Pontiac Street Performance
Home | Profile | Register | Active Topics | Members | Search | FAQ
Username:
Password:
Save Password

 All Forums
 Pontiac Performance
 Firebirds / Formulas/ TAs
 461 Stroker-Pushrod determination
 New Topic  Reply to Topic
 Printer Friendly
Author Previous Topic Topic Next Topic  

Barnstang
Tribal Scout

USA
5 Posts

Posted - 24 Mar 2017 :  08:35:40 AM  Show Profile  Reply with Quote
I'm getting close to putting the new engine together. Short block is assembled. I need some help determining the push rod length. The car is a 67 Firebird 4 speed.
Primary use will be street cruising and car shows. I doubt it will ever see a dragstrip. Maybe some spirited driving on occasion. All part # are Summit Racing.
400 block with Eagle 461 stroker kit
JE flat top pistons p/n: 196831 Dome volume -5cc
Heads are #64 pontiac 87cc (not verified)
Using roller lifter conversion kit and roller rockers
Lifters: CCA-857-16 Hydralic Roller
Rockers: CCA-1451-16 1.52 ratio Roller
Springs: CCA-995-16 Duel 1.437" outside dia 402 lbs, 1.020" coil bind height
Retainers: CCA-740-16 10 degree 1.5" outside dia & .690 inside dia
Locks: CCA-611-16 10 degree 1 groove 11/32" valve stem
Seals: CCA-503-16 PTFE Positive stop .530" guide 11/32" valve stem
Valve: Ferrea
Intake F5143 Head: 1.77 Stem: 11/32 Length: 5.11 Tip: 0.25
Exhaust F5144 Head: 2.11 Stem: 11/32 Length: 5.095 Tip: 0.25
Cam CCA-51-423-9
Intake Duration: 276 @ .050: 224 Valve Lift: 0.502 Lobe Lift: 0.335
Exhaust Duration: 282 @ .050: 230 Valve Lift: .051 Lobe Lift: 0.34
Push rod checkers: CCA-7705
Head gasket: Pontiac 979011 .48" thick compressed

The valves came with the heads un-assembled. Heads have new guides and hardened exhaust seats. Ready to bolt on.

I have new screw in studs & locking nuts and used guideplates.

In doing a little further research, There is a chart on the comp cams website for Pontiac. For my cam, it shows all the required part and those part numbers match everything I have. And it shows a part number for pushrods! CCA-7775-16 8.650" long. Why wouldn't the comp cams tech have given me that with all the other part numbers when I called a couple years ago? Having a stroker kit or #64 heads shouldn't make any difference?

Questions
Do I trust the listed push rods and just put it together? I would consider doing that if someone has built this identicle configuration...
What checker springs do i need to order?
Do I need to torque my new head gaskets down or can I determine an accurate measurement by adding the difference between compressed and uncompressed thickness?
How can I determine if i will have coil bind?
How do I determine deck height and do i really need to?
How do I determine if the heads need machined for the valve seals? I would assume I can just check it with a caliper, but need to make sure so I don't tear it back apart...I can just pull the seals out of the box and see if they press onto the guide?

What else should I check? I can transport to a machine shop if there is anything I can't check...
Are there any questions I should be asking?

Blued and Painted
Chief PONTIAC

USA
3405 Posts

Posted - 24 Mar 2017 :  11:36:28 AM  Show Profile  Reply with Quote
- https://www.youtube.com/watch?v=o5is9BsH5OU -
You also need to gut and old lifter. Insert washers and tin foil to create a solid lifter the same height as the lifter to be used minus .050 for hydraulic lifter adjustment. Or the same height then subtract .050 from the final adjusted length.
U-tube has many more video's, some good, some not so good. I like the one above.


Bull Nose Formula/ 461/ Q-Jet/
TH400/ 3.08 8.5 / R44TS.

Edited by - Blued and Painted on 24 Mar 2017 11:53:24 AM
Go to Top of Page

Barnstang
Tribal Scout

USA
5 Posts

Posted - 24 Mar 2017 :  12:59:06 PM  Show Profile  Reply with Quote
In the video, he gross valve lift from the cam card. My spec sheet for the cam shows Valve Lift and Lobe lift...and different numbers for intake and exhaust...which one is the same as gross valve lift? And if there are different numbers for intake and exhaust, it means I would come up with different length push rods for intake and exhaust? That cant be right?
Go to Top of Page

Steve C.
Crazy Horse

1674 Posts

Posted - 24 Mar 2017 :  4:42:48 PM  Show Profile  Reply with Quote
For a hydraulic cam
Cam lobe lift x rocker ratio = valve lift (theoretical)

0.3350 x 1.52 = 0.509" (intake)
0.3400 x 1.52 = 0.515" (exhaust)

You will find these of interest:
http://www.cranecams.com/faqlist.php?x_catagory=3

Go to Top of Page

Barnstang
Tribal Scout

USA
5 Posts

Posted - 27 Mar 2017 :  12:21:54 PM  Show Profile  Reply with Quote
Awesome. So, from the youtube video, I can now determine all the info I should need. I'll just average .509 & .515 and make it .512. Divide that by 2 and get .256. Again, based on the video, each turn of the rocker nut (7/16" stud fine thread) is .050. So 256 divided by 50 is 5.12 turns. Following the video, after I centerline the rocker from pivot to roller and adjust the rocker nut to get the center line to 90 degrees from the retainer, I would turn the rocker nut down 5.12 turns and adjust my checker rod and see what it measures. From there I can sharpie the top of the valve stem and rotate the cam (crank) around (checker spring on the valve of course) and see what the contact pattern is and adjust from there accordingly. I would also check an exhaust valve contact pattern as well. Then add the compressed thickness of the head gasket to my push rod length. Then find the closest matching push rod length.
I think that will do it. I'm still a bit confused that there are two different lift numbers, and the cam card shows a valve lift parameter, that doesn't match the calculation of lobe lift and rocker ratio...but as long as it works thats all that matters.
Thanks for the help. Ill post back what length push rods I come up with.
Go to Top of Page

Steve C.
Crazy Horse

1674 Posts

Posted - 27 Mar 2017 :  8:04:31 PM  Show Profile  Reply with Quote
Copy of the cam card: http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=1216&sb=1

The valve lift stated on the card is based on a 1.5 rocker ratio. Your ratio is 1.52 thus a higher valve lift.

Edited by - Steve C. on 28 Mar 2017 09:43:49 AM
Go to Top of Page

Barnstang
Tribal Scout

USA
5 Posts

Posted - 28 Mar 2017 :  08:10:29 AM  Show Profile  Reply with Quote
I have that. Where on the card do you determine that? I believe you I'm just curious so I know how to do it...
Go to Top of Page

Steve C.
Crazy Horse

1674 Posts

Posted - 28 Mar 2017 :  09:43:19 AM  Show Profile  Reply with Quote
The cam card lists the lobe lift. In your case .3550" & .3400".
Multiply the lobe lift times the rocker arm ratio and that gives you the gross valve lift.

Understanding Camshaft Specifications

LIFT.....

http://www.lunatipower.com/Tech/Cams/CamSpecTerms.aspx
Go to Top of Page

Barnstang
Tribal Scout

USA
5 Posts

Posted - 28 Mar 2017 :  12:02:40 PM  Show Profile  Reply with Quote
Oh crap. I got lost there somewhere. Sorry. Thats already in the thread...
Go to Top of Page
  Previous Topic Topic Next Topic  
 New Topic  Reply to Topic
 Printer Friendly
Jump To:
Pontiac Street Performance © 2006-2017 Go To Top Of Page
This page was generated in 0.12 seconds. This Site Sponsored By:
Powered By: Snitz Forums 2000 Version 3.4.05