ghetto wagon

Hello. I have a 94 Sierra, L03, stock Flat tappet cam.

The valve seals are shot on this thing so I would like to change the seals, While im at it I want to change the springs

I hear the Comp 981s are awesome springs and work great

I have two questions. If someone can awnswer them that would be awesome

1. Do I need to shim up the 981 springs with the stock TBI L03 heads?

2. Can I resuse my orignal retainers and locks with the 981 springs?

Please LMK thanks.

Damon

Literally a drop-in replacement for stock. Reuse all stock hardware (including exhaust-side rotator-retainers). No shimming necessary, no machine work necessary.

ghetto wagon

Thats awesome!

One more question


Can I use Stock iron head LT1 valve spring retainers to get rid of the heavy stock style ones?

Do they work w/o any fitment issues? They look like the comp retainers that are recomended...

Damon

Yes, but then you'll have to check your spring installed height to make sure it's still correct (1.70"). THis is especially true on the exhaust side when replacing exhaust rotator/retainers with non-rotator/retainers. The difference will be about 0.060" there.

ghetto wagon

Going back to this...

Are these springs TOO STIFF That they might damage my 132k Baby stock No lift Flat tappet cam and hydraulic lifters?

Or.. shouldnt I be concerened.

I want a little more performance (If they are going to be noticable) but I dont want to wreck the engine...


Searching, They seem about 60 lbs stiffer then stock. Is that alot?

titchener

If you are keeping your stock L03 cam and heads there's no point in going to stiffer springs, you won't get any more power because your useable RPM range isn't high enough to float the valves with the stock springs. The stiffer 981 or beehive springs will increase your friction a little and actually knock a little power off.

I'd just get a good quality set of stock replacement springs. www.rockauto.com sells a "heavy duty" Sealed Power stock replacement spring for around $50. a set. I've got the same problem you have (worn seals on my L03) and those are the springs I'm going to put in.

ADDED COMMENT- I looked up the specs on the Sealed Power HD springs and they are stiffer than I thought, almost as stiff as the Comp 981 springs. Both those springs may be overkill for a totally stock L03, but if you are doing some performance work to it (exhaust, better intake flow, chip tuning) it may make sense to go to the HD springs, but if you are leaving it totally stock I'd probably just go with stock replacement springs. Comp Cams also has a 980 spring that is about in the middle between the stock springs and the 981 springs.

If you go with a stock replacement spring you can get a little more RPM potential out of the spring by putting a 0.060" shim under it, the L03 cam has pretty low lift so you can shim it without worrying about hitting coil bind. A 0.060" shim bumps both the open and seat pressure by about 15 lbs.

Paul T.

ghetto wagon

Okayabout the 980s,


http://store.summitracing.com/partde...5&autoview=sku

The inside/ outside diameter is still enough to use stock retainers? It looks to be a narrower spring.

If not,

What about these? Too weak or will they be a good replacement?

http://store.summitracing.com/partde...5&autoview=sku


Also... Another ? The Overall Spring rate and pressure, That is at a rate the spring wont ever be compressed at w/ the stock cam correct? So essentially The spring would be working at lower pressures?

LMK thank you. I just want a cost effective replacment.. New GM springs cost $120!

titchener

>Okayabout the 980s,

>The inside/ outside diameter is still enough to use stock retainers? It looks >to be a narrower spring.

I'd call the Comp Cams tech line on this one, I think those springs will work with the stock retainer but they'll tell you for sure.


>If not,

>What about these? Too weak or will they be a good replacement?

FIXED: http://store.summitracing.com/partde...5&autoview=sku

Those look like stock spring replacements, fine if you are leaving the engine totally stock.

I didn't understand your last question, but regarding spring rate, this basically determines how much higher the open pressure of the spring will be than the seat pressure. Higher RPM usage means you will typically need a higher rate spring.

By the way, if $ is really tight, you can keep your original springs and just put a shim under them to get back to original stock pressure. When a spring wears it typically loses free length but the rate stays pretty constant, this means if you have the clearance to shim, you can keep using those springs. As I mentioned earlier the fact that the L03 engine has pretty small cam lift means you have a lot of room to shim. So if $ is tight just by a set of 1.250" diameter 0.060" thick valve seat shims and put them under the springs when you change the seals.

As the stock spring wears and ages it will typically lose about 10 lbs of seat pressure due to the free length of the spring shrinking over time. A 0.060" shim will boost the spring up about 15 lbs of seat pressure, putting you around 5 lbs over the stock spec. Since the rate of the spring will still be about the same, the open pressure will also be about 5 lbs above the stock spec.

rockauto.com sells the 0.060" shims cheap in the Sealed Power brand, unfortunately you have to buy 100 of them at a time but its still only $19. The only rub on shimming is that if you later decide to go to 1.6 ratio rockers you should check to make sure you have enough clearance before coil bind, it would probably be ok but I'd check it.

Paul T.

ghetto wagon

Link no work!