how to re-fresh 5.7 Hemi

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danmc77

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For those of you working on the new 5.7 Hemis - I assume the majority of people out there are buying used motors rather than the crate engines. what are you doing to freshen them up before running them? What steps are you guys taking to ensure they run as expected?

I've re-built several SB's and BB's, but all have been TOTAL rebuilds - start w/ the block and go from there - bored out etc...

I'd rather not bore out or machine the block if it's not necessary - what's involved in rebuilding a lower-milage motor that doesn't need to be bored? Do you go as far as honing the cylinders and replacing rings - what about bearings, etc?

I plan to install a Hughes cam, and I'm sending out the heads for port work - so they'll get seals and valve jobs regardless - also plan to install the 4bbl throttle body intake setup from Mopar - just wondering what else I should do to a used motor before dropping it in the car.
 
Depending on the Mileage of the hemi you shouldn't need much as far as internals go unless there was a problem. The motors with really high miles I've pulled apart still have the factory crosshatch in the cylinders and I've yet to see a ring ridge and I've pulled apart a couple 100k plus motors. Don't send your heads out check out Power Ported Performance or Inertia they have some proven head combo's that will be way less then what you will spend to have them done.
 
Thanks. I was looking into sending the heads to hughes for the porting. They offer CNC porting, blending, race valve job, cleaning, milling, re-assembly w/ new seals for $999. I like their cams too - although I don;t really know too much about their line of cams for the new Gen Hemi.

Either way - I'm in the VERY BEGINNING stages of even planning my build, so I will definetly check out the places you referenced.

BTW - the motor I'm getting is a 40k mile motor - it's defenetly getting a thorough inspection, clean and paint - just wasn't sure how far into the motor I needed to go beyond removing the heads and inspecting the cynlinders. I guess I'll be checking the cam bearing as well since I'll be swapping it out. Should I pull any of the mains to check bearing wear in the bottom end?
 
A standard short block freshen usualy consists of
Clean and degrease block
Check the deck and surface as required
puff hone the cylinders
Inspect and clean pistons, rods, and ring lands
Install std size rings or file fits as required.
Inspect thrust and mic crank rod and main sizes.
polish or cut crank
Install new rods, main, and cam bearings
Install new oil pump as required
Install new timing chain as required
Install new core plugs as required.
Clean all of the rest of the parts, put her back together with a fresh gasket set and you're done!!

If memory serves me, the head and rod bolts are torque to yeild and need to be replaced. Be carefull not to smack the parting surface of the rods during dissasembly or you will ruin the fit. The mains (dont know about the rods) are available from the factory in several very small (.0002) undersizes, A B C. C if I remember is the largest and the one I used when I built my motor. The timing chain is installed using the different colored links and the dot on the cam gear goes in the 12 o'clock position and the crank gear goes in the 6 o'clock position. The only head gaskets I was able to find at the time were stock bore only. I had a set made up from Cometic for my .020 over hemi

If you are going to freshen your hemi, I hope this helps!!! Joe:toothy10:
 
danmc77 said:
Thanks. I was looking into sending the heads to hughes for the porting. They offer CNC porting, blending, race valve job, cleaning, milling, re-assembly w/ new seals for $999. I like their cams too - although I don;t really know too much about their line of cams for the new Gen Hemi.

Either way - I'm in the VERY BEGINNING stages of even planning my build, so I will definetly check out the places you referenced.

BTW - the motor I'm getting is a 40k mile motor - it's defenetly getting a thorough inspection, clean and paint - just wasn't sure how far into the motor I needed to go beyond removing the heads and inspecting the cynlinders. I guess I'll be checking the cam bearing as well since I'll be swapping it out. Should I pull any of the mains to check bearing wear in the bottom end?
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You could probably just drop it in but, IMO I would at least pull the mains and a rod or two to check the bearings. I can't leave anything alone so I would tear down the whole thing at 40,000 miles and freshen it up. I wouldn't want to have to pull it out again for something as simple as a gasket leak or as big as a rod knock. Again IMO, take it for what it is.:toothy10:
 
I have one sitting in the shop floor right now, with 135000 miles on it, pulled a head and the bore looks perfect. Crosshatch still visable from top to bottom with no ridge. These engines dont wear cylinders, thank you fuel injection!! This engine is rebuildable, and for sale cheap.
 
replicaracer43 said:
I have one sitting in the shop floor right now, with 135000 miles on it, pulled a head and the bore looks perfect. Crosshatch still visable from top to bottom with no ridge. These engines dont wear cylinders, thank you fuel injection!! This engine is rebuildable, and for sale cheap.
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Thank you stock low tension molly rings.
 
BTW, one thing we are seeing is a failure of the timing chain tensioners. (Just saw a 6.1 failure tonight) The tension slide on the right gives up w/ llittle notice. It's only 3 bolts to replace and it is not expensive while you are there. If you are in a motor w/ 80K or more, go ahead and do it. Some last a long long time and some are toast by 100k miles. Don't gamble w/ jumping tooth over a few bucks and a few minutes extra since you are there w/ the oil pump, anyway.

BTW, Thanks for the props to www.InertiaMotorsports.com too :) We are about to get back to the A-body projects in the next couple of weeks.
 
TxSwimDad said:
BTW, one thing we are seeing is a failure of the timing chain tensioners. (Just saw a 6.1 failure tonight) The tension slide on the right gives up w/ llittle notice. It's only 3 bolts to replace and it is not expensive while you are there. If you are in a motor w/ 80K or more, go ahead and do it. Some last a long long time and some are toast by 100k miles. Don't gamble w/ jumping tooth over a few bucks and a few minutes extra since you are there w/ the oil pump, anyway.

BTW, Thanks for the props to www.InertiaMotorsports.com too :) We are about to get back to the A-body projects in the next couple of weeks.
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I consider that tensioner a maintenance part at 80K. It's also a good excuse to put a cam in:). the other things to look at are the springs on 03-04 trucks tend to fail. Those same year engines also have toner rings that can fail which is exacerbated by some of the underdrive pullies like the APS and Moto blue. They had a new toner ring design in late 04 that is much better. And, the pistons which you can't do anything about cheaply.
 
Guys - is there any reference source for engine build specs or rebuild tips (capacities, torque spec, popular mods...)? This is all great info, but is there a single source (book, web site) that you can recommend so I can read a little more about the engine and the classic muscle car swap?

I also have major questions about what engine management systems people are using, pro/cons of each - stock wiring harness/MSD/AEM/Mopar Performance/FAST - etc.

I have the stock wiring harness with my engine, but I like the MP kit that includes the 4bbl throttle body and 4bbl intake - but it's $4k!!
 
I got my low mileage (12k) engine running last weekend using the factory wiring harnesses and computer. One issue I had was fuel sitting in the crossover tube had corroded it plugging up the injectors. Once I cleaned those out it fired right up. I only plan to detail the engine with the hope that all is well otherwise. I'm trying to do my install with as little extra cost as possible. I found a factory service manual online to use for reconfiguring the wiring and for any other info I need including all torque specs.
 
boden said:
I got my low mileage (12k) engine running last weekend using the factory wiring harnesses and computer. One issue I had was fuel sitting in the crossover tube had corroded it plugging up the injectors. Once I cleaned those out it fired right up. I only plan to detail the engine with the hope that all is well otherwise. I'm trying to do my install with as little extra cost as possible. I found a factory service manual online to use for reconfiguring the wiring and for any other info I need including all torque specs.
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Any chance you have a diagram of what you kept and what you didn't keep? This might be a great way to help with a How To. I was thinking we can do a swap post and have it stickied with all the info required.

Riddler
 
Riddler said:
Any chance you have a diagram of what you kept and what you didn't keep? This might be a great way to help with a How To. I was thinking we can do a swap post and have it stickied with all the info required.

Riddler
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I'd be interested in that too. My thoughts are the stock PCM and harness with a good CMR tune using the diablo predator to interface would be the best way and probably the cheapest too.
 
I ordered my harness and computer from S & P. Not exactly cheap but the harness is configured to remove all unnessary items and the computer is flashed to match. They can flash your pcm instead of buying a new one ( I did not have one). I've heard too many horror stories about guys trying to use the factory harness.
 
a few months ago i was going to buy a 2500 ram with a knock and was researching this myself. i almost fell over backwards when i found what gasket sets go for.
 
The only gasket you gotta replace is the head gaskets and the front/rear main seals. Everything else is o ring type/stlye and can be used over again a few times. So what exactly was the price for the gasket set?
 
well i never took one apart and to tell you the truth, i couldnt find out anywhere if they were oringed or not, but i did have a feeling of it. so oil pan and everything is reuseable? i saw sets as high as 500 and change.
 
jamesdart said:
well i never took one apart and to tell you the truth, i couldnt find out anywhere if they were oringed or not, but i did have a feeling of it. so oil pan and everything is reuseable? i saw sets as high as 500 and change.
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only the exhaust manifold gaskets are replacement type. The head gaskets are mls so you can reuse those if you want and there not dammaged. Everything else is an oring. Despite common opinion the head bolts are not torque to yeild and can be reused also. If you torque them more than a few times I'd replace them though.
 
definitely good to know. i had no plans of buying anything till i tore it down, but was just doing some research and was shocked with what i found.
 
The parts for the new hemis are actually pretty cheap if you know where to get them.
 
Riddler said:
Any chance you have a diagram of what you kept and what you didn't keep? This might be a great way to help with a How To. I was thinking we can do a swap post and have it stickied with all the info required.

Riddler
Click to expand...

I'm not sure how helpful it is, but here's a summary of the circuits I added fuses and relays for. The letters and numbers represent the circuit as designated in the 05 Dodge Ram factory service manual.

Wiring Simplified.jpg
 
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