Help with my first engine build (5.9 Magnum)

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No visible cracks, they are a little dirty but looking good so far! Feeling lucky about that, there isn't a whole lot of meat between the seats on these motors...
No visible cracks is good. But because of their reputation I’d still mag them. I’ve seen one head have cracks that I could see. And two sets that showed up with magnafulux.
 
That’s a good call, I wouldn’t be surprised to find crack that I can’t see with my eye alone…

Tonight I thought I’d take on the simple job of cleaning up the heads, but then realized I still had to remove the spark plug heat shields. In my mind it was a quick job before I got to the cleaning… almost 2 hours of swearing and fighting later I had them all out. I guess I’ll be cleaning tomorrow lol.

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That’s a good call, I wouldn’t be surprised to find crack that I can’t see with my eye alone…

Tonight I thought I’d take on the simple job of cleaning up the heads, but then realized I still had to remove the spark plug heat shields. In my mind it was a quick job before I got to the cleaning… almost 2 hours of swearing and fighting later I had them all out. I guess I’ll be cleaning tomorrow lol.

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Crazyness. I’ve never had that problem. Maybe Alaskan weather vs California desert?
 
Crazyness. I’ve never had that problem. Maybe Alaskan weather vs California desert?

Could be! Definitely a lot of moisture around here, they where pretty rusted. Before I started pulling them I read in a thread that you can just twist them out with needle nose pliers lol. I felt like I needed the jaws of life on a couple of them.
 
Heads first round of cleaning is done. Got real familiar with my drill and wire wheel. Hosed everything down with break cleaner afterwords.

Also, my cam bearing tool was delivered today! I’m going to do a little more reading on using the tool properly before I attempt to use it this weekend.
 
Cam bearings knocked out today and started cleaning valves.

Questions
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1. I noticed some scoring in the block after knocking out the cam bearings. Is this something to worry about? The rear most bearing hole (I don’t know the actual term) was the most scared up. It’s in the picture below.

2. When cleaning valves, is it okay to soak them in parts cleaner to help soften the carbon build up?

3. Can I use a brass wire brush on the valves, or is that too harsh for them?

I started cleaning them with wd40 and a scotch bright pad. But can’t get it completely clean with that method.

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Questions:

1. I noticed some scoring in the block after knocking out the cam bearings. Is this something to worry about? The rear most bearing hole (I don’t know the actual term) was the most scared up. It’s in the picture below.
Those marks are from when the bearing was installed. The bearings are a press fit. No worries.
2. When cleaning valves, is it okay to soak them in parts cleaner to help soften the carbon build up?
[QUOTE/]
Yes
3. Can I use a brass wire brush on the valves, or is that too harsh for them?
Brass? Yes. I have used steel/stainless steel. You just don’t want to scratch or mar the margin. The area that actually sits on the head to seal.
I started cleaning them with wd40 and a scotch bright pad. But can’t get it completely clean with that method.
It takes a while. You can get pretty aggressive with a wire wheel on most of the valve.
Soak, scrub, soak, scrub, soak, scrub

Sorry, for some reason, I can not get rid of the last “QUOTE” tag at the end. It keeps reappearing causing my reply to be left within the original quote and leaving everyone to expand the reply I left within the original quoted text.
 
Thank you! I’ll get back at it after work today and post an update when I’m finished with the valves.
 
I have taken valves and wrapped the stem in tape and chuck them in the drill press. Brass brush and carb cleaner takes it off. Don’t push hard, let the brush do the work.
 
Cam bearings knocked out today and started cleaning valves.

Questions
:

1. I noticed some scoring in the block after knocking out the cam bearings. Is this something to worry about? The rear most bearing hole (I don’t know the actual term) was the most scared up. It’s in the picture below.

2. When cleaning valves, is it okay to soak them in parts cleaner to help soften the carbon build up?

3. Can I use a brass wire brush on the valves, or is that too harsh for them?

I started cleaning them with wd40 and a scotch bright pad. But can’t get it completely clean with that method.

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Sometimes if the cam bearing tool is tightened too much, the outer diameter of the tool arbor will be larger than cam bearing itself and score the journal like that. When knocking out the old ones, do not tighten the tool very much. You will see how this can happen when you go to knock the new bearings in. Especially the rear bearing, the tool will catch on the block.
The scoring will not cause problems if there is no raised edges. If there is raised edges, gently knock the edges down with a round file or sandpaper on something round. Don't cause more damage, just debur the scoring so it does not distort the new bearing.
 
More cleaning today, valves are all done (aside from lapping them), and the oil pan’s first scrubbing is done. Tomorrow I’ll hit the pan with a wire wheel and prep it for paint.

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Well I got the oil pan cleaned up pretty well, just needs a good degreasing and I think I could throw some paint on it. However, am I wrong in thinking a late 1960s LA pan from a 273 will fit my Magnum? (The regular Magnum truck oil pan won’t fit my A-body). I thought I read that a modification to the gasket was all that is needed. I set the pan on my motor and there is quite the gap between the engine and the pan. Maybe my cleaning was for nothing…

*in the picture the pan is on backwards, I was doubting myself flipping it around checking both ends when I took the pictures.


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Magnums used the 360 pan. A 273-318-340 pan won't work. This should Mancini Racing Center Sump Oil Pan Kit IIRC the conversion gasket is for using the one piece Magnum gasket with the LA360 timing cover and pan as opposed to the 4-piece LA gasket. If you plan to run a fuel pump you are most likely using a LA timing cover so you should be able to just use a LA360 pan gasket set.
 
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Just a heads up. I used a summit center sump pan on my magnum (added home made baffle/scraper). When I fired it up the trans cover was hitting the flex plate. Turns out the pan was overhanging the block and this prevented the inspection cover from contacting the block. Make sure the pan lip is flush with the block.

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Thanks for the tips guys! I’ll be sure to check that out when I get a new pan.

Today I worked on another one of my rigs (1970 International Pickup). But my valve springs, keepers, and retainers showed up in the mail! They look quite a bit beefier than the originals. Time to put the heads back together.

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Finally got around to lapping my valves. The larger valves are coming out great, but the smaller valves have some pitting. Is this common? The same issue can be seen on the valve seats too. It’s consistent on every set of valves.

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Like Bewy said. And notice that the exhaust valve seat has recessed into the head.
 
To actually smooth down the ports and polish is a power looser. Don’t do it.

I just installed a 750 AFB on mine. I have Hooker 1-3/4 headers into a 2-1/2 exhaust. Also like yourself, an AG, 3.55’s rolling 245/60/15’s. Will be installing a 2500 converter in the 727 soon. Still mulling over a cam, but the shortages…. Ugh! Smallest cam I have on my shelf is a 230@050 and a 236@050. Which I’ll probably do the latter (236) with Rhodes lifters on the intake inky and drop the duration some. Might work OK.
What are you expecting the sweet spot with that cam.
I have a Similar one posted as 1800-5800
Sweet spot ,500 lift
 
If I could find a valve seat cutting tool, do you think that could solve my valve seat issue? Along with fresh exhaust valves of course. Trying to avoid the machine shop if possible and do what I can on my own.

What happens if I keep lapping the valves until the pitting goes away? Would this produce other issues? I ask because I lapped one of my valves again and the pitting was less defined. It seems like I could lap them 4 - 5 times and have a usable surface (each time lapping the valve until I feel the lapping compound smoothing out, then I remove the valve and clean everything before adding compound again).
 
What will happen is you will sink the valves. This is bad….
Very bad for performance. You lose lift at the valve because it has to over come the amount you ground away. During the lift cycle, the valve spends more time in a low or dead flow area.

IF! After cleaning up the valves and seats the valve leaks, then replacing the valve becomes necessary. You may be able to get away with the pits on the valve in a cheap budget build, but do remind yourself new valves are not all that expensive in the big picture.
 
That's great information. I 've been told that the stock Magnum cams are very whimpy, but wasn't sure when I would have to start worrying about upgrading keepers and retainers with my choice of new cam. Its nice to know that I'll be able to use stock components (aside from valve springs).

I THINK the Mag 380 crate motor used stock valve gear aside from springs (which you covered), with its cam, which is more aggressive (.501/513", 288/292) than yours.

And note: with what was essentially a truck long block with headers, 9:1 squeeze, and a hot cam, they made about 400hp. (I suspect that 380 was the lawyer-friendly number.)
 
I THINK the Mag 380 crate motor used stock valve gear aside from springs (which you covered), with its cam, which is more aggressive (.501/513", 288/292) than yours.
Correct

And note: with what was essentially a truck long block with headers, 9:1 squeeze, and a hot cam, they made about 400hp. (I suspect that 380 was the lawyer-friendly number.)
Yup. I’ve seen tests with this engine between 410-415 hp. Pretty darn good for a stock truck block. It did well as a bracket engine.
 
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