I'm building a 572 street Hemi pump gas motor with a 4.500 stroker crank with Chrysler size rod journals and Manley steel rods, the #5&6 and the #3&4 rod are hitting the cam shaft
I know now that I should have used the BB Chevy rod journal size but I had the crank and rods so is there a solution?
I ran into this on a SB Chevy with stock type Chevy HP Pink rods with a 3 3/4 stroke crankshaft years ago, the solution was to have the roller cam ground on a small base circle core
Is that possible on Hemi motors?
I found the piston side of the rod where the bolt fits into is hitting the top of the cam lobes now, I will remove all the other rods and pistons to degree the cam and see what comes out

Cab. Bummer. Welcome to the HEMI world. I assume the cam is already degreed in where you want it?
How much interference? If it's not too bad can you grind the rod bolt head? Smaller base circle cam is okay if it's strictly a street motor.

Of course you could redo the crank journals and use different rods.

I was attempting to degree the cam but it won't rotate enough either way to do that
I did run into the cam hitting the rods when I slid it in so I rotated it enough to get it to slide in, I then rotated the crank assembly with all the rods and pistons installed in the block and it didn't hit the cam then
Once I set it up to TDC and rotated the cam around to install the timing gears and chain with it align for zero cam advance it hit on the #3/4 and #5/6 rods

Try degreeing the cam without the rods on then
put the rods on(you know where the crank will
be on TDC and set the cam up to the degree what
you want) then check to see if it clears.. I think
you will have to grind the rod clearance

I would degree the cam with only #1 rod and piston installed. That will tell you if you really have an issue. I have seen five degrees have a huge affect effect with a solid roller. Personally, with a solid roller and a stock cam location I always do #1 by itself.

Yep--5 degrees and she runs or hits--can really make a big diff--do that and it might clear up FWIW I use a copper wire about .050 as the feeler guage--easy to bend around and check where you can't see so well the very first 572 I ever did / same way / degreed cam and Viola! no issues

Grind it

WOW been there done that. 572 (4.50 bore 4.50 crank)

When I went to order my Callias crank from Dan at Performance Only racing he tried talking me into going with a Chevy size rod journal. I didn't because I already had a set of high dollar Crower steel rods in Mopar size that I wanted to use. Like you I assembled it and went to slowly turn it over and BAM, rod bolt hit the cam. I tried three other cams I had sitting here with zero luck. I tore the short block down and bought a set of K1 rods and had the assembly rebalanced and all was well. The old style rod bolts wouldn't clear but the new cap bolts did. This Spring I had the crank cut to Chevy size and changed up to a nitrous friendly combo with aluminum rods. Everything clears great now too and hopefully will hit the track in my small tire car.

My motor (4.5"x 4.5") has a Jesel belt system. I lined up the dots when starting to degree the cam. It had BME 426 forgings, the rod big end doesn't get much bigger. It wouldn't turn all the way. Ended up the Jesel had to be installed 3 teeth off to get it anywhere close to being the ballpark. After that no clearance issue between rod/cam. This short block has cleared a 292@.050" cam.
Doug

I've built 2 4.75 stroke motors with .500 lobe rollers and 2.2 rods. I had to barely file a small corner of 2 rods to get .025 clearance. The first lived 5 years with no issues. And a gear drive made me sleep well too!

RIP

My 605 with 2.2 journals and a large custom solid roller has .060 rod to love clearance. I run a gear drive and sleep well.

Just grind the head of the bolt and a little off the side of the rod from where the bolt head seats down 1/2" or maybe a little more. I did this on a small block Chev stroker about 20 years ago and never heard from the guy so it must have survived OK.

The only issue with grinding the rod bolts IMHO would be leaving enough material so the bolt doesn't lose enough material to weaken it.

Ya lets just grind the crap out of our rods or rod bolts instead of fixing it right. LOL. Some guys should leave the engine building to more experienced engine builders.

I'm sure it is not the bolt head hitting on the I beam rod with no nuts
I'll try removing all the rods and pistons except number 1&2 to degree the cam on Monday and post the results after that
I talked to a racer at the track last night that use to race a blown alcohol funny car with a aluminum Milidon hemi block with aluminum rods and a 4.500 stroke crank and he says he never had that issue even when swapping to different bigger cams
Thanks for the help

The fun never ends does it............

It's pretty common practice on big motors. It's the head of the bolt most of the time. You can take some off the lobe as well so you can minimize the total off each part.

Hey cab, rod notching is totally normal. I can't remember the last engine that didn't require it. Any custom rod shop offers cam cuts too.

I love it when a shade-tree mechanic (ME) takes the extra time and a little more money sometimes to do it right instead of a "hack job". LOL I could maybe see if there wasn't a choice but in most cases there is. Grind on grinders. I'm out.

Some people can get away with the hack job, me myself, I have had zero luck cutting corners. I always degree cams in with just #1 and 2 rod and pistons in. I find it rolls smoother. By the time you roll the motor over to adjust valves and put convertor bolts in and tighten them it usually seals all the rings. Good luck with your engine. Birdtracker

I certainly don't advocate "hack jobs" Mine aren't "hacked" at all. I didn't remove 2 grams of material to get clearance. Material removed was on the edge of the rod near the threaded hole. I assure you if you saw it you would NOT be concerned.

RIP

I dont see Cab as the kind of a hack man and i rest ashore that he will make this yet one monster Engine !

My 525(4.5" X 4.310.) motor with a big roller hit the rods when it wasn't degreed. Once it was set no problem with clearance... the lobe juts squeaks past the rod though.

I was asleep at t h e switch on this post

Cab having to clearance a rod or bolt is not unusual at all. It is common practice on many engine combos done by big name race engine shops everyday, it is nothing out of the norm. Guess those names most know are just backyard hacks too I would also suggest especially for the combo you are building to remove all but #1 and degree the cam in and recheck. You may be ok then but maybe not. If you have to clearance the rods a bit it is not a big deal

Maybe that's the reason I'm burning out on the sport after 42 plus years. I rairly pay anyone to do my work and I don't grind on rods, rod bolts, tap oil pans while on the car, or other shortcuts the experts say is common practice. I take it apart and fix the issues.

The piston side of the rod bolt boss on the rod is hitting the top of the cam lobes, I will remove all the rods and pistons except #1 and 2 to degree the cam and hope that fixes it
I'll update what I find themn, probalbly at the end of the week as I have a motor to dyno tomorrow and Thursday

I guess if you buy rods where they come out of the box "stroker clearanced" it's fine....... But if you modify the rod in the same manor yourself its a "hack job".

I'll have to make a note of that.

You don't need to beat around the bush. The fact you do not personally do any of this is fine by me. I really have no issue with it. Just because many others are willing to do things different from your way does not make them wrong either....

Some guys will thinks it's ok to clearance them in the block and don't say ohhh no that would never happen. I've personally watched guy's grind and continue on with their builds like nothing happened. Lol. The masking tape will catch everything

Maybe golf or something might be a better choice, but it looks like after 42 years of racing you have become closed minded and bitter.

Go pull the wings off some flies, legs off ants, set a cat on fire, not everyone does things the same way and that dont make them wrong or bad.

Go grind some rods

Im doing that right now But im almost out of tape.

What some of you guys don't realize or think about is that on a public forum like this We have anyone from a young child wanting to learn to the experienced engine builder. Some of our guys that post often and answer lots of questions are sometimes just "parts buyers" that buy from others and have engine builders that put things together for them. Not everyone should be taking a grinder to their blocks, cranks, rods, and heads as they could do LOTS of unrepairable damage. I've seen a lot over the years and like I said above I've been there done that on my 572 Keith Black build and there was no way in heck was I going to grind when I had so much on the line.

Well, you have a point, and it is valid. Just like a cylinderhead, an untutored person with a grinder can do a lot of harm. I remember a few years ago that a member used a ridge reamer and had to buy oversize pistons as the standard pistons had the top ring getting into the reamed area.

However, if the rods won't clear the camshaft or the block, what do you suggest? Buy a smaller base circle cam? Disassemble the block and send the rotating assembly out to be reground for a new set of 2.200" rods? Grind, new rods, rebalance all cost money. What about the block? If you cannot modify the block to get clearance then the whole thing comes out. What then? Buy a new block? Cut the counterweights in a lathe even though it's a heck of a job with interrupted cuts all over the place? AndyF says it can be done. Then rebalance.

Many times an experienced engine builder will grind a small bit of something to get clearance. This doesn't seem to influence longevity. I don't think they are being irresponsible.

We need to remember that an engine is just a greasy lump of cast iron and doesn't know if what you did to it was the proper method or not.

Peace to you All,
R.

This a little like, "how do you cure polio without using a needle".

Big stroke, big rods, big cams = Big cuts on the rods. No way around it, and done every single day. That's why you can buy rods with cam cuts,and so on.


Ford, and Chevy, OK, we'll try it.

Mopar, no, it was perfect when it was made...

Ran into this mocking up one of the first 427" Stroker 351 Windsor fords in the mid 90's, the combo used a 400M crank offset ground to 4.17" and the rod journals cut for mopar 340 rods. Wound up having the cam reground plus still massaging the shoulders of the bolts just a tad until I had .060" clearance.

A neat trick for mock-up is to wrap the lobe with a medium grade black (outdoor type) electrical "Zip-tie" or "Tie-Wrap" since they are almost exactly .060" thick. I also put in a Pete Jackson gear drive to eliminate the chance of chain stretch related problems down the road.

Patience is the key. It seemed frustrating at the time but I was building the Cobra so I knew fire-up was a long way off so I just "lived and learned". Since it was the first Coast High Performance stroker kit they sold so they comp'ed me some freebies (like fly-cutting my pistons for the new (at the time) Trick flow Windsor Heads, since I basically did most of their R&D for them.

I had known (from the old timers long ago) that a '5/8 Stroker (4.375" or bigger) crank in the Hemi usually wound up getting up in the cam and Paul Savadin (Paul's Crankshafts) and I had a long talk about the merits of the 2.200 BBC journals on the B/RB/hemi's for that reason as well.

Id definitely grind them as needed, if I was in that spot, I'm sure you know the risks and precautions needed to keep trash out of the engine.