New cam, new valve springs?

[Sir Dodge alot]

Hello & greetings again.

Cutting to the chase, I'm considering buying a cam, looks like an RV cam grind.
Cam listed below, that. I'm considering buying.

https://www.summitracing.com/parts/hrs-720021-11#overview

Will the factory valve springs work with this cam?
I'm not a big fan of getting higher seat pressure valve springs indue causing valve seat recession.

The new cam does have higher lift than the factory cam I have got in the engine currently, might cause coil bind using factory springs on a new higher lift cam?

And I'd like to NOT have to put in hardened valve seats in the heads just for the new valve springs.

(And have heard compounding stories where the seats falling out, destroying an engine, seats falling out PTSD?)

I've been daily driving a Dodge for a few years that has the 516 heads without any valve seat recession problems and I'd like to keep it that way.

Long winded post, apologies if some of this is a repeat from the other posts, the valve springs with a new cam is a new problem into the equation I have not thought about yet.
What say you sages of FCBO?
Thanks.

 

[496 polara]

If you have new factory springs they may be ok.If they are 50 years old,probably not. They would certainly be good for breaking in a flat tappet cam.

I would ask Howards what the recommended spring pressure is for that cam and you can have one of yours checked. Only way to know for sure.

 

[CBODY67]

IF you are looking for "more power", but don't want to get involved with a cam change, they you can also put some 1.6 ratio rocker arms in place of the existing 1.5 ratio items. With the stock

With all of the "don't want to" items252/252/.390 cam, those 1.6 ratio items can probably put you exactly where you might be with the noted camshaft, as to duration and lift, but with the factory LCA. Thereby bypassing all of the negatives of a cam change in the process.

Valve spring "coil bind" happens as the total valve lift approaches the compressed height of the spring at max valve lift. Not even close at .425" range. Existing springs can be shimmed to get their seat pressure back to where it would be for new springs. Look at the "max lift" the springs will tolerate for the stock replacement valve springs (not in the FSM, but in the aftermarket spring mfg charts).

IF hard seats are installed correctly, they don't fall out. Hard seats are in every aluminum head, stock or aftermarket, too. When my late machine shop operative did them, he would "stake" them in, using about 8 locations equidistant from each other per valve seat. Was not pretty, but worked.

With all of the "don't want to" orientations, then don't do them. Keep the stock cam and put the lifters back in the same holes they came out of. Get the machine shop to shim the existing valve springs and put them in. You've already proven that you don't need hard seats for YOUR driving cycle, too. Continue like you are going as you'll know where you'll end up. DO use the black moly cam lube on the cam lobes and lifter bases. With a dab on other places that move in the valve train and on the timing chain items (which usually only get splash lubrication). Maybe even on the rocker arm ends and where they touch the valve stems? Put some oil on anything that moves!

If you want some "new experiences", then spend the money for the cam change and expand your horizons . . . Your choice.

As to increased power to "battle" the turbo 4cyls with their 10-speed automatics, forget that. Not going to win, unless a LOT of money is spent on a ZF 8-speed for your car and all that goes with that.

Enjoy!
CBODY67

 

[57fury440]

He did not say he was looking to race anyone. The cam you are looking at is not that aggressive. I think it would work fine with the springs you have. In all the Mopar big blocks that I have had going back to 1966, I have never had a problem with valve recession. If your heads look good, I would clean them up and run them.

 

[CBODY67]

He did not say he was looking to race anyone.

The "battle" I was referring to is in normal freeway driving and related on-ramps only. In his part of the world, the on-ramps are much longer than was operative on the 1970s US75 or N. Central Expressway in Dallas, TX proper, with their "metered" on-ramps and much shorter acceleration ramps. Where you waited for a "green light" to enter the ramp and accelerate to "matching speed" of traffic.

Where he is, good advance planning, moderate throttle, early signals, and similar work well for me, even with a 180horsepower V-6 car. Surface streets can be a different matter.

CBODY67

 

[Big_John]

Will the factory valve springs work with this cam?

Yes, they should work well. Replacement stock springs, not the worn out 60 year old springs.

I'm not a big fan of getting higher seat pressure valve springs indue causing valve seat recession.

They aren't the cause of valve seat recession. Lack of lubrication, like from leaded fuel and excessive heat cause that problem. You combat it mostly by installing hardened seats, but a good argument could be made for a limited use Mopar not needing the hardened seats because of the higher nickel content in the cast iron. The cars having the most problems, from what I've seen anyway, is the SBC. Softer cast iron.

 

[Sir Dodge alot]

IF you are looking for "more power", but don't want to get involved with a cam change, they you can also put some 1.6 ratio rocker arms in place of the existing 1.5 ratio items. With the stock

With all of the "don't want to" items252/252/.390 cam, those 1.6 ratio items can probably put you exactly where you might be with the noted camshaft, as to duration and lift, but with the factory LCA. Thereby bypassing all of the negatives of a cam change in the process.

Valve spring "coil bind" happens as the total valve lift approaches the compressed height of the spring at max valve lift. Not even close at .425" range. Existing springs can be shimmed to get their seat pressure back to where it would be for new springs. Look at the "max lift" the springs will tolerate for the stock replacement valve springs (not in the FSM, but in the aftermarket spring mfg charts).

IF hard seats are installed correctly, they don't fall out. Hard seats are in every aluminum head, stock or aftermarket, too. When my late machine shop operative did them, he would "stake" them in, using about 8 locations equidistant from each other per valve seat. Was not pretty, but worked.

With all of the "don't want to" orientations, then don't do them. Keep the stock cam and put the lifters back in the same holes they came out of. Get the machine shop to shim the existing valve springs and put them in. You've already proven that you don't need hard seats for YOUR driving cycle, too. Continue like you are going as you'll know where you'll end up. DO use the black moly cam lube on the cam lobes and lifter bases. With a dab on other places that move in the valve train and on the timing chain items (which usually only get splash lubrication). Maybe even on the rocker arm ends and where they touch the valve stems? Put some oil on anything that moves!

If you want some "new experiences", then spend the money for the cam change and expand your horizons . . . Your choice.

As to increased power to "battle" the turbo 4cyls with their 10-speed automatics, forget that. Not going to win, unless a LOT of money is spent on a ZF 8-speed for your car and all that goes with that.

Enjoy!
CBODY67

Hello sir.

Thank you for the advice, I'm going to have a long and hard think, whether with new parts or putting the old cam back in.

 

[Sir Dodge alot]

If you have new factory springs they may be ok.If they are 50 years old,probably not. They would certainly be good for breaking in a flat tappet cam.

I would ask Howards what the recommended spring pressure is for that cam and you can have one of yours checked. Only way to know for sure.

Hello sir.

Do you personally think I can or SHOULD use the stock worn valve springs on the new cam during break in if I do get the new cam, also to put less pressure on the cam lobes/crown of the lifters, then swap to the factory NEW springs when the break in is done?
Regarding Howard's cam, I'd hate to get some advice from a potential parts counter guy at the other end of the phone, but I'd like to hear your take as well.
Thank you.

 

[57fury440]

Those cams were broken in at the factory with the springs they came with. Unless you have a monster cam with some serious lift and duration, it should not be necessary.

 

[496 polara]

Hello sir.

Do you personally think I can or SHOULD use the stock worn valve springs on the new cam during break in if I do get the new cam, also to put less pressure on the cam lobes/crown of the lifters, then swap to the factory NEW springs when the break in is done?
Regarding Howard's cam, I'd hate to get some advice from a potential parts counter guy at the other end of the phone, but I'd like to hear your take as well.
Thank you.

Should be fine either way.The pressures are low enough it really shouldn't matter.

 

[Sir Dodge alot]

Should be fine either way.The pressures are low enough it really shouldn't matter.

Hello sir, gotcha thanks.

I'm still having a long hard think on whether I should drop the hammer and buy the new cam or stick with the original cam.

The break in for the new cam
(when the time comes)
Is the part I'm most worried about.
Anywho, thanks.

 

[68yourker]

If you change the cam, the springs should also be replaced with the recommendations of the cam maker. Back in the 70's, I bought a 440 with a round cam, so I just replaced the cam and lifters. It was not anything earth shattering, basic plus RV grind. After about 1500 mikes, 4 valve springs broke. If somewhere along the way, the car had cylinder head overhaul, it is possible they were replaced previously. The idea behind breaking in a new cam with old springs is to save the cam lobe. There are many on line articles about "today's soft cam blanks." Make sure the engine is completely ready to start and get the RPM's up immediately-no start/stop until after the break in process. Then replace with the correct springs-many tools on the market to allow for in vehicle work. So many people are opting for a roller grind over flat tappet as modern engines have been using it for decades. Typically allows for fast valve opening/closing, better engine vacuum at idle, but they will have a much stiffer spring than stock.

 

[wyrmrider]

I would not use 50 yo springs the HP springs with a dampner will work well with new viton stem seals and a new roller timing chain (not the cheapest one the next to best one)
that said the best "modern|" cam is the Mike Jones Motorhome cam but the 256 @006 around .305 lift from Howard works well I have not looked at the Summit cam in a long time but it used to be a universal chevy profile. Lunati has an old school UDHasrold MOPAR profile which also works well and much better than the similar spec comp cam which is a chevy grind
Nothing from ISKY all chevy all the time there are a couple of other cam grinders with a bunch of MOPAR profiles from back in the day
You might also see if there are any beehive springs that fit
The big advantqge of Jones is that he will take your stock head flow, intake, and exhaust and compression into account and give the exhaust lobe and lobe centers to match
can make 40 ft lbs of torque difference on an otherwise stock build a few bucks well spent
the stock cam has lots of overlap and long closing ramps to give exhaust dillution of your intake a sort of EGR SMOG grinds, even the HP cam
you can do MUCH BETTER
there are new FT oils

 

[wyrmrider]

I just looked at that Summit cam that is NOT the HOward I would recommend note that it has much more duration and much lift than their MOPAR lyou obe which has over 450 lift with around 256 degrees of seat duration and around 204 @ 50
you do your homework
what is your advertised DR and do a compression test and post up

 

[Sir Dodge alot]

I just looked at that Summit cam that is NOT the HOward I would recommend note that it has much more duration and much lift than their MOPAR lyou obe which has over 450 lift with around 256 degrees of seat duration and around 204 @ 50
you do your homework
what is your advertised DR and do a compression test and post up

Hello sir.

I cannot do a compression test currently since the engine is down to the bare block, but if I had a guess, the cylinders are at or near 120PSI.
The compression numbers are the highest readings from another 361 in my daily driver with high mileage.

Unless the link sent you to the incorrect cam, I'll repost here: Howards Cams 720021-11 Howards Cams Hydraulic Flat Tappet Camshafts | Summit Racing

If the above is indeed the incorrect cam,
The next cam is the "same" cam just information from Howard's website directly.
Hydraulic Flat Tappet Camshaft; 1959 - 1980 Chrysler 383-440 800 to 4800 Howards Cams 720021-11 | Howards Cams

Now I'm not exactly sure of what cam is in the engine right now, (I can measure the lobes later)
But according to some information from @CBODY67 the cam in the engine is a
252/252 .390