I have run into a problem with my 1990-1991, 302 rebuild, 0.30. I started it late last fall, winter and just been tinkering with it here and there...till now. I laid all my upper mains in, laid crank in, plastigauged the journals, sat lower main caps on, with lower bearings and tightened down from the #3 Thrust bearing out, in 3 steps, until I reached 65lbs torque. Only #1, 2 showed .003, and the rest never kissed the plstigauge. I'm using Clevite 77 bearings, P series, showing .020 on back side of bearing, came out of a sealed Mahle Clevite box.

I mic'ed the mains, all were 2.27, 2.25, 2.23. Crank was ground for .020 under mains and .030 under rods. It was originally .010 under for crank and .020 under for rods. I thought maybe it was old plastigauge, but bought new today and still the same.

Took crank down to the machinist who did the work, verified the work, showed him the still evident stuck plastigauge that hadn't even squished. He said he could do .030 under but could risk ruining the crank if this didn't even bring in within spec. Really? Is this MY fault?

Now, he tells me to use an old trick involving regular aluminum foil and lay it between the lower saddle and the bearing, using multiple pieces until I find it gets me near spec. I've never heard of this.

I never ran into this problem 2 years ago when I used plastigauge on my rebuilt '90, 302, 0.40 over, with 0.020 under crank and rods. I mic'ed the new bearing and I show .105, and the old bearing shows .100, the 0.010 bearings that were from the upper side and still were well enough to mic in a spot without damage evident.

What do I do now?!!! Scrap the crank, bearings and buy new crank and new bearings? Anyone that can help me, would be great!

 

Do ya think there was any way he could have machined the crank wrong?

 

He needs to get you a new crank. He should've told you this when you had him machine it.. He should've told you the surfaces were not all same sizes..

I don't understand how he did this

 

Hey brother also Have never heard of using his little trick either but it has been so darn long since i've even done any rebuilds in forever but of course if I got mad enough i would just go get a new crank and bearings myself.

 

Well now that i think about it your probably right and if i were him i would be very ticked off

 

Thanks for the replies. I needed to edit my 1st post.

I wanted to clarify my #'s for the mains.
1. 2.226-2.229
2. 2.225-2.230
3. 2.225-2.230
4. 2.225-2.230
5. 2.227-2.230

#'2-5 are just a tolerance as I mic'ed. I'm still completely dumbfounded about why only #1 plastigauged @ .0025-.0030 and the subsequent ones 3-5 were untouched...

Machinist thinks the block caps aren't correct for whatever reason. Been through everyone of them to many times to count and still can't find why???.

 

At this point it would be best to just buy a crank kit and scrap that crank. The bearings may be out of spec too. Just because they say .020 under doesn't mean they are. I ran into that last year on a 302 I was rebuilding, the #3 in the set was way off spec. Mic the thickness of each bearing shell and compare them to the #1 you found to be correct

 

Yeah that's my thought, put all the bearing as and caps in place without the crank and measure them.. odds are some of them are labelled wrong.

 

That's basically what I did with that out of spec thrust bearing after torquing it down and finding that I couldn't rotate the crank. I set the crank in the saddles and you could rock the crank up and down on either end. It was stamped .010 under but was more like .030 or more

 

Thanks everyone for the wise and informative replies. Here's where I feel lost. If you mic a bearing shell labeled for .020 under, should it be around .120 or should it be .104-.106...

Here's the rundown on the upper and lowers.

Upper Lower
1. 0.106 0.105
2. 0.106 0.104
3. 0.103-4 0.104
4. 0.104 0.104-5
5. 0.105 0.105

Going to lay shells in next and measure with all in place without crank and see the numbers.

 

There is definitely a problem with just the caps and shells in place. I'm hoping these numbers will help pinpoint the problem.

1. 2.227

2. 2.229

3. 2.231

4. 2.237

5. 2.239

I did notice that when caps are completely torqued, I found the following gaps between shell margins.

5. 0.010
4. 0.008
3. 0.004

#1 and 2 didn't show anything. It appears that the caps are the problem. Maybe someone can confirm this.

Have my old '92, 302 on it's backside, removing oil pan, best thing I can think of is to see if the saddles from it last 5 and 4 will remove the extra clearance or it's looking like a lost cause from this point forward.

 

I removed the shells from 1, 4, 5. Retorqued and have the following #'s. I'm thinking the block is the problem now. Hopefully someone can give me an idea on what to do from this point forward.

1. 2.443

4. 2.449

5. 2.452

 

Get the block aligne bored if you haven't already but if you had it done than the machinist messed up also bear in mind that this procedure can cause you to need a different timing set for an alighn bored block hope this helps I've actually seen this a lot with factory blocks

 

Just got back from talking with my machinist. Showed the same numbers I posted. He said exactly what you said. It looks like this is just more expensive than just needing to be honed and cut once.

Just priced it as $150

 

Hey brother it looks like your making progress even though its costing you more.