76 L82 Corvette 355 engine build questions

Indycars said:

Grumpy, does it look like those rods got very hot in the big end?
Click to expand...

its hard to tell from the pictures but the rod bearings, in those connecting rods, sure look well worn,and grooved from what looks like metallic contaminants, like a failed cam lobe might produce , and the resulting bearing over heating could easily result, thats one reason Im fairly sure the rods in the pictures, would be better off if replaced, while it might be superficial,damage and the rods could be re-sized and fitted with new rod bolts and bearings, if it was my engine the rods would go in the dumpster.

links worth reading

viewtopic.php?f=51&t=2919

viewtopic.php?f=53&t=6909&p=22571&hilit=pressed+float#p22571

viewtopic.php?f=53&t=6834&p=22136&hilit=pressed+float#p22136

viewtopic.php?f=53&t=247

viewtopic.php?f=53&t=509&p=28226&hilit=hone+plate#p28226

viewtopic.php?f=53&t=978&p=1725&hilit=pressed+float#p1725

http://www.maintenanceresources.com/ref ... alance.htm

http://www.circletrack.com/enginetech/c ... rminology/


viewtopic.php?f=53&t=110&p=137&hilit=pressed+float#p137

viewtopic.php?f=53&t=852
 
How common is it to have the engine balanced when just putting in new pistons 0.030" over like mine?
I hadn't been planning on having my engine balanced because I didn't know much about it and thought it was only for racing engines. But now I'm a bit worried if I decided to reuse the old rods without balancing Id have at least problems related to that.
I didn't weigh my rods or the new pistons individually but they are 1195 grams together each.
The old pistons, rings, and pins together are about 775 grams.
I'm not sure how much stock rods weigh alone, I read 600grams which would mean Id have about a 180 gram difference in weight.
Do people usually balance when just putting new pistons in that are oversize?
Just trying to gather information.
 
your best bet here is to take all the parts you have to a local machine shop that does balance work , show them what your dealing with and ask for advice, now I know your thinking any shop will tell you, that you need to have them balance the components, but its been my experience that most shops will tell you if your new parts are only a couple grams different in weight its not mandatory on a street engine.


READING LINKS AND SUB LINKS HELPS
viewtopic.php?f=53&t=259&p=314&hilit=balancing#p314

viewtopic.php?f=38&t=3900&p=13058&hilit=internally+externally#p13058

viewtopic.php?f=53&t=204&p=13046&hilit=+balance+internal#p13046

viewtopic.php?f=99&t=3447&p=9128&hilit=+balance+internal#p9128

viewtopic.php?f=53&t=141&p=5391&hilit=+balance+internal#p5391
 
Alright guys, so I've taken some weight measurements and talked to the machine shop in my area that does balancing.
My old pistons weigh 576g and although I didn't weigh the new ones(had them pressed on before finding out about balancing) several places on the internet list them as being 610g. I called the machine shop and told them the weights and he said that it needs to be balanced with that 35g difference.

What do you guys think? Does that seem like a reasonable statement?
They charge $175 for balancing.

Also, I asked him about reusing the stock rods (he hasn't seen them) and he said they are suitable for reuse with resizing and optionally new bolts.
They charge $96 for resizing stock rods plus whatever the bolts themselves cost. I've looked up ARP bolts and they are around $70 so the total would be about $166.
With this much cost for reusing old rods, I'm thinking it would be better to just do like you say grumpy and get new ones such as Scat 25700P rods which are about $250 for a set.

Opinions? I know you have them. :D
 

I had mine balanced for just 8 grams. Those 35 grams will weight 150 lbs
at 5500 RPM.

You can play with this Excel calculator if you want to learn more.

viewtopic.php?f=99&t=6636

You will notice I put 35 grams in for the piston mass, since that's the
difference between the two pistons. If you want to know the total stress
on the rod, put in the 610 grams. At the 5500 RPM now the piston looks
like 2,624.3 lbs trying to put the rod apart.



 

Attachments

  • OutOfBalance35Grams.JPG
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talk to SCAT tech guys, before you order connecting rods, and discuss what your doing,and your options and what parts you currently have and part compatibility.
the rods you link too use 3/8" rod bolts
either rod choice is a noticeable improvement over the stock connecting rods being rebuilt.
sca-25700p_w.jpg

here the rods (LINK BELOW)
I generally use on mild performance builds requiring 5.7" rods, but Id ask about the pistons because I generally use full float piston designs
the reason is that these are exceptionally strong rods with 7/16" arp rod bolts, the rod bolt size alone increases strength over 20% but the 200k psi steel is easily 30% stronger than most oem steel rod bolts, increasing the strength of the rotating assembly by easily 50%-70% over stock components

these rods use the stronger 7/16' and its a significantly stronger connecting rod, yes the cost is about $90 more a set, but thats peanuts in the total build cost and the strength is a good increase over both stock and the other rods
http://www.summitracing.com/parts/sca-2 ... /overview/
sca-25700_w.jpg
 
I forgot to mention before that the machine shop said if I was using the stock flywheel and harmonic balancer that they don't need to be balanced along with the crank and other stuff but if I get new ones that they have to be balanced as well which costs an extra $50.
I was planning on reusing the stock flywheel so that should be okay but I was thinking it would be smart to get a new harmonic balancer because the rubber is a bit worn and cracked.
So, a couple questions.
1. Do you think I should get a lighter weight harmonic balancer or stick with the a stock replacement type (I think it's like 10.5lbs or so)?
2. Is it normal for an internal balanced engine to have to have the harmonic balancer and flywheel balanced along with the crank and everything? I mean the flywheel appears to be neutral, having no counterweights that I can tell, but the old harmonic balancer does have some holes drilled on one side which must be balance holes.
And the stock replacement one that I saw didn't look like it had any holes drilled in it.
623x.jpg
 
76GrayVette said:
I forgot to mention before that the machine shop said if I was using the stock flywheel and harmonic balancer that they don't need to be balanced along with the crank and other stuff but if I get new ones that they have to be balanced as well which costs an extra $50.
I was planning on reusing the stock flywheel so that should be okay but I was thinking it would be smart to get a new harmonic balancer because the rubber is a bit worn and cracked.
So, a couple questions.
1. Do you think I should get a lighter weight harmonic balancer or stick with the a stock replacement type (I think it's like 10.5lbs or so)?

the stock balancers designed to operate efficiently at and below 4500rpm, its NOT SFI rated and while its rather in-expensive its neither safe at high rpms or effective at reducing crank harmonic stress.
INTERESTING LINKED RELATED INFO
(yes I know you might not want to read all the links and sub links but if you do youll have a far better grasp on the concepts, and it could prevent bad and potentially costly mistakes in parts selection)
viewtopic.php?f=53&t=1042&p=1969&hilit=damper#p1969
viewtopic.php?f=53&t=141&p=1863&hilit=damper#p1863
http://www.atiracing.com/products/dampers/
viewtopic.php?f=50&t=223
viewtopic.php?f=71&t=447
viewtopic.php?f=53&t=562&p=716&hilit=damper#p716
viewtopic.php?f=53&t=279&p=342&hilit=damper#p342
viewtopic.php?f=38&t=3900&p=12449&hilit=internal+external#p12449
2. Is it normal for an internal balanced engine to have to have the harmonic balancer and flywheel balanced along with the crank and everything?
YES IT IS! IF THE SHP JUST ASSUMES THAT ANY STOCK BALANCER AND FLYWHEEL YOU WILL BOLT ON WILL BE FINE!
AND NOT EFFECT THE RESULTS ID CERTAINLY FIND A DIFFERENT SHOP TO DO THE BALANCE WORK

I mean the flywheel appears to be neutral, having no counterweights that I can tell, but the old harmonic balancer does have some holes drilled on one side which must be balance holes.
YES those were drilled to get the outer hub to neutral balance
And the stock replacement one that I saw didn't look like it had any holes drilled in it.
623x.jpg
Click to expand...


what your really talking about when you say balancer is a crank damper.
the stock harmonic damper is made to absorb crankshaft flex harmonics and they are tuned to work for the most common frequency and amplitude vibration with the stock rotating assy at a moderate rpms up to about 4500rpm.
when you start raising the intended rpm range or modify the rotating assembly components like use of different rods, pistons and converters or clutch assembles and intended rpm limits with etc then theres some potential power and durability to be considered with a correctly tuned damper.
the correct factory damper/balancer is ok for most street/strip engines that rarely operate over 5000rpm
.theres some moderately priced sfi dampers out there. I usually recommend ati or in limited some cases fluid damper
 
So, is it even worth it to buy a stock replacement type flywheel rather than just resurfacing my old one?
At least it would be brand new and not fatigued by years of use right?
I'm mean I'm not going to be racing this car or even abusing it on the street hardly at all. I just want to drive it.
 
all stock OEM cast flywheels are potentially going to fail at some point ,simply because the material used eventually heat cracks.
every time you research some component youll find that in most cases the factory selected the LEAST EXPENSIVE component it thought would work in the application, giving the re-builder a great many options to upgrade the durability, now you need to make choices because you can spend a fortune on aftermarket parts, but look into the parts you use and some components like connecting rods and fly wheels are parts ID usually suggest be upgraded.
theres hundreds of thousands of guys driving cars with stock flywheels and clutches , and only a small percentage of failures but once you see what happens you get a big chunk of respect for what can happen to your feet IF one fails
resurfacing makes it look and function better but it does NOTHING to repair micro stress cracks, a BILLET SFI fly wheel and lake wood bell housing may cost you a good deal of cash but they are a good investment in both durability and safety
grumpyvette said:
" GRUMPY??
Is my Flywheel scrap?
My Flywheel has two areas that have some checking or slight surface cracks as seen in the pics below. Is this normal? can having it Blanchard ground take care of this or does it look beyond help?"
in the last 45 plus years, Ive seen several factory dampers either come apart or have the elastomer ring fail/slip, Ive seen at least 5 or 6 flywheels fail and a couple basically grenade doing significant damage, now one fly wheel failure on a 283 chevy,really impressed me when chunks of it came loose at 6000rpm,or a bit more, cut the cars frame and blew out the wind shield , cut the clutch and brake petals out of the car in the process


Flywheel1.jpg

Flywheel2.jpeg


well as Im sure a few of your friends have been sure to mention, you have a choice too make here, you can save a few bucks and reuse the obviously damaged fly wheel knowing full well that theres a significant chance that it will fragment throwing large jagged chunks of shrapnel thru the cars interior at some point.
the surface of the flywheel appears to have little radial cracks: these are a indicator the fly wheel might be prone to coming apart under high rpm stress loads, like a quick shift under load...yeah! I know you know someone who has run a flywheel like that for years with zero problems.......its your feet and its just a mater of time.....
having high velocity chunks of cast steel pass thru your car, with a good chance you'll loose your feet in the process as the shrapnel exits the car, won,t be fun!
or you can upgrade to a billet flywheel and a blow proof steel bell housing and have significantly reduced the chances of getting a nick name like "STUMPY", "TOE-LESS JOE" or "SHORTY"
personally Id suggest investing in a good lakewood blow proof bell housing and SFI billet clutch and flywheel
10-03.jpg


READ THESE LINKS
viewtopic.php?f=71&t=584&p=21690&hilit=blow+proof#p21690

viewtopic.php?f=71&t=447&p=5542&hilit=proof+lakewood#p5542

viewtopic.php?f=53&t=1042&p=1969&hilit=blow+proof#p1969

http://www.fordmuscle.com/archives/2000/11/lakewood/
Click to expand...
 
76GrayVette said:
Can the billet steel flywheels such as the Ram 1501 be resurfaced down the road at some point should the need arise?
Click to expand...

yes Ive done it several times, the steel billet flywheels are far more durable ,than the aluminum fly wheels with friction insert surfaces, Id suggest a 30lb-36lb weight as it allows the car to launch smoothly even with slicks and not bog on shifts as much as a lighter flywheel

AS USUAL READING A FEW LINKS WON,T HURT

http://www.bizrate.com/automotive-parts ... -flywheel/

viewtopic.php?f=71&t=584&p=26279&hilit=+flywheel+billet#p26279

viewtopic.php?f=53&t=1042&p=1969&hilit=+flywheel+billet#p1969

viewtopic.php?f=71&t=447&p=840&hilit=+flywheel+billet#p840

http://www.ramclutches.com/critical%20d ... wheels.htm

http://www.aa1car.com/library/2003/bf100372.htm
 
Well guys, it's been a rough few weeks since I last posted. My dad passed away unexpectedly at only 55 years old and it's turned my life upside down.
I'm just now starting to think about my car again and trying to keep working on it. I know he would want me to finish it.

So here's a few pictures of the new parts I received.
Jegs Harmonic Balancer
jpdt.jpg

7pyf.jpg


Ram billet steel flywheel 1501
ij3z.jpg

rtva.jpg


Scat forged I-beam 5.7 rods 25700P
nkpq.jpg

giyz.jpg

breo.jpg


I've also calculated my bob weight using measurements I've taken and the big/small end weights Scat wrote on the box for my rods.
7cnv.jpg

I'm going to call the balance shop again today and make sure we are both on the same page before I take anything over to them. Just thought I'd give you guys an update and make sure I'm on the right track still.
 

Sure sorry to hear about your Dad!

Looks ok to me what you just posted. I ran the numbers thru my Excel calculator for the bob weight and got the exact same numbers. You didn't put any thing in the wrist pin locks, but I assume the machine will take that into consideration when they balance it.

On the previous page you mentioned not having to balance the flywheel and damper, so not sure what you plan on doing here. I would have it all balanced if it was me and did on my engine.

 
Indycars said:

Sure sorry to hear about your Dad!

Looks ok to me what you just posted. I ran the numbers thru my Excel calculator for the bob weight and got the exact same numbers. You didn't put any thing in the wrist pin locks, but I assume the machine will take that into consideration when they balance it.

On the previous page you mentioned not having to balance the flywheel and damper, so not sure what you plan on doing here. I would have it all balanced if it was me and did on my engine.
Click to expand...
Yes SORRY to hear about your Dad passing , I know it was a huge emotional blow when my parents passed, it sure makes you realize, how limited our time is!

YES I SECOND THOSE CONCERNS posted above,
I usually try to have my flywheel, clutch pressure plate, and damper balanced along with the rotating assembly
the parts you purchased look like they will be very well suited to the application once you have the rotating assembly balanced


related threads
viewtopic.php?f=71&t=447&p=921&hilit=beck+borg#p921

viewtopic.php?f=38&t=3900&p=28672&hilit=balancing#p28672

viewtopic.php?f=50&t=428
 
Thanks guys, its really hard as I'm only 20 and we were/are a tight family. I'm very grateful for the time I did have with my dad although I think about all the time we won't have. I'm just glad I still have my mom and younger brother as well as wonderful grandparents close by to lean on.

Anyway, I had already decided to have the flywheel, damper, etc balanced along with the other stuff.
It's good to hear my parts will be well suited.
 
Am sorry to hear about your loss. very sorry :(

This is going to be an interesting build, thanks for the pictures. :!:
 
Right, so the parts are off at the machine shop being balanced.

I had a question about which type oil pump you guys recommend.
Should I go with high pressure or high volume or just stick with standard? I've read different things about what is best.

Also, I've heard a steel retainer for the oil pump shaft is better than the standard nylon/plastic one?
 
76GrayVette said:
Right, so the parts are off at the machine shop being balanced.

I had a question about which type oil pump you guys recommend.
Should I go with high pressure or high volume or just stick with standard? I've read different things about what is best.

Also, I've heard a steel retainer for the oil pump shaft is better than the standard nylon/plastic one?
Click to expand...

yes Id strongly suggest a steel collar on the oil pump drive shaft

http://www.summitracing.com/parts/mel-is-55e/overview/

http://www.summitracing.com/parts/arp-1 ... /overview/

your oil pump selection will depend a great deal on the other mods youve done to the engine and if you installed a high capacity baffled oil pan, the standard Z28 pump is fine in about 80% of the performance builds.

related and useful links

viewtopic.php?f=54&t=64

viewtopic.php?f=54&t=4480

viewtopic.php?f=54&t=52

viewtopic.php?f=54&t=2187

viewtopic.php?f=54&t=1800

viewtopic.php?f=54&t=2294

viewtopic.php?f=54&t=4966
 
The Melling M55A Oil pump is an awesome oil pump to use on the street & strip.
Exact duplicate of the factory 1967-70 Z28 Oil pump. Provides excellent Hot idle pressure of 40-44 psi with 10w30 oil.
At 2600 Rpm crank speed there is 75-80 psi Hot.
Easy on the factory GM Melonized distributor gear & cast iron cam gear.
Engineered for 100,000 mile reliability on the street.
Use the ARP Chromemoly Oil pump driveshaft.
 
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