Ya I was going to do every rod. I just wish I wouldn't have thrown out the old cam, I could have gotten a head start on this. I ordered the Lunati 60120 cam this morning from Jegs. They drop ship it from the factory so probably wont get here til next week.
CK5
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Finally my 383 build
- Thread starter nsxxtreme
- Start date
Ya I was going to do every rod. I just wish I wouldn't have thrown out the old cam, I could have gotten a head start on this. I ordered the Lunati 60120 cam this morning from Jegs. They drop ship it from the factory so probably wont get here til next week.
Couple questions for the engine building experts.
First there is no markings indicating which direction the piston should be turned. The rods are fairly identical on both sides. Can anyone tell me which way they should be turned?
Second the rods appear to clear everything but the bottom of the bore is this the normal place they hit? and I want .050 or .060 clearence?
Lastly the rod does clear the top of the cam lobe but from what I can see it is really close. Am I supposed to get a feeler guage in there to measure the clearence and how much clearence do I need?
First there is no markings indicating which direction the piston should be turned. The rods are fairly identical on both sides. Can anyone tell me which way they should be turned?
Second the rods appear to clear everything but the bottom of the bore is this the normal place they hit? and I want .050 or .060 clearence?
Lastly the rod does clear the top of the cam lobe but from what I can see it is really close. Am I supposed to get a feeler guage in there to measure the clearence and how much clearence do I need?
63chevyll
1/2 ton status
There actually is a difference on the rods big end. The side with most chamfer goes toward the counter weight (radius side if crank), not the other rod. Look real close at each side of the rod.
And you pistons look upside-down, the valve reliefs should be the other way.
Are you running full float or press pins?
Most engine builders I deal with say .050 is good and I've used that on other 400 builds.
And yes a feeler gauge is ideal, your eye can tell a lot also.
Make sure you turn the crank 2 revolutions per cylinder while checking
Because of the cam needs to turn once
And you pistons look upside-down, the valve reliefs should be the other way.
Are you running full float or press pins?
Most engine builders I deal with say .050 is good and I've used that on other 400 builds.
And yes a feeler gauge is ideal, your eye can tell a lot also.
Make sure you turn the crank 2 revolutions per cylinder while checking
Because of the cam needs to turn once
If they wer stock rods I would agree.
Side A
Side B
I think you mean flipped the wrong direction. Upside down would be hard to do
They are pressed pins they came pre-pressed so I know they came pressed on right. So that probably means I need to flip them around.
I dont have the timing chain hooked up I just turn the cam by hand to put the lobe at its highest point of touchinh the rod.Make sure you turn the crank 2 revolutions per cylinder while checking
Because of the cam needs to turn once
63chevyll
1/2 ton status
Ha, upside-down ha, you know what I mean.
Wow, I didn't know aftermarket rods were the same on both ends. I'm going to check some rods I have now.
Wow, I didn't know aftermarket rods were the same on both ends. I'm going to check some rods I have now.
ok so a little bit closer look at one side of the rod is chamfered more then the other side. Which would mean I have the rod in the picture installed the right way. Chamfered side goes towards the counter weight which is what I have in that picture. So the valve reliefs should be correct. Keep in mind the engine is on an engine stand, and its turned upside down.
I'm going to start grinding on this tomorrow. I'm a little worried about the amount of clearence I have between the rod and cam lobe. If I grind the rod dont I have to get the crank rebalanced? It doesn't touch right now but I haven't measured the clearence either and I know its close.
I'm going to start grinding on this tomorrow. I'm a little worried about the amount of clearence I have between the rod and cam lobe. If I grind the rod dont I have to get the crank rebalanced? It doesn't touch right now but I haven't measured the clearence either and I know its close.
63chevyll
1/2 ton status
Yeah I just double checked, you have them right in your picture. Sorry for the confusion, I had a brain fart
Np thanks for the info
*edit*
So looks like I have .030 clearence between the cam lobe and rod at its highest point. From what I have read .040 is the minimum recommended clearence so I have some rod grinding to do I guess.
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Ok according to this article .020 clearence is the minimum clearence I need between the cam lobe and the rod. Can any experienced engine builders comment on that? http://www.carcraft.com/techarticles/ccrp_0808_383_stroker_small_block_chevy/viewall.html
Noone?
63chevyll
1/2 ton status
Ok, saw it. I guess if they say .020.
But I always used .050 as a rule of thumb.
But I always used .050 as a rule of thumb.
I would still use .050. I have always use .050, I got that number from a book or a machinist or something I didn't just make it up, .020 just seems too close, the stuff moves more than you think at high RPMs, I wouldn't trust that.
Mine is around .035 clearence, I've been debating on grinding. I finished clearencing the block yesterday. If I grind the rods don't I have to get the crank rebalanced? Or since its an external balanced crank I should be ok?
I thought the rods got balanced to a weight close to each other then the rest was done externally.
Well, it depends on how much you take off. I have heard the rule of thumb on new pistons is, if the piston weight changes by 10% or more you are supposed to rebalance the rotating assembly. So I would think taking .015" off one corner of a rod wouldn't really matter. But obviously you don't want to take it out of balance. I would figure out the tolerance it was balanced in and estimate what that tiny piece you ground off would weigh. I am thinking it's going to be negligable, but it would be good to know before you proceed.
63chevyll
1/2 ton status
while on the balancing topic, dont get too worried about it.
Had a long talk with a pro engine builder a few weeks abo about balancing.
Basicly, the unknown factor is always how much oil the piston/rod has on it at any given time 1-10 grams and always changing.
so a .5 gram from a rod bot wont matter as much as you think.
Had a long talk with a pro engine builder a few weeks abo about balancing.
Basicly, the unknown factor is always how much oil the piston/rod has on it at any given time 1-10 grams and always changing.
so a .5 gram from a rod bot wont matter as much as you think.
I'll post up the balance sheet that came with the crank and rods when I get home.
Good to know
