Catastrophic Engine failure. 454 gen 6
08-09-2021, 02:05 PM
#81
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08-09-2021, 02:54 PM
#82
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The valves hit and the lifters really don’t give when it’s running. The one that gave up was probably the closest (hardest hit) due to variances in deck height, but they all made contact and should all be considered a liability. If the valves seal, you’re going to get some RPM out of it and that will increase the chances for failure and even more damage.
Have you seen an engine come apart at speed from dropping a valve head? The damage is usually catastrophic (you got lucky on this).
Personally, I wouldn’t take a chance with it. A couple hundred bucks for valves isn’t a lot of money when compared to replacing pistons and rods, cranks, blocks, heads, etc.
Have you seen an engine come apart at speed from dropping a valve head? The damage is usually catastrophic (you got lucky on this).
Personally, I wouldn’t take a chance with it. A couple hundred bucks for valves isn’t a lot of money when compared to replacing pistons and rods, cranks, blocks, heads, etc.
08-09-2021, 03:14 PM
#83
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Correct. When running Lifters pretty much hydrolock, except on base circle, when it's check valve opens, and that's where the lash is set. If they didn't, we wouldn't be able to run 180-200 seat pressure and 400-450lbs open spring psi on healthy BBC's. That does not include rocker arm multiplication and the forces while running. The valve will bend with piston contact. Lifter will not help.
Last edited by SB; 08-09-2021 at 03:20 PM.
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SB (08-09-2021)
08-09-2021, 05:23 PM
#85
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I finished with the short block, but unfortunately my machinist ended up in the hospital before I could get my head back. I might clean up one of the heads I just picked up depending on how long he's going to be. If I had the head, I could have been on the water this coming weekend without a problem.
08-09-2021, 05:54 PM
#86
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Yes. It's the lighting and oil I sprayed on the deck to keep it from rusting. No pitting...
While I was just degreeing the cam I was thinking about the valves. You guys are obviously right about the lifters not having any give. Hydrolocking was a good analogy. I have ones that I already prepped from the original set of heads which are the same size. I'll put the ones that are in the heads now on the valve grinding machine and that will tell the real story. In the mean time I won't have to worry about it. Push rods are an easy check before I install them. I would have done that either way.
Cam degree #s:
Exhaust Opens 47.5*
Intake Opens 3*
Exhaust lift .4828"
Intake lift .483"
Exhaust closes 2*
Intake closes 49*
Exhaust duration 47.5+2+180=229.5*
Intake duration 3+49+180=232*
Exhaust c/l (161+65.5)/2=113.25*
Intake c/l (69+165)/2=117*
(113.25+117)/2=115.125* lsa
While I was just degreeing the cam I was thinking about the valves. You guys are obviously right about the lifters not having any give. Hydrolocking was a good analogy. I have ones that I already prepped from the original set of heads which are the same size. I'll put the ones that are in the heads now on the valve grinding machine and that will tell the real story. In the mean time I won't have to worry about it. Push rods are an easy check before I install them. I would have done that either way.
Cam degree #s:
Exhaust Opens 47.5*
Intake Opens 3*
Exhaust lift .4828"
Intake lift .483"
Exhaust closes 2*
Intake closes 49*
Exhaust duration 47.5+2+180=229.5*
Intake duration 3+49+180=232*
Exhaust c/l (161+65.5)/2=113.25*
Intake c/l (69+165)/2=117*
(113.25+117)/2=115.125* lsa
Last edited by HawkX66; 08-09-2021 at 05:57 PM.
08-09-2021, 06:05 PM
#87
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Not sure it’s just the picture, but what I can see of the bore of number 8 doesn’t look happy either.
Sorry if it seems like we’re nitpicking. Just trying to get you set in the right direction.
Sorry if it seems like we’re nitpicking. Just trying to get you set in the right direction.
08-09-2021, 06:10 PM
#88
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That cam is in 2* degrees retarded.
Neutral woukd be 115 icl and 115 ecl
4* advanced woukd be 111icl and 119ecl
Neutral woukd be 115 icl and 115 ecl
4* advanced woukd be 111icl and 119ecl
08-09-2021, 06:16 PM
#89
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Here quote of myself long ago
Mag BBC 454/502 Flat Tappet (rect heads)
.004” 296*, 296*
.006” 286*, 286*
.050” 224*, 224*
.200” 130*, 130*
Valve lift with 1.7 .510”, .510”
LSA 115.5
Merc Part#431-9830 / GM#14096209
ICL 114 ATDC
ECL 117 BTDC
GM Part#10185060 (same as above but ground with 5 degrees advance)
ICL 109 ATDC
ECL 122 BTDC
======================================
Merc Mag Roller
Merc# 431-850478 / GM#12551622
.004 300*/ 300*
.006 288*/288*
.050” 225*/225*
.200” 125*/125*
Lift .483”/. 483”
ICL 109*
LSA 115.5*
Mag BBC 454/502 Flat Tappet (rect heads)
.004” 296*, 296*
.006” 286*, 286*
.050” 224*, 224*
.200” 130*, 130*
Valve lift with 1.7 .510”, .510”
LSA 115.5
Merc Part#431-9830 / GM#14096209
ICL 114 ATDC
ECL 117 BTDC
GM Part#10185060 (same as above but ground with 5 degrees advance)
ICL 109 ATDC
ECL 122 BTDC
======================================
Merc Mag Roller
Merc# 431-850478 / GM#12551622
.004 300*/ 300*
.006 288*/288*
.050” 225*/225*
.200” 125*/125*
Lift .483”/. 483”
ICL 109*
LSA 115.5*
08-09-2021, 06:36 PM
#90
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I keep stressing - use the factory timing set. You’re asking for trouble using what you have. It’s never been right.
Take the timing set off one of the cores you brought back. I’ll bet it works just fine.
Take the timing set off one of the cores you brought back. I’ll bet it works just fine.
