thanks I only need enough to get my hands on 6bt for my project ford
Great video
Thanks!
I'm a manual for street and racing, but for off road specially creeping up hill and in mud automatic is much more comfortable and safe imo
Certainly are pros & cons of each. Low range, especially with a low rpm engine makes crawling up/down a hill easy. Having a torque converter's handy, but left-foot braking is even better when you get a handle on it. The durability & simplicity of a manual transmission is hard to beat.
@@Tinker1837 hey brother, where did you get the manual pedal set for the disco? I'm getting a frame cut 4bt from that guy in Ohio on Ebay. Looking for the nv4500 and a doubler as well
@@PavelowGunner1122 Nice! I actually couldn't find one for a decent price, BUT what I found out was that the shaft that all the pedals pivot from are the same... and so what I did was pick up a Disco brake pedal that fits right in the assembly believe it or not.
@@Tinker1837 haha, excellent! At least LR did something that makes sense in that regard. That makes life a bit easier. Where did you get your nv4500
@@PavelowGunner1122 Mine came custom setup & built-up from "High Impact"
Your build quality is great! Want to do one for me?
Chuck Taylor So long as you're okay with a completion date somewhere in 2020 at the rate I'm going haha!
What’s your cost?
Nice video, just found your channel 👍
Thanks, looking forward to hearing it fire up again after all the mods & see how it pulls along the Land Rover.
Looks so agricultural no matter what you do but very sick.
Almost as iconic of a tractor type look to them as the old air-cooled diesels.
Thank you sir
👍
Looking real nice and next comes the job of stuffing it into the Disco! What type of Sealer did you put on the tappet cover? I have always put them one with NO sealer on and the never leak, but when I did put a sealer on the rubber gasket ozzed out !
That was Ultra Black RTV. Hope it seals up, that & the front cover too. Both had rubber gaskets that were leaking when I picked it up so I figured I'd see if RTV could put up a better fight.
The new common rail cummins all use Black RTV on the front timing gasket! RTV will make the rubber gasket ozze out as it has happened to me, but if it looks like it is in there for good then I'd leave it! Once again nice build !
That is a good decision to replace all soft plugs with those billet plugs as I have had OEM soft plugs come out in the worst places and times and now I use all billet plugs in all rebuilds ! A cummins parts man told me that they make 3 different sizes of METRIC " soft plugs " so go figure !
I could see that happening, maybe it was the cold that kept the RTV firm enough to save it oozing out. That's good to hear about the plugs! Thought maybe I went overboard on that front, but anything I can do to improve the reliability is worth it to me, no matter how small.
Nice job bro, hopefully when I do my 12v it goes as smoothly, gotta do the timing cover and tappet cover. Have you ever used billet tappet covers?
Thanks! I have not, but if I do I'll probably try out the kind that have the oil breathers built in. Some I've seen look beautiful!
Amazing Google job .from Pakistan
Thanks and welcome :)
Love the build! Love the truck combo; would like to do the same swap in my D2. Are you going to mate the Lt230 case and if so, do you need an adapter? Or do you have something else in mind?
Thanks! Keeping the LT230 case & to do so I'll be pulling the "spud shaft" from the output of my current ZF auto trans & just sliding it into the LT230 input (possible thanks to it's input having an internal bearing support) with a yoke over the end. This way I can run it divorced with just a u-joint between the new 2WD style trans yoke. Also lets me rotate the case however I see fit for clearance & driveshaft angles.
Brilliant! Can't wait to see your progress! Sub'd!
Das sind super Motoren.
Agreed :)
Hey man im venezuelan in my country I have two Chinese 5ton box truck those with those cummins there the same engine they just made in China.
Do you like those engines? I have enjoyed working on mine so far.
Very Nice job.
Thanks!
Excelentemente ejecutado. Felicidades por el viseo quedo super bueno
Gracias!
Congratulações👏
Great job...
Ponta Grossa city
Brasil.
Thanks! :)
I must of missed all the gaskets, rtc, some type of gasket material throughout most of this build. I believe I noticed 1 gasket. Guess I’m blind or something.
God damn! If that's not one of if not the prettiest thing on YT, i don't know what is! I would display the shit out of it on a wall in my house or something! :D
Thanks! I think maybe I should've built a few of them.
@@Tinker1837 You should've most definitely built more of them :D
incredible job. did you use a guide all just knowledge you already had?
Thanks! Nah no guide. Thankful for a good friend & my father lending a hand when they can though. But if you're looking for more info on these engines then I highly suggest 4BTswaps.com , tons of stuff on there!
where did you get the nv4500, bellhousing, adpater plate, and flywheel and clutch? can you do a video showing the slave cylider installation?
High Impact, High Impact, Ebay, South Bend. Slave cylinder is an upgraded Valair unit that just bolts right in place of where the standard Dodge slave went in the bellhousing.
Thank you! Can't wait to see more of this project!
Lt230 need an adapter to connect to the nv4500 ? And withstand the half-axes at the declared power 550tq ?
Here is what I made to adapt them together: czcams.com/video/XNwl8IDqSb8/video.html And yes with upgrades the LT230 should hold, but we will see!
Well I suppose I'll let you know how is goes, I have a black path billet cover I'm waiting to try out. One more thing, when I pull my p pump off will it affect the timing of the pump? Besides getting the engine back to tdc? Thank you for replying to my questions!
Best of luck! It can, have to be real careful to mark things & use the timing pins on the engine & pump to keep it straight. I have a video on the subject that could help ya.
Great video. And Pure Michigan I am a new sub.
Thanks & welcome :)
Ok the question you probably don’t want to think about, how much do you think you have in this swap?
The good rule of thumb if you do the work yourself with an extensive engine swap like this is $10,000. And of course if you decide to have a shop do the work for you it could easily be double/triple that! Thankfully I've not reached that yet on my build, & I haven't crunched the numbers for several weeks now. But last I checked it was just over $7k total, likely hit $8k by the end so long as nothing too pricey breaks!
That looked like a new 4bt
Thanks? From a distance sure, but up close... my paintjob didn't end up all that great thanks to the cold in that uninsulated space.
1:30 can't forget the KDP!
Erik Kovacs Yep! Sorted that little monster out in another video, did a quick how-to on 'em.
Tink. Think you can help me with locating some parts pm me if u will. Mainly fuel system parts and fitting bolts. Really stumped. Wanna make sure i get the correct fittings
CZcams's PM systems gone, but I can try 'n help if you email me
Thanks so much
Suman Mondal
Indian man
Hope it's helpful :)
Vey nice indeed can you tell me why you have removed some of the the core plugs and replaced them with (?) do you have plans for greater cooling ability?
Those are clamp-in aluminum freeze plugs. Primarily for giving me multiple places to tap in for heater-core hose fittings & temperature/fan sensors. Secondarily to prevent them possibly blowing out due to the much higher rpm & boost it will have now vs stock. Also makes for a handy place to drain/flush from & monitor the cooling passages.
Great video. I'm building something similar and wanted to see where you found all the components for alternator and hardware. Thanks in advance
Thanks, & the alternator in this clip was just a placeholder for the larger 130-amp Land Rover alternator I'm using now, which also has an RPM trigger wire I'll be tapping into for my tachometer gauge.
@@Tinker1837 thanks for the reply
@@samuelesquivel8088 Happy to help :) Next video I have on this build is actually involving custom mounting the alternator & a pair of big batteries... if that can be of any use for your application.
Great build!!! Was just going to comment on the ugly alternator, because everything else is so nice!!!!!
@@scarface-39 Thanks man! Yeah that one is a bit scabby looking for sure.
Hi great video but quick question. What gear box did you mate it too?
Thanks, & that's a hybrid Chevy & Dodge NV4500 heavy duty 5-speed manual.
This engine to repair is for simple people
Very simple 👍
I've got a 95 Disco and have been dreaming of a 4BT swap. Love the truck, owned it for years, but I have almost 200k on it now and it is inevitable it will give up the ghost. I'll be watching your whole series. Why did you remove and replace the freeze plugs?
I removed those to replace with plugs that had ports for cabin heater / block heater / and sensors.
Very pretty! 😀
Thanks man!
buen trabajo, i love this engine
Thanks!
Good vid, love the music
Thanks man, was a fun build & I'm looking forward to keeping the mods coming! More boost, more fuel, maybe experiment with running waste oils.
Tinker awesome man, can’t wait to see. I’ve experimented with the oils and all I can say is filter it down into a drum. 5 micron filter bags are awesome and let it settle. Depending on where you live at you can mix pretty heavy with your fuel. Most fuel filters are 25 microns so it’s pretty safe.
@@BolteBuilt I've always wanted to get into it, so that's good info. Everything I look into on it sure makes it sound like filtering & dealing with the cold is the name of the game.
Tinker yeah when you run it just run some type of fuel additive on occasion for piece of mind. It can be clean but black too. If you plan on using food based oils they not only need filtered but heated too I’ve seen. I stuck with used oil personally.
@@BolteBuilt Yeah no doubt about that, probably will run additives even with pump diesel, all depending on how cold a winter we get here.
Very nice! Why did you knock out the welsh plug under the ex manifold and what did you put in there ? Looks like a yoke for hanging pictures on a gyproc wall?
The one there is my coolant heater (aka block heater), another plug in the rear is now my heater core supply, & the third is just a simple plug that I may drill+tap for additional gauge sensor.
Sir you are a great fabricator. Can you please tell, how much a 4bt vibrates? I want to put it in fj40
Thanks! They aren't too bad until the shut-down, then they have a pretty healthy shudder. I love how smooth the straight-6's are though (6BT)
That's because the 4bts are unbalanced, the 6bts are balanced. Hence the reason they are smoother than the 4bt.😁
Shakey lil devils!
That onbord fuel filter. Is that all your running? What micron/filter. Arnt the banjo bolts a restriction? Wonder if theres any benifits to bypassing it and using a remote twin fiter pass thru filter set up. An -6. Was my tought. Im identical to this bulid. Glad to see somon else had the same idea.
Or just fitting some 12mm an 90s in and running hose ends to them. And utilize the on bord with out banjos?
That's the Baldwin filter that Cummins calls for in their current recommendations. It's a real fine 5 micron level of filtration. The inner bore of those banjos are very near the hose ID size. Their could be benefits with water separation, but after I run thru a few tanks of diesel I intend to use the Baldwin filter with the water separator built right in.
Tinker right on. Deffantly the dual filters! For 300 hp i think its gonna be fine i doubt ill get any starving issues. Just checkin all bases. Cant wait to see it run!!
Wow whata speed you are flash
Fast as lightning!
@@Tinker1837 hahhaaa
Nice.Profii✌✌
Thanks
Hey tinker! I’m wondering what are the block inserts (ex: block heater) I haven’t seen some of the others you’re inserting. What are they??
Those are for helping to heat up the engine in extreme cold, via external electrical sources. If you've ever seen inside of an electric water heater, they are very similar.
How can I find these?
Search for "cummins 4bt block heater" on your preferred parts site. I found mine direct from Cummins, was even cheaper than what I found on eBay!
Did you think it would be two years later it ran?
Ha! Nope! At first I thought I'd just put the old dirty engine in there & upgrade later... then the modifications started haha
Tinker I so wanna do mine. Gonna start saving
I was patient too when looking for mine, was well worth the wait to find a deal instead of paying some of the inflated prices people were asking on account of it's rising popularity.
Cummins engine series
think this will fit in a 88 samurai lol? considering this swap
With enough suspension lift & motivation I'd sure think so!
Weighs more than the Samurai.
Amazing
Thanks!
Gerat video. I have question. In time 00:41, i think it is oli coolant cover? And is there normal gasket or did you use liquid one? I have to repair it on mine and i have no idea. Also i got hose from there going to turbo, do i have to put the Air out of the systém or it is not needed? Thank for help.
That grid heater you put on. Did you have to do much to make it fit?
baja5000 No trouble at all, goes right under the original intake elbow with the same hardware even, just remember to pick up the pair of beefy relays that go along with! Found my setup on eBay for cheap, think most 6BT guys ditch 'em when they start pushing the power up.
So its just the stock 6bt grid?
baja5000 Right! And even though the bolt pattern of that intake looks symmetrical... it is off from square by just a few mm for whatever reason. So if at first it doesn't seem like it's fitting, try & rotate it around until it drops in.
A esa caja de cambios se le puede poner auxiliar para 4×4?
You could, yes!
May này có ở Việt Nam mua liền
Cool :)
what did you do with your fuel and boost? any upgrades?
Oh yeah, lots of upgrades! It has the bigger Super HX30 turbo, pretty much the largest charger you'd want to run single, before going with compounds. Also I've done just about every upgrade to the pump, & I have videos on all those, but I'm waiting on doing my injector & head stud upgrades until a bit later.
Can I put that into my GMC Canyon 😅
Yes, do it! :D
Could you hook me up ? With a 4bt lol it would be a killer swap
I’ve been wanting to do it ! I just never swapped a Diesel so I have no idea what would need to be done
@@user-dd1mx3df2w I wish I had enough spare's to give them away, been getting pricey! You could also look into the Cummins R2.8 which is similar to the 4BT but lighter & has fancy computer bits.
Very expensive I would rather have a all mechanical engine
Nice!
Thanks :)
How was the bottom end?
No bigger injectors?
Solid & not yet, that's actually next on the list.
What belt accessory setup is that i need all of that for my 6bt isuzu npr swap
Ebay is a great source for part like those!
@@Tinker1837thank you do you know what there called or what your engine came from
Which part? Most of my parts are actually coming from the 6-cylinder Cummins engine, so cool they're interchangeable!
@@Tinker1837 thanks for the replys
the fan mount
Water outlet/alternator mount
Water inlet
Tensioner
And belt
The belt's a custom fit for my fabricated alternator mount, but the rest is from the 4BT or 6BT that either came with the engine or ebay. I have tons of specific part numbers in my build thread in the description.
You should remove paint under flywheel housing.
To keep it from potentially flaking off & interfering with the clutch operation...?
@@Tinker1837 Paint on the engine block may be flaking off, which will loosen the bolts holding the flywheel housing
By the way. Good Job
So you removed the freeze plugs and blanked them over with something?
Right! Figure it best to do so while the engine was out. All in preparation of the boost going up considerably, just to save them flying out (relying on loctite alone).
How exactly does the boost pressure cause welsh plugs to "fly out" of an engine block??
Never heard of blow-by?
Do u rebuild any type of engines? I have to rebuild an engine for Toyota 4runner 93, 3.0
I try! That shouldn't be too difficult an engine to dig into.
That thing looks like a tractor engine.
Since when do people like you care what the engine looks like? Why did you even click on video if you saw 4bt cummins?
@@MrRgaross what are you whining about?
@@TheKnightDrag0n I love that it looks that way, but an air-cooled diesel could've been even weirder looking! They are really big though 😬
@@Tinker1837 Totally, it looks pretty cool with that desert brown color, also you are right about does air-cooled diesel engines XD
They were definitely used in tractors.
A Land Rover eh? What kind of hp and torque could you expect to realize at the wheels?
Mike
Depends quite a bit on how much I turn it up, which funny enough would be me literally turning the knob on the boost bleeder... but since it's full time 4 wheel drive we're talking losses in the 20-30% range. For the sake of longevity I doubt I'll bleed off too much boost, & with the pump mods + what a set of injectors & head studs would safely allow I'd expect output at the engine to peak 250hp & 550tq.
Damned near what my Cumins/dodge puts out now. The torque is no slouch neither. Are these used in farm machinery or elsewhere?
@@mikelamothesr.8998 Quite a scattering of uses from what I've seen, from industrial to agricultural & power generation. Most you find in those applications have a bit different pump setup made to run basically on or off. But the road going pumps, like a 6BT has, are found in "step vans" like bread truck & mail carrier trucks. Shares loads of parts with a 6BT too! To be fair, those numbers I'm expecting include a much bigger turbo & bunch of pump mods. Stock 4BT like this was before would be roughly 130hp & 300tq.
Workable, are the upgrade parts readily available over the counter?
Mike
@@mikelamothesr.8998 Oh yeah, most my parts I order over the counter & just have to remember the Dodge part number/year & model, or go direct to whichever Cummins dealer is nearest And they're everywhere since Cummins is huge.
I have question.. what company makes that manifold ? and what turbo?
That is a Cummins equal-length manifold (#3901635) & a Holset "Super" HX30W turbo, which is essentially a 4-cylinder sized turbine with a 6-cylinder sized compressor & is considered the best single turbo for a 4BT (before getting into compound / dual turbos)
What trans did you use ?
That's a somewhat custom 5-speed NV4500 manual transmission. Has an advance adapters bellhousing, a larger HD Dodge clutch + flywheel, case itself is mostly HD Dodge as well, but the tail housing & 5th gear are the Chevy version that's shorter + stronger than the Dodge tail.
what is the weight of the engine ?
Fully dressed engine, transmission, transfer case, & all fluids is ~1250lbs.
very heavy...
I will follow up
Gaining ~200lbs / 90kgs compared to the stock setup.
好棒技術都不用墊片膠，you won
👍
Que características del turbo que tiene montado? Hx30w? Hx40w?
Buenas cordial saludo
Que precio tiene y cuántas velocidades tiene la caja gracias
Возьмите на работу, с уважением Геннадий, спасибо
Glad you like!
What did this overhaul cost you in full?
Just the engine overhaul was only a few hundred dollars, but if you mean with the new transmission + clutch + adapters + bigger turbo etc... well then that's more around $5k
Cuantos HP tiene ese motor y que modelo de turbo le colocastes
Where you buy the motor?
From a well drilling company. It was part of a big pump, if you check out the 1st video in the series you can see the source as I pull it out.
how much HP with the turbo?
With these original injectors & stock boost setting for the Super HX30 it will produce right around 200HP & 450TQ... at only 1600RPM! But when I step up to the next size injector, swap head bolts for studs, & bleed a bit more boost from the turbo's wastegate it would put it in the range of 250HP & +550TQ or easily more... depending on how much I push it without "fire rings" in the head gasket surface.
@@Tinker1837 thank you very much for reply and the video series. many many vids with 4bt swaps but your vids are the only one that has answered basic questions.
Hi there how is the engine going now?
Are you happy with the power Sir?
Running like a champ 💪
Will this fit on my 91 toyota mini dually truck? If so how much im i looking to spend? Thanks
Anything can fit anything with enough time & money ;)
Tinker how much money? U talking about i dont know anything abut diesel lol
Oh I can't say for sure since I'm doing all the work myself & with the help of friends. If you wanted a shop to do this for you it could easily be five to ten times more than what I've spent so far.
Tinker shit!!!! Thanks for the reply man
Diesel conversions are very expensive can put an ls into a vehicle for cheaper i did most of the work on my 07 tacoma and came out just under 10k
Why did you change all the freeze plugs?
I put in some of those clamp-in aluminum freeze plugs mainly for giving me multiple places to tap in for heater-core hose fittings & temperature/fan sensors. And partly to prevent them possibly blowing out due to the much higher rpm & boost it will have now vs stock. Also makes for a handy place to drain/flush from & monitor the cooling passages ;)