Machine shop is telling me that most stroked cranks have a interferance issue with the camshaft. Is that sound true that rod bolts would hit the cam..Most resersch I have did only says check the rod bolt to oil pan rail for clearance..

 

Never heard of that!!!

 

It depends on the stroke and the rods. Quite often you need to use a small base circle cam with a stroker engine.

 

I could see that for a 427+ exotic small block build but a 383????

 

it does happen

 

sounds scared to meeeeee.

 

Chevy High Performance did a series of articles in the last few months on a 383 buildup, in which they showed the grinding that was needed to keep the rod bolt from hitting the cam. Probably June or July issue-- you may be able to find it online,

I've read it in a few other places as well.

 

If the rod bolts hit the cam you MIGHT BE ABLE TO HEAR IT. My 383 has no such problems

 

it simply SHOULDNT happen if you had a reputable shop do the machining for you....even on the exotics.

 

The bolt head on a stock (or similar) rod will hit a stock base circle cam if not ground down, you can get rods with screw caps (the bolt screws directly into the rod) or a small base cirle cam. If done right it will not affect the strength of the bolt.

 

From my understanding it is a possibility. I am not sure of what the minimum clearance should be. When I ordered my rotating assemble from the machine shop I had them grind the rod bolts. He knew which ones were the potential problems and ground then a tad. I haven't had time to assemble the engine but did install the crank, rods and pistons temporarily. I do have a little grinding to be done on oil pan rail as a couple of rods hit.

 

Yes it is not uncommon. The shoulders of some of the rod bolts may need a little clearancing. Small base circle cams are made for this as well. You can have interfearance at the oil pan rails as you have learned. If you are doing this yourself, be prepared for a little grinding but this is not brain surgery.

-Mark.

 

If you buy cheap crap that's what your going to get. It's not like this is the first stroker small block ever built. If you buy cheap crap from vendors that don't give a rat *** if works is when you run into problems.

I've built lots of 383 & 396's and it wasn't until I got cheap crap from a Vendor "Motor Builder" by the name of Bill Mitchell's Hard Core Racing is the first time I ever came across crap that every rod hit cam lobes. It was in a 4 inch stroker kit 427.

It just beyond me that a vendor is such slimmy pond scum that they market stuff that they know doesn't work. National advertising parts to poor unsuspecting people.

Like just this past week the post of a broken piston. To make the most profit the builder installed the cheapest crap pistons that he could buy. Right on the side of the piston it said, "Claimer"

 

The problem is not with how much dough you layout. The 350 block was not intended to be used with a 3.75" and larger crankshaft. Because it was not intended that way does not mean with a few minor alterations that a larger crank cannot be used. I have seen blocks that were designed for large throw cranks and high lift cams. They raise the position of the cam in relation to the crank for additional clearance. One thing to keep in mind is that not all 350 blocks are 100% identical. Some will reguire little to no grinding of the oil pan rail while others will need a few area clearanced. The same goes for the camshaft/rods. There are rods that state they do no interfer with the cam. Many of these are the H beam which are more costly than I beams.
Unlike building a 350, the 383 will need to be checked for proper clearance. It's just part of the process. If nothing is touching does not mean that it's all set to go. It may be fine at 0 rpms but at 6000 rpms it may hit. That's not the best way to find out that it was not in spec.
I do agree that buying from ebay from someone who is able to sell parts for less may not be the best idea. They are selling parts and may not have any idea of any potential problems. A good machine shop/engine builder will know what needs to be done and will not let the parts go unless they are prepared properly or at least let the buyer be aware of what may need to be done.

 

My Eagle stroker kit had that problem using six-inch rods. Had to releive the block just under the camshaft tunnel to make it work.

 

With rotating kits from FlatLanderRacing 3.750 and 3.875 with big H-beam 6 inch rods I've only ever had to grind the pan rails on 350 four bolt blocks and I've never had any issues with my big lift solid roller cams specifically Crane Cams that are the .930 smaller base circle.


Scum like BM probably sells 1000's of stroker kits a year and they know that every one of them doesn't work without grinding on every rod for clearance. They don't care. They don't inform you! They will even sell it to you with additional charges for a balanced assembly knowing that you will have to grind and then get it rebalanced.

Over the years I've got more aftermarket parts that don't fit and have to be modified. Just like the header tubes that you have to dent the pipes to clear the steer or frame. Or the nearly $600 aluminum radiator I put in and it didn't fit because the moron welder put the end pans on wrong. Then the replacement I went down to Summit Racing and picked up you couldn't fill because the moron put the internal tranny cooler so high up that it filled the hole below the pressure cap.

I called the owner of BeCool and said I would send him a real Corvette radiator so they could make a real jig to not screw everybody who bought one after me. He told me that he was assured that their exact match C-3 radiator was correct. So I sent him pictures of the two pieces of crap that I had compared to a real brass one. I hope somebody lost their job.

 

gkull - tell us how yu really feel

I do agree with you though, why are people buying motors off the internet and don't even know what parts are in them ?

I have heard of a couple of these motors loosing there cheap Chinese balancers, now that would be great wouldn't it, your timing your engine at 3000 RPM with your head a foot away from the balancer trying to see the timing mark and it flies off the end of the crank.
Now you could really say you got ripped off.

If you use I beam rods chances are you are going to have to grind a little of the shoulders