Improving Air Flow And Displacement On Our Cheap Cherokee's Straight Six - Trucks! S11, E7

Подписаться 1,6 млн

Просмотров 542 тыс.

50% 1

Project Cheep Cherokee's back in the shop so we can do a budget bore and stroke on our four liter straight six for more power. And, we'll show you how to create more displacement and let it breathe better by port matching the intake and cylinder head.
Follow POWERNATION Everywhere:
www.powernationtv.com
/ powernationtv
/ powernationtv
PARTS USED IN THIS EPISODE:
Comp Cams: Xtreme 4x4 Hydraulic Flat Tappet Camshafts for fuel injected, AMC High Energy Timing Set, High Energy Hydraulic Lifters.
More Info: pntv.us/pb_pt_6613
Dupli-Color: Dupli-Color semi-gloss enamel paint (3).
More Info: pntv.us/pb_pt_6622
Dupli-Color: Dupli-Color Truck Bed Coating, aerosol.
More Info: pntv.us/pb_pt_6621
Royal Purple: Max-Tuff assembly lube.
More Info: pntv.us/pb_pt_6619
Spectre Performance: ProFab Quik-Kit Air Intake Fabrication System.
More Info: pntv.us/pb_pt_6618
Summit Racing: Replacement injector set.
More Info: pntv.us/pb_pt_6615
Summit Racing: Valve spring retainers (12).
More Info: pntv.us/pb_pt_6616
Summit Racing: Valve spring set (12).
More Info: pntv.us/pb_pt_6617
The Eastwood Company: Pre Painting Prep Aerosol.
More Info: pntv.us/pb_pt_6614
Auto Body Color & Supply Co.: Red scuff pads.
Kimberly-Clark Professional: SCOTT Shop Towels.
Napa Auto Parts: Labor to Press Rod Bolts
O'Reilly Auto Parts: Remanufactured Cylinder Head
O'Reilly Auto Parts: Crank Kit 4.2l, Connecting Rods, .040 Pistons, Shipping, Piston Rings, Cam Bearings, Valve Keeper
O'Reilly Auto Parts: Remove Broken Bolt, Freeze Plugs, Install Freeze Plugs, R&R Cracked Head, Head Gasket, Conversion Set, Head Set
O'Reilly Auto Parts: .040 Bore, Chem Dip, Magnaflux, Align Hone, Install Cam Bearings, Zero Deck, Press Piston Pins, Balance Rotating Assembly X2
O'Reilly Auto Parts: Microfiber towels 2-24 pack
O'Reilly Auto Parts: Oil Pump, Pickup, Oil Filter, Thermostat, Thermostat Gasket, V-Belt, Harmonic Balancer
O'Reilly Auto Parts: Case of Brake Clean
O'Reilly Auto Parts: Rubber Oil Pan Gasket, Rubber Valve Cover Gasket, Main Bearing Set .020
O'Reilly Auto Parts: Motor Mounts
O'Reilly Auto Parts: Six Oil Filters (2)
O'Reilly Auto Parts: Knock Sensor
O'Reilly Auto Parts: Intake gasket, Nitrile Gloves
O'Reilly Auto Parts: 8mm Valve Locks

Авто/Мото

Опубликовано:

21 сен 2020

Ссылка:

Скачать:

Готовим ссылку...

Добавить в:

Мой плейлист

Посмотреть позже

Комментарии : 459

@abovegroundgarage 3 года назад

Sunday morning with Stacey David made my childhood weekends something to look forward too

@tonypage1525 3 года назад

GEARZ

@robblowe8525 3 года назад

Yeah I started watching got rod tv and was a addicted from there

@abovegroundgarage 3 года назад

Hot rod and Got rod tv are two different things, I think Got rod tv was toward the end of the channel listings

@johngeorge4731 2 года назад

Agreed! These were my "Saturday morning cartoons"

@immelting9834 2 года назад

Me too.

@corporalpunishment1133 3 года назад

You guys are killin it, awesome videos dudes I like the fact it's a budget build not a make 1000hp build keep up the good work. Your video production is excellent I love it.

@riskybiscuit5594 3 года назад

You guys really know how to keep me coming back.

@lancemiller6039 3 года назад

thanks for the cost break down! wish all shows did that!

@oby-1607 3 года назад

We had a 1988 Jeep Cherokee and it took us to all the fishing lakes around us in a 150 mile radius. But the body rusted out and the transmission failed and the engine had countless issues. But we loved it for what it could do.

@brandonhobbs1435 3 года назад

Great build, been building one myself for a little over a year, dual purpose

@Limeyfrog 3 года назад

Love XJs. Watching from Europe. I couldn't get this kind of info anywhere else. Love the show. Keep going.

@colormesarge 3 года назад

Bleepin' Jeep if you haven't come across them yet.

@shepardsinsequence 3 года назад

Love y’all from Europe, from Phoenix AZ USA 🇺🇸❤️ Europe

@mikedavidson1437 3 года назад

@@shepardsinsequence q1!!+!q

@loganthesaint 3 года назад

I know you love them... I happen to work on them for a living. I don’t have nice things to say. However, I own an Xj.

@Timman57 3 года назад

How is it i just watched the last episode and was searching for the next segment and then this finally pops up the day after, talk about lucky

@BarnStangz 3 года назад

I was thinking the same thing... Good thing for Google's AI.

@BobTheStrangeMan 3 года назад

SAME

@larrykenyonkeeplearning619 3 года назад

Nice build and really on the cheep side.. can't wait for the dyno 100%

@cherylmartin4050 3 года назад

I was at a FC Jeep Jamboree in IA. There was a mail Jeep truck with a Volvo B-20 red block with turbo conversion. It was super cool, lots of power. Pulled me in the seat- awesome

@Toolery357 3 года назад

Lookin good gents! Cant wait to see the dyno sheet!

@TwentytenS4B8 3 года назад

4:58 Engine assembly is a little more than just torque spec and sequence although those are vital. Your bearing and piston clearances matter just as much if not more. Also piston ring end gap depending on your plans. You want to open them up if going with a power adder unless you like busted ring lands. And checking the end gap should be standard in any build unless you like blowby on a new engine. Too much crankshaft thrust clearance? You might end up driving over the crankshaft the first time you give it the beans. Just got your block back from the machine shop after a line hone and overbore? Check the clearances on the pistons and bearings. Never just assume all is copacetic. And don't spin the crankshaft until all the main caps are torqued to spec. The mains are not round until they are torqued and spinning the crank before the mains are torqued means you run the risk of scuffing the bearings and possibly the journals.

@corymetzker818 8 месяцев назад

Or maybe everything was already measured and checked before hand........ for television time and such

@MeatPez 16 часов назад

They actually did btw. That aside, those low reving straight sixes are MUCH more forgiving and actually thrive in slightly looser tolerances relative to newer or performance specs.

@sbjennings99 3 года назад

Awesome informative Video experience Y'alls God Bless Ya Prayers 🙏

@andoniades 3 года назад

Great vids! Could you guys create a Playlist for the Project XJ? I've been purchasing some of the products you've mentioned. Thanks!

@solarflare1008 3 года назад

Nice job and if possible I want to see this job but in six double overhead cam engine. Thanks.

@otsenres1636 3 года назад

Good paint tips!

@Godwinsgarage-jackofalltrades 3 года назад

As a hig school student weekend mornings were spent watching speed TV

@domthebomb420big_jucie5 3 года назад

I’m so happy I see my favorite RU-vid channel using O’Reillys stuff cause I work at O’Reillys good ole store 6382 keep up the amazing videos

@larryharris937 3 года назад

I love Murphy N.C. !

@lawrencenicolaides2361 3 года назад

I6 the best

@partsisparts9568 2 года назад

What happened to finishing the 4.6 build? Dyno results? I was interested in finding out how you tuned it with the FI system?

@seniorxj2931 5 месяцев назад

My thoughts exactly!

@RegulerShowTV 3 года назад

I finally realized this is the same guy from the Eastwood Company’s RU-vid, it all makes sense now.

@chrish5096 3 года назад

And LMC truck!

@Trials-and-Tribulations 3 года назад

He started with Power Nation first, remember this was made in 2007 I saw this when it was first aired on tv. You can buy this on dvd They just upload the video this year. Look at the date its uploaded lol

@johnsheetz6639 3 года назад

Xjs are the 5.os of the 4x4 world I love'em

@trailerparkmark1 3 года назад

nice show

@chipthemechanic4127 3 года назад

You guys should post a link to the full build, that way people can follow it. I'm thinking about doing this for my jeep, and don't really know where to find info on stroking it. Thanks

@jeanjeudi1111 3 года назад

Great to see this build going forward and I like the way you are holding the cost down. I like to keep the engine bay clean and neat as well but prefer a light color since it's much easier to see everything. Good work, good info

@davidelliott5843 3 года назад

David Vizard is the absolute top man for engine breathing. The stuff he did with the Austin A Series (Mini) is stunning.

@donalddenning2383 3 года назад

Looking good

@meunomeeplissken3088 2 года назад

Os caras são fera , os melhores

@jakehelmkamp2784 3 года назад

Speaking words of wisdom let it breathe

@brantardrey7360 3 года назад

I started mechanics in 68 on Stingray bikes and lawn mowers right around 70 I took into machine work in high school and rebuilt a go-kart engine for myself took a year and I was introduced to head porting in 71 and somewhere late 70s I took a hand at it but all through the 80s and 90s I did head work porting on my own and sold heads built things buy and sell engine parts I know that that Jeep engine is capable of 300 horsepower with proper head work and some compression and a cam head porting takes a long time to do a set of V8 heads can take 40 hours if you're doing it right and doing it meticulous and Blueprinting but it sure does make a difference

@ziadkadi 3 года назад

Nice work. Wish I never sold my2 door xj

@UCMJ_Family_Law_Expert 3 года назад

From less than 50 horsepower to a brand new motor. I can only imagine the difference for the owner.

@camthekiller121 3 года назад

I worked on a mint 2004 4L Cherokee at work today, had an oil leak but that was about it still ran pretty good

@shawnbrodrick8673 3 года назад

The only longevity issue is the loss of zinc in motor oil,but you can use an additive

@soggyspaghetty5799 Год назад

I’ve seen all types of engine’s on this channel the only one I haven’t seen is a Chrysler 318 it would be cool to see one pushed to the max

@whitey2shotpewpew825 3 года назад

Check the throttle body as well. On the newer 4.0's it tapers down bad on the bottom side. Not sure about the older ones.

@rncboy2 3 года назад

I tell people all the time when rebuilding any type of engine balancing the rod weights just like you guys stated and then balancing the crankshaft is the life of the engine and the oil is its blood. Without the first results in a short life for a engine then they tend to hate on companies and or machine shops when in reality it was the one who decided that rebuilding a engine was a good idea for their first time.

@Arthagnou 3 года назад

someone should have designed a tunnel port exhaust style head for the jeep...the 4.0 was so durable because it wasnt powerful enought to hurt itself.

@WilliamAaronson 3 года назад

2j swap the jeep, call it supajeep

@GIXXERyan 3 года назад

Haha exactly! It better last forever it makes low power and doesn’t rev.

@chrish5096 3 года назад

Exactly what an Older guy told me when i went to rebuild my ford 300i6. Told me its prolly the best motor i coulda picked to rebuild bc its durable and doesnt have enough hp to do damage to itself if im not perfect with everything

@countryjoe3551 3 года назад

That's typical for all the old Detroit straight 6 engines. They wouldn't turn high enough to hurt themselves. There is really nothing that magical about them.

@revolutionday1 2 года назад

Edelbrock makes an aluminum head for this engine.....IF you can find one.

@bigredracer7848 3 года назад

412👍's up guys thanks again for have fun working for us all

@williamwilde9867 3 года назад

Where’s the rest of this series, wanted to see the the house and torque gains

@edwardbrodie2190 2 года назад

Anyone know what episode number the next in this series was? I want to see the dyno results after the build but can't find it.

@trefontaine 3 года назад

What do you do if your crankshaft main bearing clearance isn’t in spec? Every time I’ve seen you guys do this, it’s always perfect.

@ironsticksportinggoodsllc2417 3 года назад

Get the crankshaft reground if you have verified the correct size bearings are being used.

@markchidester6239 3 года назад

Prime time to pull the wiring harness out for inspection repair and or replacement. It's a Chrysler product, definitely needs some repair at a minimum.

@MrMatQ 3 года назад

What amount of force is required to tighten connecting rod bearing and main one in Jeep Grand Cheroke 4.0?

@Timman57 3 года назад

Looking forward to doing something similar with a jeep 2wd 5 speed in my 71 gremlin

@Brock_Landers 3 года назад

As much crap as Gremlins always seem to get, I'd still love to have one and build a turbo 4.6 stroker and take it to the strip.

@Timman57 3 года назад

@@Future-Preps35 yeah that has been popping up but haven't quite checked it out, I have a spare 401 laying around for my 74 javelin amx that if I go as far as spending some big money on the 6, im just going to use some bulltear mounts and throw the 401 in the gremlin

@Timman57 3 года назад

@@Brock_Landers would be great! I also have a 92 Nissan 240sx that I took the 2jz out of and I have it sitting and waiting for a project, I expressed the idea of a 2jz and t56 in my gremlin on some forums and people thought the straight 6 tuner power plant sounded rad, and then a guy stole my idea so I kinda lost interest because I was trying to be the first 2j gremlin but I should have kept my mouth shut. Plenty of late 70s z28s I'm sure got embarrassed at the red light by a few gremlin Xs back in the day with a good ol 258 under the hood, the torque is there and you gotta love that amc 6 reliability.

@johnsheetz6639 3 года назад

Sweet!! I think that would be Peppy

@watrousmark401 3 года назад

Make the effort to use OBD II intake, head, and wiring. The intake flows so much better and you can access the ECU with HP tuners, ask me how I know.

@theartistdiamond9397 3 года назад

I've done this to shovelheads. But you do want to polish those surfaces after grinding.

@TwentytenS4B8 3 года назад

Yup, there will be too much turbulence in the airflow.

@johnnon6583 3 года назад

Didn’t you remove the squish band when you increased the cc’s of the head?

@gupp22 2 года назад

Where did you get the beaker with valve used in determining head combustion chamber cc’s.

@matthemberry2156 3 года назад

Idk about removing part of the squish band to get back 3 points of compression. Seems like one step forward and two back.

@vengeanceizmine9878 3 года назад

Optimally, it should have been done with the correct piston. But you are correct. He should have just left it alone. A 9.6 with good quench is better than 9.3 with no quench.. Especially with an iron head and pump fuel.

@andycampbell6032 Год назад

how come no follow up with power numbers?

@mitchellpatterson1829 2 года назад

One thing I should point out, they kept saying "Cherokee rods" and "Cherokee pistons" this WILL NOT WORK with a 258 crank. The 4.0 has a deck height of 9.45". If you use the 6.125 connecting rods on the 3.895" stroke of the 258 crank it will shove the piston about a quarter inch into the head. The 4.0 piston has a compressed height of 1.601" so you can either use the 258 connecting rods, which will increase your quench height, and make the engine sensitive to fuel, or get custom pistons with a +/- 1.3" compressed height. The second option maintains the total combustion volume, and lets you run the same fuel as a stock 4.0L.

@_.incredible_magnum._291 3 года назад

Mans was snatching those crank barrings out bruh😂😂

@bgjohn3rd 3 года назад

how often do you calibrate the torque wrenches?

@autoSerega 3 года назад

Приветствую! Классное видео, большой лайк!

@Joeameturexpert 3 года назад

9.6:1 is just fine for 87octane. If your worried just knock 2* of timming out of it

@TwentytenS4B8 3 года назад

This was my thoughts. They could safely run 87 octane pump gas on 9.6:1 unless they planned on using a power adder in the future which almost always requires premium anyway regardless of compression ratio.

@mitchellpatterson1829 2 года назад

Really depends on the quench height too. You can get away with lower octane at higher compression with a tight quench. That can be difficult to do though mixing and matching parts for a stroker.

@strangerdanger1271 Год назад

Did they ever dyno this? I am not finding that episode.

@terrylittlejohn 2 года назад

i have a 05 4.0l wrangler with the keyway cam gear! can i use the older pin style cam timing chain set with cam bolt button ?? i`m doing a cam swap and it`s going to take 3 months to get the keyway newer style cam from comp! i can`t wait that long!! any help please!

@glengillham5428 3 года назад

When using Plastigage and soft bearings like 77 style, it is important to measure and torque \ compress the Plastigage in a warm area. The plastigage is actually harder than the 77 bearing in cold weather and will dent the bearing and give a false reading

@richardcontinijr9661 3 года назад

Thanks for the tip

@kowpow2259 2 года назад

I could never bring myself to grinding the cylinder head away for a .3 decrease in compression. I'd just put the higher octane fuel in it. Not worth your time.

@beargibson3100 Год назад

My question is why you kept the renix efi?

@Joe.Dillion 2 года назад

So are the 4.0 pistions wrist pin stock location ?

@chrismason598 3 года назад

The jeeps intake :"i cant breathe"

@bryantcurtis2665 3 года назад

Chris Mason Bubba Wallace:I can’t drive🐒💨💨💨

@sethh8892 3 года назад

@@bryantcurtis2665 George Floyd: I can't breath

@PhantomPhaze 3 года назад

4.0L Lives Matter

@cesarprieto8279 3 года назад

Do you know what head you used? 0630 or 7120?

@corey0189 3 года назад

Waiting for low n slo

@Clearanceman2 2 года назад

Seems like a throttle body would have been a good choice too.

@swakage13x 2 месяца назад

This is the kind of stuff I need to do when I get my hands-on my own motor But I want the possibility of being a little closer 2 350 horse power Before slapping a turbo on it

@3ziz1981 5 месяцев назад

I am not an auto mechanic but I would know why lowering the compression ratio and gain more power?

@glowhdvideos1004 Год назад

why is bearing tolerances very important with plasty gauge?

@kodylehman6289 2 года назад

What is the part number for the crank shaft

@7t2z28 2 года назад

I"m a little disappointed that you didn't degree the cam. You can't always trust that the timing is where it's supposed to be. Don't have to do each lobe, but it's a good idea to check number 1 intake and exhaust. I've found cams to be off by about a tooth or two.

@alloyspeed1889 3 года назад

Did they put a holley efi on this or something? How do you tune these engines with a stock computer?

@beastlydookie81 3 года назад

They’ll probably cover that when they upload the next part

@Tshizzle42o 3 года назад

I can only imagine thebamount of wear in my engine. 2004 grand cherokee 4.0 240000mi. Makes all kinds of noise when its cold

@VWdude278 3 года назад

There's a lot of of useful information in these video's to help teach people who want to learn more about building their own project car/truck. This would be a good series if these hosts would ditch the scripts along with the forced enthusiasm's, the annoying announcer and the the chugging guitars in the back ground.

@firstnamelastnameisallowed7943 3 года назад

I am still baffled at jeeps decision to discontinue the 4.0L. It was like the cummins of the gasoline engine! Sounds great, awesome torque, would run forever if you dont EVER over heat them! Inline six......ok you get the point. Stock 4 liter is a good engine but the 4.6 like they are building here is just badass!! I have done a few over the years in YJ's and TJ's that had a blown 2.5L so we did the bigboy swap and man its amazing the difference and how happy our customers were. Believe it or not the swap is very simple to do also! Engine mounts are the only welding you need to do and those almost fall into place on their own! Cant wait to see what this engine puts out that they are building!!

@billgates1682 3 года назад

Poor efficiency.

@sidneysanders5726 Год назад

Listen to the engine run, you can hear slight misfires not enough to trigger the misfire monitor to pop a DTC but enough to make it fail tighter 2007 emissions standards. Some 4.0Ls run smoother than others, sometimes even with rotor, cap, wires and plug replacements it still runs a little rough. And with that much raw fuel running through the cat, epa felt that it wont pass, the 3.8L V6 used in 2007 to 2010 ran smoother and had a little more horsepower, but the 4.0L was still superior.

@johnhill484 6 месяцев назад

Anyone else disappointed that the video wasn't finished. I wanted to see them put it back on the dyno!

@babooseven 3 года назад

Crazy seeing all that weight hanging off of that stand.

@autohog 6 месяцев назад

Do we ever find out the dyno results of 2200 spend?

@Thelongmanable 3 года назад

*_Who takes compression out of a low hp engine oh that's right NO POWERNATION!!!_*

@juhomaki-petaja 3 года назад

Or NO PENETRATION

@Thelongmanable 3 года назад

Lol 😂😂😂

@juhomaki-petaja 3 года назад

@@WhiteG60 You are so right!

@JohnDeer49 3 года назад

Came here looking for this comment

@streetsmart1164 3 года назад

(Tim)"What are you doing to that Jeep engine, cylinder head, AL ? (AL) "Tim, ...I'm lowering it's comprehension ratio and power" (Tim) "OOOHHAAAH ??!!!"

@ubroberts5541 3 года назад

A light tack coat done first promotes adhesion and helps prevent fish eyes. Has little to do with runs.

@copisetic1104 3 года назад

I want my time back after watching!

@peterjames2004 3 года назад

i thought the rear and front main seal had to be fitted with 1 side lower than the other so it didnt leak

@josealcala4344 3 года назад

Do 4.0 sport trac

@user-ys7hz9ls6x 3 года назад

Очень интересно!

@greglawson740 3 года назад

what about the ECM tune?? who's doing that?

@immelting9834 2 года назад

" were going to pick up a fair amount of HP" - quote after head work and gasket matching everything. Ok, well how much ??

@jayh9635 3 года назад

Drop the pre 2000 log intake and get yourself the later intake. 20 free hp without any machine work.

@richardeberline3585 2 года назад

Quick question? When installing the cam bearing is it true that touching the bearings where it contacts with cam without gloves on, the oil from finger ruins the integrity of bearing because the oil will not properly protect the bearing do to the oil on fingers!

@mitchellpatterson1829 2 года назад

Skin oil is salty, it's just a good practice not to get salt on bearing, or sealing surfaces.

@watrousmark401 3 года назад

No mention of the cam being used or the machining necessary for high lift valve springs 🤔

@shawnbrodrick8673 3 года назад

Comp cam,probably the only cam they make for that motor

@jennBourne 3 года назад

Haha, this episode aired in like 2015. Sorry to those who thought it was new. It's still great though. I miss those guys.

@basshead. 3 года назад

2009

@jennBourne 3 года назад

@@basshead. damn, I'm old I didnt think it had been that long lol

@thetreblerebel 3 года назад

It's funny tho, these builds are actually getting more and more popular among younger enthusiast. Maybe not the really older engines but the 4.0L is a Jeep guys LS

@parttimetourist 3 года назад

Why PR instead of OHC?

@johnj2496 2 года назад

The 99+ "octopus 🐙" intake flows better

@seniorxj2931 5 месяцев назад

Does anybody know what the new dyno results are?

@saviervazquez436 3 года назад

I had a question for you guys I'm looking to buy jeep cherokee sport what year is the best year to buy and how much Is the average price for OK condition in the PA area

@RobertBreckenridge13 3 года назад

Oklahoma condition Jeeps are hard to find in Pennsylvania.

@thetreblerebel 3 года назад

So...what if your tolerances are not within spec? Is it back to the machine shop? Return your bearings?

@TwentytenS4B8 3 года назад

If the tolerances are off in the negative, then yes back to the machine shop. If they are positive well time for a new block. You can always take material off but you really can't put it back on. So if they hogged out your mains too much, you need to see if they have an oversize bearing to take up the difference. If not, the block is junk. Same with crankshaft journals. If they spec out too much in the negative and there is no oversize bearing, the crank is junk. Or it could be you ordered the wrong bearings. This is why it's important to check clearances even after getting a block back from the machine shop.

@Aladinscave 3 года назад

If you are going to spend time and money on building a performance motor why would you lower the compression? Especially if it’s only 9.6 to 1 .....

@swhite209 3 года назад

At around the 9:55 mark, said it was to avoid the extra cost of Premium fuel. Probably lowered it a touch more to give a bigger window to avoid knocking from premature ignition.

@Aladinscave 3 года назад

swhite209 my point is why run the low octane when you chase power, maybe they don’t have high octane fuel available all the time or maybe his pockets are empty after the build? Lol

@nicholasrhodes4550 3 года назад

@@Aladinscave If you're gonna offroad it, you don't want an engine dependent on premium fuel. You might need to borrow fuel to get back out or use backroad gas stations-which won't have premium... Sounds like he thought this through a bit.

@swhite209 3 года назад

Not to mention you have people like where I live who would still run it as a daily driver from what I've seen. This is the first video on the project I've watched so I don't know the whole plan.

@404_unavailable_69 3 года назад

To avoid using higher octane fuel. Its still a stock head . Maybe if it was an aluminum head they would of left it alone .

@agoodandy1 2 года назад

I’d have kept or got more compression the more it is the more horsepower, as these engines made low numbers of horsepower. All you would have to use is a better grade of gas. When I do mine I want 10:1.

@utahcountypicazospage5412 3 года назад

I wouldn’t cut the chambers down at all 9-6 to 1 is nothing in compression and would make the motor snappy want to lose some compression get a bigger camshaft

@frankdehne1949 3 года назад

I think 9.6 to 1 was my factory compression on my 87 Wrangler with a 258 and I loved the way it ran I did have to use premium fuel though. It really came alive when I dumped the Carter carburetor and put on I think it was like a motorcraft two barrel and ditched all the emissions and computer

@tommylyeah 3 года назад

Deshrouding is the way to go. I woulda just got a thicker HG if I was only tryna lower the static CR. 9.6:1 is nuthin'.

@XPFTP 3 года назад

11 months ago was a jeep 4.0 rebuild..

@jacobvanhalteren7452 3 года назад

wouldn't the larger cam reduce dynamic compression making it possible to run 9.6:1?

@juhomaki-petaja 3 года назад

There is no difference between 9.3 and 9.6. From fuel perspective.

@jacobvanhalteren7452 3 года назад

@@juhomaki-petaja Depends on engine design. Certain cylinder head shapes or piston shapes can change where the hot spots are in the cylinder changing what fuel might need to be run. There's no real "use premium at this compression ratio and regular at this one". Every engine is different. An engine with a good cooling system might easily get away with 10:1 compression like the LT1 with reverse cooling where other engines with the exact same geometry (IE earlier small blocks with similar cam) would probably need premium to run 10:1. Smaller cam = lower compression or higher fuel grade since the compression is not being relived by cam overlap IE Dynamic compression.

@v.e.7236 3 года назад

A cam has no affect on CR? That's pre-determined by your choices in piston, combustion chamber size and gasket thickness, deck height, etc.

@jacobvanhalteren7452 3 года назад

@@v.e.7236 there are 2 types of compression ratio 1. Static Compression Ratio - what most people think of and what you have described 2. Dynamic Ratio - Depending on the cam, the intake valve may hang open momentarily as the piston begins the power stroke effectively reducing the stroke and therefore compression see more here - www.enginebasics.com/Advanced%20Engine%20Tuning/Static%20vs%20Dynamic.html#:~:text=Dynamic%20Compression%20Ratio%20(DCR)%20is,concept%20in%20high%20performance%20engines.&text=Definition%3A%20The%20Compression%20Ratio%20(CR,to%20the%20combustion%20chamber%20volume.

@v.e.7236 3 года назад

@@jacobvanhalteren7452 You may be confusing cylinder pressure w/ compression ratio. While there may be a slight drop in cylinder pressure, due to valve position, the compression ratio actually increases as RPMs increase w/ overlap. There is a scavenging effect that comes into play w/ that cam design w/ that creates this increase. There is some myth and some science behind what you hear and read about. Be well, sir.

@tchrishoward 3 года назад

My question is will this (4.2 crankshaft) work in a 2002 4.0L coil pack engine? My concern is crank position sensor not picking up and timing/ignition issues. Thanks for any help

@tchrishoward 3 года назад

I have a 1978 4.2L engine that's toast that i can get the crank from (for core), and a 2002 4.0L coil pack engine that needs rebuilt.

@TwentytenS4B8 3 года назад

Your crank position sensor picks up signals from the reluctor wheel that is mounted on the crankshaft. So if the 4.2 crank has the same size reluctor and the same amount of teeth, you should be golden. Just make sure you time the crank and cam properly. This means you need to make sure you can mount the reluctor from the 4.0 crank on the 4.2 one.