96 3100 Rods

[ForcedFirebird]

It's bubble wraped and will be ready to ship in the morning, but might not go until Sat morn, depends what time I finish a job tomorrow.

Let us know how it goes

[94GPGTP]

It's bubble wraped and will be ready to ship in the morning, but might not go until Sat morn, depends what time I finish a job tomorrow.

Let us know how it goes

When did u get thecam shipped out?? thanx

[ForcedFirebird]

When did u get thecam shipped out?? thanx

Yep. I didn't get it out until this morning, though. 2 day priority it should be there Thurs/Fri. It was $15 to ship.

[94GPGTP]

ok good deal.. ill let u know when i get it

[94GPGTP]

Well today brought the heads from this motor to the machine shop to get the head job done... also i brought the piston that had the bent rod and a replacement rod for them to press out and swap.. well they claim that when pressing out the rod that the piston will be destroyed by it mushrooming by the wristpin.. I dont know if they r telling me the truth or not..

I get a call about 4 hours later they tell me both of my heads are cracked.. one is near a spark plug and the other is cracked in between the combustion chamber... So basically these heads are junk...

Now im in need of 2 heads... This is pissing me off b/c i have a bent rod, bad cam, bad timing set, Bad heads.... This makes me confused because the motor ran smooth and no problems with it.. I think this is a bad build to begin with...

[ForcedFirebird]

Well today brought the heads from this motor to the machine shop to get the head job done... also i brought the piston that had the bent rod and a replacement rod for them to press out and swap.. well they claim that when pressing out the rod that the piston will be destroyed by it mushrooming by the wristpin.. I dont know if they r telling me the truth or not..

I get a call about 4 hours later they tell me both of my heads are cracked.. one is near a spark plug and the other is cracked in between the combustion chamber... So basically these heads are junk...

Now im in need of 2 heads... This is pissing me off b/c i have a bent rod, bad cam, bad timing set, Bad heads.... This makes me confused because the motor ran smooth and no problems with it.. I think this is a bad build to begin with...

Take the heads somewhere else and get a second opinion.

If you need some good cores, I have a set :P


EDIT: Actually I can give you a rebuilt set if you want.

[94GPGTP]

well i was talking with taylor and he made a good point.. i unfortunatly didnt put any markings on the heads.. he told me since i didnt they could possibly swap them with bad ones and try to sucker me into buying heads through them which in general gets them more money.. and making the whole thing up.. well the only positive side i have is that one head has 2 heli coils in it and the other well i dont know..

When i get them back tomorrow i am going to get pics of the "cracks" and post em up..

ForcedFirebird Give me some more info on the heads you have..

[SappySE107]

Doesn't have to cause a problem to be cracked. If its not all the way through, you wouldn't know. Vans have more problems with this on the rear head but anything is possible.

[3100 MPFI]

I just mentioned that in the short few years I have been working on these engines, I have NEVER seen a head crack. I have seen them WARP, but not CRACK.

I also mentioned that when I take parts to a machine shop, I write down my casting numbers, and then I make a small engraving on them (in an exposed area like the side of the head) of a symbol that will NEVER be seen coming from GM (gotta love the double-male symbol for GAY).

I also mentioned that I have not heard of a piston mushrooming trying to get the wrist pin out. I have had some pistons swapped out before and got the old ones back just fine. Them saying that strikes me that they are trying to press the pins out without heating them up first (or however they do it). I got a full set swapped out, and the stock ones were not mushroomed in the slightest (camaro pistons on 3100 connecting rods with the 3100 pins).

[ForcedFirebird]

I somewhat agree on the cracks. I also have not found any cracks on any of the 60* heads I have encountered, although I have found many cracks on aluminum heads in general (all of them overheats).

Yeah, there are a lot of crooks in the biz, but people like me just hope that doing good business will create more in the long run. Sucks, but it does happen in every business category.

Taylor is right, heating/cooling parts makes the job a no-brainer. Dipping the wristpins in dry ice for about an hour will make them practically fall in without any force. Aluminum is going to expand with heat much faster then the steel pins, and they should come out fairly easy with the proper tools.

I have the cores I can send out anytime if you are going to take them local.

[SappySE107]

I have had heads with cracks and seen them at the machine shop. Its more common than I thought.

[ForcedFirebird]

I have had heads with cracks and seen them at the machine shop. Its more common than I thought.

Really? Although you have seen far more 60* head then me, I'm sure.

Is there a potential weak spot the is common, or multiple areas of concern?

[SappySE107]

Between the valve seats and between the spark plug and the valve seat. I think its from overheating...due to bad LIM gaskets.

[jp_grasshopper_007]

Taylor is right, heating/cooling parts makes the job a no-brainer. Dipping the wristpins in dry ice for about an hour will make them practically fall in without any force. Aluminum is going to expand with heat much faster then the steel pins, and they should come out fairly easy with the proper tools.

The pins should be stuck in the rod not the piston, dry ice isn't going to do anything. How a shop is going to "mushroom" the wrist pin I have no idea. They will have to pressed out, that could damage the pin (maring the outside surface) but more than often not so bad it can't be reinstalled in a stock eng. As far as not knowing if the shop is fucking you or not, don't take your shit there. If you can't trust them don't use them. But, those heads crack, in those spots. See em all the time. LIM gasket leaks for a long time, eng over heats, blows head gasket.

[ForcedFirebird]

The pins should be stuck in the rod not the piston, dry ice isn't going to do anything.

It's worked in the past for my machining mentor.

Cooling the metal will decrease it's size.