I'm rebuilding a small block Chrysler V8, and I have a question, how hard should it be to turn the motor over without the heads on? It's been rebuilt from the ground up(all new bearings, piston rings etc...) I torqued all the mains and the rod caps and I think something went VERY wrong with it because I need a 3 ft long breaker-bar for leverage to turn it over. This is only the second time I've done a rebuild so i'm not sure what to expect but I dont think it should be so hard to turn over. please help. :ohcrap:
yeah, that sounds bad... did you oil the pistons/rings before installing? (i have to ask) did you try to turn it over before installing the pistons? what i'm wondering is at what point did it get hard to turn? i have a spec for it at home, but i'm not home right now...
Oh joy, someone ruining something that I'd love to get my hands on. Just
I assume you gapped the rings properly (if this was the problem I doubt you'd have gotten the pistons in the bores to start with) and I assume you plastigauged ATLEAST all the main crank journals and had suffient clearance.
Well, wait. You know what? I've seen this happen so much and it can be avoided. Let me tell you a tip that will allow this to never happen again. Torque all your mains, spin the crank a few revolutions to check for binding. Do the same EACH time you install a rod on the crank. I don't care how many books you come across that say hold up on torquing the rod bolts until you have all the rods in - do it one at a time, as you go, and spin the crank a few turns to make sure you have no binding. Do this and it will NEVER happen to you again because if something is wrong you'll see what it is.
Now... I'm going to go ahead and say your problem is the rods are in backwards. You have a big chamfer on one side of the big end of the rod on one side, and the other side has a smaller chamfer. The big chamfer faces the crank cheek (to clear the radii ground in the crank) and the small chamfer faces the other rod. Now, to make sure this happens this is what you need to check for. All of the rods on the left side (driver's side) should have there "mark" (little raised "-" basically, on the rod right above the big end of the rod) facing to the FRONT of the engine. On the right side of the engine (passanger's side) all of those marks should face the BACK of the engine. I'm going to say this is the cause for you're trouble - this isnt done the way I said. So check this and let me know what you come up with.
Umm, DodgeRida i think you got mixed up there, you said the the left side (drivers side) and then you said the right side (drivers side) so one is really the passenger side and the other is the drivers side, which way are you looking at it to detemine this, the front or from inside? Thought i'd point that out and ask.
well, half of the engine is from england...
Haha well then that makes sense. Thanx Dodger for clearing that up, now he can work on both the drivers side AND the drivers side.
Sorry, brain fart. I edited it now.
I did plastigage it, and im ALMOST 100% sure i put the pistons in the right way, I also checked the ring gaps, they were ok. The pistons had a notch cut in the top that was supposed to face the front of the engine, which I did. however, say i mixed up the pistons out of their order they were in the engine, could that be my problem?? also, at the bottom of the rods there were these marks, instead of something simple like 1,2,3,4,5,6...etc., they had the wierd things like half moons, clovers, boxes and the haynes manual mentioned nothing of this, so i had no idea what the exact order to put the pistons in.(i assumed it didnt matter) by the way, i did oil it up before and after i put them in, and it had always been hard to turn over since i torqued it and put it together. Since it was so hard I loosened the main & rod caps and oiled them well which did help a little bit. i'll be takoing the rod caps off to make sure theyre on right although i did not separate the rods from the pistons, but if i mixed them up DodgeRida is probably right.
The rods are in as DodgeRida described.... the bearings are a little shiny (by shiny i mean when i got them they had a dull look to them) by the oiling holes except for one, cylinders 7/8, where it was shiny all over but by the oil holes. :banghead: I suppose now need new bearings because these had fine dirt in them?? :ticking:
Check the bore size as well, and the piston size. You may be putting the pistons into bores that are too small. :2cents:
If you didnt seperate the rods and pistons then the pistons have to go in
the exact same hole that they came out of or else you're going to have
major trouble. One trouble is the trouble you are having now.
About these numbers... You can find them at the parting line of the big end of the rod. The parting line being where the cap and rod meet on one end. Also, where that number is, the number should be facing the closest engine block skirt, or else it's in wrong.
I say if you put them in the right hole, facing the right direction (which would be the notch on the pistons facing foward since you didnt seperate the rods and pistons) it will work out. By the way, 1-3-5-7 on the left side (driver's side) 2-4-6-8 on the right side (passanger's side).
It just so happens that I'm building a big block chrysler and I have the piston and rod assembles out on my assembly table in order as we speak. If the batteries in my camera will allow, I'm going to take a picture for you.
This should explain it. Print this out and keep it handy when you put it
back togethor. Keep in mind they are upside-down so the ones on the left go
on the right and the ones on the right go on the left...
About the bearings. If they aren't scratched but just brighter than before then you're in OK shape to use them.
These are where the numbers are. They should be on the same side (theres a
number in this location on the rod and on the cap. They should be stacked
over each other.) and they should also face to the closest skirt. For
example, the numbers on the left side piston/rod assemblies should face the
left side of the motor. The ones on the right should face the side side of
So orientation is way more than putting the notches on the pistons to the front. The notches in the pistons face the front, the notches on the rods on the left side of the motor face the front, the notches on the rods on the right side of the motor face the back, and they have to be in the right hole, and the numbers on the rods & caps facing the closest skirt.
I'd like to throw in that possibly within a week's time I'll be assembling my engine and if you will hold off until I assemble mine I'll take a picture for you while it's assembled and then you cant go wrong.
no, you see, THERE ARE NO NUMBERS, just wierd shapes and im not sure what order the "shapes are supposed to be
Well I don't know what to tell you then.
you know sometimes they stamp the # across the parting line on small blocks... is it possible that this is the case and maybe the shapes are actually half of a number?
Hang in there DodgeRida67.
Pinstriper38 you need to check a few things:
did you check for runout on the crank? I assume it rotated freely without the conrods attached? I don't know much about the foibles of Mopar engines, but if it has a rope seal you would probably have about 15 ft-lbs resistance and with rubber seal be able to rotate by hand;
when you put the thrust bearing cap on did you rock the crank front to back and hold it tight against the face with a lever while tightening?;
because you didn't remove the rods you probably didn't test for bending?;
did you keep the bearing caps with their associated rods? It always pays to pin punch the caps and rods:- e.g. three dimples for No3 , this identifies them easily and the orientation of the cap to the rod;
are you sure you have the caps oriented the right way?
did you change the rod bolts and if so check that the tunnels where still true?
I think DodgeRida67 is probably on the money when he suggests you have some rods out of kilter. Where the crank journals (pins) meet the throwers you will notice the metal is not squared off, but rolled. This is to impart strength. The rods and caps are chamfered on the side that mates to the rolled edge so that they don't bind. If you put a left bank rod on a right bank (vice versa) crank location the rolled edge will try to mate with a squared of surface and pinch the two paired conrods, located on the same pin, together causing them to jam.... it will also damage your bearings.
nope, theres a "shape" on each side, for example on the big end of one rod, theres this shape of a clover on the cap and the actual rod. some of them dont even have anything on them. Dodge just couldnt make it simple and put 1,2,3,4,5,6,7,8 on them :banghead: which is why i think its binding, because they (the piston/ rod assy.) may be out of order and i dont know what order theses "shapes" are supposed to be, if they are out of order that is what i think is causing it to bind.
Well I hate to tell you this but if they definately aren't numbered then you're going to have to make a choice. You're going to have to bore the cylinders, new rings, new pistons, have the rotating assembly balanced and then the numbering won't matter, only putting them in the correct side of the engine and facing them in the correct direction will.
I'm sorry what's runout? Yes it did rotate freely without them attached.
No I did not.
Yes. I did keep the caps on with the cylinders as soon as they came out.
I think I did switch 2 of the pistons. Probably they will all come out tonite and i will sort them according to DodgeRida's post. By the way, DodgeRida let me know when you finish rebuilding your big block and send me the pic. If i cant settle it i guess i wasted my time, money, and effort. no way can i afford to buy new pistons, balance it, and bore it on my own money. I'm only 14 and i cant afford this.
I suppose he's talking about thrust play or clearance. It's the amount of
"front-to-back" play the crank has. Should be between .002" and .007" I
Okay. Hopefully that will be this weekend. maybe tuesday... maybe wednesday. Can't say for sure.
If you didn't seat the thrust bearing your end play will be wrong and may be insufficient to take up all the intolerances of the conrods. You check runout with a dial gauge to see if the crank has a woof in it, while only clamping it with two outer bearings.
Ok, I think I figured it out. I re-arranged the pistons to DodgeRida's instructions, and I did have a few switched. However, when I did torque all the bolts it "locked" again, I think was because on the crankshaft's cyl. 6&7 journals, there a a few small nicks and they are catching on the con rod bearings. Which is making it hard to move. (they are faint) is there a way I could get rid of these without re-grinding the crank and buying new bearings? Other than that it will spin fine...
You are obviously on a shoe string budget? Try using the bearings on two good conrods to establish if you have a damaged set on 6 & 7. When you talk about nicks, you don't mean the metal has gauled and is sitting proud do you?
Definitely shoe string budget, but i do want this rebuild done right. the nicks look like you could get them out by using some very fine sandpaper or something...
You can carefully file the high spots with fine tooth, then use fine grit emery ribbon to level it. When you are satisfied the surface is true, reuse the same ribbon with some oil and polish to brighter than Brini Maxwells' teeth.
Usually, as I think someone already posted, you should turn the crank after torquing each of the main and cap bearings to ensure that each of the journals are true. I would follow wally's advise on the nicks on the crank and check the bearings for grit and nicks as well. :2cents:
Geez. A rebuild gone down the crapper... none of this is the way to get it done. http://blog.myspace.com/images/blog/moods/iBrads/aggravated.gif
Well DodgeRida, hows your rebuild coming along? You done or almost done the engine yet?
Trying to get ahold of my machinist so I can get my block back... It's been in for over 2 weeks getting decked, oil clearance measuring, cam bearings installed too.
that's almost reasonable, considering the lead times during the race season... :ohcrap:
Well I finally got ahold of him and I should be picking it up tomorrow.
First trip (bore & hone) took a month, second trip (crank grind, balancing, rod/piston assembly) also took a month. This trip (if I get it tomorrow) will make 3 weeks. :sleep: