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Hi guys, how's it going. I just have a couple of questions here. I have a 4G32 chain type saturn engine with stock internals, well except for the camshaft, it used to have a cam#1 then recently had it replaced with a cam#6. There was a significant improvement on the engine, but at RPMs over 6500 it started experiencing this thing they call 'valve float', or so I've been told... had the engine checked and found out that the springs lacked the tension it had before. I tried to look for brand new OEM springs but had no luck, so I'm just wondering if anybody can give me an advice as to what type of valve spring I'd should try replacing it with? Somebody mentioned about the Isky 455/456 dual valve spring, has anyone used tried using them? Is it safe to use these type of springs, or would be too firm, I'm just afraid that it might damage or stress the valve train..
Thanks.

JP

Hi and welcome to the site,
Yep, over 6500 and your valves will bounce. If you want to rev higher than that, and your motor has been built to handle the revs (just noticed - it hasn't - "stock internals" ) , you have basically 2 options: Heavier springs or spacers under the existing ones. Someone may still supply dual springs but Ive never seen them for a Saturn. Heavier springs will put extra stress on the valve train. If you want a set of heavier springs I have an unused set from Crow Cams that I decided not to use because the engine is in a street car and needs to last a while. PM me if interested and I'll try to find them. Half new price plus postage.
T.

Thanks for the reply.

contact RPW.com.au

what they said but you better off with a regrind than a pollution cam, which would have run out of HP by 6k anyway so your reving for no gain, high rpm = high cost , at the moment the cost will be dropped valves , get a regrind, follow the grinders specs for springs AND max rpm

shuggy wrote:contact RPW.com.au

thay will do a cam and spring set for $400 incl post... i spoke to them today!

yeah, best thing is i can take my car to them, they fully rebuild the engine and match port exhaust/intake to the ports and jet and tune the carb on the dyno to match and recurve the dizzy. expensive but easy

Thanks for the info guys, not quite familiar with this engine yet. Although I'm not trying to set it up to race specs, I only have a stock carburetor, I just want to maximize my current set-up or maybe add a little kick to it ..well, if this old horse still has. I have another question here, since my concern is about the tension of the valve spring which I think a dual valve spring has more than what my engine needs, will it make a difference, make the dual valve spring less rigid if I'll just remove the inner springs?

@Torana68: What do you mean by 'pollution cam'?

@shuggy: Do you know of any grinders who do springs at OEM specs?

Thanks again.

JP

pollution cams = post 1975 cams, number 6, 7 and 8
You will always get greater revs for less spring tension (read valve train wear) when using oppositely wound dual springs too. Just a thought

dont waste money on std springs, they are "standard" get a decent cam and springs to suit

One thing I was told regarding valve float or valve bounce (what ever u want to call it) is u can run double valve springs, however u will only find second hand sets now as I got in contact with Ron Masing about it and he sold his last set about 6 months back and he doesnt know where to get new ones.
The reason people run double valve springs is that springs have a resonate frequency....basically at a certain RPM they vibrate and send waves up the springs and they dont want to bounce any faster. What double valve springs does is the second set has a different size, thus giving it a different resonate frequency so the engine can rev higher.

If you want to build a race engine, personally I would get new pistons/rings, new bearings, twin webers, #5 cam and freshen up the head and check oil pump. Ground up rebuild basically.
Ive been thinking about this for a while but after speaking to someone who had a 4G32 twin cam with twin webers and #5 cam and he was only getting around 115hp (or something...cant remember exactally, but it wasnt much) he upgraded to an SR20. But if ur after nostalga i would do rebuild as i said above.

Ive never heard of spacing the valve springs, thats interesting and something i would never have thought of.



Cheers Matt

Thats dead right although if the springs are wound in opposite direction resonate frequencies are eliminated.
I'm sure a engine builder could find something to suit your requirements

how do u mean "if the valve springs are wound in opposite directions it elimates resonate frequency" is this in a single or double valve spring setup?


Cheers Matt

kodos wrote:Thats dead right although if the springs are wound in opposite direction resonate frequencies are eliminated.

From my understanding this isn't 100% correct.

The inner and outer springs will have DIFFERENT resonating frequencies. The 2 frequencies can have harmonics (where both springs resonate together) but it is less likely to be in the "normal rev range" of an engine.

galant573 wrote:but at RPMs over 6500 it started experiencing this thing they call 'valve float', or so I've been told

Is it valve float or valve bounce?

Valve float is insufficient spring tension for the closing speed of the valve.

Valve bounce is spring harmonics causing loss of seating pressure.

Double valve springs with a bit more seat pressure should fix both if these types of issues without too many bad side effects.


Cheers.

Rally_2.6LC wrote:how do u mean "if the valve springs are wound in opposite directions it elimates resonate frequency" is this in a single or double valve spring setup?


Cheers Matt

Double springs yes. Where the inner spring is manufactured with a clockwise twist and the outer has a anti clockwise twist (or vise versa)

And yep, a little extra seat pressure is good too. But the beauty of dual springs is you dont have to go really heavy springs and so save your valve train

According to the Jap shop manual, local market 4G32 belt drive had the same valve springs as 4G32GS (factory twin carb) engines which had max power at 6700rpm...... Give them a go.............

Roger

, it used to have a cam#1 then recently had it replaced with a cam#6.

I'd be interested to know................Is the #6 from a chain drive 4G32GS motor?

Roger

nope 6 is a pollution cam , 2 is the GS...
Roger

Thanks for that............were they in ADR27A engines? (Post July 1976)

Coincidently, the belt drive GS is a #6. Came in Aust market importeds 4G32, 4G37 .........L300, Cordia, Nimbus etc

Roger

The No.6 cam has the same duration and lift as a No.2

well over the years they have been describes as bigger than a 5, same as a 5 , a pollution cam (my vote!) etc so post up the factory specs , all them and lets have a look...

its a factory polution cam to allow for the exhaust gas valve to opperate propperly

and i was 90% sure #3 was GS cam

your at least 90% wrong, 2 = GS

ok cheers whats 3 then?

from memory GTO

I think we're getting confused here, as the belt drive and chain drive use a different numbering sequence.

No 6 for BELT DRIVE is definately 4G32GS and 4G32 for EC according to the Jap manual dated 1981. According to 1980 manual, #6 is for GS and CAL (Chrysler Aust Ltd). The 1979 manual says #6 is GS only, but Australia didn't get belt drive till 1980.........Confused??

I have CAL info but it only mentions cams #1 and #6 but this info is for 4G32 as per Colt and 4G37 as per Cordia and Nimbus. I know the 4G37 has the #6 as I removed one for a spare 4G32 I have.

Regarding valve springs. These are white or yellow for GS and AUS, otherwise red or green for all other markets non GS.

This is all belt drive info only

Roger

PS
Anyone have specs for #4 chain drive cam??

the only ones I worry about are chain ones, if 6 is for belt pollution and GS then its a pollution cam, as it would be in '79 and newer engines, it wont be a preformance cam. Once pollution regs kick in preformance goes down hill but best it to quote all timing specs for 2 and 6 (both belt and chain wont be a 2 for belt Im thinking) then you will see whats what.
Roger

There was a cam that we played with that was a #5+2. It was a bit wilder than the #5 and this is the one the Gosford Dyno Lancers were running till Hilly and Belly went to BDA Escorts.

Hi guys, found this catalogue. Seems like these Isky springs are quite stiff..

http://www.iskycams.com/springbook.pdf

Torana68 wrote:well over the years they have been describes as bigger than a 5, same as a 5 , a pollution cam (my vote!) etc so post up the factory specs , all them and lets have a look...

Bugger, have just spent considerable time writing up a list complete with GTOs etc and it got lost somewhere.........................
How do I find my saved posts?? Maybe it's there.

Just to clear up queries on 4G32GS camshaft debate anyway.....

The # 2 for chain drive (from manual dated Oct '73) and # 6 for belt drive have exactly the same timing, lift variation minimal.
In open 24 BTDC, close 64 ABDC
Ex open 67 BBDC, close 21 ATDC
Valve lift is:- Cam # 2, Inlet 36.52mm, Exhaust 36.57mm
Cam # 6, Both valves 36.5mm

GTO all 4G35 and SOHC 4G32 single & twin carbs
In open 32 BTDC, close 60 ABDC
Ex open 63 BBDC, close 29 ATDC
Unfortunately, I have no info on Cam # or lift. I probably have the part # though

Roger