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Okay, this sounds so simple, but I cannot find it in a bulding manual... When you tighten four bolt mains, which sequence do you follow? As I have been do the pre-fitting, I have been tightening the inners and outers equally in three increments. For example I go to the inners and do 35, then the outers at 35, and then I do them all in 55 and then 70.

Or should I go down the line of inners and fully tighten them in the three increments and then go to the outers? It's a pain because all of the engine building videos I've seen show a 2 bolt main being built.

Thanks for any input.
 

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Dont think it really matters........You are doing the right thing and doing it in steps...........

I would start in the middle and work my way out with one torque....then increase it and do the same again and then the last time with the final torque.
 

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Doc here, :pimp:

"When in Doubt..Center out.." (I learned from an olde poet..).. in a criss~cross pattern..

The important thing as Poncho points out..Two step is the proper thing to do..35 then 70..

Doc :pimp:
 

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On all the blocks we machine for other shops and engine builders we line hone all the blocks that go through our shop and use the ARP hardware and using a bolt kit we snug the center bolts then torque to 40# then snug the outter bots and torque to 40# then the inner ones 65# then the outter bolts 65# With the ARP lube as we send a sheet with every block on the torque specs and sequence on how they are torqued so the customer can come out with the same results.

And we have found the torquing the outter bolts first DOES change the housing bore diameter.
 

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Thanks for the insight CNC. Never seen this written any where, but makes sence and does point out that true machinist tend to look at "what happens when".

Trees
 

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I snug the center cap, and the rear cap, loosen the rear cap bolts and seat the thrust bearing.

I then torque in sequence at 35 lbs, longer bolts first, then the outer bolts, and I also torque all the caps at 35 lbs. (Do all caps at 35, then 50 and then 65). I then torque to 50 lbs, in the same order, and then finally 65 lbs. I spin the crank as I go to check for binding. I use moly lube on the bolts.
 

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I start in the middle, snugging to #35 first, and in a widening circular pattern (middle to out) I snug them all. Then back to the middle and go to #80 in the circular pattern, middle to out. Then back to the middle again taking them to the final seating pressure ...again middle to out in the circular pattern. If you look at the head bolt pattern, it's basically the same way. Good Luck! ...Mark
 

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11echo said:
I start in the middle, snugging to #35 first, and in a widening circular pattern (middle to out) I snug them all. Then back to the middle and go to #80 in the circular pattern, middle to out. Then back to the middle again taking them to the final seating pressure ...again middle to out in the circular pattern. If you look at the head bolt pattern, it's basically the same way. Good Luck! ...Mark
80 pounds on a 7/16 main bolt HMMMMMMMMMMM
 

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nitro_baller4692 said:
does anyone ratate the crank when they torque the mains?
how about puttin lube on the shoulder and threads of the bolt?
Why would you ratate the crank when torquing the mains and we use all ARP hardware and and we use the ARP lube on the threads and the washers. And we have used 40# the 65# as I have described above on the bolt kits and on the studs we torque them to 40# the 70# as this has worked for our shop for 32 years now with no related problems so far and on those studs we use the CMD-3 high pressure lube on the threads and washers.
 

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Why would you ratate the crank when torquing the mains

i have not seen anyone talk about using a mic. or a dial bore gauge,if you torque all the caps down without turning the crank how would you know what main is the problem,if there is one.
has anyone hear heard of bearing missalignment,yeah bearings have locking tabs but some people still screw things up.
i'm not trying to offend anyone,i just think a crank should be rotated after every step in the assembley process of the rotating assmbley.
 

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nitro_baller4692 said:
Why would you ratate the crank when torquing the mains

i have not seen anyone talk about using a mic. or a dial bore gauge,if you torque all the caps down without turning the crank how would you know what main is the problem,if there is one.
has anyone hear heard of bearing missalignment,yeah bearings have locking tabs but some people still screw things up.
i'm not trying to offend anyone,i just think a crank should be rotated after every step in the assembley process of the rotating assmbley.
If you read my post about line honing all the blocks that go through our shop and to do that process a Sunnen bore gauge is used to check the demension of the housing bore.

And the Crank sould not be rotated till ALL the caps are Torqued as you want the bearings SEATED in there housing bores and if blocks are line hone properly there should not be any misalignment.

And again in most cases cranks will not spin freely until the mains are all torqued and the bearings have seated in there housing bores.
 

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And again in most cases cranks will not spin freely until the mains are all torqued and the bearings have seated in there housing bores.

if the crank don't spin freely,then the crank needs to be checked for straightness or the align honing was done incorrectly.i've never had a engine that i assembled have the crank not spin freely.i will find the problem and fix it as to whats necessary.
when checking the bores with the gauge are you checking front and back on the main saddle and are you checking top to bottom and also just off the parting lines on both sides?
 

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CNC BLOCKS N/E "80 pounds on a 7/16 main bolt HMMMMMMMMMMM"

...I'm talking big block Chevy here, as I recall the torque setting on the mains is 110 ft/Lb.s is it not!?? ...What are you talking about??? ....Honda?
 

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11echo said:
CNC BLOCKS N/E "80 pounds on a 7/16 main bolt HMMMMMMMMMMM"

...I'm talking big block Chevy here, as I recall the torque setting on the mains is 110 ft/Lb.s is it not!?? ...What are you talking about??? ....Honda?
I believe when the post was started they are talking SBC as the final torque they were talking about was 70 ans assune is a SBC as there nothing evr mentioned about torquing anything 70 foot pounds.

If thay are talking about a BBC I am way off.
 

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nitro_baller4692 said:
And again in most cases cranks will not spin freely until the mains are all torqued and the bearings have seated in there housing bores.

if the crank don't spin freely,then the crank needs to be checked for straightness or the align honing was done incorrectly.i've never had a engine that i assembled have the crank not spin freely.i will find the problem and fix it as to whats necessary.
when checking the bores with the gauge are you checking front and back on the main saddle and are you checking top to bottom and also just off the parting lines on both sides?
Thats hard to believe as we had a block come in with low oil pressure and the crank spun fine when it was installed as the customer said, it should have as the mains were .002 to .0025 over the high side as the block came out of a truck I believe at the parting line they were right on.

So by putting a crank in and seeing if spins freely don't cut it at our shop and thats what I mean buy line hone all the blocks that come through our shop it takes the THE GUESS WORK OUT or we call that the fudge factor or when guys check the crank by if it spins freely.LOL
 

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nitro_baller4692 said:
Why would you ratate the crank when torquing the mains

i have not seen anyone talk about using a mic. or a dial bore gauge,if you torque all the caps down without turning the crank how would you know what main is the problem,if there is one.
has anyone hear heard of bearing missalignment,yeah bearings have locking tabs but some people still screw things up.
i'm not trying to offend anyone,i just think a crank should be rotated after every step in the assembley process of the rotating assmbley.
Those aren't locking tabs. They are there for ease of referance only.

The difference here is clear, between someone who does it right on a racing engine, and someone who get's it done on a street engine.

Street engine are much more forgiving then the things CNC is making.

The forces of a car hooked up at 7500 are way different then a street car you might see 6500 with tires spinning, for a split second every so often.
 

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i've built everything from lawnmower engines,top fuel drag boats,stock cars cup by the way,truck pullers,mud boggers,alky,nitro,gas,nitrous,street motors so every one has a way that works for them i'm not saying anyones right or wrong ,this was the way i was tought and it works for me so thats what i do.
we should not continue to bicker back and forth but if thats what you want to do thats fine.

cnc, i was not saying that if every crank spins that every thing is fine with the bore there are going to be veryations,more so on an engine that has been run.

johnsongrass,race engines have grater clearances then a street engine so i don't know what the heck your talking about,the difference is in how the parts are preped and conditioned before being put together.yes bearings are different but it gets totally different parts.a race application is what i'm talking about.
 

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CNC BLOCKS N/E ...Well I thought it was about "Main bolt tightening sequence" ...I guess I need to clarify that I was mainly talking about the pattern of tightening the main bolts, not so much as to the torque I was shooting for. I didn't want to split hairs here, and again I'm stating this is my $0.02 only! "Use it or lose it ...as you wish".
 

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nitro_baller4692 said:
i've built everything from lawnmower engines,top fuel drag boats,stock cars cup by the way,truck pullers,mud boggers,alky,nitro,gas,nitrous,street motors so every one has a way that works for them i'm not saying anyones right or wrong ,this was the way i was tought and it works for me so thats what i do.
we should not continue to bicker back and forth but if thats what you want to do thats fine.

cnc, i was not saying that if every crank spins that every thing is fine with the bore there are going to be veryations,more so on an engine that has been run.
Wow with all the engines you build you must have quite a machine shop that you own whats the name of your bussiness as I am just trying to compare apples to apples here to see if we are both on the same page.
 
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