crankshaft rebuild trouble
10-12-2009, 01:28 AM
#11
Thread Starter
Join Date: Oct 2009
Location: hawaii
Posts: 13
ok well just checked both the main cap bearings and the rod bearings and there both std. and everything looks pretty clean. would the fact that I had it bored out with the new crank, pistons, rods, beagings, heads, valve train, timing chain. the only thing thats origional is the block. everything else is brand new never been ran before. and bored out too.
10-12-2009, 02:24 AM
#13
Thread Starter
Join Date: Oct 2009
Location: hawaii
Posts: 13
well i just found out whats going on. every rod and main cap goes in smoothy except one rod. its the only one that i have to actually tap to get it into place n everytime I put it in it is impossible to turn so I guess ill have to take that rod out and get it machined. thanks for the help though
10-12-2009, 06:18 AM
#14
Thread Starter
Join Date: Oct 2009
Location: hawaii
Posts: 13
ok so ive been messin around wit the engine for a while and ive found a few things. I first torqued the rods to 45 because thats what was the max reccomended by scat. but I started stepping down the torque limits because it says thats the max and as I steped down the torque I was able to spin the crankshaft more and more easily with more pistons attached. and ive been looking on the internet to try and find what the torque limits are for a 347 stroker but im not having very good luck. most sites dont have for a 347 stroker but they do have for a 289 and they all say 19-24 is this correct and does anyone know the correct torque limits for a 347 and could that be the problem.
10-12-2009, 11:08 PM
#15
Join Date: Oct 2009
Location: NC
Posts: 10
I had the same problem it was the bearings i used a micron meter to check them and i was right the bearing that came with the kit was to thick. There should be a number on the bearing that you can go by, but you best bet is to measure them with i micron meter you can go to your local parts store they will let you use it to measure the bearing. Good luck
10-12-2009, 11:39 PM
#16
6th Gear Member
Join Date: Jan 2007
Location: AR
Posts: 5,469
Do you have the caps on the right way?
If either the main caps or the rod caps are on backward, they will NOT fit right.
You need to get a good SBF rebuild book. Don't be shy about this, I bought one before doing my first Ford after doing many Chevys. There are too many little issues that will f you up if you don't do just one right.
Plasti-gages and feeler gages MUST be used at a MINIMUM. You MUST check ring gaps, piston skirt clearance, and rod and main clearance. Too much can go VERY wrong when depending on the work of others and/or good luck in these areas.
There are for sure other issues that can bite you in the *** to be sure, but, get any of the above to loose, or even worse too tight, and you are going to have a miserable and very expensive day....
and btw, leaving the rod bolts loose for clearance ain't going to make the grade....
can you spell catastrophic engine failure?
If either the main caps or the rod caps are on backward, they will NOT fit right.
You need to get a good SBF rebuild book. Don't be shy about this, I bought one before doing my first Ford after doing many Chevys. There are too many little issues that will f you up if you don't do just one right.
Plasti-gages and feeler gages MUST be used at a MINIMUM. You MUST check ring gaps, piston skirt clearance, and rod and main clearance. Too much can go VERY wrong when depending on the work of others and/or good luck in these areas.
There are for sure other issues that can bite you in the *** to be sure, but, get any of the above to loose, or even worse too tight, and you are going to have a miserable and very expensive day....
and btw, leaving the rod bolts loose for clearance ain't going to make the grade....
can you spell catastrophic engine failure?
Last edited by JMD; 10-12-2009 at 11:44 PM.
10-14-2009, 09:33 AM
#18
6th Gear Member
Join Date: Dec 2006
Location: Citrus County, FL
Posts: 8,007
just a quick side note:
you don't find torque specs based on the fact that its a 347, you need to know what they are from ARP for those bolts. and yes, make sure the caps aren't on backwards and that they aren't mixed up. the "tang" on the bearings should face each other when the cap is installed.
you don't find torque specs based on the fact that its a 347, you need to know what they are from ARP for those bolts. and yes, make sure the caps aren't on backwards and that they aren't mixed up. the "tang" on the bearings should face each other when the cap is installed.
10-14-2009, 02:41 PM
#19
Thread Starter
Join Date: Oct 2009
Location: hawaii
Posts: 13
Im getting plastigauge today to check the bearing clearences. I havnt checked the main cap bearings. I know the caps themselves are facing the right way but I didnt know the main caps bearing had a tang and were sposed to face a certain way. The rod bearings have a tang on them and are facing the journal walls as specified by scat. What does the rod clearance need to b and what tool do u use to check that.
10-15-2009, 02:25 AM
#20
3rd Gear Member
Join Date: Aug 2009
Location: Washington
Posts: 723
By rod clearance are you meaning the clearance between the rod caps of the two rods on that crank journal? If so, you would use a feeler gauge. As far as clearance, it would be best to talk to Scat and see what they recommend.
As much as I hate to say it, you may have to completely take that motor back apart and have the block checked to make sure your main webs are round and within spec. If you do that, you might as well have the crank and rods checked also.
As much as I hate to say it, you may have to completely take that motor back apart and have the block checked to make sure your main webs are round and within spec. If you do that, you might as well have the crank and rods checked also.