Dirtbik3r

As many of you know, I bought the sdpc tpi crate engine last summer. For those of you who do not know what engine this is, it comes with vortec heads machined for a .525" lift. The rockers are 1.6 scorpians and the motor has a 9.6 to 1 compression. They also grind down the valve guides a bit for fitment. On top of the heads lie their "tpi baseplate." They shove a lt4 hot cam (218int, 228exh @ 50 thousanths) in the 350ci block and claim it puts out 360bhp with 415ft/lbs. Before I broke in the motor, I decided to put in a holley stealth ram with #30lb injectors using the maf computer. Anyway, 2000miles later on a brand new motor i started noticing my oil level decreasing. Let me also say that I never really felt a good amount of power from the engine. It felt like my old 305TBI.

So I decided to investigate the oil problem. Spark plug numbers 3 and 5 had a significant amount of oil on them. So i did a wide open throttle compression test on these cylinders... 175psi. I then hooked up the leakdown detector guage and the readings were around 8% leakage which is very good. Nextly, I took of the driver's side valve cover. I shoved a constant supply of compressed air into the number 3 cylinder using the leak down tester. I wanted to take a closer look at the exhaust valve seal. These are the seals that are the most prone to heat; usually the ones that leak oil. So I proceded to take off the rocker arm and valve spring. I used an on the car valve spring compressor to get the keepers out. As I pulled the spring out, it was broken. The springs sdpc uses utilize an outside spring with an inner dampener or helper spring. I noticed this was not the only cylinder like this. Most of the helper springs in all 16 springs were shattered. The shattered metal then cut into the valve stem seals(the good positive seal ones, not umbrella). So I figured out my oil and knock problem. I always got non-audible knock counts I could only read on a scan tool.

Not enough spring pressure causes valve float which causes poor performance and poor combustion.

So I called up sdpc and they said 6months ago, they magically switched the valve springs in this engine. I wonder why... For those that need to know specs on this engine because sdpc does not release them, they are as follows:

valve closed spring height: 1.735"
100lbs @ 1.735" (valve closed)
285lbs @ 1.210" (valve open)
Spring diameter: 1.250"

*There is no shims used*

But there is a solution. Not a cheap one. Competition cams has come out with the "beehive spring design." If you don't know what this is, check http://compcams.com . They basically utilize a lighter spring for less rotating mass with a special design which replicates a variable suspension spring.

Beehive spring: #26915-16
Steel retainers(7*): #787-16
steel 7* keepers: #501-16
valve seals: #601-16

Beehive spring specs:
O.D.: 1.055/1.290
I.D.: 0.650/0.885
Seat Load: 105@ 1.800
Open Load: 293 @ 1.200
Coil Bind: 1.140
Rate(lbs./in.): 313
TitaniumRetainer: 772,762
SteelRetainer: 774,783,761,787
Cup/Seat: N/A
Shims: 4753

Here is the complicated part. These springs are installed at 1.800" and not 1.735" like the sdpc springs are. After endless hours on the competition cams tech line, we figured out that you can install the 1.800" springs at 1.735". It'll basically change the spring pressure by about 20 more pounds and have a maximum lift of a little more than .525". Also, their 1.290" diameter will fit on the vortec spring seats. Just remember that with these heads and valvetrain, zero lash is 1/2 to 3/4 turn more.

*I posted this in the tpi board because it is helpfull information, not just a complaint. I will be installing the new springs later this week and I hope to see some performance and power gains.

3.8TransAM

There have been many manufacturer issues in the last few years with valve springs and with roller lifters.

U just joined the club :-)

Ask me how I became a member :-)

later
Jeremy

cgtms

Thanks for the information and let us know how it turns out for you. I have a SDPC TPI baseplate kit with modified Vortec heads, SLP runners and LT4 Hot cam. Are they (SDPC) doing anything for you?

I still have the 1.5 stock rockers and based on what happened with your car, I may not switch to 1.6 rollers yet. Currently I am making around 268 HP to the wheels and about 328 FT of tq. With 20% losses, that puts me at 321 HP and 393 FT at the crank. Not bad, but not 360....I can't believe that going to 1.6 rockers would gain me 40 HP. I expected around 330 to 340, so I am a little short, but much better then the 225 that I started with.

I have dyno tuned the car and after logging many, many hours of dyno time, 268 is best can do with my setup. I have long tube headers with magna flow cat and 3" exhaust, TCI 700R4, 26 LB injectors with 45 PSI fuel pressure. I make peak power at 35 degrees total advance and 12.8 AFR at WOT.

So I am not sure where they get 360 HP? It may not be SAE corrected HP. My short block is stock L98, but I think their create motor has the same setup....

Good luck in your repairs. I hope my springs hold out! I can't dump any more money into her right now.

Dirtbik3r

Nope. They claim that the motor has a 6month warrantee and it's my problem and not theirs. I do not see how that's my fault. Am I the one who made valve adjustments, grinded down ring gaps, installed cam, rod, and main bearings? -No. So I'm a little confused.

cgtms

That really sucks. I have used them a lot in the past, but now....
I think they are aware of the valve spring issues on their modified vortec heads....

Damon

The dampener supplies only a very small amount of pressure. I've sometimes used single coil springs on heads with the inner dampener removed (2 times now on unmodified Vortecs which won't fit the dampener coil of a typical Comp 981 spring). Never a valve float problem, at least in the sub-6000 realm. Knock count issues causing power reduction I could beleive- broken stuff banging around in the valvetrain I could see how that would be a problem.

The only thing you did wrong was not notice the problem while you were still in warranty. That's how life goes sometimes.

Dirtbik3r

That's definately how life goes. Problem was I got the crate in July '05 and did not get the engine in and running until january '06. College gets into the way like that. The dampeners that were in these spings were stronger and thicker than the ones i normally have seen. Hopefully these new springs do make a difference and hopefully the metal fragments not floating around the valvetrain will stop my knock problems. My WOT high load timing is 34d advanced above 3000rpms. The knock sensor was subtracting at least 15degrees. I can't wait to get the springs in.

Kevin91Z

iTrader: (1)

Manley Performance makes a spring that works with the Vortec heads. Its part number 22410-16. It is 1.250" outside diameter, has 130 lbs closed at 1.750" and 320 lbs open at 1.200". They retail for less than $75 at Summit or Jegs. I used these springs in my last engine with a ZZ4 cam and L98 heads and my dad used them in his last engine with Vortec heads and a ZZ9 cam. They're not "beehive" or "conical" springs, though.

Damon

Kevin raises a good point- you don't have to go with beehives.

Another set of springs I've personally used on Vortecs with unmodified guide bosses is the the Crane 99846 spring- with the dampeners removed. It's spec'ed for a 1.75" installed height and has pressures almost identical to the springs Kevin mentioned- plus a max lift of .560", assuming that 1.75" installed height is adhered to.

I installed a set of these with a pretty radical flat tappet solid (250* @ .050, .540" lift). Spun out to 6700 RPMs without any valvetrain issues. If I had it to do over again I wouldn't do it like this, but it worked.

Just something to keep in mind.

rjt76

sdpc=broken springs. ask me how i know this.

Dirtbik3r

A picture is worth a thousand words. Take a look at the scrap metal I found under the valve covers. Also, check out the valve seal. I threw the others out. They were all ripped up pretty bad.

Fevre

SDPC must not like repeat customer or mind bad press, since they knew of the problem and have since changed springs an offer to send you a set of new springs for free would have cost them less $100 would have gone a long way. I'll never order anything from them.

JB97C5

Hmmmm...

I always thought the price was too good to be true on that engine.

slohand

man i can't believe this. i have the crate vortec tpi witht the hot cam. last may as i pulled away from a stop light the car started running REAL rough. i looked over everything i new to do and then took it to the chevy place. turns out #5 cyc intake valve spring broke. so have $360+ worth of diagnostics and repairs i'm back in business. car runs good. about 2 weeks ago...pulling away from a stop light....car starts running a kinda of rough again. i, again check it all out and can't find anything soooo, back to the chevy place and $360 later it's the exhaust valve spring that is broken. not as bad as the intake which was shattered but still borken. i thought about checking the springs again but figured it just couldn't be that again. duh

yup blind luck, or the hand of God, kept this thing from punching a hole in a piston. soooo, i call scoggin and find out brian, who was the tech who first tested this engine, is back selling parts. i get him in the phone and tell him what happened. he says he never heard of this before but now recommends i replace all my springs just to "be safe".

he is recommending i go with ls2 spring that are good for 600 lift, i thing he said. course the are about $160+ something else and the joy of replacing them all.

i agree with you guys, this is a manufacture/design problem and should be covered by the one who made the mistake the us poor schmucks who paid good money for it. so ya, i'm a little PO d right now to say the least. think i just might forward this link to them if i can figure out how to do it. maybe they can a least warn others. they should send out notices to anyone who bought this problem, lest someone decide to hire a bottom feeder and go for blood.
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one more thing...............

rjt76 how you know about borken springs?

Fast355

iTrader: (2)

Doesn't suprise me one bit. Ask me how I know. Lets see, this June my 2,500 mile GM Goodwrench L05 broke a valve spring at idle, introduced the intake valve to the piston, bent the valve, and I had to pull the heads. Talked to the service manager at my local Chevy dealer. They were swamped at the time. It was going to be about a week before I could get my Van back running. So GM paid for my labor, the Comp 981s, and the Manley ProFlow valves (I cut the heads for 2.02/1.60s, and cleaned up the bowls, don't tell). They also gave me a new piston with pin, a new ring set to match, new gaskets, and paid for the single piston to be pressed onto the rod. I got a check for $589.xx to fix my engine. I am greatful that the Service Manager did not push me off, nor did the representative. It is afterall a TBI engine in a Van that was originally carbed and should not have a warrenty at all if you read the fine print.

slohand

Dirtbik3r....did you ever get the springs on? was wondering if you did how the car ran with the timing back in.

Dirtbik3r

Ya I did. Car runs stronger and without knock. Seems like these heads dont want a full 34SA at wot. But more like 30-32. I havn't lost a drop of oil and the pressure stays high. Also, the word about the springs I put in is that they give you another 500rpms without valve float.

slohand

Hi Guy,

glad to hear it. i was feeling a little guilty becasue i had recommended this engine to you in a post several months back. this spring issue sux but other than that i have been happy with mine. there are still some tricks to getting more out of her but i have pulled several ls1 cars including ss cars. i was also pulling a stock cobra all the way through first until they missed second. couldn't line up a rematch but would have loved to of run it again.

ya, about 100 i think it would have been bad but it was pure joy listening to that blower wine in my window as my ol girl pulled past the front bumper on that thing..

next best was the audi s4 who nailed it first with awd. ran him down and had 3 cars by 70 mph, oh ya.

anyway, i really hope you get this thing dialed in and have some fun with it.

one more question....any problems putting those springs in and about how much did you end up spending on them? i plan on doing mine in the next couple of weeks. ain't worth the risk not to do it.

1989GTATransAm

iTrader: (3)

Dirtbik3r you can also use +.050 valve keepers. That will give you some more spring clearance. I like the Comp Cams 918 beehive springs better. Comp seems to overrate the poundage on the valve springs. They run lighter than advertised.

blacksunshine'91

iTrader: (10)

I also had problems with that engine. I bought mine in Oct 2005. I had mine in my car for barely three months, less than 500 miles. Went to let it warm up one day and all I hear is serious rod knock. Turns out that the spring colapsed and started a whole chain reaction. It took several phone calls and bitching, but I did get a new engine shipped to me and they agreed to pay half of the labor for getting it swaped out. I do concur that they appear to be a bit shady with their guarantees. They tried to skirt responsiblity with me also, but I wasn't having it. What's wierd is that the originall had 1.6 rockers (not Scorpions). The replacement did, yet they were 1.5's. I called them and they said that if I took them off they'd send me a new set of Scorpion 1.6s. I didn't have the time to wait so I just kept the 1.5s.

D's89IROCZ

I was offered a spring called the SD1007 . It is 120 lbs @ 1.8" and 350 lbs @ 1.2" good for 570 lift and is stock diameter. They work pretty good for me .

1bad91Z

iTrader: (1)

I enlarged/cut the spring pockets and used Comp dual springs with dampner for Hyd. Roller upto .600 lift. They worked out fine!

RevItUpZ28

iTrader: (1)

Wow man, thanks for the heads up. I purchased the SDPC motor back in summer of 2004 and luckily haven't had any problems with the valve springs cracking.

Because of a leaking oil pressure sending unit, I threw a rod bearing and the motor is getting freshened up quite a bit right now. While I have it apart I will definetly be upgrading the valve springs, retainers, pushrods, (etc.) --all thanks to this post.

slohand

Revitup....

Glad you saw this thread. Sux about your engine. Any warning signs before she went? Also will be interested in what springs you go to when you change, if ya don't mind.

Lastly, what a shock, your just down the road. As a matter of fact we just signed a lease in Greenville and are in the process of putting in a Once Upon A Child over there. Maybe you can bring the beast by sometime when we get it open.

Good Luck with your project.

RevItUpZ28

iTrader: (1)

Hey man,

I'm going with the beehive comp cam springs, chromemoly pushrods, chormemoly retainers, etc. The car is now going to be a 383 Vortec HSR (3.75 stroke, 5.7 rods, 4.030 18cc dished pistons), etc. I'm hopeing to run low 12's with the LT4 hotcam, 3500 stall, and 3.73's on ET Streets.

I moved away from Greenville a while back, never did update the info on here. I visit Greenville about every 6 months. Check out the car club I started there, I had a lot of fun with those guys/gals when I went to college there.

slohand

congrats on finishing college. it ain't as easy as it looks.

i am going to change the springs on mine before my luck runs out too.

your next setup sounds like it should hum. ever thought about going 406 or so while your in there?

i was looking at your dyno run and the numbers. they aren't bad, but since scoggin claims 357hp (and they say that was underrated), they would seem a little low. did you ever have a chance to stop light race a ls1? if so results?

the only differences i can find or don't know are.... a 52mm tb, gutted my cat, ported and gasket matched the plenum.

the reason for the question is i have nearly the identical set up i would expect similar numbers and with the cars the ol' girl has pulled it would seem they are higher.

also, if you don't mind, where is c.a.m. and jeff who did your dyno work?

oh ya, many years ago i had to leave ECU to get an education, (what a party school) ended up with Yosef at ASU.

RevItUpZ28

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