Author Topic: Dz302 rod bolts  (Read 1333 times)

deadmetalprez1952

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Dz302 rod bolts
« on: February 23, 2017, 05:15:25 PM »
Hey guys, anyone know the limits of the stock rod bolts? I have heard on other places on the Web that they are a weak points. Anybody have any issues with them, I would like to know from guys that actually wind out their 302! Feedback is greatly appreciated!

Stingr69

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Re: Dz302 rod bolts
« Reply #1 on: February 23, 2017, 05:30:11 PM »
Why risk it?  Rod bolts are cheap insurance.

deadmetalprez1952

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Re: Dz302 rod bolts
« Reply #2 on: February 23, 2017, 05:58:08 PM »
Don't you have to have the rods resized after new bolts? That's probably not cheap is it? If it's as simple as just putting new bolts in than yes it is cheaper insurance...

69Z28-RS

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Re: Dz302 rod bolts
« Reply #3 on: February 23, 2017, 07:36:10 PM »
When I have rebuilt my own engines (engines I was familiar with and knew had no problems except needing rings, bearings (and maybe pistons), I've always reused them (at least for the first rebuild) and never had any problems... but one should do what they feel comfortable with..

I DO always resize the rods... and line bore the block.. when I have to rebore/rebuild an engine... this makes them like new (or better than new)...

Gary
Gary W / 09C 69Z28-RS, 72 B 720 cowl console rosewood tint
69 Corvette convertible, silver/black 350 hp,
60 Corvette white/red, 72 Corvette coupe, '70 Mach I 
90 ZR1 red/red #246, 90 ZR1 white/gray #2466
72 El Camino, '55-'56-'57 Nomads, '55-'57 B/A Sedan

deadmetalprez1952

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Re: Dz302 rod bolts
« Reply #4 on: February 23, 2017, 09:43:55 PM »
Thanks, this bottom end is clean and has low miles, I will use new rod bolts.

bcmiller

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Re: Dz302 rod bolts
« Reply #5 on: February 23, 2017, 10:48:15 PM »
Good ARP rod bolts are important. Technology has improved the past 50 years.
Bryon / 1968 Camaro SS 396 - now 468 ci, M21, 12 bolt
Looking for 68 Camaro with body number NOR 181016

dutch

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Re: Dz302 rod bolts
« Reply #6 on: February 24, 2017, 01:09:10 AM »
New rod bolts are probably the best insurance you can get for any high winding engine - along with carefully checking (mag'ing) and taking any nicks out of the rods themselves. New bolts can be installed in very little time and since the rods are out probably anyway the bottom ends should always be matched to the journals they are going on to assure the proper bearing clearances are maintained. Rod bolts should always be torqued down to spec a couple of times prior to final assembly anyway so doing it and then honing the big end doesn't involve a large amount of time and expense. As mentioned newer metallurgy has improved the clamping force and reliability of bolts now - probably again your best investment in a rebuild..

deadmetalprez1952

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Re: Dz302 rod bolts
« Reply #7 on: February 24, 2017, 02:36:46 PM »
So I actually decided to just get new rods. After all is said and done it will be 3 and change to get arp bolts and have the stock rods resized. So I will be getting rid of a set of stock dz302 rods with 950 miles on them. Are these valuable at all to a restoration?

X33RS

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Re: Dz302 rod bolts
« Reply #8 on: February 24, 2017, 03:06:29 PM »
Probably better off.   I went the same route with my build.  I priced bolts, remachining the big ends, mag,  bushed etc....and I wasn't that far off from a brand new set of Eagle Sportsman cap screw rods, which are stronger, lighter, and give me piece of mind.  So naturally I boxed the stock rods and bought those.   Given the value of these blocks now, and the fact that I want to wind it up and have a little fun, the choice was very easy for me.

30-35 years ago would have been different.  After market choices were limited, these blocks were still a dime a dozen, and people didn't care so much about numbers.

 I can tell you back then, when I didn't have as much money and putting engines together on the cheap, I would buzz these small blocks to 6500 all day with stock rods and original bolts still in them and never had a failure.  Call it luck or whatever, but I won't do that these days.   

69Z28-RS

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Re: Dz302 rod bolts
« Reply #9 on: February 24, 2017, 07:44:55 PM »
Some of us, myself included, are still *skeptics* when it comes to comparing anything aftermarket to GM engineering HP or SHP parts...  The HD rods from the Z28 engine are valuable for building any stock high performance engine; I always try to use those rods when building any small block.

As far as the 'originality' in a 'DZ' block are concerned...  only YOU and any ultimate owner who breaks it down will know whether it has, or does not have, factory internals.  The judges haven't figured out how to check those parts as yet.. :)
Gary W / 09C 69Z28-RS, 72 B 720 cowl console rosewood tint
69 Corvette convertible, silver/black 350 hp,
60 Corvette white/red, 72 Corvette coupe, '70 Mach I 
90 ZR1 red/red #246, 90 ZR1 white/gray #2466
72 El Camino, '55-'56-'57 Nomads, '55-'57 B/A Sedan

Stingr69

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Re: Dz302 rod bolts
« Reply #10 on: February 24, 2017, 08:30:28 PM »
I spin mine up pretty high on Eagle full floating rods and never give them a thought. 

X33RS

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Re: Dz302 rod bolts
« Reply #11 on: February 24, 2017, 09:49:40 PM »
My thought process, this day and age,  is that the engine is a better piece with stronger and more durable parts inside.  An engine rebuilt with correct stock rods does not make me want to pay more for it, lol.

 While the stock stuff is okay and will work fine with proper machine work and money spent, it's still a 50 year old part. No telling what some of this stuff has been through or how many times it's cycled 6,000 or 7,000 rpm.  Eventually fatigue sets in.   This isn't much concern for those that want a cruiser.

Like Stingr, I run Eagle full floating cap screw rods.  They were checked for roundness and proper bearing crush etc..  The only issue we had was that the bushings in the small ends just needed a very light hone for the clearance that we wanted to see.  Not a big deal and typical of any floating rod.   Not to mention the benefit of being lighter (as well as the JE pistons being lighter) there isn't as much stress on the parts when things are slinging around at 7,000.   

deadmetalprez1952

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Re: Dz302 rod bolts
« Reply #12 on: February 24, 2017, 09:57:48 PM »
I got a good deal on a set of crower sportsman full floaters. I pick them up tomorrow. They should be more than enough rod.

deadmetalprez1952

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Re: Dz302 rod bolts
« Reply #13 on: February 25, 2017, 08:55:26 PM »
Soooooooooooo I picked up the crower rods today, brand new, really nice pieces. Only problem is they are for a small journal crank. Big bummer... I'm having trouble finding information on the subject, but does anybody know the maximum amount that can be machined out of the big end of the rod? Can they be bored out to fit a large journal crank? From looking at the rods it looks like there is plenty of material...

z28z11

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Re: Dz302 rod bolts
« Reply #14 on: February 26, 2017, 04:26:34 AM »
I think I'd stick them on eBay and buy a set of large journal rods. Most machine shops start at $80.00 and up an hour for shop time, by the time you get finished boring 8 rods, honing and resizing, I'd be willing to bet you can get a decent set of aftermarket floaters for less money -

Just my $0.02 -

I have reused my rods for a couple of rebuilds, but I agree with the statements earlier in the thread - cheap insurance for a block cast from Near Unobtainium.

Steve
1968 Z28 M21/U17 BRG/W
1969 Z28 X77/M20/VE3 LeMans/W
1969 L78 X66/N66 Cortez/BVT
1969 Z11 L48/M35/C60/C06