Chris Prack

It would be understandable to who that he mix forged and cast rods in one motor?

I have not seen this motor in person but would be willing to bet I could write a laundry list of things I would have a problem with were it my motor. It's a total hose job.

jp944

If the rods were all balanced, what's the problem? Lots of people mix forged and cast components in the crank, rods and pistons. I'd rather have a mixed set of perfectly balanced rods than a set of matching forged rods that are off by 8 grams. Again, I'm curious what the actual weights are.

Matt Sheppard

Both of those rods pictured are forged. Cast rods are thinner in the beam and obvious when you see one. The casting #'s on the background rod are on the other side of the beam and will have an "ORAST" at the end of it's part # - it's forged. Now, I still think it's sloppy to mix one forging design with another, but that doesnt nec. mean it's a mismatched set of rods in the motor. They may be matched end for end and constitute a serviceable set of rods. Their weights being this or that much off are pure speculation until you have these specific rods weighed: big-end/small-end on the proper jig.

Regardless, the comment that one of them is cast is simply misinformation.

Mike S

This is slightly off topic, but what's the purpose of the hole or circle in the bottom portion of those pistons? Never seen that before.

jp944

It was surprised.

Robby

5 grams is actuallythe weight of a nickel, NOT a penny... in any event, my opinion of his work, based on all of this is getting pretty low too- It really is starting to look like he just started grabbing whatever parts he could find & threw them on- that makes me sick- I'd like to give the guy the benefit of the doubt, but, the guy wont even respond- would rather write big general posts trying to make everyone feel bad that he's leaving RL... a local guy had an engine rebuiilt- an 87- turned out to be an 86 NA block thay JA rebuilt & sent IIRC- there were quite a few little things like this that happened w/his situation- he was pretty irritated too, after ~10months of waiting, considering that JA had told him ~3-4wks origionally....

Chris Prack

Matt your correct. I need to stop using the computer at work.............

Dave

Just when I thought it couldn't get any worse!
I just went out to take a few more pics and check the part number on the rods, the part numbers on both DO end in oRAST but the digits preceeding this are different. Good eyes, Matt! HOWEVER!! when I flipped the #4 piston/rod over to read the number I noticed something I hadn't caught before, THE WRIST PIN IS HALF WAY OUT!!! This is NOT the cylinder that is gouged from an errant pin! that make 2 that were loose!!! On further inspection there is just a slight scratch in the #4 cyl wall also. As I stated before, there was no sign of the retainer(s) in the pan when the first motor was torn down.
I was so livid that I didn't write down the part numbers from the rods or take pics, maybe later when my blood pressure is lower.

Chris, Good luck with the laundry list. it's only a block, crank, rods and pistons at this point and I've already found a dozen flaws in it, there can't be much left! (I hope!) I don't have a suitable scale so the weights will have to remain a mystery.
The pistons in the current block have a much smaller dished area than the '86 pistons but I dont think it's as small as the one in the pic you posted. The dish is flat-bottomed like the larger dish and about 1 1/4" diameter, maybe it's my monitor but the pic looks like it's just a 1/2-3/4" dimple. More pics when I calm down, when I have time I'll pull the other 2 pistons. I'm also trying to find the pics of the blue rod caps. Now I have another reason to worry. The blue rod was removed and reconditioned but the other 3 were not removed from the engine. How much effect on weight would reconditioning this rod have??

Z-man

Dave:
Sorry to hear of your continuing woes.

Regarding the weight: why not make your own balance type scale? You won't know the exact weight of each, but you'll be able to see if they are close to each other.

Hang in there...
-Z.

IceShark

I suppose there is some special trick to weighing the rods so that the weight distrubution is similar over the entire length of the rod so it would be best to take them to a local machine shop and ask them to weigh them. For a gross measurement you could also just take them to a local coin shop. They usually have pretty accurate scales for light items to weigh coins & bullion. Or if you know someone that reloads ammunition - they will have an accurate scale for weighing powder though I don't know if it will go high enough to weigh a rod - my reloading scale is in the attic and I don't remember how high it went.

Sam Lin

To balance rods you need to hang them horizontally, one end to an immobile object and the other end hanging on the scale, then flip it around and do it for the other end.

Sam

Robby

Coin scales- that's a good one- I was thikning postal scales- you can get some at gas stations here, that are dirt cheap- And they sell TON'S of them b/c SO MANY people like to know exactly what their letters weigh! Not sure if these would work for rods either though as I have no idea how much that stuff weighs- the postal ones are good to w/in~1g up to close to ~2OZ maybe- the OTHER types of scales people use for the really expensive "letters" would probably work better, but, I've never had the need for them, nor would I want to spend the $- I would kind of like one to play w/one day, but.... I was always told a nickel weighed 5g, but, I assume it's possible for there to be some sort of tolerance range there too...



-I just had to use one of the cool new smileys...

visualpascal

Nickles do weigh 5g, you need a pretty intense scale to see a difference... Bills weigh 1g.

--Chris

Legoland951

Dang you are having so much problems with your motor I am willing to donate my 83 n/a shortblock so you can have your car up and running (had a blown headgasket) if you can get someone to come pick it up and ship it. There are no visible scores on the cylinders and I am pretty sure the rods are forged.

Dave

I had considered rigging some sort of balance beam to compare the two assemblies that are already out of the block, I'll give some thought to what is laying around that would be good for this. I have a small scale that does 1/4 oz increments up to 17 oz but the assemblies are several lbs so that won't do it, motor oil on my hops scale doesn't sound good either.
Lego, Thanks, but I don't need anymore engines! the second AMW engine and the head have been redone as needed and reside under the hood of my car. I don't believe this setup will last as we only fixed what we saw and didn't dig fir more. When it goes, I have my original engine that needs only rings and bearings to be perfect. My problem is not that I'm without an engine but that it took so long and a few thousand dollars more than it should have to get it right (maybe not "right" but running).