H-I-J '76 Nova re-fit. - Page 136

Greg Reimer 7376 · 07-26-2019, 08:30 PM

After much engineering and introspection,trial and error and work, some neanderthal invented the wheel. We've been re engineering and making it better ever since.

Nmbr1GMfan · 07-26-2019, 09:45 PM

Quote:

Originally Posted by Greg Reimer 7376

After much engineering and introspection,trial and error and work, some neanderthal invented the wheel. We've been re engineering and making it better ever since.

So true!

Dissident · 07-26-2019, 10:24 PM

Autumn and Todd,
Congrats on getting it all put together and running!

Wishing you good luck on some good engine testing on the dyno.

Regards,
HB2

Dissident

Greg Reimer 7376 · 07-26-2019, 11:22 PM

Several years ago on the Tech pages, a member told about his 66 Nova 283 car that ran the ET's that it did, then he changed the pushrods for a new set that was a different length. The car picked up almost two tenths and almost that many miles per hour. All he changed was the pushrods, but he found that the lift was closer to the .398" figure that was the maximum legal lift. It was less with the shorter pushrod. He was wondering if going to a 1.6 rocker would help as long as the lift stayed legal at the valve. That would have been a way to get back lift on a short configuration,but the rockers weren't legal. They must retain the original ratio. About a half dozen of us motor heads discussed this at length, and we created a multi page thread that sounded like an engineering textbook on how to determine proper push rod length and proper valve train geometry.When a cylinder head needs,let's say .075" taken off the deck surface to bring combustion chamber volume down to specs, the block needs .040" off the deck on it to get the deck height down, the pushrod is effectively 1/8th of an inch too long, and the tip of the rocker might not track well on the valve tip.Since then,roller rockers became legal,and it became a simpler task to achieve optimum valve train geometry by switching pushrods. I've seen engines with different length push rods on the intakes vs. the exhausts, This is one of the things that changes the relationship of parts to one another,with the inevitable conclusion that nothing seems like it will ever fit right.You got to that point with your intake, now you will have a much more trouble free engine assembly because everything will fit right. One thing about a small block Chevy that is great, if a casting gets machined too far and can't be made to work right, another intake or head is readily available. Can't wait to hear how your car runs!!

Nmbr1GMfan · 07-27-2019, 09:24 AM

Runs good but having some real tuning issues so we're on our way down to start addressing those and swapping some parts. We'll see how it goes today.

Nmbr1GMfan · 07-27-2019, 04:01 PM

And this is the face you make when your crap burns up again!

jcw31 · 07-27-2019, 05:51 PM

from the looks I hope it didnt wipe out the cam

Nmbr1GMfan · 07-27-2019, 06:05 PM

Quote:

Originally Posted by jcw31

from the looks I hope it didnt wipe out the cam

Yeah, the cam is in 6 pieces.

Rod Greene · 07-27-2019, 06:39 PM

Wow how does that happen? I can feel your frustration.

J&S Racing · 07-27-2019, 06:41 PM

Ouch...
Like many others I was rooting for you guys.

Your not the only one, my new 565 for the dragster ran wicked for 10 passes before it broke a valve.

Was this the cam from the other motor?? Possibly part of you oiling issue?

07-26-2019, 08:30 PM	#1351
Greg Reimer 7376 VIP Member Join Date: Nov 2008 Location: Glendora,Calif. Posts: 1,111 Likes: 164 Liked 649 Times in 208 Posts	Re: H-I-J '76 Nova re-fit. After much engineering and introspection,trial and error and work, some neanderthal invented the wheel. We've been re engineering and making it better ever since.

07-26-2019, 10:24 PM	#1353
Dissident Member Join Date: Jan 2016 Location: Colorado hills Posts: 123 Likes: 11 Liked 73 Times in 36 Posts	Re: H-I-J '76 Nova re-fit. Autumn and Todd, Congrats on getting it all put together and running! Wishing you good luck on some good engine testing on the dyno. Regards, HB2 Dissident

07-26-2019, 11:22 PM	#1354
Greg Reimer 7376 VIP Member Join Date: Nov 2008 Location: Glendora,Calif. Posts: 1,111 Likes: 164 Liked 649 Times in 208 Posts	Re: H-I-J '76 Nova re-fit. Several years ago on the Tech pages, a member told about his 66 Nova 283 car that ran the ET's that it did, then he changed the pushrods for a new set that was a different length. The car picked up almost two tenths and almost that many miles per hour. All he changed was the pushrods, but he found that the lift was closer to the .398" figure that was the maximum legal lift. It was less with the shorter pushrod. He was wondering if going to a 1.6 rocker would help as long as the lift stayed legal at the valve. That would have been a way to get back lift on a short configuration,but the rockers weren't legal. They must retain the original ratio. About a half dozen of us motor heads discussed this at length, and we created a multi page thread that sounded like an engineering textbook on how to determine proper push rod length and proper valve train geometry.When a cylinder head needs,let's say .075" taken off the deck surface to bring combustion chamber volume down to specs, the block needs .040" off the deck on it to get the deck height down, the pushrod is effectively 1/8th of an inch too long, and the tip of the rocker might not track well on the valve tip.Since then,roller rockers became legal,and it became a simpler task to achieve optimum valve train geometry by switching pushrods. I've seen engines with different length push rods on the intakes vs. the exhausts, This is one of the things that changes the relationship of parts to one another,with the inevitable conclusion that nothing seems like it will ever fit right.You got to that point with your intake, now you will have a much more trouble free engine assembly because everything will fit right. One thing about a small block Chevy that is great, if a casting gets machined too far and can't be made to work right, another intake or head is readily available. Can't wait to hear how your car runs!!

07-27-2019, 09:24 AM	#1355
Nmbr1GMfan VIP Member Join Date: Aug 2013 Posts: 1,766 Likes: 1,197 Liked 1,957 Times in 492 Posts	Re: H-I-J '76 Nova re-fit. Runs good but having some real tuning issues so we're on our way down to start addressing those and swapping some parts. We'll see how it goes today. __________________ Todd Greene

07-27-2019, 04:01 PM	#1356
Nmbr1GMfan VIP Member Join Date: Aug 2013 Posts: 1,766 Likes: 1,197 Liked 1,957 Times in 492 Posts	Re: H-I-J '76 Nova re-fit. And this is the face you make when your crap burns up again! __________________ Todd Greene

07-27-2019, 05:51 PM	#1357
jcw31 Junior Member Join Date: Jan 2013 Posts: 82 Likes: 0 Liked 2 Times in 2 Posts	Re: H-I-J '76 Nova re-fit. from the looks I hope it didnt wipe out the cam

07-27-2019, 06:39 PM	#1359
Rod Greene Senior Member Join Date: Mar 2002 Location: TN Posts: 514 Likes: 355 Liked 204 Times in 72 Posts	Re: H-I-J '76 Nova re-fit. Wow how does that happen? I can feel your frustration. __________________ Rod Greene Real men shift for them selves. Slowly working on TA Challenger for D,E/S and a 72 Challenger for SS/K, L as if I don't have enough other projects.

07-27-2019, 06:41 PM	#1360
J&S Racing Member Join Date: Sep 2013 Posts: 280 Likes: 102 Liked 288 Times in 78 Posts	Re: H-I-J '76 Nova re-fit. Ouch... Like many others I was rooting for you guys. Your not the only one, my new 565 for the dragster ran wicked for 10 passes before it broke a valve. Was this the cam from the other motor?? Possibly part of you oiling issue?