Old School vs Magnum on 86 Dodge W100

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Yep, standard HD 435 4 speed. From our friends at Novak, gotta love these ratios.
NP435L (Ford, Dodge, GM) 6.68 3.34 1.66 1.0 8.26
Axle gears are most likely 3.55s but lower gear ratios were optional.
 
In your case, it may be more effective cost and performance wise to talk to Oregon cam grinders and ship your core to them for regrinding and re-hardening.
 
Rolltide6019 said:
Thanks nm9stheham. I'm leaning toward Carburation but may change my mind. I don't much about Cam selection so I may need to pick your brain. All I know at the moment is I need a new one b/c mine is pitted pretty badly. Crank and Cylinders seem ok although the crank will need polishing, maybe oversized as there is some scaring on 2 journals.
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The parameters change a bit when you move to carbs, so it should indeed be re-visited if you go that route. Having the engine/truck's objectives clearly figured out and in mind is important to that selection process. Will it be a daily driver? Maybe some off-roading? And so on....

OK on the crank; BTW, the journals become 'undersized' if they are turned down in diameter to clean them up. If you get the chance to post some good pix the 2 scarred journals, maybe folks will be able to help you evaluate.
 
nm9stheham said:
The parameters change a bit when you move to carbs, so it should indeed be re-visited if you go that route. Having the engine/truck's objectives clearly figured out and in mind is important to that selection process. Will it be a daily driver? Maybe some off-roading? And so on....

OK on the crank; BTW, the journals become 'undersized' if they are turned down in diameter to clean them up. If you get the chance to post some good pix the 2 scarred journals, maybe folks will be able to help you evaluate.
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Hey guys, sorry I've been out a while... took the crank to have it polished and heads redone. Question: How much ware can my calendars have before I need to bore 20 over? Stock is 3.91 and mine measure about 0.002 under (so 2 to 3 thousands wear). My son is trying to save wherever he can and doesn't want to buy new pistons unless he has to. I can't find a chart or guideline on this specification so I appreciate the help!!
 
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Rolltide6019 said:
Hey guys, sorry I've been out a while... took the crank to have it polished and heads redone. Question: How much ware can my calendars have before I need to bore 20 over? Stock is 3.91 and mine measure about 0.002 under (so 2 to 3 thousands ware). My son is trying to save wherever he can and doesn't want to buy new pistons unless he has to. I can't find a chart or guideline on this specification so I appreciate the help!!
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I guess this is known as Piston to wall clearance if I'm reading correctly...
 
Not 100% sure how to answer.... Is this on the 5.2L?

So do you mean your cylinders are measuring something like 3.902 or 3.903"? The bore diameters ought to be measured about 1" down from the top and then around 3" down from the top, so you can see how much of what is called taper is in the bores. Measure inside to outside, not front to back, to see the worst wear. And if you are using telescope gauges, those take a lot of practice and care to get valid readings.

Use a fingernail and feel the top of the bore, where the ring travel stops, and see if you can catch your nail on the edge of the ridge left there. It is not a definitive check, but if you cannot feel a ridge with your fingernail, that is a very good sign.
 
nm9stheham said:
Not 100% sure how to answer.... Is this on the 5.2L?

So do you mean your cylinders are measuring something like 3.902 or 3.903"? The bore diameters ought to be measured about 1" down from the top and then around 3" down from the top, so you can see how much of what is called taper is in the bores. Measure inside to outside, not front to back, to see the worst wear. And if you are using telescope gauges, those take a lot of practice and care to get valid readings.

Use a fingernail and feel the top of the bore, where the ring travel stops, and see if you can catch your nail on the edge of the ridge left there. It is not a definitive check, but if you cannot feel a ridge with your fingernail, that is a very good sign.
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Thanks for jumping in nm9stheham. There is no sign of a ridge at the top and yes, as you say, I've used a bore gauge to measure 3 points to see if there is taper. I'm about to do it over again now to make sure but last night, there was about 0.002 (0.003 worst case) throughout. That would make the bore about 3.908 against the factory spec of 3.91.
 
Rolltide6019 said:
Thanks for jumping in nm9stheham. There is no sign of a ridge at the top and yes, as you say, I've used a bore gauge to measure 3 points to see if there is taper. I'm about to do it over again now to make sure but last night, there was about 0.002 (0.003 worst case) throughout. That would make the bore about 3.908 against the factory spec of 3.91.
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And yes, 1994 5.2 magnum.
 
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Good on using a bore gauge. Don't you mean 3.912"? Do you mean .002/.003" of taper, or just different than the nominal 3.910" bore diameter with no taper?

The Magnums have a reputation for low bore wear, reportedly due to the fuel injection: less fuel excesses washing down the oil on the cylinder walls than in a carb system.

For keeping the original pistons, the next step is to measure ring side clearance to see if the ring grooves are not excessively worn. Measure a ring segment with a mic to get the right height find one that is not much worn from stock spec of 5/64" (.078") , then insert into the groove and check the clearance with a feeler gauge against spec. Worn ring grooves allow the ring to twist up and down excessively and will wear it out quickly. The top groove tends to be the worst.

Have you measured the pistons on the skirts to check diameter? IDK how high or low on the skirt that should be measured for that year piston, but you ought to be able to find the info somewhere or in a FSM.
 
nm9stheham said:
Good on using a bore gauge. Don't you mean 3.912"? Do you mean .002/.003" of taper, or just different than the nominal 3.910" bore diameter with no taper?

The Magnums have a reputation for low bore wear, reportedly due to the fuel injection: less fuel excesses washing down the oil on the cylinder walls than in a carb system.

For keeping the original pistons, the next step is to measure ring side clearance to see if the ring grooves are not excessively worn. Measure a ring segment with a mic to get the right height find one that is not much worn from stock spec of 5/64" (.078") , then insert into the groove and check the clearance with a feeler gauge against spec. Worn ring grooves allow the ring to twist up and down excessively and will wear it out quickly. The top groove tends to be the worst.

Have you measured the pistons on the skirts to check diameter? IDK how high or low on the skirt that should be measured for that year piston, but you ought to be able to find the info somewhere or in a FSM.
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Good catch on the bore... you are correct. Without sending a picture of all the data, variance was from 0.0025 to 0.0035. All cylinders were pretty consistent and no significant "out of round" measurements. I have not measured the ring grove or piston skirt... good thought.
In the past hour, I've been thinking of going ahead and having the cylinders bored 20 over and buy a master rebuild kit that has new everything (pistons, cam, bearings, gaskets, oil pump, etc.) from Engine Tech. Reuse my Crank and rods. Does this sound like wisdom? I STILL have to make a final decision on EFI vs Carburation.
 
I'd save the bore for next time
now the dscision on how to hone?
I used to do what i cakked a minimum hone with a torque plate
very once in a while you would find a hole that did not clean up but ot often, especially with a magnum
do the finish the rings want in the ring travel area
below that you can leave coarser
bvvc what compression height with pistons
with your motor you could use a coarse bottle brush with a few strokes with a fine one
 
A 1989 to 1993 ---- 318 or 360 might be an easier change over electronically. They have the same body. And more power than the carb'd engines.
 
Rolltide6019 said:
Good catch on the bore... you are correct. Without sending a picture of all the data, variance was from 0.0025 to 0.0035. All cylinders were pretty consistent and no significant "out of round" measurements. I have not measured the ring grove or piston skirt... good thought.
In the past hour, I've been thinking of going ahead and having the cylinders bored 20 over and buy a master rebuild kit that has new everything (pistons, cam, bearings, gaskets, oil pump, etc.) from Engine Tech. Reuse my Crank and rods. Does this sound like wisdom? I STILL have to make a final decision on EFI vs Carburation.
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In my opinion, it does, but I am sure there are differing views on this matter. I have re-ringed a coupla engine in the past, with worse wear than you have, and had much less-than-satisfactory outcomes. So anymore, I'll always re-bore. Good bores and good ring seal is a fundamental of a good running engine. And with the kit, you get all the other parts, like a new oil pump, which I always replace. If the truck will be kept for some years, it makes sense to me to do it as good as it can be.
 
nm9stheham said:
In my opinion, it does, but I am sure there are differing views on this matter. I have re-ringed a coupla engine in the past, with worse wear than you have, and had much less-than-satisfactory outcomes. So anymore, I'll always re-bore. Good bores and good ring seal is a fundamental of a good running engine. And with the kit, you get all the other parts, like a new oil pump, which I always replace. If the truck will be kept for some years, it makes sense to me to do it as good as it can be.
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Thanks for the input, I agree. However, got BAD news this morning from the machine shop that both heads had cracks in them - so we're back to square one. My son just learned a hard lesson about buying an engine he knew nothing about. Total loss at this point - except the cost of experience. Now I have to decide if I try to get some Reman heads for the Magnum ($450 at a minimum) or tear the original 318 LA down and see what's involved in rebuilding it. Heads may be bad on it also. 1 step forward, 2 steps back...
 
You might want to ask about the cracks in detail from the shop, and then inquire here. How deep and long and numerous are the cracks?

If those are 302 heads, then that is supposedly common.... Some guys here will refuse to touch them, and some guys here will run them all day with the cracks. I don't know enough about the 302 crack situation to be of much help, except what I have just reported.

Those Magnum heads have smaller combustion chambers, nominally 62 cc versus 68 cc's for the LA318 heads. So the compression is better for low RPM torque, which is an attribute to pursue for a street truck IMHO. The chronic issue with smog-era 318's was low compression ratio and it takes pistons like KB167's to really correct that.

Are you planning to cam up this engine at all?

BTW, I would expect more wear in the LA318 block, but you gotta measure to be sure. The Magnum block is .015" shorter so has a bout .25 point better compression from that alone. Seems like the block is OK...yes?
 
nm9stheham said:
You might want to ask about the cracks in detail from the shop, and then inquire here. How deep and long and numerous are the cracks?

If those are 302 heads, then that is supposedly common.... Some guys here will refuse to touch them, and some guys here will run them all day with the cracks. I don't know enough about the 302 crack situation to be of much help, except what I have just reported.

Those Magnum heads have smaller combustion chambers, nominally 62 cc versus 68 cc's for the LA318 heads. So the compression is better for low RPM torque, which is an attribute to pursue for a street truck IMHO. The chronic issue with smog-era 318's was low compression ratio and it takes pistons like KB167's to really correct that.

Are you planning to cam up this engine at all?

BTW, I would expect more wear in the LA318 block, but you gotta measure to be sure. The Magnum block is .015" shorter so has a bout .25 point better compression from that alone. Seems like the block is OK...yes?
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I wish I were more experienced on whether my cracked heads were a problem or not. The machinist seemed to feel they were unusable. I don't know whether they are 302 heads - if someone tells me how to check, I will.
Regarding "camming up" I had planned to go back stock to save my son money. The truck would be used as a second vehicle and we weren't looking for a "performance" engine. Not that I would mind some performance but the truck is geared so low, I don't see where its worth the additional cost. We really just want a good running engine that's dependable and get rid of the old 2bbl carburetor that's such a dog. My son is disheartened (as you can imagine) after hearing about the heads so I'm looking for a way to help keep him going forward best I can. My options at the moment seem to be A) commit to re-manufactured heads for the magnum (another 450 on top of the rebuild kit) or B) tear into the LA and start over; that may lead to more bad news depending on the shape of the block, heads, crank, and cam. Since my magnum block is in good shape, I may could use it with the LA heads. I guess there are other options like buying another 5.2 magnum from the salvage yard but they we're taking more risk by not knowing it's condition. Not sure what the next step is yet....
 
Well, I would mill .030" off of the LA318 heads to get down to the same chamber size and keep the compression ratio advantage of the Magnum.

But....LA318 heads will be a shaft rocker system... that will be the problem.... no oiling passages up through the Magnum block to oil the shaft rocker setup. Almost sounds like the reman magnum heads are the way to go. Maybe check out the present Magnum pistons for ring skirt diameter and groove wear, and, if good, put them back in after a hone in the block, to save $$ for heads. Sometimes you gotta compromise....

OK, on the cam. That makes life easier since you are not going with a hi-po build. But it all sounds up in the air now.
 
your magnum motor have a roller cam core?
should work fine
92-93 5.2 magnum cam is best if you can score one

Q anyone run la heads stock rockers and pushrod oiling?
oil would come through the hole on the pushrod cup and fill the shaft bathtub
I've drilled the LA heads and oiled from the oil pressure tap - not hard to do
or magnum heads work fine too
on your heads just look for the casting number under the valve cover
on reman heads make a checklist seats? guides? valves / stem seals? springs?
you might see if there are any Enginquest heads available
and contact a&a midwest one of our members who does not sell junk (used car dealer level "totally rebuilt heads" )
someone post his link
also put a wanted in - some member may have some "take offs" that they want to move
 
My Duster currently has a 5.9L Magnum short block with Edelbrock heads and RPM intake (LA top end). I pulled the short block out of a junkyard 2000 Dodge Ram 2500 with unknown miles; pulled the heads and the cylinders still had cross-hatching with no ridge whatsoever so I plopped it in the back of my Jeep and took it home. I did nothing to the bottom end besides install new rod bearings. The engine routinely sees 5500 RPM and I've had it past 6000, about 5000 miles on it so far and it basically runs like a new engine.

Just some food for thought. If your son is up for the work it might save the most money to just find another Magnum engine, either from a junkyard or off Craigslist or Facebook Marketplace (IF you can hear it run first or be able to pull the heads and inspect the cylinders before you buy it). My shortblock was $150 from the local pull-and-pay yard if I remember correctly.

EDIT: By the way factory Magnum heads are almost guaranteed to be cracked between the valve seats. Like others said though it's usually not actually a deal-breaker it's just that for most engines 99% of the time cracks=no good so that's probably what your machinist is thinking. I haven't run cracked heads myself yet but if the cracks are small and shallow and I needed to throw something together super cheap...
 
MopaR&D said:
My Duster currently has a 5.9L Magnum short block with Edelbrock heads and RPM intake (LA top end). I pulled the short block out of a junkyard 2000 Dodge Ram 2500 with unknown miles; pulled the heads and the cylinders still had cross-hatching with no ridge whatsoever so I plopped it in the back of my Jeep and took it home. I did nothing to the bottom end besides install new rod bearings. The engine routinely sees 5500 RPM and I've had it past 6000, about 5000 miles on it so far and it basically runs like a new engine.
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So are you oiling the LA shaft rockers just with the pushrod oiling of the Magnum block? Seems like an 'iffy' setup.....

Or did you do something else for shaft rocker oiling?
 
Please define "cam is bad".

No offense to the op, but I see a lot of generalizing in your posts, and lots of conclusion jumping. I see that you're here to learn, so please slow down a bit.

On the cracked heads, buy engine quest heads and be done with it. I would recommend this even if yours weren't cracked yet. If you can't afford them, this is the wrong sport for the team you're betting on.

Whatever you do, if you aren't running the factory efi computer or some other rev limiter, you need to upgrade your valve springs. Magnums have a VERY low rpm limit and will float valves. This results in bent valves if lead footing is involved.... ask me how I know!

That Magnum motor is, imo, better than the 318 in every way. Don't forget an electric fuel pump if it wasn't mentioned elsewhere
 
nm9stheham said:
So are you oiling the LA shaft rockers just with the pushrod oiling of the Magnum block? Seems like an 'iffy' setup.....

Or did you do something else for shaft rocker oiling?
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Pushrod oiling plus external oiling tee'd off the oil pressure sender port on the block. You might remember my build from a couple years ago I think you were active in the build thread, I bought used open-chamber Edelbrocks and had them drilled to supply oil from the back of the head through the rear-most rocker shaft bolt. I actually had to weld up and re-drill smaller holes in the rocker bolts because it was pumping way too much oil up top and my hot oil pressure was quite low but since then it's worked great. Gives me some extra peace of mind with the constant oil flow since I'm running an almost-.550"-lift hydraulic roller cam with factory stamped LA rockers and it sees a lot of street use at idle and low RPMs.
 
MopaR&D said:
Pushrod oiling plus external oiling tee'd off the oil pressure sender port on the block. You might remember my build from a couple years ago I think you were active in the build thread, I bought used open-chamber Edelbrocks and had them drilled to supply oil from the back of the head through the rear-most rocker shaft bolt. I actually had to weld up and re-drill smaller holes in the rocker bolts because it was pumping way too much oil up top and my hot oil pressure was quite low but since then it's worked great. Gives me some extra peace of mind with the constant oil flow since I'm running an almost-.550"-lift hydraulic roller cam with factory stamped LA rockers and it sees a lot of street use at idle and low RPMs.
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OK, that was the setup I was thinking of... could not connect you to it! The big point to the OP is the LA318 heads on the Magnum block need an oiling path added. Since this is a standard truck use, and a stock cam, the ports ought be adequate. But the open chambers are not going to be as good for compression... a step backwards unless you mill them down some IMHO.
 
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