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  1. #1
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    Feb 2015
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    Any ideas on 5.7 build and heads

    I've looked through the forum but haven't found a definite answer on this.If I can save my long block and rebuild it,is there a better set of heads to buy,as in a better year that has less issues?This is my daily driver,so I'm not looking for all out power,just reliability.I thought it may be cheaper to buy a set of rebuilt or new heads then rebuilding mine.If I rebuild the motor,I was going to try to find a mild cam since I'm in there.But I'm in California,so it has to pass smog,and I just want a reliable build.Thanks,any and all input is greatly appreciated.
    R.I.P 2005 Magnum R/T [B]PEL Inferno Red,Flowmaster CB,3865 SC,BT pink thingy, Afe CAI,CSRT wheels w/BT 3mm spacers,BT shifter ball,Lower baffle mod,245/275 staggered BFG Sport Comp 2's,front license plate mod,Arrington catch can

    New 2005 Magnum R/T Bright Silver Metallic,Flowmaster Delta CB,K&N CAI,Lower baffle mod.....Dropped Valve.Hopefully more to come /B]

  2. #2
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    Any good machine shop should be able to peen the seats or install slightly oversize seats.

    But as with anything - budget and goal ALL PLAY A PART.

    You could add a Frank Racing Sidewinder to your combo, its a good cam and can keep the MDS.
    2010 Detonator Yellow Challenger
    "DETONATOR"
    2006 Charger R/T,[B] FRI 392 [B]
    "Daddys Toy" Hemi Rgeisrty#556

  3. #3
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    Thank you!Thats what I was hoping to get from somebody.Im familiar with small and big block Mopars,and I even have an old 392 lol.But I don't have the first clue about these newer Hemis.I don't have any engine builders around here that I'm aware of that are familiar with them either.I know an engine is an engine,but from experience on building a 340 stroker years ago,a lot of builders are Chevy and Ford guys that build a lot of what they know,and not a lot else.As far as budget,I'm only looking to spend maybe 3k tops.I did find an 06 Hemi on EBay for $1500,$300 to ship.Its out of a 2006 Magnum R/T,so I don't think there's any issues between 05 to 06 exchange.I was thinking buy it and install the cam and fix the heads before putting it in.Who sells a stroker kit to rebuild the hurt one if we went that route?

  4. #4
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    The difference between 05 and 06 Hemis is the coil packs and valve covers....05 had the plug wires on it and in 06 they went with coil on plug with no wires

  5. #5
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    Jun 2012
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    D/FW, Tx
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    And the coils are actually different electrically as well as physically.
    2005 Dodge Magnum RT. 12/16 - Inertia big valve heads, Eagle intake, non-MDS lifters, Spartan Plus cam, Shorty headers. 390 RWHP, 390 RWTQ.
    01/2017 - Bilstein shocks.

  6. #6
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    Does it take a different harness?

  7. #7
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    Jun 2012
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    Yes. But you can buy just the connectors and cut and solder or you can buy adaptors.
    On my build, they installed big valve heads and a 5.7L Eagle intake and I just kept the coils. Simple and they work fine.
    I don't think you'll see any difference by updating the coils. Just less wiring and less $ in your pocket.
    Last edited by Feathermerchant; 02-18-2017 at 11:39 PM.

  8. #8
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    Feb 2015
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    Curious about why it's important to have the vin on a different motor,as in when I go to look for one,they tell you Vin has an H (as an example) or what the 8th digit is.Im looking at a few takeouts and I've been asked or told this.Thanks

  9. #9
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    And the other question is more of an opinion.I found a 76k mile complete engine for 2k shipped to my door.Is that the smart move,or rebuild mine?The reason why I'm asking is Im sure that the new/used engine has the same chance of dropping a valve as mine did.So that should be adressed before install,which means pulling the heads ect.Or fixing my current would be more costly,but I think I'd just buy some Inertia Motorsports heads that supposedly have fixed the valve problem and that may be worth the piece of mind over a used motor...thoughts?

  10. #10
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    Jul 2013
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    When my 05 dropped it's valve seat I got a 0 mile motor with a 3 month warranty for $2700. The gasket set it shipped with was complete trash, but the motor is super strong. Only regret I have is not changing out the lifters, but I was strapped for cash at the time and had to make a decision. Car runs great though, and the motor has over 40k miles on it now, just noisy lifters and now an exhaust leak at the passenger header.

    My suggestion would be even if you find a good used motor, replace the heads. It isn't worth the trouble twice.
    2005 Dodge Magnum RT -- Black -- 193k as of Feb '17 Current Mods: NGK Platinum Plugs|Taylor Shorty Wires|K&N CAI|White LED interior Lights|KW V2 coilovers|Poly Bushings everywhere|Hawk Ceramic Brake Pads|Braided Steel brake flex line|5 spoke steel wheels 18x7.5 up front 18x9 out back|3.06 Wavetrac 215mm Differential|2009 Challenger Axles|Adjustable Rear Control Arms|2011 SRT Steering Rack|2010 Challenger RT front seats
    Up Next: Exhaust|front strut bar

  11. #11
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    Thanks for the reply.Yeah I don't have much expendable cash at the moment,especially since I just bought the car 3 weeks ago lol.I just now received the pink slip in my name.My wife isn't especially happy with my purchase,after me taking a 5 hour train ride to go grab it.I agree on getting the heads done,i was going to try to go through a known vender who sells heads that are supposedly fixed from having that issue again.I even looked at takeout engines,about 2300 to my door for 65k miles.I wish I could find a low mileage short block from somebody on here,then I could just buy heads and be done.I guess replacing the lifters wouldn't be that expensive?But only on a fresh rebuild right?I guess no reason to replace them on a used motor.And I need a new intake also from what I hear on here.I don't know anybody away from this forum that knows anything about these cars locally.Are you worried about the heads on yours again?

  12. #12
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    I'm not concerned about the heads on my new motor because the valve seats were reinforced. Now, on the flip side, I've had to replace the oil pan gasket, the rear main seal has a slight drip, and the timing cover gasket also leaks. The valve covers were leaking as well. The only gasket that hasn't been an immediate issue is the head gaskets, and even that isn't something I trust, but one issue at a time.

    I plan on doing a 426 stroker, so I'm just saving up for 6.4 or 392, I don't care if it comes from a RAM 2500 or a Charger/Challenger. I've been focusing on all the other aspects of the car in the meantime, and the brakes are up next because now that I'm close to 200k miles, the calipers are not cutting it anymore. The car had a great first owner, but the one or two owners that had it before I bought it beat the crap out of it, and I'm catching up on a lot of issues slowly.

    My car dropped the valve seat about 8 months into ownership, so I know the feeling. My other half was in the car when it happened, and she was less than thrilled about it, but the car has grown on her, so the eye rolling I used to get doesn't happen anymore.

    My suggestion would be to look around on ebay for wrecked cars. There's no shortage. If you know you're going to swap the heads, take a cheap block, send it to a machine shop, you can sell the used heads as-is, and put that towards getting the upgraded heads. Should save you a good chunk of change, and the machine shop can check the rest of the internals for you. The valve seat dropped in my motor at 147572 miles, and aside from the valve seat coming out, the rest of the motor was in incredibly good shape. These motors were designed by Mercedes, not Mopar, so they're extremely capable, it was just a bean counter issue when it comes to the steel valve seats in the heads. No different than many other cars out there. The thing to keep in mind is that the Magnums didn't sell well enough to stay in production. It's hard to say it was an enthusiast car, but it wasn't for everyone. For a car to be considered profitable, it has to sell 100k units annually, the Magnum barely sold 50k units in 4 years. First year 30k sold, and after that, the numbers were significantly lower and lower. It can't be surprising that the Magnum didn't sell (and weren't going to) in high volume, so the financial decisions just made it possible for any to exist at all, and we just have to try and look at that as the bright side.

    I could dig out the parts list from when my motor was rebuilt, but the intake was junk, it would just be too dangerous to even try. When my intake got removed, it sounded like a baby rattle because there was so much metal in it from the valve seat getting destroyed. There was metal in the cats, there was metal in the oil pan. It happened when I was on the highway, so it really destroyed everything with no shot at redemption. If you get a pulled motor that's complete, that would be the best starting point. Only thing to keep in mind is that some of the sensors were updated after 06, and they are not compatible.

    I was in the same position with my car, so I absolutely understand the situation, it's definitely tough to say what the best way to go is. I got a 0 mile motor for cheap, but I did pay the price later on. If it's not an issue of time, I would get a pulled motor, change all the gaskets and replace the heads with new ones. Lifters are a tossup, but they're easier to do while it's all apart, mine are just noisy, but they're not terrible.

  13. #13
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    Mine had 131k on it,and it ran so damn good lol.I paid 3k for it,sold a beater daily driver for 1500 and thought I did well.Put a few new sensors on it and that was it.I love the wagons,their probably my favorite just because theres not a bunch around here,especially if they are done up nice.I missed my last one,and wanted a safe daily driver that I could pick up my kids in after work.Normally if it wasn't this car, I would kick it to the curb and buy another cheap beater for commuting,but this one grew on me,and had a freshly rebuilt frontend ect.Drove nicer then my old one with 49k on it.First scare was the trans,but that checked out good after all.I would have never guessed this was coming.I see your point though,get a complete used motor for 1700 or so,pull the heads and have them redone and check the motor out.I think with the heads done,even if it was to get hot again like I'm assuming it did in the past,the motor would be solid.Im still trying to find out why the vin matters when buying a takeout motor.Thanks for your input.Shouldnt be so hard to make up my mind,but I'm not 20 with extra money anymore lol.Have to be smart about it.I barely talked the wife into letting me bring this one back from the dead.

  14. #14
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    The VIN matters because of the amount of computers in the cars. If your car is an 05, try to find an 05-06 motor from a Charger or 300. The motor I got, the place was picky and engraved my VIN into the block, didn't matter much to me, but the knock sensors may be different on newer blocks, and the accessories are mounted differently on the SUVs and trucks. I haven't looked super closely, so I don't know if the accessories are just mounted differently, or the holes are actually positioned differently.

    Keeping it within the LX family and around the same production years will be your best bet to ensure everything is going to work. The motors are stout, the heads just have their problems. If I did more research and knew what I was up against, I would have had the car dropped off at a shop to replace the heads the day I bought it. I didn't immediately DD the car after buying it, it was a few months of preventative maintenance and cleaning it up before I started driving it a lot, but of course, right when I was ready to make it the DD is when the valve seat dropped.

    If you get a pulled, complete motor, I would replace every gasket while it's apart, let a machine shop inspect the cylinder walls while the heads are being swapped, and you can check the timing chain, clean everything up, and call it a done deal.

    My car wasn't as cheap as yours, but it was still very cheap for the market. The biggest thing that made me replace the motor was that the chassis is rust free. I wouldn't have been able to find a cleaner car, and I would have had a tough time selling it without a working motor.

  15. #15
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    Thanks buddy,this gives me a game plan.This whole upcoming weekend is all mine,some family are taking the wife and kids to some Bday partys ect.Gives me two full days to pull the heads and inspect,then pull the motor.I may just pull the motor right off the bat though,seeing as I cant believe there's not going to be some really bad damage.

    I appreciate the heads up on the vin,that makes sense to me now.I'll make sure its from a 300/Magnum like you suggested.I found a few with around 75k on them for cheap,may be a good starting point.I felt like I got a good deal because the PO thought the car needed an engine harness,but it ended up being just a Pep Boys sensor that need to be replaced with an OEM one.They are very sensitive to factory sensors.There are a few door dings and scuffs,but overall its really clean and stock besides the exhaust and CAI that was on it.Otherwise fully loaded.And like you stated,zero rust.Even my last one was originally shipped from the Jersey area and had some bubbling by the roof to hatch seam.I checked that right away on this one.Thanks again,all your suggestions are appreciated.I also think it would be hard to find one this cheap and clean,and unless the next one had this problem addressed,it would be the same time bomb ticking eventually.Im already going to be nervous for a few thousand miles im sure.I think I may install new fans while im in there.I don't recall hearing them.



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