[kossenwj]

I have a 2005 Magnum with a 5.7 with well over 210,000 miles. It is pretty much stock outside of the billet tech catch can and Mopar CAI. I have decided to change the head gaskets (and all that job entails). It's been a few years since I've been able to wrench (kids and graduate school over the last several years have really killed my play budget), but now my Magnum has an exhaust leak due to my attempt at trying to replace the leaking exhaust gasket from underneath and finding/breaking a few of the bolts, as well as a leaky valve cover gasket, and constant bubbles in the coolant system with disappearing coolant.

I have a few questions with this future project...

Mostly, are there other things I should think about doing while I'm in there?

- I have thought about having the heads decked with new guides/seats/etc... - is it worth it?

- How about dropping the oil pan, pulling the pistons, replacing piston rings and honing the cylinders?

- Anything else that anyone has seen problems with with Hemi's with this much use that I should aim to replace now once it's apart? (timing chains?, broken valves?, anything else I might be forgetting?)

-My father-in-law drag races, with some dealer connections, and has been pushing me to use Cometic head gaskets, which he receives a great discount on, though since this is just a stock setup with no future performance mods planned, should I just go for a Fel-Pro (or other manufacturer?) head gasket set (which includes all the gaskets needed for the job) and save the money?


My goal with all of this is to bring my Magnum back to its previous trusted daily driver status, as I surely miss the beast and all its space.

 

[magnuman]

Welcome to the forum. If it were me, FWIW, before I tore it down I'd do a compression check. Also, does it burn any oil? If the compression is good and it doesn't burn any oil, I'd leave the bottom end alone and only pull the heads. When the heads are off inspect the valve lifters and, if/when re-installing, make sure they go back in the same holes and will be rotating in the same direction as when you took it apart. If they're bad (scored, pitted worn rollers, axle play, etc.) I'd replace them and also replace the cam.....probably with a mild performance cam. If you're going to do the heads and need a cam/lifters, pick up a set of 6.1 valve springs, a 6.1 timing chain tensioner and, if needed, a timing set. I'd also replace all of the valve seats and, with that many miles on it, it will most likely need at least some new valve guides too. No need to replace ones that are still within tolerance. You may also need a few new valves. A top end gasket kit for the 5.7 from Rock Auto runs about $200 (Felpro) and, IMO, on a pretty much stock 5.7 there is no need to get the additional head gaskets, as the top end kit comes with them and they're more than adequate. You'll also need all new head bolts.....about $20 a side. Have fun.

 

[ChoochG]

It's a slippery slope when you start doing performance mods, but it sure is a lot of fun . If you just want to restore it to driver status I would (like he ^ said) do a compression check to see if any of the bottoms end work is necessary. If not then replace the valve seals for good measure and go with the cheaper fel pro gasket kit.

2006 Magnum RT, eagle heads, 6.1 cam, 6.4 intake, SRT headers, Magnaflow catback, custom tune, SRT rims... and more

 

[kossenwj]

Thanks for the info!

I'll plan on checking the compression before touching the bottom end. --- FYI, it does use about 1 quart of oil every 3-5k miles, to answer your question...

After some more research and on magnuman's suggestion, I'll have the heads sent out and have them taken care of (definitely new valve seats and whatever else needs replaced).

I may be optimistic, but I'm hoping I don't have to go looking for a new cam and lifters... (mostly out of respect for my wallet and wife...) though I always like the excuse to get some more "reasonable" oomph out of the this beast!


Another question, how much can milled off the heads before I need to look into new push rods?

 

[2005rtmag]

Oil burning at a qt every 3 to 5k miles isn't really oil burning in my opinion. But with rebuilt heads giving the engine more dynamic compression and with 210,000 miles it could increase. Make sure something is done to the heads to keep the valve seats from falling out. My new 65 Chevelle 327 V8 burned a qt every 1,500 miles which was typical for a chevy back then. A hotter cam will give more hp at the top end but will decrease torque at the low end. A lower gear rear diff is needed to take full advantage of a hotter cam. My 2 cents.

 

[magnuman]

Thanks for the info!

I'll plan on checking the compression before touching the bottom end. --- FYI, it does use about 1 quart of oil every 3-5k miles, to answer your question...

After some more research and on magnuman's suggestion, I'll have the heads sent out and have them taken care of (definitely new valve seats and whatever else needs replaced).

I may be optimistic, but I'm hoping I don't have to go looking for a new cam and lifters... (mostly out of respect for my wallet and wife...) though I always like the excuse to get some more "reasonable" oomph out of the this beast!

Another question, how much can milled off the heads before I need to look into new push rods?

Using a quart of oil every 3000-5000 miles isn't too bad at all. Some of that is probably getting past the crappy PCV system. If you pick up a catch can, you'll be able to see how much you lose. It'll also help a little with fuel consumption and performance.

IMO, the valve seats on an 05-06 and some early 07's is important insurance that MAY preclude dropping a seat in the future. I had them all replaced in both of my 5.7's and one head with the lowest mileage (my 05 Magnum with about 80K on it) was a possible candidate. The machinist said that when he was cutting one of the intake seats (the ones that drop the most often) out of one of the heads, it started spinning in its bore before he even had it half cut out. He said that could have dropped under the right circumstances.

As far as cams go, like 2005rtmag said, performance cams usually take a little power off the lower RPM in favor of more mid and top end of the power range. A good cam, along with a good, low restriction exhaust system can give you as much as 50-70 horsepower. The secret is to go more on the mild side as opposed to the radical side. I have quite mild cams and good exhaust systems in all 3 of my Hemi's and they perform very well, especially from about 3000 RPM on up. My Magnum, with its mods. (see signature), on the highway I'll usually get 27-29 mph and an occasional 30 mpg, plus they have a bunch more power than when completely stock.

On the heads, I milled .030 in. off of all of the 5.7 heads. I understand that's about as much as you'd want to go without having to deal with other valve train issues. At .030 in. off, I haven't had any problems and it raises the compression ratio by about a half point.