Trickflow Valve springs & Scrub pattern

[Ivoryk3ys78]

Let me say right off that we should have measured this stuff right off. So.. you can be gentle, live and learn.


So in the Racers Forum I posted a thread on 408 Performance evaluation because I felt the MPH in the 1/4 was way off from what I would have expected from this combo.

One of the things that I mentioned may be an issue is the spring pressure at installed height is borderline. Looking at the documentation that came with the Trickflow heads for the ones I bought that have the PAC 1903 spring it says that it is 120lbs at 1.9 isntall height. Well in that thread on the Racers section it was pointed out the actual specs should be 120 @ 1.875.

So I ordered a spring checker and a valve spring micrometer and a Crower calibration spring and shims. I figured we would be seeing 110ish at 1.9 but we are actually showing an install height of like 1.937 and spring pressure at the seat of 90 of the one spring we have tested thus far.. so crazy light. We had used the Crower calibraton spring and our tester was very close to that within 5lbs so we think the reading is right.

I bought shims that would do up to .090 and it looks like with the install height actually being higher then what it is speced at we would need to go further then that and use a Valve Spring Locator. We tested the same spring at 1.8 and came up with 130.. so a bit low but within range on that one.

I am running Comp Ultra Pro Magnum 1.5 rockers and smith brothers pushrods. The pushrods.

I have a Howards Cam 600/615 254/260@050 108CLA .018 recommended lash. If you look at essentially the exact same cam on Hughes site they are recommending [email protected] install height. I talk to Howards and they recommended at least 130-135 area.

I am going to post a couple pictures.. it is a really messed up scrub pattern that shows the valve must be turning. We did not do b3 geometry correction. I know we saw the scrub pattern after breakin before we put the inner spring back in and at that point it looked like a normcal scrub pattern. I doubt it was perfect but not like this.

On question is do you think that that is most likely completely tied to the really low spring pressure or something else? It would be nice to adjust the spring install height and solve both issues.

I am thinking of getting spring locators and after checking some more springs set it to 1.8 if that seems to be within a range close enough. I would rather not have to buy new valve springs.

 

[yellow rose]

The scrub doesn’t look THAT bad. What you are seeing is valve float. You have an uncontrolled valve train and it ain’t happy.

I would use minus .050 locks to get the installed height down some so you don’t need all those shims.

Then call Mike at B3 racing engines and let him help you get the geometry right. It looks like, from what you can see in the pictures that the geometry is ok, but could be better.

That’s why I’d talk to Mike and let him help you.

Edit: yes, you need spring locators. Get those first to close up the installed height and go from there. The spring needs something to locate it, or it WILL move all over the place, especially when you are seeing the valve train issues you are.

 

[MOPAROFFICIAL]

Good for checking, late is better than never , speaking..' pre destruction '

Valve float , like yellow rose said.
Fix it before it runs the valve job
...if it already hasn't .
I always check everything.

 

[Ivoryk3ys78]

Thanks a lot YR.

That really helps

The scrub doesn’t look THAT bad. What you are seeing is valve float. You have an uncontrolled valve train and it ain’t happy.

I would use minus .050 locks to get the installed height down some so you don’t need all those shims.

Then call Mike at B3 racing engines and let him help you get the geometry right. It looks like, from what you can see in the pictures that the geometry is ok, but could be better.

That’s why I’d talk to Mike and let him help you.

Edit: yes, you need spring locators. Get those first to close up the installed height and go from there. The spring needs something to locate it, or it WILL move all over the place, especially when you are seeing the valve train issues you are.

 

[Ivoryk3ys78]

Yes.. thanksfully before destruction..

We did a leak down test on all cylinders before checking this. We heard no leaking at all at the valves. Just a minimal amount in the crankcase.

Good for checking, late is better than never , speaking..' pre destruction '

Valve float , like yellow rose said.
Fix it before it runs the valve job
...if it already hasn't .
I always check everything.

 

[Ivoryk3ys78]

Do the valve spring locators need to exactly match the spring? I don't see any on summit that match up exactly.

Pac 1903 show
OD of 1.459
Id of inner spring .794

 

[Sprayin73]

Definitely valve float. I’d also put my money on incorrect pushrod length. Just eyeballing the wear in one pic makes me think your too short, if you haven’t already check that. These guys have already given you good info about bringing the spring rate up, I personally would go with the higher rate listed by Hughes, than what Howard’s said. Looking at the flow numbers on those heads your still flowing good up at .700 lift, 301 is what the chart said, plus or minus I’m sure. That said, looking at your cam choice and the problem you stated about trap speed being down from what you expected. Valve float definitely hurts performance, but I wondered if I could go over your combo with you. Actual Static compression? Tire size? Transmission final drive ratio? Rear end gear? Car weight? Type of fuel you are trying to run on? Carburetor? Intake manifold? Header primary size? Open or full exhaust? Most of all your expectations? We’ll get you straight man. Can talk here or private message me if you’d rather. Totally up to you.

 

[crackedback]

Get the minus retainers or locks and get that seat pressure up and run it. JMO

IIRC, there are locating seats that are .060 thick too.

 

[Ivoryk3ys78]

I think the pushrods are okay. WE have like 2 to 2 1/2 adjustment screw threads showing. Tried to set it up how Smith Brothers called for.

The car wont be raced a lot but now and then in the summer. I grew up with this stuff with my dads Roadrunner and my brother Satelite. We would go to Mopar nationals and some other races years ago with their cars.

I can not see well enough to drive the Duster so my brother is my driver. I had a chance to built an engine how I wanted for it and I really wanted to built a very strong engine. Don't really care if its real streetable. Putting this together and picking all the parts I would expect in the 550hp range at peak. I would think it would get the car in the low 11s easy and maybe if the chassis and converter is right be capable of high 10s. I don't know that I want to put a roll bar in so I figured we would need to put street tires on if it did well and track MPH like a dyno. So seeing the MPH so far off I really felt something had to be wrong with the engine. So this is where I am.

Here is a link to my post with the build.

Stroker Performance Review

Definitely valve float. I’d also put my money on incorrect pushrod length. Just eyeballing the wear in one pic makes me think your too short, if you haven’t already check that. These guys have already given you good info about bringing the spring rate up, I personally would go with the higher rate listed by Hughes, than what Howard’s said. Looking at the flow numbers on those heads your still flowing good up at .700 lift, 301 is what the chart said, plus or minus I’m sure. That said, looking at your cam choice and the problem you stated about trap speed being down from what you expected. Valve float definitely hurts performance, but I wondered if I could go over your combo with you. Actual Static compression? Tire size? Transmission final drive ratio? Rear end gear? Car weight? Type of fuel you are trying to run on? Carburetor? Intake manifold? Header primary size? Open or full exhaust? Most of all your expectations? We’ll get you straight man. Can talk here or private message me if you’d rather. Totally up to you.

 

[Sprayin73]

Alright, first let me say great job on the build. Family builds are the best, no amount of money can replace those good times. Looking at your build thread I think I’ve got your trap speed issue. The desk top dyno software is a great tool, but only as good as the info entered into it. Even then it will only get you close. That said, I looked at the specs on the camshaft 254 at .050 the recommended static compression ratio is the minimum. With that duration at .050 you really need to be 12.5:1 to 13:1, to take full advantage of the cam. Second issue is gear selection, 4.10 id say your coming through the traps at around 6000 rpm, with that tire. If your higher than that, it’s likely because of spinning down low. I watched the video, the car seamed to loose traction a bit off the line, and at the top end of the track had plenty left when you crossed the traps.

You did a great job gathering parts, the single plane manifold was a good choice for your target. Not worrying about street manners this would be my recommendation.

First if you intend to stay with that cam bump compression to 13:1, the DCR (Dynamic Compression Ratio) is some of the problem. With that cam and 11.8:1 your well in pump gas range, and leaving a lot on the table. You can degree the cam up and down to move where your torque comes in, if you installed the cam at center line, she should be coming in at around 3400 I’m thinking, so your stall at 3500 was a good choice for a street car, however if you were to retard the cam about 5 deg moving your torque curve up, and run a 4500-5000 stall you could keep the power band right in the sweet spot throughout the run. Of course it’s best to dyno the engine and find your peak torque and put the converter right there. Lastly gear, with that size tire and your target, not concerned about street ability, I would step it up to 4.88 in the rear, and get control over that launch. If these things were done your trap speed would increase as well as E/T drop.

Ok so that was to maximize the use of that cam with those heads. If you didn’t want to bump the compression, my opinion you would be much more happy in the 244-246 duration at .050 range. With those heads .600 lift is right on, from .600 to .700 the increase is minimal, so stay .600, when choosing a cam you can go up to 1.6 rockers if you cannot find a camshaft with the correct duration close to .600 lift to get you where you want to be. A custom cam grinder would be prefect for this situation and cost you just a little more than another shelf cam. Plus you save money keeping the 1.5 rockers. In this case the converter could stay the same but your peak RPM would come down a bit because of the reduction in cam duration. Going from 7400-7500 down to 6800-7000. Would suggest 4.56:1 gears for tire size and that combo.

Basically, with the car weight, the static compression ratio, cam you chose, converter and 4.10, with that tire. Your not making as much torque as you could with the engine, and the gear is leaving a lot on the table at the end of the 1/4 as far as getting the RPM up to offset the lack of efficiency.

Remember all Is for nothing if you cannot get spin on launch under control, if you spin at launch trap rpm will be higher and MPH lower. I like to mark the tire and slow motion camera the launch, so you can see wheel spin, adjust preload or ballast as needed.

Hope this helps, that’s a great build you should be proud of it...

 

[yellow rose]

I think the pushrods are okay. WE have like 2 to 2 1/2 adjustment screw threads showing. Tried to set it up how Smith Brothers called for.

The car wont be raced a lot but now and then in the summer. I grew up with this stuff with my dads Roadrunner and my brother Satelite. We would go to Mopar nationals and some other races years ago with their cars.

I can not see well enough to drive the Duster so my brother is my driver. I had a chance to built an engine how I wanted for it and I really wanted to built a very strong engine. Don't really care if its real streetable. Putting this together and picking all the parts I would expect in the 550hp range at peak. I would think it would get the car in the low 11s easy and maybe if the chassis and converter is right be capable of high 10s. I don't know that I want to put a roll bar in so I figured we would need to put street tires on if it did well and track MPH like a dyno. So seeing the MPH so far off I really felt something had to be wrong with the engine. So this is where I am.

Here is a link to my post with the build.

Stroker Performance Review

Im not sure who told you the adjuster needs that many threads showing, but that is dead wrong.

The ball of the adjuster should be down .281 plus .050 minus .000 and that’s where they should be.

When you hang the adjuster that far down, a few things happen.

One, the cup of the pushrod is so low, that the oil that should be coming out of the rocker to lube the adjuster and cup that the cup doesn’t get direct oil. You are now relying only on splash oiling and the mist that is blowing around in the valve cover.

Two, by making the adjuster that far down, you actually slightly REDUCE the rocker ratio. On most rockers, the adjuster is at an angle away from the shaft. Probably not saying it the best way, but look at the adjuster and it’s relationship to the tip of the rocker. Rocker ratio is simply the difference in the length from the center of the adjuster to the center of the shaft, and the length of the center of the shaft to the tip of the rocker.

So, dropping the adjuster usually makes the distance from the adjuster to the center of the shaft LONGER, thereby reducing the rocker ratio.

And, hanging the adjuster that far down changes the geometry on the pushrod side of the rocker. There isn’t much you can do about the geometry on that side of the rocker, but misadjusting the length of the adjuster just makes the geometry on that side of the rocker worse.

I suspect by the time you get the valve side geometry correct, you’ll need new pushrods anyway, so when you measure for them run the adjuster out .281ish.

Also, at some time in the past, someone made the command decision to change the RADIUS is the seat in the lifter. Virtually every new lifter I’ve seen lately (since I started paying attention anyway) now has a 3/16 radius and NOT the common 5/32 radius that most pushrods have.

When I put my junk together I caught it, and said piss on it and let it slide, and it bit me right on the ***.

What happened is I needed to pull the rockers off for some reason I no longer recall. A simple task to put the rockers back on became a giant crap sandwich.

That small radius on the pushrod end allows the pushrod to drop down out of the seat, and if your not careful, you set the lash with the pushrod sitting on the edge of the seat.

Since my valve to piston is kinda tight, and I missed the couple of pushrods that slid out of the cup, I got bent valves.

When you get the correct radius on the ball of the pushrod, they about can’t slide down like that. Plus, it’s the correct radius on the pushrod for the lifter.

We (FABO member lead69 and I) just did a tunnel ram 340 and his lifters had the big radius. You could almost stand 10 feet from the engine and throw the rockers on and the pushrods stayed in the lifters.

If you don’t have a radius gauge, call Smith Brothers and ask them to send you one. Then you can measure the radius accurately and get the correct ball on the pushrods for the lifters you have. I’d be surprised if you do NOT have the 3/16 radius.

EDIT: the 9/32 adjuster distance (.281) is for BALL adjusters and NOT for CUP adjusters. Just want to be clear on that, and PRH pointed out in his post below.

 

[PRH]

The comp rockers have a very narrow range for correct adjuster position, and it has nothing to do with what rockers that use std ball adjusters would be like.

Screw the adjuster up into the rocker as far as it will go. Go back down one turn...... that’s the optimum position.
Use the correct thickness feeler gauge between the valve and rocker, expand the pushrod checking tool to take up all the clearance.
Order pushrods that length with a 5/32” radius.

The star pattern on the rockers is from a lack of valvetrain control(inadequate spring pressure).

Using a dial caliper, verify spring the height mic reads correctly.
I have seen several that were pretty far off(as ridiculous as that sounds).

 

[yellow rose]

The comp rockers have a very narrow range for correct adjuster position, and it has nothing to do with what rockers that use std ball adjusters would be like.

Screw the adjuster up into the rocker as far as it will go. Go back down one turn...... that’s the optimum position.
Use the correct thickness feeler gauge between the valve and rocker, expand the pushrod checking tool to take up all the clearance.
Order pushrods that length with a 5/32” radius.

The star pattern on the rockers is from a lack of valvetrain control(inadequate spring pressure).

Using a dial caliper, verify spring the height mic reads correctly.
I have seen several that were pretty far off(as ridiculous as that sounds).

Dammit...I forgot he has Comp rockers.

You are correct, one turn down. If the OP does have 2 threads showing those are way to far down and the chrysler number of 9/32 doesn’t apply.

I know the rocker takes a 5/32 ball, but I’d bet the lifter takes a 3/16 ball, unless they are very old, or the exception.

 

[Ivoryk3ys78]

I appreciate the help and the suggestions everyone.