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Old 12-16-2008, 05:40 PM
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Valve train questions

I pulled the valve covers and intake on my 350 to address some valve train issues (don't ask--stupid stuff) and decided to uprade the rockers to roller while I'm at it but 2 things came up:

1) a couple of the hyd lifters have much different spring strength--they're hard to push down when full of oil but when empty there are a couple that seem real weak. How important is the (empty) strength of the spring--when they're pumped up will it matter much? These are the el cheapo Speedpro cam and lifters. The cam is fine and I don't want to replace everything now if i can get by.

2) rolling the pushrods on the table, about half of them are less than perfectly straight. Not what you'd call bent, but there's a noticeable wow to them when they're rolled, probably a couple thousandths off at one end. Just a mild street engine--do I have to worry?

Thanks in advance!!
Jim

(first post--I've been lurking and reading for awhile)

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Old 12-16-2008, 07:38 PM
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I wouldn't worry about the spring thing,


Get new pushrods and find out why they are bent. Even a little weakens them.
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Old 12-16-2008, 07:44 PM
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On the push rods....this may be stupid I'm sorry, but are you sure the surface is flat? Many guys like glass because it's flatter than a table top. Not having seen it, it's impossible to say. Roll them on a nice, flat piece of glass.

As far as the lifter seat, pushing them down is no problem. They will go down easily if they are empty. If they are stuck up after they bleed down, that's a problem.

Lifters are cheap, and a PIA to do, why not throw new ones in while you're there.
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Old 12-16-2008, 07:53 PM
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OK, thanks--that's what i was hoping to hear about the lifter springs

About new lifters--can I do that? I thought you always had to keep the lifters with the camshaft after they were broke in.

I will try the piece of glass, but since some of them rolled good and some didn't, I think they are not totally straight. Actually though i am not completely sure they were straight to begin with--more el cheapo stuff. I am going with self aligning roller rockers because i noticed there was more room in the pushrod guide holes than I thought should be there--maybe that's why they're bent.

Thanks!
Jim
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Old 12-16-2008, 08:08 PM
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Quote:
Originally Posted by MorrisonLC
OK, thanks--that's what i was hoping to hear about the lifter springs

About new lifters--can I do that? I thought you always had to keep the lifters with the camshaft after they were broke in.

I will try the piece of glass, but since some of them rolled good and some didn't, I think they are not totally straight. Actually though i am not completely sure they were straight to begin with--more el cheapo stuff. I am going with self aligning roller rockers because i noticed there was more room in the pushrod guide holes than I thought should be there--maybe that's why they're bent.

Thanks!
Jim
Lifter's are less than $5 for "stock" ones. If you get hardened pushrods you're looking at $80-90. You can put in new ones and keep the cam.. Load them up with assembly lube, don't forget.

Personally, I like guide plates better than self aligning rockers. Just my opinion, people will tell you differently.
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Old 12-16-2008, 08:20 PM
How fast is fast enough?
 
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You can run new lifters on an old cam... But you're looking at $40 for a set of lifters or $80 for a set of lifters with a new cam... I'd get the kit to be safe, and you could even change the cam specs while you're at it (if its not quite what you want).

then again you could just slap the lifter in and run it. Since its a speedpro cam the ramps are pretty lazy and they're more tolerable to new lifters on an old cam.
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Old 12-16-2008, 08:20 PM
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Since your cam is already broken in, you can drop in new lifters.
Install new hardened pushrods.

You might be suprised how much better your power is if your valve train is not flexing all over the place.
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Old 12-16-2008, 08:39 PM
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That's good to know--I thought camshafts and lifters had to be broken in together. It is a lazy cam--the RV grind, pretty much stock engine. I will get new pushrods, but doubt if I'll do guide plates on this engine, don't want to pull the heads again right now. I am going to self-algning rockers because one of the guide holes in the head was so worn that a rocker arm slipped off, bending the pushrod and damaging the valve stem. Got that fixed, simplest way to correct the guide hole problem seemed to be with self-algning rockers

Thanks for all your input
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Old 12-16-2008, 08:41 PM
How fast is fast enough?
 
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Quote:
Originally Posted by MorrisonLC
That's good to know--I thought camshafts and lifters had to be broken in together. It is a lazy cam--the RV grind, pretty much stock engine. I will get new pushrods, but doubt if I'll do guide plates on this engine, don't want to pull the heads again right now. I am going to self-algning rockers because one of the guide holes in the head was so worn that a rocker arm slipped off, bending the pushrod and damaging the valve stem. Got that fixed, simplest way to correct the guide hole problem seemed to be with self-algning rockers

Thanks for all your input
That's why your pushrods are bent. DO NOT MIX SELF ALGNING ROCKERS WITH GUIDE PLATES/HOLES. It'll bend your pushrods.... As seen in exhibit A.
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Old 12-16-2008, 08:50 PM
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Quote:
Originally Posted by MorrisonLC
That's good to know--I thought camshafts and lifters had to be broken in together. It is a lazy cam--the RV grind, pretty much stock engine. I will get new pushrods, but doubt if I'll do guide plates on this engine, don't want to pull the heads again right now. I am going to self-algning rockers because one of the guide holes in the head was so worn that a rocker arm slipped off, bending the pushrod and damaging the valve stem. Got that fixed, simplest way to correct the guide hole problem seemed to be with self-algning rockers

Thanks for all your input
What year is this thing? Is it aluminum heads with stock guide plates? If so, those really aren't guide plates, they were there for assembly reasons. If you had non SA rollers with those plates, you'd have problems.

What AP said too, clearly don't mix them, thought that was obvious.

As to the lifter/cam what you don't want to do is move lifters from bore to bore, once broken in but putting in a new one is OK. Think about it, if you collapse a lifter, you don't have to replace a cam, right?
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Old 12-16-2008, 08:53 PM
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Just let me make one more point on these second line rockers. Again, I see nothing wrong with them on a stock motor, save your money. You're not talking gumball machine crap here.

I have about $15K in my motor. I have a roller cam. I ordered LS7 lifters for my Gen1 small block. They said AC Delco on the box, they were $600. I said, no wrong lifters. I got the right part number. LS7 lifters, they said GM Performance. $125. Both rated to 7000 RPMs, SAME FKN LIFTERS.

There's a time and place to spend money, this isn't one of them.
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Old 12-17-2008, 06:33 AM
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That's all good info, thanks, I appreciate it. The pushrods aren't bent because of self align rockers because those haven't been installed yet. I know the warnings re: guide plates/holes and self-algning, I'll make sure there's no interference or else ream out the guide holes. This is a gen I block with cast iron heads c. 1975, not a high end motor, but it's in a off road vehicle, gets revved pretty good when wheeling and climbiing, has to hit 5000 sometimes.
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Old 12-17-2008, 06:52 AM
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5000 isn't all that high. You'll be fine. Look at Harland, Summit, Scorpion, get some chro mo pushrods, adjust them right, you'll be good.
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Old 12-17-2008, 07:05 AM
How fast is fast enough?
 
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Its funny what offroaders consider high and what racers consider high... "yea bob, we're hitting the traps at 8,000 RPM, trying to keep it down to get a few extra passes out of her" VS "that Jeep pegged 4500 when he was chargin up that pass!"

Of course a lot of offroaders use nearly stock engines...
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Old 12-17-2008, 07:46 AM
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Quote:
Originally Posted by ap72
Its funny what offroaders consider high and what racers consider high... "yea bob, we're hitting the traps at 8,000 RPM, trying to keep it down to get a few extra passes out of her" VS "that Jeep pegged 4500 when he was chargin up that pass!"

Of course a lot of offroaders use nearly stock engines...
I guess they don't have time to wind it up. It's all torque.
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