Stroker 416 crank main & rod questions

[djwhog]

OK finally going back together on the stroker 416 340 today. About darn time... :headbang:

A few question of what others are doing. Here is what I have.
Eagle 4" forger crank and H rods with forged Ross .030 over pistons. Using clevite fully groved mains. So with the cam, head work modifactons etc. , it specs out to about a 535-550 HP engine. Block web looks much thicker than most 314-340s, but is not a TA block, so I did not go with a 4 bolt main kit, felt it was not needed at this level and would weaken the block.

So... :lurk:

1. Should I use better than stock main bolts? Current bolts do look fine.

2. What are you guys with this setup ending with for main bearing and rod bearing clearances?

3. Is the spec on these rods with the ARP bolts 75 ft lbs? That is what I was told. The socket size is a 12 point and i think these are 7/16 size bolts in the rods, not the standard cap screw type. The head of the bolt says " ARp Eagle 1.6 8740 .

If it is 70 + lbs I feel a standard 12 point snapon socket is iffy, will flex or crack and not give an accurate reading. I did order a set of thin wall 12 point snapon impact sockets. That was the best I could find. Most HD applications are 6 bolt sockets and heads... So this is new to me.


thanks guys!

 

[djwhog]

Well looking very good so far. Just need to end gap fit each on the rings.

OK the mains ended up as follows to be exact.

#1 .002
#2 .0019
#3 .002
#4 .0022
#5 .002

 

[moper]

I notice you ask about main bolts, and then have clearances done the next day...So at this point, maybe this is all moot. But...Stock bolts are not enough IMO. Two bolts in a MOpar LA is stronger than 4, because of the webbing of the block. But the 2 arrangement is limited by clamping force. I always replace main bolts with ARP studs in strokers. Bolts are ok fro stock or mild builds. Not for non-standard strokes. Now, when you upgrade the fasteners, you have to also have the crankshaft main bores corrected. Becuase the better clamping forces the caps out of the correct shape. So that would need to be done. Plus, you need to remove the cam bearings and oil galley plugs to clean the residue out after the work. So, it's a decision that should have been made a while ago. IMO, you will have cap walk issues over the life of your new engine. How bad or how fast, that's up to your habits and the engine itself. Cast stroker cranks tend to be harder on the bearings and block than the more expensive ones.

On the bolts...My 12 pt Snap Ons work just fine..lol. You just need to be smooth and hold things steady...lol.

Clearances...I like .0015-.002 on the mains. Rods can be slightly more. But any extra space in the mains means lost volume to the rods. Also, make sure the bearings have enough chamfer with the crank's large radii.

 

[djwhog]

Thanks for the input Moper. It is not to late, I have plenty of time and can get a stud kit and have it line bored. If I do, what do you use for caps, are these stock caps good enough. And where do you get your arp studs from? I have seen many post here saying that the ARPs can not be used in #5 becasue of oil pump clearances...

I was told by many other people stock was good enough for the bolts, but I have had 2nd thoughts and that is the reason for the post. Also I have a forged crank not a cast unit. I put it toghter just to see where it was sitting at. Many other 340s I have built are in the .0015-.002 mains and .002-.0025 rods. I have heard many rumors not to make the stroker to tight and wanted to know what others are doing.

Also I have seen on many threads there is an issue with HV oil pumps and a stud in #5 hitting the pump, was there ever a real fix for this ie shorter stud?

And thank you for all the help and details too! I think once I get the info on the studs I will get it machined for them. I do not want a weak link in the bottom end!

 

[lenweiler]

I like the stud idea. But here's the bugaboo. Generally, one should line hone the main bore when going from cap screw to a stud. Now, that being said, the line bore is not always necessary. It just works out that way.
If I was using a stock block, I would go for Hueghs main girdle. But that's me.

 

[340mopar]

There is no doubt that studs are better than bolts (I am running them in my 340). But being that the LA uses the same size as the B/RB with a much heavier crank and a 3.75 stroke on the RB the bolts will also be fine in the LA application. I align hone all of my motors it's not much extra and it is nice to put everything in line instead of "within tolerance". If you use studs in the LA you will either have to cut down the stud and run the nut without the washer (which is what I am doing) under the oil pump or run bolts on the rear cap because the stud, nut and washer hits the pump. I have heard of some people using one stud and one bolt on the rear cap. Because of the different clamping forces I would not do this.


Chuck

 

[djwhog]

I agree. All clamping should be equal. That being said I do not see the point if you stud they need to be all studs. You are only as strong as the weakest link. A few others have mailed me about a few options that will work. And here is a quote from another members post with a contact # to solve the issues.

"I have been informed from ARP that they were not aware of this problem and purchasing a ARP bolt that is the stock length is the correct way. I have to buy it from CV Products (FYI there number is 1-800-448-1223) Will cost around 10.00 shipped to my door. I started with a very good base and didn't have to turn the crank. Had the whole assembly balanced and they said it was extremly straight for a stock crank. I installed the crank with the ARP studs in place and all the clearances on all 5 journals was .0015 and can rotate it by hand. I was told by the machine shop that if it would rotate by hand after I torgued the studs I didn't have to linebore it. If it would bind up at all I would have it Linebored no questions."

 

[dartman366]

I agree. All clamping should be equal. That being said I do not see the point if you stud they need to be all studs. You are only as strong as the weakest link. A few others have mailed me about a few options that will work. And here is a quote from another members post with a contact # to solve the issues.

"I have been informed from ARP that they were not aware of this problem and purchasing a ARP bolt that is the stock length is the correct way. I have to buy it from CV Products (FYI there number is 1-800-448-1223) Will cost around 10.00 shipped to my door. I started with a very good base and didn't have to turn the crank. Had the whole assembly balanced and they said it was extremly straight for a stock crank. I installed the crank with the ARP studs in place and all the clearances on all 5 journals was .0015 and can rotate it by hand. I was told by the machine shop that if it would rotate by hand after I torgued the studs I didn't have to linebore it. If it would bind up at all I would have it Linebored no questions."

I have run my 366 for 13 year's with one stud and one stock bolt in the #5 main with no problem's,, I remedied that problem on my new 408 by re-spot facing the #5 main cap where the bolt fit's under the pump by an additional .190 then you can use a cut down (shortened) stud and the appropriate nut and it will clear the pump housing (but alway's check it), I take this must be a street engine by the clearance's, my 408 was set-up with .0028 all the way thru,, as far as the rod bolt's, the best way really is to use a rod bolt stretch gage, mine was set at .005 stretch and came out to be 70# of torque.