#41  
Old 03-08-2022, 08:19 PM
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The rod bolts stretch at their RPM limit, causing the rod big end to go out of round, causing the bearings to seize on the crank, and the brittle rod exceeds its tensile strength and usually breaks under the pin eye. Perfect storm. The stock bolts are like butter bolts
2 approach’s - inspect and rework stock rods with added quality rod bolts and limit rpm’s, or pop for high quality aftermarket rods.
Especially for the bigger main 421/428/455’’s.
I was lucky to buy 455sd rods long ago, and still had them fluxed, polished, peened,, and sized both ends. F-in bulletproof.

  #42  
Old 03-10-2022, 02:15 AM
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So I found that the cam that was in my 455 is basically the same one (SPC-8) that I would replace it with. That being said, has anyone used or installed this cam (Butler/Comp SP Street Performance Cam, Hyd FT, 284/296, 240/246, .507/.510, 112 Hyd. CCA-BP6018SP ) and would it make much difference with my rebuilt 455?

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Old 03-10-2022, 08:02 AM
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It would be OK in a 455 build with good flowing aluminum heads and 10.5 to 1 compression or close to it. Not the best choice for your 2200rpm converter. I'd put a better converter on my "wish list" if you end up using that much cam in your new 455 build.......

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  #44  
Old 03-10-2022, 10:13 AM
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Question 455 rebuild

I have read all the posts, did I miss the suggestion to have the block 'zero decked'? That (used?) to be a good recommendation to live with today's fuel quality.

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Old 03-10-2022, 12:24 PM
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On new street builds I usually shoot for 5 in the hole to leave a little room for another freshen up.Tom

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  #46  
Old 03-10-2022, 02:22 PM
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Unclescratch: It is my understanding the machinist is just going to clean up the deck, not zero deck but he will have all the assembly there to check.
Cliff: I have ( and will install) the Quadrajet you redid for me and also have the Edelbrock 87cc out of the box heads. The SPC-8 cam you recommended is the same that was actually in the engine and actually mics out at taller lobes( even with wear) than the new replacement cam. Also replacing the Performer intake with a new Torker II.

  #47  
Old 03-18-2022, 01:29 PM
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After reading comments in other threads here, I have decided to install the Butler BP6014SP rather than the SPC-8 cam on my rebuild.
Two questions:
1. Do I need to degree the cam or just set it up at mark to mark on the timing set?
2. Do I need to remove the inner valve spring at initial start up as Butler advises?
The heads have maybe 1200 miles on them and have used 1:5 roller rockers.

  #48  
Old 04-24-2022, 09:09 PM
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So I picked up my short block last week along with the reground crank and the new Eagle forged rods mounted to Icon forged pistons. At pre-assembly, I noticed the rod/piston combinations were not installed correctly with either the valve reliefs 180 out or the rod chamfer/ bearing notches 180 out. After taking rod/pistons back, the machinist just wanted to re-number to different bores to get correct line-up of valve reliefs and rod chamfers but that would leave the bearing notches facing towards crank, not the cam. I insisted that he install pistons for correct bias for valve reliefs and rod chamfers.

Here is my question: Can remove/ re-install press fit forged pistons onto forged connecting rods do any damage to piston or rod?

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Old 04-25-2022, 04:16 PM
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Posts 47 and 48... you take a chance ANYTIME you trust someone else’s measurement or calculations. Folks here have talked about timing set being inaccurately marked. No legit engine builder would chance the dot to dot install, neither would I.

Pressing pistons off rods for re-use is a tricky deal. Most here do it recommend it. Some can do it though,I have..... careful is the key word...

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  #50  
Old 05-03-2022, 07:59 PM
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Default Degreeing cam

I degreed the cam BP6014SP dot to dot and found the cam has a 112 intake center line, not the 108 that the cam card says( or recommends). Does that mean I have to advance the crank +4 to get to the 108 intake center line that Comp Cams recommends ? Timing set has multiple positions.

Also, machinist verified he installed rod/ pistons backwards. Everything good now with that.

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Old 06-07-2022, 10:38 PM
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Default Rebuild complete

So I finally completed the rebuild of my 455 but still some issues. After initial start-up, car liked 38-40 degrees advanced for cam run in at 2000 rpm and appears to have seated the rings well. Timing at crank never really settled down and now appears to like 18 degrees at idle although that also appears to bounce around. Vacuum at idle is right at 9 psi. I have not re-adjusted the valves after initial start up. I re torqued the heads and tried to drive around my area to complete the run-in and verify ring seating. Car did not want to idle smoothly and on slow acceleration bucked and popped with medium acceleration smoothing down a little.
I don't want to be chasing down gremlins by replacing parts on the off chance that would help.
I did replace harmonic balancer, rods, pistons, cam, intake manifold, plugs rebuilt and ported the Edelbrock heads and put in a new mag pick-up in the MSD distributor( the gap between rotor and pick up was too wide and has been adjusted.
I did not replace or rebuild the Edelbrock carburetor with the Cliff rebuilt Quadrajet yet and the plug wires( 8.5 mm) are not new.
Any ideas on where to start would be appreciated.

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Old 06-08-2022, 06:33 AM
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Your condition is indicative of the jetting being lean and or having a vacuum leak, especially with your low amount of idle vacuum for that size motor.

Low vacuum and popping back thru the carb when applying throttle ( but not at idle ) can also be due to the firing order being wrong.
Please double check that,

On those heads the outside valve cover bolt holes break into the intake ports, so you should be running studs to clamp the valve covers on that are sealed to avoid vacuum leaks.

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  #53  
Old 06-08-2022, 10:43 AM
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Quote:
Originally Posted by West Coast GTO View Post
I degreed the cam BP6014SP dot to dot and found the cam has a 112 intake center line, not the 108 that the cam card says( or recommends). Does that mean I have to advance the crank +4 to get to the 108 intake center line that Comp Cams recommends ? Timing set has multiple positions.

Also, machinist verified he installed rod/ pistons backwards. Everything good now with that.
Can you post a picture of your cam card?

  #54  
Old 06-08-2022, 01:01 PM
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Steve, I will chase down those issues today . I don't want to run the Edelbrock carb but needed a known working carb for the initial run in. Cliff set up the Quadrajet just for this engine but I have not ran it yet.

War Dog:Cam card attached.
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  #55  
Old 06-08-2022, 08:01 PM
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I did verify correct correct plug wiring firing order and enrichened idle mixture to two turns out from closed. Also verified that all cylinders firing. Interesting that when i temporarily clamped off the attached vacuum hoses, only the PVC hose( from front of carb to valve located in valley pan) had any effect. RPMs dropped down immediately and engine ran much slower, then recovered when clamp released. I am going to re-adjust the valve lash pre-set ( 1/2 turn in from zero lash) as the upper valve train sounds noisy on start up.

  #56  
Old 06-08-2022, 08:48 PM
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Quote:
Originally Posted by West Coast GTO View Post
Steve, I will chase down those issues today . I don't want to run the Edelbrock carb but needed a known working carb for the initial run in. Cliff set up the Quadrajet just for this engine but I have not ran it yet.

War Dog:Cam card attached.
Wait, you have a Qjet set up by Cliff for that engine? I would definitely start with that carb then work on the tuning! Those Edelbrock carbs get quirky on motors with any kind of a cam over stock.

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  #57  
Old 06-08-2022, 10:50 PM
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Yes, I do have the Cliff Rebuilt/ set-up for this engine carb but needed to use a known carburetor for the initial start up/ ring seating( even Cliff recommends using a known carb).

  #58  
Old 06-14-2022, 11:52 PM
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I installed the Cliff built carb , adjusted the valves, verified correct plug wiring order.
On start up, choke worked great, passenger bank( 2, 4 and maybe 6) had noisy lifter clatter than did settle down when warm( not new John Hi-lift, set at 3/4 turn from zero lash) but timing at balancer still erratic at warm up. Vacuum right at 14 Hg at idle.When revving off idle , car pops back through carb whether a slow rev or fast. Timing at crank 18 at idle( erratic) and right at 38 above 2000 rpm.

Any suggestions regarding popping/ backfiring?

  #59  
Old 06-15-2022, 06:33 AM
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You need to pin this down.
Try this get the motor fully warmed up and pull each plug wire off one at a time and see if you find a cylinder that when the spark is killed the popping is stopped or reduced greatly.
If this takes place then more then likely have the fit g order wrong, or a ignition issue like arcing over in the cap or across wires.

At worst you have intake valves the are leaking which can be found by a leak down tester.

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  #60  
Old 06-15-2022, 04:49 PM
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Steve,
New cap and rotor and verified/corrected mag pickup distance from stator. I did verify correct wiring order but will do that again. Not a new coil ( MSD Blaster) or plug wires( MSD 8.5). I did not adjust idle mixture screws from Cliff setting after installing the Quadrajet. I did rebuild the Edelbrock heads, ported/ polished, new viton seals and lapped each valve but did not check spring pressure.
I will go through your suggestions one at a time

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