SoCal Jet Boats
Tech Talk => Engine Mechanical / Electrical => Topic started by: hotrod56cars on January 29, 2008, 07:37:08 PM
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So I looked up some used GM dimple rods, and some new aftermarket H beams, and some new aftermarket I beams, and some used aluminum rods, and I have no idea what I'm looking at as far as which is better for what. They are all within $100 of each other for a set of 8.
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I'd go "H"
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I've spun the dog piss out of my stock bottom end in my blue boat . What are you planning on doin with this motor ?
-beerjet-
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I've been doing alot of reading in my quest for my SB or BB build. The majority of what I've read has been saying "Forged H Beam" are the strongest. I don't know squat about this, but I read pretty good. I'm sure some of the engine building guru's can tell us why or why not. Mark
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If and when I go rebuild the cruisers motor , I'll go all scat cast and save my dough for something more important . H-beams are tops in strength though.
-beerjet-
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I bought the Eagle Stroker kit all forged with H-Beams.
On racingjunk.com I found Eagle H Beams for $349 a set I've seen used Gm Dimples sell for that much still needind an R&R at the machine shop.
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shit, just look at them and you can tell the the "H"s are the strongest. If anythings gonna break it's the rods and it gets real ugly down there in a hurry when that happens, right Brad?
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I've spun the dog piss out of my stock bottom end in my blue boat . What are you planning on doin with this motor ?
-beerjet-
The engine I got with my boat had two hyperwhatever pistons melt/fall apart and caused a stock cast rod to break which went through the oil pan... :P I am going to eventually put a blower on it, with a "big" pulley on top. I know it's a contradiction, but I want it on the smallest of budgets. I've done a little bit of research and I think I can do it, with a little help from my friends. ;)
shit, just look at them and you can tell the the "H"s are the strongest. If anythings gonna break it's the rods and it gets real ugly down there in a hurry when that happens, right Brad?
Exactly what I was thinking, besides the part about the H's being the strongest because I really don't know.
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I've seen one of those eagle rods bent into an "S" and didnt break.
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The engine I got with my boat had two hyperwhatever pistons melt/fall apart and caused a stock cast rod to break which went through the oil pan... :P I am going to eventually put a blower on it, with a "big" pulley on top. I know it's a contradiction, but I want it on the smallest of budgets. I've done a little bit of research and I think I can do it, with a little help from my friends. ;)
Exactly what I was thinking, besides the part about the H's being the strongest because I really don't know.
I think all rods are forged
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I think all rods are forged
Tripey, you're the second person that I heard that from today. Hmmm... but my engine builder said my block has cast 3/8 rods in it. ;)
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Tripey, you're the second person that I heard that from today. Hmmm... but my engine builder said my block has cast 3/8 rods in it. ;)
I would be looking for a new engine builder ;)
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I would be looking for a new engine builder ;)
Now it makes sense, the last time I read that you had me really confused. :D
There were several TV shows and many race car owners that like using that guy to build their engines for them (marcsrollin has a better memory than me on who specifically used that engine builder, besides my last engine of course). I've never seen casting flash on forged cranks or forged rods. Both the crank and all of the rods in my block have casting flash/marks. I was looking at the forged 489/496 Eagle stroker kit, I think it was like $1150 new (crank, rods, pistons, pins, bearings, rings). There are many dimple rods available ready to run for $250 - $300 for a set of 8, most with ARP bolts.
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Chevy dimple rods are cast, made of a higher grade metal than regular cast Chevy rods.
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If yer gonna buy rods, get the "H" beams. I think I told you I was thinking about throwing the new old flatty in nostagia flats. If I do I will slap in "H" beams and a roller. Maybe aks Ralph or someone to drive.
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... Maybe aks Ralph or someone to drive.
That's a cool idea, but will Ralph drive a Chevy? ???
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I've ran my dimple rods to almost 6k several times. I'm pretty sure they have 7/16 rod bolts. After I finished my motor and paid my machineist,I asked him what rpm should be my max. He tells me I wouldn't take it over 5k for very long, wtf, I asked him, he tells me ohh your dimple rods are plenty strong, there just too heavy for high r's. Shit if he'd told me that b-4 I'd bought better/lighter rods. Just my .02
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I've ran my dimple rods to almost 6k several times. I'm pretty sure they have 7/16 rod bolts. After I finished my motor and paid my machineist,I asked him what rpm should be my max. He tells me I wouldn't take it over 5k for very long, wtf, I asked him, he tells me ohh your dimple rods are plenty strong, there just too heavy for high r's. Shit if he'd told me that b-4 I'd bought better/lighter rods. Just my .02
The general conscensious seems that the H-beams are the ones to get for a jet boat.
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I have a friend with dimple rods in his full roller motor and he ran his all the time OVER 6K in his V-Drive , and never had a problem.
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Wow, I just had a very experienced engine builder tell me all chevy rods are forged... :banghead: So now I've been told by one very experienced engine builder that all chevy rods are cast and another very experienced engine builder tell me that all chevy rods are forged... check the parting line on the top rod - you be the judge.
[attachimg=#]
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Damn i got an extra set lying around here, im gonna go look at em ;D
2sav
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Wow, I just had a very experienced engine builder tell me all chevy rods are forged... :banghead: So now I've been told by one very experienced engine builder that all chevy rods are cast and another very experienced engine builder tell me that all chevy rods are forged... check the parting line on the top rod - you be the judge.
(Attachment Link)
wide parting line means forged - narrow means cast (two halves of mold)
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Get the H-beams. If anyone needs any parts shot peened, cryo-treated, or heat treated for strength send them to me and I'll have the company get it done at a minimal charge. They'll just throw them in with our aircraft parts...