Rod strength and folklore

SYCLONE#1531

SYCLONE#1531

'MOFOFAST
Re: Rod strength and folklore

My stock rods were fine when I tore my engine down. They saw lots of 30psi passes without failure.
 
SloGN

SloGN

9Sec Alky V6
Re: Rod strength and folklore

ziembic said:
My very humble opinion on this is that it is hard to know what caused what. Unless your data logging when your motor decides it time to check out, you can only go with speculation and a careful dis-assembly.
Sure it is easy to see that a head gasket or water jacket let go and water ended up in the cylinder and wammy we have the end. But what about a situation where the bearings let go in a catastrophic manner. Could it have been the rod bolts loosening that led to larger clearances that led to wobbling that led to wammy. Or could it have been an oiling situation that led to bearings becoming welded to the rods which leads to more heat and wammy. Or could it be rod failure where it just snaps, which puts the engine way out of balance and wammy.
My long winded point here is what comes first the X or the rod. In the end it is an engine that's service life has come to an end. Unless an autopsy is very revealing, I think it is easier to blame a mechanical component than ones in-ability to tune or over zealousness with the components at hand.
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Well I can't see that the stock rods for a syty are weaker than the rods in the Buick gn engines .

The gn engine makes 450 HP easy and takes.a beating for a long time
 
midnightbluS10

midnightbluS10

Banned
Re: Rod strength and folklore

Throws said:
Sadly, we lose a lot of info this way... unless you quote it.

-P
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Maybe he doesn't like.to share? :dunno: or too many newbs question his information or just plain ol call him out as being wrong when they have no idea that the man they're talking to/about knows more about Syty's, cars, trucks, boats, and anything else with an engine and transmission than probably at least 93% of the active members on this site.
 
Beavis

Beavis

Still plays with trucks
Re: Rod strength and folklore

Dave P is a very smart man, and sadly when challenged he pulls his info out, or leaves it up long enough for the person he wants to see it, then pulls it back. I wish he didnt, cause a few times myself and others went back to view something, and it was long gone.....hurts a good conversion and/or repair session.


I dont have anything to donate, but would love to see the results of testing on the rods. It does sound like it all comes down to one thing, a good solid tune.
 
ziembic

ziembic

Donating Member
Re: Rod strength and folklore

I think I have some 4.3 rods. They are from a jasper engine though. If we wanted to test it I donate it to the cause.
 
bezerk

bezerk

New member
Re: Rod strength and folklore

SloGN said:
Well I can't see that the stock rods for a syty are weaker than the rods in the Buick gn engines .

The gn engine makes 450 HP easy and takes.a beating for a long time
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tha main thing about comparing these things, that the 4.3 have more bolts per cilinder(heads), so they rather puke the bottom end instead of blowing a headgasket.
 
Icarus-54

Icarus-54

Donating Old Member
Re: Rod strength and folklore

The later l-35 rods(96&up) have more meat where the rod come into the big end,but less at the parting line.Where as the stock rod is just the opposite.
 
Quickstop [UK]

Quickstop [UK]

Combating adversyty.
Re: Rod strength and folklore

Has anybody got any photos of the respective rods side by side? Thanks for that info Jack!

I would love to see the data on the rods and the UTM results...

Hmmm.
 
8

89shortbox

Member
Re: Rod strength and folklore

All the load is put on the upper half of the rod during the power stroke and even in a detonation situation. So I dont see how a rod bolt upgrade would help power wise. I do know that good rod bolts are more important in higher revving motors because the piston and rod are yanked back down with such speed and force on the intake stroke at rpm that the weight of the two can fatigue the rod bolts. 5500 rpm should never be a problem. 7000 is a different story.
 
Jimmy

Jimmy

Banned
Re: Rod strength and folklore

IMO detonation and overboost kills the rods.

I've ran rock solid 25 psi on L35 rods with EGT's that would make NASA blush,but it never knocked and is still all together 12 years and 100k later.Well except for the front diff
 
Icarus-54

Icarus-54

Donating Old Member
Re: Rod strength and folklore

Quickstop [UK] said:
Has anybody got any photos of the respective rods side by side? Thanks for that info Jack!

I would love to see the data on the rods and the UTM results...

Hmmm.
Click to expand...

Cant show you a picture cause the camera is broke,when you get old you drop things
 
SloGN

SloGN

9Sec Alky V6
Re: Rod strength and folklore

bezerk said:
tha main thing about comparing these things, that the 4.3 have more bolts per cilinder(heads), so they rather puke the bottom end instead of blowing a headgasket.
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But add a set of cometics and that problem is solved. Actually the 84-85 GN's use the steel shime gaskets that never fail unless they rust lol. but thats another thing



But just think of all of the small block that are built and abused using stock rods with good pistons. I understand it's a v8 but when comparing hp per hole they make the same or more that most of our 4.3l due.


I really think the biggest issue with thse engines dying is the tune-up. knock will kill any motor. The pistons in these engine just don't seems to be built heavy duty enough for severe duty.


Now back to the GN they have steel inserts around the wrist pins and the oil control ring has no holes behind it; all the oil drains off the oil ring thru 2 grove on the side of the piston to the wrist pin. the upper rings have steel reinforcements in them. they also have a full skirt at the bottom.
 
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