Mar 23rd, 00, 06:24 PM
This may sound funny but do all of you guys plastigage the connecting rods to the crank?
After the machining to both the block and the rods. Every engine builder I know say that there is no need to, because the shop should provide you with the right size bearings.
Mar 23rd, 00, 07:05 PM
Do you dare to find out the hard way?
what is that funny knock, Why is my oil pressure so low?
Better to find out during assembly that the clearance is too large and can be repaired, rather than going through the aggrevation of trying to get the machine shop to warranty a crank and bearing job.
if the machine shop assembled the short block I would not double check thier work, only if I was doing the final assembly.
Mar 23rd, 00, 08:04 PM
I guess you're right. Thanks. On one of my engines I had a knocking sound and when I pulled off the oilpan I noticed that the bearing was "spun". Only one connecting rod bearing was like this. The crank shows absolutely no signs of wear nor does the connecting rod. But when I put the two together with new bearings there is near 1/16 inch play. How can this be repaired without having to pull everything apart and machined. If there is anyway.
Mar 23rd, 00, 10:01 PM
It's always a good idea to check clearances my friend bought some rebuilt rods for his VW and one of the rods wass off by .002"
Mar 24th, 00, 12:55 PM
Remove the rod cap next to this one. Remove the bearing shell and look at back side. Note numbers such as .020. This denotes an oversize bearing for a remachined crank shaft, and you'll need to get the oversized bearing. If the bearings are standard size you need to go the hard way and get crank turned and replace the rod, or both rods preferred. Good luck and hopefully it will be the easy solution, but I'd not bet on it.
Mar 29th, 00, 04:44 PM
i,ve built well over 150 motors and i have never checked bearing clearances.if you have a dependable machine shop they know their sh@@.now one thing i highly suggest check all bearings for the right size,have got a few mixed sizes b-fore.
Mar 29th, 00, 05:11 PM
Boy Tim, you have balls the size of boulders. 150 motors and never checked clearances? How many are still running? Every engine should be checked for clearance. I don't care who machines it, we are all human and by nature we make mistakes. I don't like doing it twice, so I make sure that it's done right the first time. Most people don't have the equipment but, I check all the journals with a micrometer in at least three places, then install the bearings in the rods, torque them and measure them with a snap gauge 90 deg. to the mating surface. I also do the same to the mains. If you have some slight variations, you can sometimes mix the bearings up and come up with better numbers. The only way to be sure is to check. Go ask the boys that build Winston Cup engines if checking clearances is important. If the clearance isn't important, why do they sell plastigauge?
[This message has been edited by 68RS (edited 03-29-2000).]
Mar 29th, 00, 08:12 PM
Back when I worked in a machine shop, we also sold engines we machined. Unless the engine was specifically going to be used in a high performance application, we just assembled them, with no plastigage or miking the clearances. We never had any comebacks for clearance problems. But those engines all came with warranties, so my hard earned money was covered. My last engine, my 454, this was thoroughly measured for clearances. You can't be to safe when there isn't a warranty. As far as NASCAR engines, these cost way more than any of our engines and see more abuse than ours will ever see.
67 Camaro LS6 454/TH400/12bolt 3.73
Mar 30th, 00, 03:28 AM
I must say that I most DEFFINATELY havent built quiet as many engines as tim but, I too dont check w/ a plasti-gauge. As he mentioned using the same reliable machinist means alot as mine is a ex-racer and owns his own shop and is the only machinist in the shop and is as thorough as I am (with the exception of using the PLASTI-GAUGE) I do however, check all parts and visually look at bearing sizes and so forth and so on.
"Knock on wood" Havent had one to go down as of yet and I RIDE EM HARD AND PUT EM UP WET!
[This message has been edited by 71 Camairo (edited 03-30-2000).]