magnum bore wear???

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steveh

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always heard high mileage magnums don't suffer from bore wear like the la series engines...why is that?

I have a lead on a new set of kb107 std bore and rings for $200. great price but not sure about buying them before finding a good used short block first.

weighing cost vs benefit...is it a risk worth taking or should I slow down and find a block first???
 
My 5.9 had max .004 wear at about 80,000, well within rebuild tolerance. I think the wear has to do with fuel injection. I'll let others comment further. I'd only buy in advance if you're OK with re-selling if necessary.
How much are you saving?
 
I have seen 100k motors with OEM crosshatching still on them. Sounds good to me, plenty of rolled low mileage trucks in the yards.
 
Its the moly rings used today they are soft just look at one of them and you will see little flakes missing on the sealing surface ,plus a different bore finish (smother).
 
The wonderfully controlled computer F.I. Is one. Dry good reason as to why there so nice after many years and miles. No real big rich/lean conditions to contend with.
 
Mine has 150k,crosshatch perfect. Seen several,with minimal bore wear. Quite a few machinists comment,how much better the Magnum machine work quality is,compared to LA blocks.
 
Biggest reason for minimal wear is lack of lead in the gas................
 
a lot a folks have said why magnums don't suffer from bore wear...but would you risk buying a set of standard bore kb107s and speed pro molly rings for $200 before having a block on hand?

based on the comments so far, sounds like its ok???
 
I never had a problem with lead. Although I never ate paint chips as a child...lol.

I used to mix leaded gas with the "mandatory" unleaded at the pump as long as it was available...early 80's if I recall.

I attribute the modern bore wear mainly to the port injection systems. Good metal composition/materials contributed to it also. I'm not sure about the late small block Chevy or LS style GM engines, but the Mopar Magnum & Ferd Windsor small blocks definitely held up to multiple street miles vs the old school carbed engines.
 
beside eating lead paint..I worked in a gas station for two years...pumping leaded gas...including ethyl....oh ethyl liked to get pumped from behind.....lol
 
SAE technical papers: #640824, 720689, 710367,860090; maybe these will help
 
JBurch said:
SAE technical papers: #640824, 720689, 710367,860090; maybe these will help
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Interesting

SAE tech article # 640824 via www.sae.org

Abstract Wear and corrosion in gasoline engines are strongly influenced by the halogen acids formed during the combustion of fuels containing tetraethyl lead and the accompanying chlorine and bromine scavengers. While modern technology in metals and lubricants has provided improved products which tend to resist and suppress wear and corrosion, this paper presents another approach, namely, the reduction of halide scavengers which are major contributors to the problem. The results of numerous tests both in the laboratory and on the road show that reduction of fuel halide scavenger concentration does significantly diminish corrosive wear and rusting in gasoline engines. Furthermore, these benefits are realized in passenger car service with no adverse change in engine performance or durability, as long as the fuel contains a phosphorus combustion-chamber deposit modifier.
Click to expand...
 
70aarcuda said:
beside eating lead paint..I worked in a gas station for two years...pumping leaded gas...including ethyl....oh ethyl liked to get pumped from behind.....lol
Click to expand...

if old ethyl did it a lot, she probably suffered from bore wear too!!!
 
Now for a little history.......I read about the effects of lead and cylinder wear 30-35 years ago; don't remember the exact source of the information, it may have been an SAE paper, or some other source of automotive information. It was about cars, so I read it. The subject was interesting and unusual, and some of it just stuck in my head. Up to that point in time TEL was so posed to be good and we needed it for it's anti knock properties and as an exhaust valve seat lubricant. The article stated that there was a significant decrease in cylinder wear in Taxi cab and Police fleets in engines running on no-lead gas. Investigation discovered the lack of abrasive boride compounds formed during combustion (there is a lot of heat and pressure to break down molecular bonds and reform stuff). Since FI wasn't common place at the time I read the article, I'd say that FI isn't the major reason for lack of cylinder wear, logic says that you could still run leaded gas thru an injector and get cylinder wear. Though lead was/is a good lubricant, you shouldn't use it on your joy stick, Eythel is blonde, she doesn't know any better, too much lead causes nerological disorders and that is evident.
 
We've come a long way, in the 50's/60's/ it was common to need a valve grind at 60,000 mi.,,, and re-ring or overhaul @ 100 - 120,000 mi.s,

now seldom hear of an overhaul.. not uncommon for engines to go 300k.. if reg maint. is done...
 
HuH, you learn alot of new stuff in a day. Interesting about the lead. Would make sense as how when lead stopped being used in fuel, POS cars started lasting longer. Look at all the 80's garbage that is still on the road today. You know they are the biggest POS cars on the road yet somehow they are still going. Would make sense that lead was causing additional wear. Look at what oil you run affects your engine wear
 
PanGasket said:
HuH, you learn alot of new stuff in a day. Interesting about the lead. Would make sense as how when lead stopped being used in fuel, POS cars started lasting longer. Look at all the 80's garbage that is still on the road today. You know they are the biggest POS cars on the road yet somehow they are still going. Would make sense that lead was causing additional wear. Look at what oil you run affects your engine wear
Click to expand...

All cars used unleaded gas since '75. All cars of the 80's ran on unleaded gas.


They are still POS, but not because of the lead....
 
krazykuda said:
All cars used unleaded gas since '75. All cars of the 80's ran on unleaded gas.


They are still POS, but not because of the lead....
Click to expand...

Actually, in 75 318's were so clean some did not come with Catalytic Convertors. As far as I know they were the only ones.
 
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