Throwing together my 408w and I seem to be having binding issues. I am using main cap studs. Part numbers I am using are as follows:
crank: 4-351W-4000-6200
rods: 2-350-6200-2100 *yes, these are chevy rods. Decided to use the 2.1 rod journal. matches crank
main studs/girdle: MSS-1020
using clevite tri metal standard size bearings used for crank and rods (upper and lower bearing halves put in correct places)
using icon pistons if that matters?
heads, timing chain, etc not installed so no compression to fight.
assembly internally balanced and rings file fit by Arlington Machine Shop. The man I spoke with notified me that the tolerances are on the tight side but should work great he assured me. Also said I can use 10w-30 as I intended.
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here's what i know: rotating assembly is stiff and must be turned with breaker bar with main caps "snug" but rotates smoothly. When main caps are fully torqued (90ft pds in 2 steps with arp moly lube and a dab of red thread sealer(*optional in DSS instructions)) it will not turn with breaker bar+cheater bar. Is this normal? All parts are brand new and I have heavily coated every bearing in engine assembly lube and cleaned everything prior to assembly.
Did the crankshaft rotate prior to the con rods being installed? If so, you probably have a problem with the con rods being too tight on the crank or the pistons/rings seizing in the bores.
I think everybody already covered it but my VW seized up just like that on brand new assembly. I had a miss boxed set of rod bearings for one rod. The box said one thing and the rod bearings said something else. You can systematically find the problem by installing one set of bearing shells at a time, spin the engine until it seizes and thats your problem area. I could be a journal was not cut right or wrong bearings. Sometimes the thrust bearing is a suspect area.
If it rotates "smoothly" before the mains are torqued to spec but doesn't afterwards, I would start by trying one main at a time to see which one is doing the binding or if maybe you have the wrong set installed (ie, they all bind).
I have learned to rotate the crank (at least some) after doing any torquing before moving to the next part to be torqued...You know right away if something binds and what it is.
You may need to have it align honed with the switch to main studs. What is the bearing clearance? The main caps themselves, they didn’t get mixed or swapped around did they?
Good advice by Allen. Install one thing at a time and test. Way too tight though. I had a similar issue with a 289 recently while trying to use a Canton main stud girdle I previously used on another 289 build. When the rear main was torqued, everything locked. So I decided to abandon the girdle. Everything works nicely without it.
main caps were align honed. Will double check on rod direction. I suppose based off what Idouble619 said, I should have 4 of each facing one way or the other. Had machine shop connect rods to pistons because the pistons use spiral locks.
No, I did not plastigauge. I know some manufacturers have minor defects etc but I figured the $$$ I spent would mean quality control.
crank would rotate by itself before rods were installed
here's what i know: rotating assembly is stiff and must be turned with breaker bar with main caps "snug" but rotates smoothly. When main caps are fully torqued (90ft pds in 2 steps with arp moly lube and a dab of red thread sealer(*optional in DSS instructions)) it will not turn with breaker bar+cheater bar..
-with nothing torqued, just snug:
the crank by itself was tough to spin but will with just a breaker bar.
tough to spin with crank and rods installed but will with breaker+cheater bar
-with mains only torqued, rods snug:
will spin but tough with breaker+cheater with only crank
will not spin with breaker+cheater bar with rods and pistons installed
last night I verified that rods were all facing correctly. rechecked all rod and crank bearings. all standard size, upper/lower all placed correctly. still does not spin with just mains torqued and rods/pistons installed.
Once you get this straightened out, regarding the rods, look closely at the big ends. Each rod has a small chamfered side which is not much more than a round over and the other side has a big chamfer in it. Each of these larger chamfered sides faces the crank side when the rods go on the journals. At the same time you have to make sure your pistons are pointing forward. I always pair them up and even label the cylinders they go in before hand on top of the pistons with a sharpie. Its kind of easy to get the things twisted around.
Its definitely time to take it apart and and check the reassembly step by step.
On a freshly installed crank with lubed bearings and then torqued crank a with no rods should spin very freely when rotating the counterweight by hand. There should be no bind in any part of the rotation. You should also have a small amount of for and aft free play (did you properly seat the crank thrust bearing?) Main caps need to be properly placed and in the correct orientation.
Installed and lubed crank with rods attached and torqued down should spin freely (once it starts rotating) with 25lbs or slightly via a beam torque wrench on the front off the crank. That's including a lubed rear main seal and wrist pins.
This will likely start a firestorm but first thing I would do is call ARP and find out the correct torque. Torques in the shop manual are for use with a 30 wt oil. Changing the lubricant on the thread changes the torque. Flame suit on...
I don't think fastener torque will affect how tight the bearings are.
With a factory style rebuild, plastigauge is fine. With a custom build such as this, it's necessary to check everything with a micrometer before assembly to prevent situations just as this. Custom crank and custom rods may require custom bearings.
Simple... you have the wrong bearings. I had the same problem many years (and two engines) ago. I replaced the crank shaft and was given the newly machined shaft along with a set of crank and rod bearings. I was new to all this stuff, so here's what happened:
Put the new crank in.
Torqued all the caps to spec.
Couldn't turn it.
Tried assembling it with a friend turning the crank while I was tightening the caps and squirting oil on everything while tightening.
Locked up again.
I took it apart, brought the crank and the bearings back to the machine shop. The guy looked at the markings on the crank, looked at the bearing package, rolled his eyes and told me the bearings were .001 too thick. Gave me a new set, I went home and put it together and everything worked nicely.
Measure everything with precision instruments; calculate clearances; compare with specs; and go back to your machine ship with the results if you trust them. If not, find a machine shop with a solid reputation for precision work and well running engines. Anything less and you are assembling a grenade.
You only coated the rotating assembly side of each bearing correct? My first reassembly when I was 15, I put lube on both sides of main and rod bearings then torqued the engine to spec. It should have rotated by hand without the heads but wouldn't. The guy supervising me let me go ahead with what I was doing knowing I would run into a problem. It was his teaching method. I had to undo everything I did, clean the bearings, block, and connecting rods of the excess lube and reassemble the rotating assembly with the outer side of the bearing installed dry.
This time after assembly everything turned smoothly without binding anywhere.
I’m not calling you out, just commenting that lube can and should be applied in generous amounts to all the rotating parts. If you had problems rotating the bottom end when lube was applied to both sides, you had a problem different than a well lubed bearing. Likely you did create some unnecessary wear on the dry bearing until lube found its way there. Speak with a engine assembly professional and they will advise you as I have.
You can and should retorque during assembly just to be sure you didn’t miss anything.
I hadn’t considered someone would coat the back side, but reading it again I see what he was saying. It is a good point however for new engine builders that they should have someone watching them and guiding them. It does not make anyone any less intelligent or any less capable to have a knowledgeable set of eyes behind them, it’s just that we don’t know what we don’t know and what seems like a good idea is sometimes what may cause damage.
I think this is a great set of responses! When I first read a link I try to think of all the possibilities. Not that I am the best, but I have quite a bit of experience. You guys got everything listed that I thought of and a little more. You guys are a great team.
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