Valve Springs?

[lineman1984]

I am replacing the cam, lifters, pushrods, and timing chain on the 360 I just picked up. Summit Racing recommends I replace the valve springs when I replace the cam. Is this necessary? It will add a new complexity to this job but, I will do it if I have to. I know that a full head reconditioning is best but I cant afford that right now.
Thanks,
Justin

[LM14]

It's best.

Get springs that are matched to the cam profile. Your cam card will tell you what rate and installed height for your application. Not enough spring pressure will allow the lifters to bounce, too much will speed up wear. You can take the existing springs off and see if they fall into the pressure range the cam requires at installed height. Old springs very rarely meet the stock criteria after a few weeks of running. Valve springs lose rate very fast, almost scary fast.

I've had roller cams that killed $450 springs every 12 nights of racing (on solid roller cams with huge lift numbers an steep ramps).

No matter the style of engine build, I always replace the springs with the recommended springs for the cam. Actually it's cheap insurance. It can also help in the case of a dispute if you have problems with the cam with the manufacturer.

Be sure to use a break-in lube with ZDDP and a ZDDP oil after that.

SPark

[banjopicker66]

If your new camshaft is stock, then I wouldn't think that new springs are absolutely necessary, but it really is best. If the old springs are too weak, they may float which can cause you all sorts of engine problems. Anyway, the work you do for a valve grind job will repeat a lot of work you are doing to change the camshaft.
I have always changed springs, and haven't regretted it.
If you are installing a camshaft with a non-stock grind, then you really should.

I hope others will chime in and give good reasons whether to change or not change springs at this time.

However, it is possible to change the springs with the heads on the engine. There are 2 ways to do this:

1. Shadetree method: You will need a valve spring compressor, and the room around accessories to do this. (For example, you may need to remove the carburetor.) On one cylinder (at a time), bring the piston to TDC, where both valves are at the highest. Next, rotate the engine backwards 1/2 turn of the crankshaft. Feed a length of soft cotton rope down the cylinder until it will take no more. Now, GENTLY rotate the engine back up to the highest position until it will rotate no more. Don't force it, or you may snap a valve face in half. The piston and the cotton rope will hold the valves up while you R&R the springs. Use the spring compressor to R&R the springs, and move onto the next cylinder.

2. A little less than shadetree method: You will need a compressor (a small pancake type will do) and the quick disconnect air hose connector used between a compression gauge and the spark plug hole. Rotate the engine until the piston is at TDC for the compression stroke on that cylinder. Screw the air hose connector into the spark plug hole. Connect it to the air compressor line, and the air pressure will hold the valve in place. R&R the springs as above. When you connect the air line, the crankshaft may rotate, as the air pressure may force the piston down, just as the ignited fuel/air mixture does in the running engine.

The second method is a bit risky, in that you may drop a valve if you inadvertently push down on a valve stem too far and release the air pressure in the cylinder.

However, I have had great success with both of these methods, which I used mostly to change the valve stem seals rather than as part of an engine build.

Hope this helps.

[yellodog]

many manufacturers offer a cam kit with springs. cheaper that way, and you'll get the recommended springs.

[MeZapU]

Stock springs are weak. 45+ year old stock springs are very weak. Replacing them is advisable if you plan on revving the engine past 4k rpms. Getting some valve float and dropping a valve will ruin your day. A mild replacement set of springs is not very expensive. Around $100 or so. The price goes up to match more and more aggressive camshaft profiles.

[lineman1984]

Well, it looks unanimous. Springs it is! This motor is not going to be a high performance screamer so, springs shouldn't cost too much. Just looking to get a mild cam with a nice little lope at idle. I don't plan on winding her up I just wanna embarrass a bowtie every now and then. I am using Summit parts and will use the springs they recommend. I do have one other question. The heads I am using come off my 352 and I want to swap them over to my "new" 360. I have the book "How to rebuild your Ford Big Block", (the one with the yellow cover). I will inspect my valves and seats as I replace springs and associated hardware. But, What is the likelihood of the new springs snapping one of my valves and causing a catastrophic failure. I don't plan on abusing the motor, just cruising and a few longer weekend trips. I know that anything is possible but, would like an idea on what to expect. THANKS EVERYONE! You folks are my go to source for any questions I have about Me and "Bernadette's" relationship issues!!!
Justin

P.S. Bernadette is the truck.

[banjopicker66]

I would be concerned about the '66 valve seats not being hardened and therefore not suitable for unleaded fuel.
What year are the 360 heads? Check the casting number between the spark plug holes. Probably a C6 number on your earlier heads.

If D2 or later on the 360 heads then it will have hardened seats from the factory.

The earlier, non-hardened valve seats can sink themselves into the head. I would also be concerned that new springs will accelerate that process. If you have the heads off - and I know the finances are tight - now is the time to have the seats replaced and the valves ground, which is basically a valve job.

I may have a few details wrong, so others, please chime in to confirm or correct my comments.

[64 f100]

Nothing is ever easy, it seems. All you wanted to do was pep up your truck a little. Welcome to the world of reality checks. My suggestion is leave it alone until you have the money to do it right. Myself, I would go for a 390 and forget that gas hog 360. Like the 352 the 360 is a low compression engine which is great for todays gas, but weak on performance. I actually like the 352 better than the 360. The bore is larger on the 360 than the 352 and means you have a larger space to fill with gas and oxygen. The results are mostly in how much gas you use. The actual difference in compression is not much from the swept volume. My suggestion is to check your valve springs and see what condition these are in, then make a decision on whether or not to replace based on the cam selected recommendation. Another suggestion I will make at this point is find a set of heads with smaller combustion cambers. A significant drop in chamber size would help with performance in what you want and actually help some on fuel mileage. Although that is not going to be that significant with a 360. Those heads are scarce and somewhat hard to find. The heads were early 352 and 406 heads Coaz-D castings would be ideal, as chambers are roughly 59CC. There are a few other heads with almost that small a chamber but are hard to find also , all are pre 1964 numbers that I know of for high performance. I really suggest you wait until you have enough money to do it right. When you build an engine you need to look at the whole package. Timing chain is inexpensive and a very mild cam will most likely help but there are a lot of if's involved. New lifters are almost a must have when changing cams, as a general rule as are springs. Sometimes you can find used stuff in good condition, mostly thinking of heads here.

Rich

[LM14]

You do realize that just a bit more pep with a cam change will require the cam, springs, seals, just as well do a valve job, consider seats, might get into switching a shaft or 2, might need some rockers, could have valves that are past grinding that need replaced, then there's gaskets, just as well change the intake, new carb would be nice.......

The flip side is to stab in a new cam, drop in new lifters and go! The problem with that is you will never get the full benefit from your new cam with the old leaking valves, weak springs, worn rockers, stock intake....... You will probably be disappointed with your spending vs your gain if you don't so it right.

Once you break the seal, it never ends. Picture a snowball rolling down a big hill.

I wouldn't waste any money on a 360. At least go to a 390 by swapping out the crank, rods and pistons. Check your head casting numbers to see what valves and ports you have. Some early heads aren't worth the time of day.

I've done a ton of research on hardened seats vs old style seats. Here's what it seems to boil down to.
1. If the engine is basically a stocker and will normally be under 3500RPM, forget wasting any money on hardened seats.
2. If you plan to turn constant RPM's above 3500, go to hard seats.
3. If you plan to increase valve lift, duration or spring seat pressure with the cam change, go with hard seats.
4. Many of us will never drive our hobby trucks far enough in it's/our remaining lifetime to have a valve seat problem. We'll never drive it enough for it to matter.

As some have said above, sit back, be honest with what you want from the engine, the uses you have planned for it and how much you can afford to spend.

I find it costs at least twice as much to do any improvement to an engine than most people plan for. They talk themselves into the project by justifying the costs and rounding down, forgetting the little things and ignoring the cost of things like gaskets, hoses, clamps and the amount of time required to tune the engine around the new parts to get the most out of them.

How much is that little bit of lope driving around town worth to you? It could be as cheap as a cam/lifter kit or as expensive as a total engine build. I guarantee it will cost more by the time you are done than you said it will before you started the project. Only you can decide what it is truly worth to you. True costs are sometimes hard to swallow and even harder to justify.

JMO, rant over,
SPark