[TAQuest]

Originally Posted by Steve C.

Regarding the valve springs. You stated the cylinder heads were, quote.... "The heads are pre-assembled ones"

And weeks ago I suggested they the single valve springs with no damper, p/n 5767.

If in fact they are installed at 1.800" then Edelbrock rates them at 120 lbs on the seat. And as already suggested they should of been tested.


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I don't have a tester and the shops around here are busy until summer, maybe fall.

So what springs do you recommend? Thanks

[TAQuest]

Originally Posted by TCSGTO

I ran a Crower solid flat cam that had near .550” lift with 1.65 rockers with the stock Edelbrock springs with no problem. I only shifted at 5500-5700 though.

Like others said they aren’t the best springs but they work ok for a broad range of mostly street applications. They are a single spring with a flat damper. At least the ones that came with my heads were.

If you want a decent upgrade the Lunati 73100 springs work well. They are the same OD and when installed at Edelbrock’s standard 1.8” height gave around 135# seat pressure on my heads.

Good info on the spring upgrade. Can anyone see why the Lunati 73100 springs wouldn't be the best for this application?

[johnta1]

You need to know what the installed height is for the valves to figure out the springs needed.
Then need to know the lift of the cam, the manufacturer's recommended seat/open pressures for it.
Then check for coil bind then retainer to valve guide clearance.

[TAQuest]

Originally Posted by johnta1

You need to know what the installed height is for the valves to figure out the springs needed.
Then need to know the lift of the cam, the manufacturer's recommended seat/open pressures for it.
Then check for coil bind then retainer to valve guide clearance.

I was hoping that someone had done this with these heads by now and had the springs all figured out. They have been out a long time now. These were purchased 15 years ago.
Thanks for your help.

[Steve C.]

"Can anyone see why the Lunati 73100 springs wouldn't be the best for this application?"

Evaluate that spring installed at 1.800 with 0.489" valve lift. How far is it away from coil bind ?


Potential for spring surge ? Is it only a race thing? ..... from Comp Cams, "Anything more than 0.150 inch may cause spring surge, which can greatly reduce the available spring load needed to close the valve."

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[TAQuest]

Originally Posted by Steve C.

"Can anyone see why the Lunati 73100 springs wouldn't be the best for this application?"

Evaluate that spring installed at 1.800 with 0.489" valve lift. How far is it away from coil bind ?


Potential for spring surge ? Is it only a race thing? ..... from Comp Cams, "Anything more than 0.150 inch may cause spring surge, which can greatly reduce the available spring load needed to close the valve."

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You are saying I need a spring that is closer to coil bind. Between .150 and .060 to be just right, not have coil bind or spring surge.

[TAQuest]

What springs are out there that fit that range with the 1.800 installed height? Needing one with around a 1.150 coil bind.

How about Comp Cams 986

1.430 Dual Spring 120 @ 1.780, 280 @ 1.250, Coil Bind @ 1.150 (Set)

[Steve C.]

http://knuckledraggin.com/wp-content...he-popcorn.gif



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[NeighborsComplaint]

Springs are not your problem. Distributor and carburetor are. You have a lean intake backfire when opening the throttle and probably too much advance. In your videos, you are not revving high enough to enough consider valve float.

I am still running the same Crane springs I installed in in the late 90's. Last rebuild I checked a spring and they were within 5% of new. Your Edelbrock springs have never even been run and you are only revving to around 3,000 RPM in the vid and your back fire occurs off idle.

When you whack the throttle, your carb is gulping air and doesn't have enough fuel to compensate. It pre-ignites and backfires through the carb. If there is any kind of accelerator pump or power valve/piston adjustment on that Edelbrock carb, you need to sort that out.

[TAQuest]

Originally Posted by NeighborsComplaint

Springs are not your problem. Distributor and carburetor are. You have a lean intake backfire when opening the throttle and probably too much advance. In your videos, you are not revving high enough to enough consider valve float.

I am still running the same Crane springs I installed in in the late 90's. Last rebuild I checked a spring and they were within 5% of new. Your Edelbrock springs have never even been run and you are only revving to around 3,000 RPM in the vid and your back fire occurs off idle.

When you whack the throttle, your carb is gulping air and doesn't have enough fuel to compensate. It pre-ignites and backfires through the carb. If there is any kind of accelerator pump or power valve/piston adjustment on that Edelbrock carb, you need to sort that out.

Important! I noticed valve train noise in the first place. It didn't sound right. You might not be able to hear it in the video but I could hear it. Something is wrong.

The carb; works perfect on another vehicle.

The timing; Tried moving the timing and the backfire out the carb is the same.

The springs; They can go bad for various reasons. We drove the car for 10 years now with the timing chain two teeth off because of how the previous owner installed it. About 10 tanks of gas a year. Plus the single springs on there were set up too far from coil bind. They could have easily gotten hot an annealed, lost their seat pressure.

There's no reason not to change the springs. None.

I would like to move forward with some new springs and would like some help getting just the right ones. Valve springs are one of the most important things in an engine for performance and the ones I have in these heads right now are far from optimum, especially with the new cam.

Thanks for your ideas.

[steve25]

A pop back thru the Carb is a sure sign that the firing order is off and even if the order is off and the motor is not fully back firing it can sound like the valve train is ticking , but it piston slap or rod knock.

Go back thru all your valve adjustments and set them .005" on the loose side, yes things will be noisy, but no harm will take place ,if the back fire stops you found the issue.

[pastry_chef]

You would need to have a nearly flat exhaust lobe for it to cause the inlet backfire. Easy to verify with a valve cover off and watch it idle for 30 seconds.

[TAQuest]

Originally Posted by steve25

A pop back thru the Carb is a sure sign that the firing order is off and even if the order is off and the motor is not fully back firing it can sound like the valve train is ticking , but it piston slap or rod knock.

Go back thru all your valve adjustments and set them .005" on the loose side, yes things will be noisy, but no harm will take place ,if the back fire stops you found the issue.

Firing order has been checked, double checked, triple checked.

I very carefully set the lash on the lifters. Very carefully. I'm 100% confident they were set perfectly. I spent a lot of time on it so I wouldn't have to come back to it.

[TAQuest]

Originally Posted by pastry_chef

You would need to have a nearly flat exhaust lobe for it to cause the inlet backfire. Easy to verify with a valve cover off and watch it idle for 30 seconds.

I can do that. Better yet (and less messy) I can rotate the engine by hand and check and see if the lift is still .326 and .336.

[TAQuest]

One thing I think we all can agree on here; The springs in these heads are not the best. I want the best for this application. Thanks.

[steve25]

Your having issues with a new Cam and lifters but the same heads and short block points to something wrong with the heads then, but not too likely at all that it's spring related unless you have some busted ones, more then likely at this point a non sealing Intake valve seat or two!

I am sorry to say , but at this point I think you need to pull both heads and check them out fully!

[TAQuest]

Originally Posted by steve25

Your having issues with a new Cam and lifters but the same heads and short block points to something wrong with the heads then, but not too likely that it's spring related, more then likely at this point a non sealing Intake valve seat or two!

I follow your excellent reasoning. I did a compression check and there wasn't any leak down.

There wasn't any problem during cam break in. Lunati suggests a fairly aggressive break in and it went well. It only started backfiring out the carb after the break in when I revved it to get an idea of where the odd valve train noise was coming from. It was like a 'whack' noise. It was intermittent and moved around. On both sides.

I agree it points to a problem with the heads. That's why I want to install new springs.

[TAQuest]

Originally Posted by steve25

Your having issues with a new Cam and lifters but the same heads and short block points to something wrong with the heads then, but not too likely at all that it's spring related unless you have some busted ones, more then likely at this point a non sealing Intake valve seat or two!

I am sorry to say , but at this point I think you need to pull both heads and check them out fully!

Normally, if it were winter time, I would take the heads to the shop and have them rebuilt. However, the shops are very busy and this car would miss a whole season. Trying to avoid that right now.

[TAQuest]

I want to do this myself. I know a lot of you don't like that idea but it's what I'm going to do. I do greatly appreciate your help on this DIY project. Thanks

[TAQuest]

I made a video of the valves operating while rolling the engine over to get an idea of the cam lobes after break in. No lobes are gone. I did see a little 'bounce on one of the valves on #1 cylinder. Check out the video and see if you see the valve open and close quickly out of cycle. Like a 'bounce' right near the end of the video.
Video link;
https://share.icloud.com/photos/0dB2...r_Township,_MI