TRW Speed pro forged pistons... and what kind of piston rings?!?!
09-16-2003, 10:52 PM
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TRW Speed pro forged pistons... and what kind of piston rings?!?!
Hey guys...
I'm getting to the point in the engine rebuild on the 75 that I need to figure out the new parts to replace the old!
Its a 350 small block with 5.7 rods... Has pitted walls on 1 and 3 so she's getting punched .030!
So heres my question:
1. Does anyone have any previous expierence using TRW parts? Are they better quality then the rest of the choices?
2.Are the forged pistons that are summit part number TRW-L2256F30 suitable for a mild rebuild with a high performance future?
3.What kind/brand of piston rings are recomended nowadays? Chrome moly? Or would cast Iron still work? Are gapless rings the way to go?
My goal is to get the motor back on the road, maybed 250-300 horsepower... Then tear it back down when funds arent a problem and swap in some aluminum heads, intake... etc, but while the bottom end is apart I would love to set everything up for a 400-500 horsepower future!
I currently have 882 heads, which I belive to be 76cc's, at least thats what mortec said they were!
Unfortunately currently money IS an object... so I would like to get it finished up for under a grand... hopefully!
Thanks guys! Cant wait to get it on the road again! :party:
I'm getting to the point in the engine rebuild on the 75 that I need to figure out the new parts to replace the old!
Its a 350 small block with 5.7 rods... Has pitted walls on 1 and 3 so she's getting punched .030!
So heres my question:
1. Does anyone have any previous expierence using TRW parts? Are they better quality then the rest of the choices?
2.Are the forged pistons that are summit part number TRW-L2256F30 suitable for a mild rebuild with a high performance future?
3.What kind/brand of piston rings are recomended nowadays? Chrome moly? Or would cast Iron still work? Are gapless rings the way to go?
My goal is to get the motor back on the road, maybed 250-300 horsepower... Then tear it back down when funds arent a problem and swap in some aluminum heads, intake... etc, but while the bottom end is apart I would love to set everything up for a 400-500 horsepower future!
I currently have 882 heads, which I belive to be 76cc's, at least thats what mortec said they were!
Unfortunately currently money IS an object... so I would like to get it finished up for under a grand... hopefully!
Thanks guys! Cant wait to get it on the road again! :party:
09-16-2003, 10:58 PM
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Re: TRW Speed pro forged pistons... and what kind of piston rings?!?! (ZD75blue)
Oh... This motor might in the future recieve shots of nitrous, and or turbocharging! So ARP rod bolts for sure... And maybe a scat crank... next time around! :yesnod:
09-17-2003, 12:00 AM
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Re: TRW Speed pro forged pistons... and what kind of piston rings?!?! (ZD75blue)
My engine builder strongly recommended the Speed Pro Forged Pistons over the Keith Black hyperreutectic. They are not that much more expensive.
I was not going to step up and buy a Ross or JE piston, so I felt the forged piston was a good compromise.
I did buy the nicer Speed Pro rings ($109) vs. the less expensive that are listed recommended with pistons in the Summit catalog. I am not sure why. I just went with the engine builders recommendation.
She aint failed me yet, but then again I only have @600 miles on it.
I was not going to step up and buy a Ross or JE piston, so I felt the forged piston was a good compromise.
I did buy the nicer Speed Pro rings ($109) vs. the less expensive that are listed recommended with pistons in the Summit catalog. I am not sure why. I just went with the engine builders recommendation.
She aint failed me yet, but then again I only have @600 miles on it.
09-17-2003, 07:57 AM
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Re: TRW Speed pro forged pistons... and what kind of piston rings?!?! (hudman)
I have the Speed Pro hypereutectic pistons and they are not supposed to be used with NOS, not sure if it is do to the teflon coating on the side of the piston or something else.
09-17-2003, 08:27 AM
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Re: TRW Speed pro forged pistons... and what kind of piston rings?!?! (gdh)
I'd like to build it so it can handle anything I want to throw at it!
What kind of compression ya running hud?
I'm trying to get something that will run on 87 no problem, but still have instant throttle response... a hard goal to tackle... but I'm gonna try!
What kind of compression ya running hud?
I'm trying to get something that will run on 87 no problem, but still have instant throttle response... a hard goal to tackle... but I'm gonna try!
09-17-2003, 10:10 AM
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Re: TRW Speed pro forged pistons... and what kind of piston rings?!?! (ZD75blue)
I think the piston is something like 10.5 or 11 or so (at least that is what I remember from the Summit catalog), but with the stock BB iron heads from '68 that had smaller chambers (seems like 106 cc comes to mind, maybe wrong there), he did a calculation that said the the CR would be 9.8 or 9.9.
Mine will run without detonation on 93. However, I run 93 and plus 3-5 gallons of 100 mixed in. Car seems to like it a lot and I do not want to take the risk of having any detonation. Besides, I like the smell!
Small block will be different and your heads will be make a difference. I am definitely no expert here. Others need to chime in.
My engine builder was very bullish on the forged piston vs. the hypereutectic. He said the forged would be worth 1000 RPM or more without running the risk of breaking a skirt. I do not really tach mine above 5000-5200 or so anyway, so it probably does not make a difference, but because they are only $75 or so more, I thought better safe than sorry.
Good luck.
Mine will run without detonation on 93. However, I run 93 and plus 3-5 gallons of 100 mixed in. Car seems to like it a lot and I do not want to take the risk of having any detonation. Besides, I like the smell!
Small block will be different and your heads will be make a difference. I am definitely no expert here. Others need to chime in.
My engine builder was very bullish on the forged piston vs. the hypereutectic. He said the forged would be worth 1000 RPM or more without running the risk of breaking a skirt. I do not really tach mine above 5000-5200 or so anyway, so it probably does not make a difference, but because they are only $75 or so more, I thought better safe than sorry.
Good luck.
09-17-2003, 11:03 AM
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Re: TRW Speed pro forged pistons... and what kind of piston rings?!?! (ZD75blue)
I rebuilt my engine in 1996. I used TRW forged pistons (11:1). This is what GM used originally in the LT-1. Part # L2304F-30
I used MOLY rings. Sealed Power # T8325M-30.. GM used MOLY rings as well in the LT-1.
I fitted the pistons at .004, and the end gaps of the rings were within spec. No ring grinding required.
The engine uses less oil now than it did when it was new.
Barry
I used MOLY rings. Sealed Power # T8325M-30.. GM used MOLY rings as well in the LT-1.
I fitted the pistons at .004, and the end gaps of the rings were within spec. No ring grinding required.
The engine uses less oil now than it did when it was new.
Barry
09-17-2003, 11:30 AM
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Re: TRW Speed pro forged pistons... and what kind of piston rings?!?! (Barry's70LT1)
I rebuilt my engine in 1996. I used TRW forged pistons (11:1). This is what GM used originally in the LT-1. Part # L2304F-30
I used MOLY rings. Sealed Power # T8325M-30.. GM used MOLY rings as well in the LT-1.
I fitted the pistons at .004, and the end gaps of the rings were within spec. No ring grinding required.
The engine uses less oil now than it did when it was new.
Barry
I used MOLY rings. Sealed Power # T8325M-30.. GM used MOLY rings as well in the LT-1.
I fitted the pistons at .004, and the end gaps of the rings were within spec. No ring grinding required.
The engine uses less oil now than it did when it was new.
Barry
09-17-2003, 12:15 PM
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Re: TRW Speed pro forged pistons... and what kind of piston rings?!?! (ZD75blue)
When in doubt, err on the side of "overdesign", i.e. go with the forged pistons over the hypereutectic. This will afford you the opportunity to add NOS, or build for more power without rebuilding your shortblock later. The downside of forged pistons is that they must be fit at looser clearances which can result in additional noise (piston slap) while the engine is cold and possibly increased oil consumption. Probably not that much of a concern for your hobby car, or any performance car for that matter.
Choose Moly faced rings hands down!! The moly is there for wear resistance and scuff resistance. They also will yield better oil consumption (if that's even a concern). CI face rings are for budget rebuilds for grandma's '73 Caprice ONLY. Chrome face rings wear well also but are less common, take longer to break in, and are more prone to scuffing. You don't need to pay the extra for "Speed Pro". A friend who works for the plant that makes their rings told me they are no different than the standard "Sealed Power" moly faced rings used for standard rebuilds. The only differences are that the "Speed Pro" rings are available so that you can custom grind the gaps, and the higher price. In fact, the only difference in the manufacturing process is that the "Speed Pro" rings skip the gap grind operation at the end of the line. There's lots of opinions out there about this, but I feel custom grinding the gaps is over rated as a power adder, but if it makes you feel better do it. Better to have the gaps too large than too small (to avoid ring gap butting--especially with NOS or blowers/turbochargers). The same is true for some of the "gapless" rings out there.
Use ARP rod bolts as a previous post noted. The conn-rod bolts are really the weak link in the system. Premium bolts will raise your allowable max rpm considerably. Just make sure your machine shop resizes the rods after the new bolts are installed. I like the "wave lock" design ARP has. It eliminates the stress risers that are inherent in the knurling process of the OEM style bolts.
Good Luck!! :thumbs:
Choose Moly faced rings hands down!! The moly is there for wear resistance and scuff resistance. They also will yield better oil consumption (if that's even a concern). CI face rings are for budget rebuilds for grandma's '73 Caprice ONLY. Chrome face rings wear well also but are less common, take longer to break in, and are more prone to scuffing. You don't need to pay the extra for "Speed Pro". A friend who works for the plant that makes their rings told me they are no different than the standard "Sealed Power" moly faced rings used for standard rebuilds. The only differences are that the "Speed Pro" rings are available so that you can custom grind the gaps, and the higher price. In fact, the only difference in the manufacturing process is that the "Speed Pro" rings skip the gap grind operation at the end of the line. There's lots of opinions out there about this, but I feel custom grinding the gaps is over rated as a power adder, but if it makes you feel better do it. Better to have the gaps too large than too small (to avoid ring gap butting--especially with NOS or blowers/turbochargers). The same is true for some of the "gapless" rings out there.
Use ARP rod bolts as a previous post noted. The conn-rod bolts are really the weak link in the system. Premium bolts will raise your allowable max rpm considerably. Just make sure your machine shop resizes the rods after the new bolts are installed. I like the "wave lock" design ARP has. It eliminates the stress risers that are inherent in the knurling process of the OEM style bolts.
Good Luck!! :thumbs:
09-17-2003, 12:21 PM
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Re: TRW Speed pro forged pistons... and what kind of piston rings?!?! (LemansBlue68)
When in doubt, err on the side of "overdesign", i.e. go with the forged pistons over the hypereutectic. This will afford you the opportunity to add NOS, or build for more power without rebuilding your shortblock later. The downside of forged pistons is that they must be fit at looser clearances which can result in additional noise (piston slap) while the engine is cold and possibly increased oil consumption. Probably not that much of a concern for your hobby car, or any performance car for that matter.
Choose Moly faced rings hands down!! The moly is there for wear resistance and scuff resistance. They also will yield better oil consumption (if that's even a concern). CI face rings are for budget rebuilds for grandma's '73 Caprice ONLY. Chrome face rings wear well also but are less common, take longer to break in, and are more prone to scuffing. You don't need to pay the extra for "Speed Pro". A friend who works for the plant that makes their rings told me they are no different than the standard "Sealed Power" moly faced rings used for standard rebuilds. The only differences are that the "Speed Pro" rings are available so that you can custom grind the gaps, and the higher price. In fact, the only difference in the manufacturing process is that the "Speed Pro" rings skip the gap grind operation at the end of the line. There's lots of opinions out there about this, but I feel custom grinding the gaps is over rated as a power adder, but if it makes you feel better do it. Better to have the gaps too large than too small (to avoid ring gap butting--especially with NOS or blowers/turbochargers). The same is true for some of the "gapless" rings out there.
Use ARP rod bolts as a previous post noted. The conn-rod bolts are really the weak link in the system. Premium bolts will raise your allowable max rpm considerably. Just make sure your machine shop resizes the rods after the new bolts are installed. I like the "wave lock" design ARP has. It eliminates the stress risers that are inherent in the knurling process of the OEM style bolts.
Good Luck!! :thumbs:
Choose Moly faced rings hands down!! The moly is there for wear resistance and scuff resistance. They also will yield better oil consumption (if that's even a concern). CI face rings are for budget rebuilds for grandma's '73 Caprice ONLY. Chrome face rings wear well also but are less common, take longer to break in, and are more prone to scuffing. You don't need to pay the extra for "Speed Pro". A friend who works for the plant that makes their rings told me they are no different than the standard "Sealed Power" moly faced rings used for standard rebuilds. The only differences are that the "Speed Pro" rings are available so that you can custom grind the gaps, and the higher price. In fact, the only difference in the manufacturing process is that the "Speed Pro" rings skip the gap grind operation at the end of the line. There's lots of opinions out there about this, but I feel custom grinding the gaps is over rated as a power adder, but if it makes you feel better do it. Better to have the gaps too large than too small (to avoid ring gap butting--especially with NOS or blowers/turbochargers). The same is true for some of the "gapless" rings out there.
Use ARP rod bolts as a previous post noted. The conn-rod bolts are really the weak link in the system. Premium bolts will raise your allowable max rpm considerably. Just make sure your machine shop resizes the rods after the new bolts are installed. I like the "wave lock" design ARP has. It eliminates the stress risers that are inherent in the knurling process of the OEM style bolts.
Good Luck!! :thumbs:
09-17-2003, 04:47 PM
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Re: TRW Speed pro forged pistons... and what kind of piston rings?!?! (ZD75blue)
When your old bolts are pushed out and the new ones pushed in, it can distort the big end of the rod. When the machine shop resizes it, they machine a small amount off of the cap and rod joint faces. This effectively makes the rod bore undersized (as well as a bit oval) but this allows them to hone it back out to the correct size and regain the roundness and straightness that the rod blue print spec requires. They can also use the pin bore as reference during honing to assure that the rod's "bend and twist" (that is the parallelism between the pin bore and crank bore axes) is in spec too.
09-17-2003, 05:05 PM
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Re: TRW Speed pro forged pistons... and what kind of piston rings?!?! (LemansBlue68)
When your old bolts are pushed out and the new ones pushed in, it can distort the big end of the rod. When the machine shop resizes it, they machine a small amount off of the cap and rod joint faces. This effectively makes the rod bore undersized (as well as a bit oval) but this allows them to hone it back out to the correct size and regain the roundness and straightness that the rod blue print spec requires. They can also use the pin bore as reference during honing to assure that the rod's "bend and twist" (that is the parallelism between the pin bore and crank bore axes) is in spec too.
09-17-2003, 05:14 PM
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Re: TRW Speed pro forged pistons... and what kind of piston rings?!?! (ZD75blue)
And just as a counter point to all the forged piston recomendations I believe GM uses hypo's on the LS1/LS6 plus a whole hot of other eng's. If you are not going NOS or forced induction then the hypo's are a better choice for there tight fit and strength, believe they are stronger than forged but more briddle, they don't bend they break.
09-17-2003, 09:03 PM
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Re: TRW Speed pro forged pistons... and what kind of piston rings?!?! (Fevre)
Yeah...
Nitrous is in the future, or maybe a turbo...
8.62:1 with the 76cc heads... 9.5 with the 58cc... I figure with flat tops I can do most anything with it after the fact...
The machine shop I'm using will evidentally be making more then I thought! :crazy:
Nitrous is in the future, or maybe a turbo...
8.62:1 with the 76cc heads... 9.5 with the 58cc... I figure with flat tops I can do most anything with it after the fact...
The machine shop I'm using will evidentally be making more then I thought! :crazy:
09-17-2003, 09:52 PM
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Re: TRW Speed pro forged pistons... and what kind of piston rings?!?! (ZD75blue)
I just bought some SpeedPro light weight forged pistons LW2606 with the new coated skirts, they are really nice and really expensive, $500 US with the rings.
Now if you are worried about money at this time and are planning to make 300HP I can't see buying expensive forged pistons for this application, a nice KB flat top hyper piston is fine and you can rebuild to 500HP and still hit it with with a 100 shot of NOS. :D
Now if you are worried about money at this time and are planning to make 300HP I can't see buying expensive forged pistons for this application, a nice KB flat top hyper piston is fine and you can rebuild to 500HP and still hit it with with a 100 shot of NOS. :D
09-17-2003, 10:57 PM
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Re: TRW Speed pro forged pistons... and what kind of piston rings?!?! (MotorHead)
I had two badly worn rod bearings and when the bearings go, the rod ends and the crank get all out of whack as mentioned before. Thus, the crank must be turned and the rods resized to get everything back round and in tolerance.
I also went with a full ARP bolt kit (rod bolts, head bolts, all acessories, etc.). Again, not a lot of money for a lot of piece of mind.
Based on what was said above about the Speed Pro Rings, I guess I got took on that one. I had close to $500 in my pistons and rings as well. I guess I could have gotten away with cheaper rings. Oh well-to late now.
I also went with a full ARP bolt kit (rod bolts, head bolts, all acessories, etc.). Again, not a lot of money for a lot of piece of mind.
Based on what was said above about the Speed Pro Rings, I guess I got took on that one. I had close to $500 in my pistons and rings as well. I guess I could have gotten away with cheaper rings. Oh well-to late now.
09-18-2003, 03:23 PM
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Re: TRW Speed pro forged pistons... and what kind of piston rings?!?! (hudman)
The arp set is going in... mainly because of my failure to bag everything successfully! :nopity
09-18-2003, 11:02 PM
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Re: TRW Speed pro forged pistons... and what kind of piston rings?!?! (ZD75blue)
ive heard good things of the new gapless rings, much less blow by and more power
MAtt
MAtt
