968 pistons alone for more HP/TQ?
11-24-2006, 02:35 AM
#16
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More accurately, I should have said w/ GT cams or headers. Seems reasonable to me.
How much hp have your 5.3L engines put down?
How much hp have your 5.3L engines put down?
Originally Posted by GregBBRD
330hp rwhp from a stock engine with just a bigger piston....you actually believe that? Ask about the money back guarantee before you sign up.
greg brown
greg brown
11-24-2006, 06:53 AM
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Hi John,
That seems like a cool option. I wonder if anyone has done this?
It would be great to have some other options for increased HP/TQ than either a full stroker or forced induction.
Can't wait to see you monster at Sebring!
Constantine
That seems like a cool option. I wonder if anyone has done this?
It would be great to have some other options for increased HP/TQ than either a full stroker or forced induction.
Can't wait to see you monster at Sebring!
Constantine
Originally Posted by John Veninger
Or you could go with a stroker crank and custom rods leaving the stock 100mm pistons. Nice 6.0L motor.
This saves piston cost and boring.
Stroker always = busting the bank
The non-stock bits on a stroker are actually better than the stock bits in this case.
One may argue that the stock rods are great, but I'm happy I can now use "chevy style" rod bearings with the custom rods since the stock 928 bearings are "soft".
This saves piston cost and boring.
Stroker always = busting the bank
The non-stock bits on a stroker are actually better than the stock bits in this case.
One may argue that the stock rods are great, but I'm happy I can now use "chevy style" rod bearings with the custom rods since the stock 928 bearings are "soft".
11-24-2006, 07:06 AM
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Hi Greg,
Would like to see what the HP/TQ numbers are of that engine you built if you can find them. As I've said it would be nice to have other engine options for people to build up since a full stroker is a bit expensive for most people. Would be great to maybe sell a kit with all the hard parts needed.
In your engine builds have you ever used aftermarket pistons coated to work with our engine block with any success? That would be a great to keep the costs down a bit.
I'm sure others are intersted as well.
Constantine
By the way, are you the one who built Mark A.'s motor?
Would like to see what the HP/TQ numbers are of that engine you built if you can find them. As I've said it would be nice to have other engine options for people to build up since a full stroker is a bit expensive for most people. Would be great to maybe sell a kit with all the hard parts needed.
In your engine builds have you ever used aftermarket pistons coated to work with our engine block with any success? That would be a great to keep the costs down a bit.
I'm sure others are intersted as well.
Constantine
By the way, are you the one who built Mark A.'s motor?
Originally Posted by GregBBRD
I've built one of these engines using the 968 pistons in a '91 GT. Had a custom rod built by Carrillo to make the piston fit. The engine was really screwed up from a powder coated intake that they didn't get all of the bead blasting material out of....so it needed to be bored and have new pistons, anyway. The tradeoff was the cost of the rods. We would have properly drilled the crank, regardless of the piston used, so that doesn't count. Runs pretty good. I have dyno numbers...somewhere. Not a stagering change, just a normal increase in displacement thing.
greg brown
greg brown
11-24-2006, 07:11 AM
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Hi Dennis,
I'm wondering if you would need Ti valves and stronger springs to help with the higher RPMs? And how would our 2/6 rod bearing RPM problem fair, would the re-drilled crank suffice or would you need a dry sump. What RPM ranges were you thinking of for the motor?
I thought you were playing with 911s now?
Great discussion,
Constantine
I'm wondering if you would need Ti valves and stronger springs to help with the higher RPMs? And how would our 2/6 rod bearing RPM problem fair, would the re-drilled crank suffice or would you need a dry sump. What RPM ranges were you thinking of for the motor?
I thought you were playing with 911s now?
Great discussion,
Constantine
Originally Posted by Dennis K
Constantine - I've always wanted to build a big bore "screamer" rather than a stroker and get the hp via rpm rather than displacement. I talked to Marc Thomas about this last week when talking about options for replacing my dead motor. He said he's built a couple motors like that were fairly stock and ended up at around 330 rwhp. With more mods like B1 cams, 968 valves and headers it'd be around 370 rwhp.
Erkka - awesome ascii art!
Erkka - awesome ascii art!
11-24-2006, 07:33 AM
#20
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Originally Posted by Constantine
Hi Erkka,
Obviuosly you are way ahead of me on the actual "nuts and bolts" of my hypothetical musings. From what your saying it would seem other rods would be needed if one were to go with 968 pistons. Decking the block would seem a bit more involved than I was hoping to have to do.
Constantine
Obviuosly you are way ahead of me on the actual "nuts and bolts" of my hypothetical musings. From what your saying it would seem other rods would be needed if one were to go with 968 pistons. Decking the block would seem a bit more involved than I was hoping to have to do.
Constantine
Ian in Norway
11-24-2006, 08:24 AM
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Originally Posted by Ian928
How about increasing stroke 2(really 4) mm by welding on material and regrinding the crank? This has been discussed before (search for mini-stroker or something similar). I know this has been done with success on other engines. 4mm extra stroke(300ccm) is not bad for power I guess...
11-24-2006, 02:30 PM
#25
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Constantine:
I'll dig up a couple of dyno sheets and see what the last one we did made.
We gave up on coated aftermarket pistons years ago. We either use the proper Alusil piston or we use Nickosil. I've got a stroker engine here now that was built by another person with Ross pistons that were coated. It galled and ruined the block in 50 miles. Wrong compression ratio, wrong main bearings, wrong rod bearings, etc. It's like I gave an engine to my dog and had him build it. I've always compained that the damn tool people will sell tools to anyone....even if they shouldn't have them. If people could get the stuff to do it, I'm sure that they would try and do brain surgery at home.
Yes, I do Mark's engines. We are doing another for him right now......finally gave up after all those hundreds of race hours.....we'll try to do better this time.
Heh John:
I've got Mark's pan off....you want to buy some naked pictures?
greg brown
I'll dig up a couple of dyno sheets and see what the last one we did made.
We gave up on coated aftermarket pistons years ago. We either use the proper Alusil piston or we use Nickosil. I've got a stroker engine here now that was built by another person with Ross pistons that were coated. It galled and ruined the block in 50 miles. Wrong compression ratio, wrong main bearings, wrong rod bearings, etc. It's like I gave an engine to my dog and had him build it. I've always compained that the damn tool people will sell tools to anyone....even if they shouldn't have them. If people could get the stuff to do it, I'm sure that they would try and do brain surgery at home.
Yes, I do Mark's engines. We are doing another for him right now......finally gave up after all those hundreds of race hours.....we'll try to do better this time.
Heh John:
I've got Mark's pan off....you want to buy some naked pictures?
greg brown
11-24-2006, 03:05 PM
#27
Originally Posted by GregBBRD
Constantine:
I'll dig up a couple of dyno sheets and see what the last one we did made.
We gave up on coated aftermarket pistons years ago. We either use the proper Alusil piston or we use Nickosil. I've got a stroker engine here now that was built by another person with Ross pistons that were coated. It galled and ruined the block in 50 miles. Wrong compression ratio, wrong main bearings, wrong rod bearings, etc. It's like I gave an engine to my dog and had him build it. I've always compained that the damn tool people will sell tools to anyone....even if they shouldn't have them. If people could get the stuff to do it, I'm sure that they would try and do brain surgery at home.
Yes, I do Mark's engines. We are doing another for him right now......finally gave up after all those hundreds of race hours.....we'll try to do better this time.
Heh John:
I've got Mark's pan off....you want to buy some naked pictures?
greg brown
I'll dig up a couple of dyno sheets and see what the last one we did made.
We gave up on coated aftermarket pistons years ago. We either use the proper Alusil piston or we use Nickosil. I've got a stroker engine here now that was built by another person with Ross pistons that were coated. It galled and ruined the block in 50 miles. Wrong compression ratio, wrong main bearings, wrong rod bearings, etc. It's like I gave an engine to my dog and had him build it. I've always compained that the damn tool people will sell tools to anyone....even if they shouldn't have them. If people could get the stuff to do it, I'm sure that they would try and do brain surgery at home.
Yes, I do Mark's engines. We are doing another for him right now......finally gave up after all those hundreds of race hours.....we'll try to do better this time.
Heh John:
I've got Mark's pan off....you want to buy some naked pictures?
greg brown
With a bit of proper research into the right parts, it is not difficult to GET the right parts. Obviously knowing how to put the proper parts TOGETHER can sometimes challenge people. If it had a stroker crank that was made to fit into the 928 block, I would not understand how someone could fit the wrong mains. It should be the same mains that the Stock engine uses. Are you specifically speaking to the clearance that was chosen? Because I would expect a stroker crank manaufacturer to just make the crank mains the same Diameter as the stock engine, and then the clearance would be the same with the stock main bearings. The rod bearings again would be dictated by the crank rod journal and the rod. Again, was the clearance wrong here? Its almost MORE difficult to challenging to get the proper bearings when you build anything "chevy" or "ford sized" since there are so many options - materials. Over sized, under sized, this clearance, that clearance.
Please don't take this the wrong way Greg, but this stuff is not rocket science as long as some attention is paid to the details and assembly proceedures.
For example: I had my heads rebuilt by a reputable shop but they were damaged in transit, so I had another gentleman with a good bit of 928 head and welding experience fix the surface damage and just check up on the valve seating to make sure everything was in shape for assembly. Well, during this, it seems that he found blast media material (from the original cleaning of the head) in the oil passages. It may even be in the side rail oil areas that I will have to remove the oil plugs to get at. If the heads had NOT been damaged in transit, I would have put these heads on the motor and ran it, since that is what I expected to be able to do with rebuilt and assembled heads.
The lesson is to always double check work, and triple check the details that the builder (in this case ME) may not have had original control over. In a SHOP environment, I have found that this is many times lacking.
Its the little things, as we all would expect, that makes a long lasting build. Taking off the high spots from the edge of the piston rings so it doesn't scratch the walls while wearing, having the engine machinist resize the big end of the rods if you replace the rod bolts. These things are rarely done on a "get the new parts and slap it together" kind of build.
11-24-2006, 04:46 PM
#28
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Brendan:
You're completely correct and i agree with everything you've said. It isn't rocket science...it's should be just pure logic and paying attention.
The main bearings used the wrong narrow early thrust bearing. If you have a wide thrust bearing block, a wide thrust bearing crank, and you know the engine is going into an automatic car, you need to use the proper wide thrust bearing. If you groove all the main bearings, so the rod bearings get oil through 360 degrees of rotation, you need to groove the front main bearing also....or buy an early bearing that is already grooved.
Most all of the stroker cranks use Chevy rod bearings and Chevy sized rods. The cranks all have a larger radius at the edge of the rod area, which requires the rods to be relieved and the rod bearings to be champhered. Standard Chevy stuff.....need to buy a different rod bearing.....easy to get. The builder had the rods with the relief and used bearings with no champher. Needless to say, the rod bearings were pinching and skuffing where the champher wasn't.
My point is, that if you are going to charge someone dollars to do something.....you need to at least have the basic mechanical skills and brains required to accomplish the task.
We have a saying here whenever we see crap like this:
If it was easy, everyone could do it and we would have nothing to do!
In my shop, we work on piles of 928's. It's way over 50% of what we do! Over 50% of what we do on these cars is to fix what other people have screwed up. It's a good thing for me, but it sucks for the 928 owners....no wonder so much time is spent on this forum trying to get people to do their own stuff.
greg brown
You're completely correct and i agree with everything you've said. It isn't rocket science...it's should be just pure logic and paying attention.
The main bearings used the wrong narrow early thrust bearing. If you have a wide thrust bearing block, a wide thrust bearing crank, and you know the engine is going into an automatic car, you need to use the proper wide thrust bearing. If you groove all the main bearings, so the rod bearings get oil through 360 degrees of rotation, you need to groove the front main bearing also....or buy an early bearing that is already grooved.
Most all of the stroker cranks use Chevy rod bearings and Chevy sized rods. The cranks all have a larger radius at the edge of the rod area, which requires the rods to be relieved and the rod bearings to be champhered. Standard Chevy stuff.....need to buy a different rod bearing.....easy to get. The builder had the rods with the relief and used bearings with no champher. Needless to say, the rod bearings were pinching and skuffing where the champher wasn't.
My point is, that if you are going to charge someone dollars to do something.....you need to at least have the basic mechanical skills and brains required to accomplish the task.
We have a saying here whenever we see crap like this:
If it was easy, everyone could do it and we would have nothing to do!
In my shop, we work on piles of 928's. It's way over 50% of what we do! Over 50% of what we do on these cars is to fix what other people have screwed up. It's a good thing for me, but it sucks for the 928 owners....no wonder so much time is spent on this forum trying to get people to do their own stuff.
greg brown
11-24-2006, 06:31 PM
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Hi Greg,
Okay, in my book you would be the one who would know the best the type of engine build I am thinking about.
I give it to you, what 32 valve 928 engine configuration would give a good "bang for the buck?" Something around 350-400 at the crank with a bit of zip. Kind of head work needed, things to do when you are in there. What engine build impressed you, besides Mark A.'s full stroker that lasted so dang long, with the results after you were done.
What I'm thinking about is reliable bump in HP/TQ without breaking the bank and will last in an NA configuration. Do not want to introduce other subsystems (blowers or Turbos with associated plumbing) in the engine bay that increase the chances of something going wrong.
Not wanting any of your secrets, just something for others like me to consider. By the way, do you ship engines out of your shop or are these local builds?
Appreciate in advance your thoughts,
Constantine
Okay, in my book you would be the one who would know the best the type of engine build I am thinking about.
I give it to you, what 32 valve 928 engine configuration would give a good "bang for the buck?" Something around 350-400 at the crank with a bit of zip. Kind of head work needed, things to do when you are in there. What engine build impressed you, besides Mark A.'s full stroker that lasted so dang long, with the results after you were done.
What I'm thinking about is reliable bump in HP/TQ without breaking the bank and will last in an NA configuration. Do not want to introduce other subsystems (blowers or Turbos with associated plumbing) in the engine bay that increase the chances of something going wrong.
Not wanting any of your secrets, just something for others like me to consider. By the way, do you ship engines out of your shop or are these local builds?
Appreciate in advance your thoughts,
Constantine
Originally Posted by GregBBRD
Constantine:
Yes, I do Mark's engines. We are doing another for him right now......finally gave up after all those hundreds of race hours.....we'll try to do better this time.
Heh John:
I've got Mark's pan off....you want to buy some naked pictures?
greg brown
Yes, I do Mark's engines. We are doing another for him right now......finally gave up after all those hundreds of race hours.....we'll try to do better this time.
Heh John:
I've got Mark's pan off....you want to buy some naked pictures?
greg brown