I just put my LE3 Cam in my 383 engine, and the motor will not do a full revolution because the rods are hitting the cam. Did anyone else ever experience anything like this or did they mess up grinding my cam?

 

Its the rods you are using. Are they H-beams or I-beam rods. I have heard of people complaining about clearance issues using the H beam rods because they are wide in comparison.

You have 2 options really. Clearance the rods or go with a small base circle cam.

 

The more lift on the cam the smaller the base circle. If this hits now then the base circle is not really the problem, I'm betting you have I beam rods and that's the issue. Almost any time you need to clearance the rods for this.

Bret

 

"Everything must be modified"

A quote that should be known by all those who ever install an aftermarket part.

 

The block requires clearencing at the pan rail (be careful not to break through a water jacket, these are thin wall blocks) the rods (if they are stock I beams) require the top of the rod bolt/shoulder to be clearenced, and lastly the bottoms of the cylinders may require clearencing. All of this should have been done by whoever built/mocked up the motor. Hope this helps, Prorac1

 

It turns out the rods have to be clearenced, I spoke to LE today. Also they are Eagle I- beams. When I bought the motor, I bought it as a short block, so there was no cam in it, so aparently they were not worried about the engine ever having a cam in it. Thank you everyone for your input, I appreciate it.

 

That happens a lot w/ I beams and big cams, We try to use H's all the time. You gotta tear it down and check each cylinder one at a time.

 

What if you do all the work yourself and don't need a shop?

 

marktisch- Do you have a shop in New Jersey? If so, where is Sommerville, Central Jersey? I already took the motor to a machine shop, but if I ever have to do anything again, I would perfer to take the motor to shop more familiar with the LT1. Thanks.

 

Brett, if the cam was ground on a small base circle it would most likely fix the problem..longer pushrods would be needed but thats the jist of it...If this is a balanced assembly I would stay away from knocking any meat off the rod...but I'm a stickler when it comes to some things, some people are not..

 

I use Lunati Pro Mod I-beam rods with my 396". When I had my 388" I had no clearance problems cam(cam was 236/242 112 ls, .590 lift, hyd roll) or block wise.

When I went from a 3.750" to 3.875" stroke...I went small base circle because I was worried I would have that problem...new cam was 257/261, 104 ls, .657 lift, sol roll.

Ends up I had to clearance the block ALOT (bottom of bores, pan rails) and it clears the cam very well.

Some guys grind the rods....IMO...This is not the shop's that built your short block problem in any way. How could it be...if the rotating assembly turns over fine...they did their job.

 

As I've mentioned many times, I have test fitted lots of rods in these things and the best "medium price" rod for clearance is the Lunati "Pro-Mod". No grinding required! Crower makes a rod that is decent as well for strokers. But some grinding as "Prorac1" suggested is commonly needed and not a big deal, or shouldn't be for someone putting together a stroker. If it is, get help!.

I agree with Joe that it should be rebalanced, unless it's a backyard job on a daily driver. I assume that if you are using the LE3 cam, it's not a DD?

The comment by "Machinist One" is quite perceptive. You less experienced guys need to read it and take it to heart. Unloess you are using OEM or other high quality stock replacement parts, be prepared for stuff like this when building a motor. There are many people who would be better of in the long run spending a few bucks with a guy like Bret to get the right parts put to gether right the first time. When you go to an engine builder they will have the benfit of experience as well as skill. They will KNOW how to make a given combo work. This costs but can save in the long run. I am going to guess that you are not going to enjoy disassembling your rotating assembly after grinding, having it rebalanced, cleaning everything, then putting it back together. Of course, that is the way to learn and some people enjoy wrenching. I see it as a necessary evil and would rather drive the thing than work on it!

Rich

 

Joe,

Sometimes it is the problem, but most of my base circles are in the .900 range anyways. We could always reduce the thing another .050, but I gotta know ahead of time.

As much as I want the assembly balanced perfectly in the case where you have to take some off the rods. All that's going to do is cause a overbalance, which isin't always a bad thing, yes if I was putting the thing together I would want it perfect as well, but problem is I'm not. Another problem is that this only happens on thru bolt rods, not cap screw rods, so either the rods should be fixed or that should be mentioned before the cam is cut. Either way as Rich said, the guy should know this ahead of time.

Bret

 

Rskrause, I agree with you 100%, the motor is at a local machine shop now having everything taken care of. I am not happy about all the problems I've been having putting this car together, but a little more money now sure beats having to buy another engine down the line. Also this car is a daily driver. I would have tried the rods, but the ones in the motor are Eagle I-beams, and trust me, they will not work. Thank you everyone for your replies.

 

What if you do all the work yourself and don't need a shop?...............I dont know about you, but i dont have a boring machine, a hot tank, a balancer, etc. But i get the idea, if you assemble it yourself, than you have to check it yourself. Many, Many, MANY times..................Yeah, i had to learn that the hard way to, lol. Hope this helps. Prorac1.