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ok guys, I will start out with the engine combination as i know every one wants to know that first, Its based off the 500hp engine in the hp chart, 30over 460 with 9-1, trick flow power port 290heads with 120lb springs, it has the 274xe cam, msd probillet dist, blaster 2coil, 6al ignition, holley blue pump, 850holley, running inital timing at 17 and full at 36. so engine wont rev past 5400rpm and almost seems like its hitting the rev limiter but its a lot more aggressive and engine will loose rpm and pop and miss. if i lower rev limiter to 5300 it comes up on the limiter fine and if i raise limiter higher were it would never hit it still misses and pops.so things i have tried so far, changed coil, changed plug wires, tried another msd box,checked that i am getting lots of fuel even swaped another pump i had,changed plugs and narrowed gap from .45-.35, swapped holley 850 to a 750 edelbrock, checked rocker arms didnt find any loose and reset to 1/2turn preload. Im not sure if its a ignition problem or valve float. I have a hard time believing its valve float as their brand new heads and springs. Only thing i haven't changed is the cap and
rotor and i cant see the pickup causing any problems as it ohmed fine.
 

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ok guys, I will start out with the engine combination as i know every one wants to know that first, Its based off the 500hp engine in the hp chart, 30over 460 with 9-1, trick flow power port 290heads with 120lb springs, it has the 274xe cam, msd probillet dist, blaster 2coil, 6al ignition, holley blue pump, 850holley, running inital timing at 17 and full at 36. so engine wont rev past 5400rpm and almost seems like its hitting the rev limiter but its a lot more aggressive and engine will loose rpm and pop and miss. if i lower rev limiter to 5300 it comes up on the limiter fine and if i raise limiter higher were it would never hit it still misses and pops.so things i have tried so far, changed coil, changed plug wires, tried another msd box,checked that i am getting lots of fuel even swaped another pump i had,changed plugs and narrowed gap from .45-.35, swapped holley 850 to a 750 edelbrock, checked rocker arms didnt find any loose and reset to 1/2turn preload. Im not sure if its a ignition problem or valve float. I have a hard time believing its valve float as their brand new heads and springs. Only thing i haven't changed is the cap and
rotor and i cant see the pickup causing any problems as it ohmed fine.

Before installing the heads did you check spring installed height, seat pressure and open pressures?



S
 

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Discussion Starter #3
Before installing the heads did you check spring installed height, seat pressure and open pressures?



S
I don't have the tools to test them, all i did was pull the inner springs out for cam break in, and reinstall them after break in. I was hoping a out the box head would be good enough not to have to screw with for my power levels
 

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I don't have the tools to test them, all i did was pull the inner springs out for cam break in, and reinstall them after break in. I was hoping a out the box head would be good enough not to have to screw with for my power levels
It is up to the end user to make sure the parts are suitable. This sounds like a spring issue. I would remove a valve spring and have it checked for seat and open at the installed height.



S
 

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Discussion Starter #5
It is up to the end user to make sure the parts are suitable. This sounds like a spring issue. I would remove a valve spring and have it checked for seat and open at the installed height.



S[/QUOTE

would a on engine spring tester work to see if springs are bad, like proform 67597. could any thing else cause this? I was a little worried that maybe the cam is going flat but seem to run fine, valves never had any loose rockers and cant hear any noise from valve train but is hard to tell with the puller headers. i didnt have this problem right after break in seemed to rev up fine, had alot of problems with a off idle stumble and getting the timing curve were it needed to be. The only thing that happened was while i was checking total timing the throtle cable stuck the throttle and it ran on the limiter for a few seconds before i got it shut off, would this damage the valve springs?
 

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It is up to the end user to make sure the parts are suitable. This sounds like a spring issue. I would remove a valve spring and have it checked for seat and open at the installed height.



S[/QUOTE

would a on engine spring tester work to see if springs are bad, like proform 67597. could any thing else cause this? I was a little worried that maybe the cam is going flat but seem to run fine, valves never had any loose rockers and cant hear any noise from valve train but is hard to tell with the puller headers. i didnt have this problem right after break in seemed to rev up fine, had alot of problems with a off idle stumble and getting the timing curve were it needed to be. The only thing that happened was while i was checking total timing the throtle cable stuck the throttle and it ran on the limiter for a few seconds before i got it shut off, would this damage the valve springs?
Bent pushrod(s)?
 

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You don't necessarily need a spring tester. Just measure the installed height and calculate the pressures, coil bind clearance, etc. based on the specs published for the springs.


.
 

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Discussion Starter #9
You don't necessarily need a spring tester. Just measure the installed height and calculate the pressures, coil bind clearance, etc. based on the specs published for the springs.


.
but how would that tell me if the springs were bad? the only thing that would do is check that the installed height is right.
 

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Discussion Starter #10
the trick flow spring specs are 120lbs @ 1.950" installed height, 394 lbs @1.175" open, 390lb per inch spring rate. The springs recommended for cam are 112lbs @ 1.950 installed height, 355lbs @ 1.175, 347lbs per inch rate, i dont see this being a problem as long as the trick flow springs are installed at the right height.
 

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but how would that tell me if the springs were bad? the only thing that would do is check that the installed height is right.
With the actual physical installed height, specs on the spring, and actual lift at the valve, you can calculate the actual pressures on the seat and over the nose, and also calculate spring bind clearance. Of course none of that will tell you if you have a damaged spring, but it will tell you if your pressures are correct or possibly causing a problem.

For example:

If your actual installed height is 1.85, and your cam has .600 lift, your pressures are going to be 159/393 which is way too much and may have damaged the cam and/or lifters.

If your actual installed height is 2.05, and your cam has .550 lift, your pressures are going to be 81/295 which is too low, and may be causing valve bounce on the seat.

All this stuff has to be checked and verified any time an engine is built. There is no "close enough", or assuming that it's fine.


.
 

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Discussion Starter #12
With the actual physical installed height, specs on the spring, and actual lift at the valve, you can calculate the actual pressures on the seat and over the nose, and also calculate spring bind clearance. Of course none of that will tell you if you have a damaged spring, but it will tell you if your pressures are correct or possibly causing a problem.

For example:

If your actual installed height is 1.85, and your cam has .600 lift, your pressures are going to be 159/393 which is way too much and may have damaged the cam and/or lifters.

If your actual installed height is 2.05, and your cam has .550 lift, your pressures are going to be 81/295 which is too low, and may be causing valve bounce on the seat.

All this stuff has to be checked and verified any time an engine is built. There is no "close enough", or assuming that it's fine.

.
first engine i have ever built so their has been a bit of a learning curve, i guess checking my installed height and spring seat and open pressure are the next things i will check
 

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Discussion Starter #13
So i have ordered some tools to check spring height and pressure, The only thing im wondering is if the installed height and pressures are accurate to the trick flow specs, are they close enough to what the cam recommends or should i buy the comp springs that are recommended.
 

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Discussion Starter #14
So now that winter is almost over its time to start working on this thing again, I checked the seat pressure on the springs and they all checked fine,Next thing i checked was to see if i wore a lob on the cam so i used a dial indicator to check the valve lift and i was sure it had wore lobs (pretty difficult to measure hyd flat tappet lift with lifter bleed off). Pulled lifters and found no wear on lifters and cam, but found that my cam bearings were bad, and with further investigation i found that i had internal wear on the lifters at the pushrod oil metering valves. So long story short im in the process of rebuilding the engine with a new cam shaft, becided this time to go with a solid roller camshaft and matching springs. Camshaft is a lunati voodo 640/650 lift duration 261/267 110 separation, Im also looking to deck the block to increase cr and help with quench, the block is a d9 with 10.322 deck height and im using speedpro h418p piston (1.752 compression height) i am planning to stay .005 in the hole with .040 head gasket which will give me .045 quench and right around 10-1 compression, will i have enough piston to valve clearance with the tfs heads?
 

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So now that winter is almost over its time to start working on this thing again, I checked the seat pressure on the springs and they all checked fine,Next thing i checked was to see if i wore a lob on the cam so i used a dial indicator to check the valve lift and i was sure it had wore lobs (pretty difficult to measure hyd flat tappet lift with lifter bleed off). Pulled lifters and found no wear on lifters and cam, but found that my cam bearings were bad, and with further investigation i found that i had internal wear on the lifters at the pushrod oil metering valves. So long story short im in the process of rebuilding the engine with a new cam shaft, becided this time to go with a solid roller camshaft and matching springs. Camshaft is a lunati voodo 640/650 lift duration 261/267 110 separation, Im also looking to deck the block to increase cr and help with quench, the block is a d9 with 10.322 deck height and im using speedpro h418p piston (1.752 compression height) i am planning to stay .005 in the hole with .040 head gasket which will give me .045 quench and right around 10-1 compression, will i have enough piston to valve clearance with the tfs heads?

The valve notch in the 418 pistons is for the std size valve. You had better address the radial issue.



SJ
 

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Before installing the heads did you check spring installed height, seat pressure and open pressures?



S

same as I thought, springs no good for this combo
 

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same as I thought, springs no good for this combo

Rich,

Springs checked out for the original cam. XE274H

I see the combination is changing to a SR with appropriate springs.

Piston to valve clearance radially is a concern now.




SJ
used 2b RHP

:D
 

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Discussion Starter #18
Rich,

Springs checked out for the original cam. XE274H

I see the combination is changing to a SR with appropriate springs.

Piston to valve clearance radially is a concern now.




SJ
used 2b RHP

:D
What do you mean by radially? the size of valve for valve cut out thats in the piston? I was really hoping to reuse my pistons as they have very little run time and are already set up with truck rods that are resized with arp bolts. What is my best option, run different pistons, fly cut valve reliefs or not deck block as much? Should i wait to deck block after i have gotten to test fit cam to see how much valve clearance i have?
 

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What do you mean by radially? the size of valve for valve cut out thats in the piston? I was really hoping to reuse my pistons as they have very little run time and are already set up with truck rods that are resized with arp bolts. What is my best option, run different pistons, fly cut valve reliefs or not deck block as much? Should i wait to deck block after i have gotten to test fit cam to see how much valve clearance i have?

A couple of points.

The longer duration roller cams more aggressive lobes are going to get the valves very close to the pistons. The TFS heads have a larger diameter valve than the notches in the pistons are designed to handle. Valves WILL hit pistons.

Secondly though we have made great power with the H418 cp pistons we don't push the hypers much past 530 hp and about 5,500 rpm. Will cast pistons and OEM rods go higher? Yes but...

Given the parts you've outlined... imo you are really pushing your luck.



SJ
used 2b RHP



:D
 

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Discussion Starter #20
A couple of points.

The longer duration roller cams more aggressive lobes are going to get the valves very close to the pistons. The TFS heads have a larger diameter valve than the notches in the pistons are designed to handle. Valves WILL hit pistons.

Secondly though we have made great power with the H418 cp pistons we don't push the hypers much past 530 hp and about 5,500 rpm. Will cast pistons and OEM rods go higher? Yes but...

Given the parts you've outlined... imo you are really pushing your luck.



SJ
used 2b RHP



:D
What piston would you suggest? im hoping to keep this engine pump gas friendly, would like right around 10-1 and plan to keep redline at 6000rpm
 
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