So yesterday I had 7/8 Pistons installed and was able to turn the crank with a socket. It took a little bit to get it started, but once it started moving, it became easier. Today, I installed the 8th and can't hardly get it to budge. I gotta believe it shouldn't be this hard. Anyone have any ideas?

I feel like I have targeted where the problem might be. When I loosened all of the piston rod bolts, it became much more manageable to turn. My engine guy had told me to torque them to 50. I decided to plastigauge one of the rod bearings. At 50lbs of torque, I was getting .001 in. I decided to try torquing to 40 as I believe the 351 manual suggests and it was .0015in. However, I torqued crank journals 4 and 5 to 40 and left the rest hand tight and it was once again impossible to hand turn the crank.



What should the rod bearings read on the plastigauge? Any ideas of what the problem might be?

Are they stock bolts?

.001-.002" is fine for clearance on both rods and mains. Stock rod bolt torque is 40-45 ft-lbs. Main bearing torque is around 100 ft-lbs.

You don't want to turn the crank without torque on any caps or mains. You also want plenty of oil in there. If you turn the crank with the bearings loose it could spin them out of place and you could crush the locking divots when you tighten the caps.

So, clearances look ok but you need to look at each bearing again and see that they haven't turned. If they did you'll be buying a new set.

Another thing to look at is the chamfer on the side of the rods. The large chamfer needs to go next to the end of the crank journal, small chamfer goes next to the other rod. This can be wrong if rods are installed wrong on pistons, piston/rod is installed in wrong hole, or if piston/rod is installed backwards in right hole.

rods.jpg

Thanks. I'll check it tomorrow for correct install and bearings haven't turned.

Checked the rod install and they were backwards from the picture Phil posted. I took everything out, re-installed the correct direction, used copious amounts of lube on the bearings, and I'm having the same issue. Once I get more than 5 installed- it gets exponentially more difficult to turn. The 7/3 journal was so tight, I could not get it to go on with both rods. It actually jacked the bearing up so I know I'm gonna have to get at least 1 new bearing (if they even sell them that way.)

So my question is whether there should actually be a little play between the rods as well as between the rod and the side skirt? Am I right to assume that they need to also have enough room to move freely of each other?

I'm beyond frustrated and starting to wonder if the rods the engine shop gave me are too wide for the crank.

Thanks for the help...

How about a quick sketch of which holes have which pistons installed as viewed from the bottom? Something is wrong.

Here is a sketch of what was installed. When I had them flipped (1 where 5 is, 2 where 6 is, etc.) they notched side of the bearing faced inwards.

You need to find out if those pistons were labeled according to your diagram or the firing order diagram. Can't think of a better term to describe the second option.

So I spoke with my machine shop this morning and he talked me through it. I had the rod caps on backwards for one. I also had installed the pistons mirror image (flip flopped the cylinder banks.) I went out to the garage this morning and re-installed everything the way he explained it to me. Fortunately I have gotten my system down as far as intall goes and it only took me about an hour to do them.

WE ARE IN BUSINESS!! Everything seems to be installed correctly. I can turn the crank using a short breaker bar with one hand relatively easy. I plastigauged the bearings and at 50lbs of torque per his suggestion for these rods, I was at .0015.

Clearly I was the one who was inexperienced. I had swapped the cylinders so that the little groove on the bearings were facing outwards. This was opposite of what Scott at MPG had installed the pistons and so the install was meant for firing order. For the record, I have two small block FORD books that I have read through at least twice and a complete video tutorial on how to re-assemble an engine. I will say that some of the finer details didn't seem to come up in either of the books or the video (ex. the cylinder numbers are stamped on the rods, the rod cap number lines up with the rod number and faces outwards).

Again- thanks for the guidance... this experience will only make it easier to build the next one!

Good deal. Now how do you feel about degreeing the cam in?

What the deuce?! Yah-- I just tried watching a video on how to degree the cam. Help please. SO MANY NUMBERS, MEASUREMENTS, and NEW TOOLS I DO NOT HAVE!

Just spoke with Scott at MPG and he had already degreed the cam (he built it as a custom cam.) His only suggestion if I wanted to be very thorough, is to make sure that 0 TDC on the balancer is in fact the TDC before I install the heads.

Thank goodness I don't have to degree this thing-- will save me a lot of time and headache!

I was just teasing you.

More progress today. My buddy Levi came over and helped out-- it's amazing how much quicker things go with an extra set of hands!

We were able to get the oil pump, oil pan, heads and rockers installed.

Taped off to be ready for paint. Plan to paint this weekend and then I'll be ready to start installing accessories, intake manifolds, and start organizing installation. Need to run new fuel lines, and still figure out everything else I need for the EFI and Explorer front dress conversion.

Lookin good Eck

What is that pan from ?

What oil pump are you running? KBanks special or something new?

Disregard my previous. I'm now reading about high volume pumps causing premature dizzy gear failure and cam wear.

Much easier now than after the motor mounts are snug.