Stock Magnum rods/pistons durability ?

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DrEamer

DrEamer

I suffer from cars on the brain!
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I have the heads off my 5.9 Magnum that has just short of 150,000 miles on it. The bores look good with cross hatch marks, and my measurements so far looks like the bores are good and round. I checked the compression before I took it out of the donor truck, and it was in the 145-150 psi range, with one cylinder at 135. My original thought was to freshen up the rings and bearings, have the block hot tanked and new cam bearings put in, and putting a Performance Injection Equipment top end kit on. My main concern is with the 150k miles, the rods and pistons may be a little tired for a projected 400-450 horsepower engine. I was wondering in anyone had ran something with that kind of mileage on them. I could just put new rods and pistons in, but at that point I might just as well go all the way and do a stroker kit. The engine is not going to be ran hard, just a fun street cruiser.
 
Just have the machine shop install good ARP rod bolts and resize them. They will be good for 600 HP.
 
before reusing the pistons check the top center of the pistons I have seen them drop down from over heat
 
if you do not have the PIE top end kit yet, I would recommend you read up on them. Some have had decent luck with them but some have said some very bad things about them. I have never dealt with them but I have heard of them in the Dakota RT community.
 
Disassemble it and check or have the machine shop check the block. Bore wear, ridge, and taper will tell you if it needs bored. A good hone and new rings may be all is needed. (probably not) Boiling the block and new cam bearings and you might as well bore it and have the line bore and decks checked. Bore it and you are replacing pistons. Might as well get a stroker kit. Now it all needs balancing. A stroker really needs good heads. Port yours or bolt on some aluminums? See how this all can get out of control so fast?:BangHead: You need to figure out what you want before you start.
 
toolmanmike said:
Disassemble it and check or have the machine shop check the block. Bore wear, ridge, and taper will tell you if it needs bored. A good hone and new rings may be all is needed. (probably not) Boiling the block and new cam bearings and you might as well bore it and have the line bore and decks checked. Bore it and you are replacing pistons. Might as well get a stroker kit. Now it all needs balancing. A stroker really needs good heads. Port yours or bolt on some aluminums? See how this all can get out of control so fast?:BangHead: You need to figure out what you want before you start.
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Ditto on this!!! I speak from experience. I started "freshening up my 318, and end up with a 408 with aluminum heads..... Many many dollars later! It's a slippery slope, so stop, think about what you want and budget it and stick to it.
 
blk00rt said:
if you do not have the PIE top end kit yet, I would recommend you read up on them. Some have had decent luck with them but some have said some very bad things about them. I have never dealt with them but I have heard of them in the Dakota RT community.
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I have talked to Chris a couple of times, and he seems all right. I know of one person who used him and, his only complaint was that he took a lot longer then first stated to finish his engine. I tried to find any mention of bad work on the Dakota RT forum, but their search function did not find anything. I did find some positive post from about 8 or so years ago when they were a site vendor. If you have some links, or can point me in the right direction, I would love to see it.


toolmanmike said:
Disassemble it and check or have the machine shop check the block. Bore wear, ridge, and taper will tell you if it needs bored. A good hone and new rings may be all is needed. (probably not) Boiling the block and new cam bearings and you might as well bore it and have the line bore and decks checked. Bore it and you are replacing pistons. Might as well get a stroker kit. Now it all needs balancing. A stroker really needs good heads. Port yours or bolt on some aluminums? See how this all can get out of control so fast?:BangHead: You need to figure out what you want before you start.
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Understood, I have been down this road before, and as mentioned, it is a slippery slope. it starts with it is only a little more for this and that, then the little extras add up too quickly. The one saving grace for me is that I am into my current engine for next to nothing. So even if I were to do something like buy a create engine, it will not hurt me money wise to not use it. I would love to have aluminum heads, but a set of ported cast EQ heads will get me where I want to go. I will have to get the engine down to the machine shop, see what I have, and plan from there.
 
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DrEamer said:
I have talked to Chris a couple of times, and he seems all right. I know of one person who used him and, his only complaint was that he took a lot longer then first stated to finish his engine. I tried to find any mention of bad work on the Dakota RT forum, but their search function did not find anything. I did find some positive post from about 8 or so years ago when they were a site vendor. If you have some links, or can point me in the right direction, I would love to see it.




Understood, I have been down this road before, and as mentioned, it is a slippery slope. it starts with it is only a little more for this and that, then the little extras add up too quickly. The one saving grace for me is that I am into my current engine for next to nothing. So even if I were to do something like buy a create engine, it will not hurt me money wise to not use it. I would love to have aluminum heads, but a set of ported cast EQ heads will get me where I want to go. I will have to get the engine down to the machine shop, see what I have, and plan from there.
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The forum monitors must have took it down then I remember a couple of threads on there where PIE was cutting peoples frames to get headers to fit and not boxing it back in. Their tunes were only close enough to get a truck running and then they had to be tuned by someone else. Are you on the facebook group for the dakota RT owners? If not get on there and ask Shane Locke and Steven Zeal, they have more knowledge on the subject then I do. I just know from the pictures I have seen over the years I would not spend my money with them.
 
blk00rt said:
The forum monitors must have took it down then I remember a couple of threads on there where PIE was cutting peoples frames to get headers to fit and not boxing it back in. Their tunes were only close enough to get a truck running and then they had to be tuned by someone else. Are you on the facebook group for the dakota RT owners? If not get on there and ask Shane Locke and Steven Zeal, they have more knowledge on the subject then I do. I just know from the pictures I have seen over the years I would not spend my money with them.
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Thanks for the information. I went ahead and am trying to join the Dakota RT Facebook group. They just need to approve my membership. Since my interest in using PIE is for a top end kit only, not in using their tuning or actually working on my car, it might be different. That said, how a business conducts itself is important to me. If I do not use them, I'm not sure who I will use. It seems so hard to find someone who is good with Mopar heads. I have heard of issues from even the more known shops.
 
the two that I have never heard anything bad about is Brian at IMM engines and Flying Ryan at FRP. Ryan is more of a tuner but he has shops that he deals with for engine builds.
 
I bought a set of bare Engine Quest castings to have prepped locally. A few months later I found out about IMM engines here on FABO. From what I have seen, If I could do it over again or on my next pair, I would call IMM and get their prepped heads.
Maybe give them a call and see if they fit your build plans.
 
blk00rt said:
the two that I have never heard anything bad about is Brian at IMM engines and Flying Ryan at FRP. Ryan is more of a tuner but he has shops that he deals with for engine builds.
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Bobzilla said:
I bought a set of bare Engine Quest castings to have prepped locally. A few months later I found out about IMM engines here on FABO. From what I have seen, If I could do it over again or on my next pair, I would call IMM and get their prepped heads.
Maybe give them a call and see if they fit your build plans.
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I have actually talked to Brian at IMM, he is actually a very nice guy. Brian and Chris at PIE know each other, and have quite a debate between them about the set up of the EQ heads. IMM uses the original iron/steel valve guides, and puts on beehive springs. The iron guides have been known to go bad, so he uses proprietary valves with hardened chrome stems as a solution. PIE uses replaces the guides with bronze ones, and uses a traditional spring. Their thought is that the bronze guide is foolproof and, the regular spring as the advantage of having the inner spring as failsafe if the outer spring were to fail to help prevent dropping a valve. IMM's response is most OE guides are steel/iron and last the life of the engine. I'm not sure I buy the argument against beehives. I work at a car dealer, and a walk through the shop will prove that there are a lot of OE beehive springs that do not fail. As a side note, some friends of mine have seen a IMM head failure, granted it was on a set of Chevy head, but still a concern. I have not seen it directly, so I try to take that with a grain of salt.
 
My first 5.9 build was a junkyard 2001 motor with abouta100k miles on it. i just had it cleaned, crank polished, honed and new cam bearings installed. I rebuilt it with the same pistons and rods, didn't touch the rod bolts (I know, everybody says that's a no-no) or anything. New rings and bearings, and a regrind on the cam. Took my time assembling it. Motor eventually got a turbo and was probably pushing close to 550hp when I finally broke a ring land on one piston from probably a lean condition under heavy boost. Rods, crank and cylinder walls still look good after tear down. Bearings were worn from lots of boost pressure but aside from that everything looked good.

I bought another JY 94 5.9 with a ton more mileage and started down the same path. Dropped it off at the machine shop and my guy said the cylinder bores were great. So, polished the crank, honed cylinder walls and stabbed new cam bearings in it. I'll probably go with forged pistons and rods this time due to my HP goals but the Magnums are pretty stout (at least in my limited experience) using the factory parts.
 
Since this has been brought back up to the top, I have put a little bit more research in. I have revisited a build that IMM did a couple of years back.( Link below) It really seems like a nice package at a reasonable price. Plenty of power for the street for what I want. The cam may be a little big, but other then that, looks interesting. I may need to call IMM to see how the engine that they built held up. Thoughts?
Build Your Own 455HP Pump-Gas Magnum V8 For Around $4,000! - Hot Rod Network
 
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I love that Sledge hammer build. Look at the TQ/HP at 5500 RPMs. That's a lot of fun and probably plenty of mileage on the motor if you don't push it much beyond that RPM range.
 
subcom said:
I love that Sledge hammer build. Look at the TQ/HP at 5500 RPMs. That's a lot of fun and probably plenty of mileage on the motor if you don't push it much beyond that RPM range.
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My racing days are behind me, so I doubt that I'll ever see much over normal RPM's anyway. I just want be sure to have enough engine to be fun in my heavy E body.
 
Dennis74 said:
Does anyone have any more facts concerning the EQ heads from Imm versus PIE's heads. Level 1 port job with pretty impressive flow #'s at PIE for $1500.
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As I recall, the flow numbers were very similar, but keep in mind they are using different flow benches.

As this has been brought back to the top though, I might as well update it. I went ahead and built a 408 stroker out of my Magnum. After talking to the machine shop, it might of not needed a bore, but since I was going replace the pistons anyway, it made sense to do so. If nothing else, I know everything is in good shape now. The other development is since Trick Flow has started making their heads, I will most likely be using those. With the shipping cost that both PIE, or IMM thrown in, the TF head are not much more when you catch one of the $100 off promotions at Summit Racing. I have heard of members ordering one head at time to get the best deal, but is not too hard to do.
 
Thanks DrEamer, only want to do this once and I have read lots of comments concerning the advantages of aluminium. Trick Flow does look like a good head but I have no experience with aluminum heads at all. Thanks for pointing me in the direction of that slippery slope.
 
150K+ Grand Cherokee 5.2L, freshened (rings/bearings/timing chain and tensioner) with a 270HR cam, M1 single plane and a 750 Holley ran countless low 8 second passes in the 1/8mi. and limited street duty for me in a Dart with 4.30:1 gears. Then I sold it to a guy who used it for his daily, and beat it on Thursday TnT Drag nights and bracket raced it Sunday afternoons for several years. He moved to Florida and offered it back to me and I bought it back. I drove it while I was prepping a solid lifter 11:1 360 with J-heads, etc. When I swapped the 360 in (it was only .7 quicker), I sold the 318 Mag to a bracket racer for use in a '65 Dart after installing a dual plane M1 and a 600 Holley. Zero problems with anything, period! They are extremely durable at modest power levels, especially N/A.
 
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