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Old 09-26-2006, 09:14 PM   #1
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Default Piston/Rod stuff(It has pics)

So I went to my garage, took my old '95 tranny apart and reassembled all of the internals outside of the transmission case. Then I decided to tear the oil pan off of the L36 I have in my garage. Here is what I found.... It'* not interesting to many people, but I find it useful.

Here is the standard rod and piston assembly. I intend to get an actual weight on these pieces sometime. The poor L36 guys need all the edge they can get, and if lighter rotating assemblies can be made, then a few more horsepower are freed up.


The cap has 7/16" bolt heads(3/8'* bolts?) and they were surprisingly easy to remove with a 12" 3/8th ratchet.


The piston head slightly wiped off. I think that it could be changed out for a flat top with valve reliefs for alittle more compression



The bearing had a nasty groove in it. What I found funny is that the saddle and cap had wear and not even the slightest showed on the sides of either bearing. Maybe that'* normal? I don't know, I haven't torn many of these things apart this far.


Then for chits and giggles I laid one of my forged H-Beam rods next to it for a little comparrison. The H-beam is 6.658" long..... Just about the same length as the piston and rod of the L36...




I personally think that the L36 powder metal rod(?) is a bit on the heavy side, and a set of I-beams would free up some weight there. The piston is a not forged from what I can see, and it feels fairly light. I'm sure you could order some custom lightweight pistons with valve reliefs as mentioned earlier and save a little weight... Maybe it'* just that the thing has sat for so long, but I can not get the wrist ping to rotate inside the rod leaving me to conclude it'* a press fit. If that'* true, then a full floating wrist pin setup wouldn't hurt either. Lighter is faster, and I wonder what gains an L36 could see from this....

Thoughts? Insight? I'm interested in this stuff, fill me in on what I missed and correct anything I have wrong!
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Old 09-26-2006, 09:19 PM   #2
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of topic question...
when you cars done will it look like this?
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Old 09-26-2006, 09:22 PM   #3
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Pete.... no. That'* a sissy Ford 3.8L. Unless it'* a splitport(which that one isn't), it can't hold a candle to the L36. I have the 4.6L currently and will be upgrading to the 5.4L Lightning engine to start, replacing the M112, and intake setup of the lightning for something with a little runner and a Procharger P-1SC or maybe even an F-1R.

Additionally, I hate chromey crap on my car. I like it to be satin finish or just plain dirty.


*EDIT*
It looks like this....
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Old 09-26-2006, 09:53 PM   #4
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Yeah the old ford 3.8s sucked ***. Like 160 max HP and head gaskets went laft and right.

Hmm....dont look like that 4.6 with supercharger will clear your hood.

That supercharger looks like the one in my F150

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Old 09-26-2006, 09:55 PM   #5
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You do have to admit tho it is a pretty beefy rod for your run of the mill 3800 V6... and look at the abuse we give them..

But any weight reduction that doesn't sacrifice structural integrity would get my vote..

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Old 09-26-2006, 10:15 PM   #6
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Quote:
Originally Posted by Shadow
Hmm....dont look like that 4.6 with supercharger will clear your hood.
5.4L..... And anything will clear my hood with the help of my good friend sawzall!

I believe that rod is too beefy. Hence the weight problem. What I found interesting is that GM did a machine cut on the rods/caps. Unlike the Ford cracked caps in my engine...
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Old 09-27-2006, 12:08 AM   #7
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Quote:
Originally Posted by MyLittleBlackBird
Quote:
Originally Posted by Shadow
Hmm....dont look like that 4.6 with supercharger will clear your hood.
5.4L..... And anything will clear my hood with the help of my good friend sawzall!

I believe that rod is too beefy. Hence the weight problem. What I found interesting is that GM did a machine cut on the rods/caps. Unlike the Ford cracked caps in my engine...

Oh yes 5.4..Ithe valve covers looked like the ones on my dads Towncar so i assumed 4.6. My truck has a 5.4 but its the 24v version.
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Old 09-27-2006, 12:53 AM   #8
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Since you brought up the piston/rod assembly, I was wondering about something a week or so ago..
I know that the L36 and L67 rods/pistons aren't mix and matchable. So, what is different about them as far as dimensions go?
I think I've read that the the pin is larger, and the L67 parts are most definitely beefier.. But are the rods and pin positions different?
If they are different in one way it may be able to help the L36 out..
Say if the rods are the same length but the pin position on the L67 piston is higher. That opens up the possibility for a slightly longer rod, and there is already an aftermarket for L67 pistons.. You could most definitely get lighter of both..
So, that would mean there is a possibility for a better rod to stroke ratio.
Anyone have both assemblies laying around?
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Old 09-27-2006, 01:35 AM   #9
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Hmmm....dished pistons. Never knew that.
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Old 09-27-2006, 09:45 AM   #10
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From the looks of it, the pin could be moved up a bit before reaching the oil ring. On an aftermarket piston, you could have a different compression height and move the ring packs up a little to accomodate for more rod. I wonder how long the rods would hold up if someone were to take a drill and punch out the thin centerline area... If I had a gram scale handy and a test engine, I'd give it a shot
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