Max valve size for 4.0/4.6 heads?

Started by BlownMGB-V8, December 08, 2022, 11:26:48 AM

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BlownMGB-V8

#51
December 15, 2022, 09:01:40 AM
Close but the first one limits cam lift to about .400" and the 2nd one even more. Ideal would be:

coil bind: < 1.000"
Installed Height: 1.560"
closed pressure: 110-125#
rate: > 275# or open pressure > 300#
OD: < 1.240"
ID: > .850"

Such a spring is possible but maybe not available. The easiest thing to change is the OD and ID.

Jim

BlownMGB-V8

#52
December 15, 2022, 09:47:30 AM
So far the 4.6L Ford springs seem to be coming the closest.

PAC 1231X is the closest I've found so far:
https://www.racingsprings.com/index.php/valve-spring-11368.html

That one will work with machining of the inner boss from .852 to .720"

Jim

MGBV8

#53
December 15, 2022, 10:08:23 AM
What is the OEM installed valve spring height on the Rover heads, 1.6"?
Carl

BlownMGB-V8

#54
December 15, 2022, 10:20:07 AM
1.560"

TFS-15411 is another  similar possibility

Jim

MGBV8

#55
December 15, 2022, 10:31:19 AM
That short?  Wondering how everyone is running the 50232 without experiencing coil bind.

BTW what is the difference between the Crower 50232 & 53232 cams?  If the 53232 is for Rover, how is it different?
Carl

mgb260

#56
December 15, 2022, 11:15:38 AM
Carl, Rover cam has a different nose for the retainer plate.

MGBV8

#57
December 15, 2022, 11:26:16 AM
I thought that only applies to the 4.0 & 4.6 engines.

Okay, it's a short nose cam for the crank driven oil pump engines only.
Carl

BlownMGB-V8

#58
December 15, 2022, 11:56:42 AM
It seems like a very small diameter spring to be developing  a 300# spring rate. Guess it would be light weight though.

Jim

mstemp

#59
December 15, 2022, 12:45:13 PM
Carl,

Marc at D&D sold me a special set of springs with my Crower 50232 cam. No name or box with them though, just RV-911-16 as a part number on the invoice.

Notes from machine shop that did the work:

"Had to cut the spring seats pockets 0.100 to 0.135" to get 1.665" to 1.675" installed height.
Stock retainers tight to the springs, springs needed chamfer to fit.
Distance to coil bind 0.025" to 0.035".
Seat pressure 105#, open pressure 225#, this is lower than Crower recommendations but recommended by supplier of cam."
"Recommend Howards Cams Spring #98111. Better rate, fitment to retainers and more room to coil bind."

Looking back at these number, I have put a lot of faith in D&D, so far no issues but that room to coil bind looks close!

53232 is for non disy Rover as Jim N mentioned.

MGBV8

#60
December 15, 2022, 01:33:30 PM
Back in the day D&D simply used the manufacturers part numbers.  I have cross referenced some of them.

I bought my Crower cam (50232) & lifters from Dan LaGrou ( he knew I was going to install it in a 3.9) with a recommendation for a specific valve spring.  A machinist friend of mine opened up the throat of my late Rover heads & installed a set of now NLA Crane springs that had better coil bind numbers than what Dan recommended.  I can't find the paperwork & I do not know if the spring seats were cut deeper.  I don't think the top of the guides were cut down before the new seals were installed.  Don't think there was any info on that back then.  May still need doing.

I do know that my late Rover heads with the throat opened up out flowed my stock Buick 300 heads that were not cleaned up.

I am thinking that the 50232 is too much cam for a near stock late Rover head.  I may step down to the 50231.
Carl

mgb260

#61
December 15, 2022, 01:47:15 PM
Carl, I would keep the 50232. Your 3.9 is bigger than my 215. Plus Crower has 4 degrees advance built in for lower compression, if over 10 to 1 I would retard., On the Rover heads, the valve guides are lower than the early heads and have modern seals. Still use steel inserts in the rocker hold down holes. I'd go for the larger oddfire valves I mentioned above. 75-76 have the long keeper like the Rover. The 77-78 looks like you could use a modern 7 degree. Z28 Chevy valve springs all over Ebay for reasonable price.

mgb260

#62
December 15, 2022, 01:54:43 PM
Jim, when you do the Rover rockers are you going to use an aluminum tube instead of the springs? If so, you need .015 on each side of rocker on each side of tube. Also, a good number for oil clearance on the rockers. On the TA stud rockers the poly locks stick up a bit and valve covers may not be tall enough. There are 1/2" spacers available on Ebay.

MGBV8

#63
December 15, 2022, 02:01:37 PM
I believe RV-911-16 is an Elgin spring.  Maybe NLA.
Carl

mgb260

#65
December 15, 2022, 02:36:53 PM
Jim, you could start a cottage industry with beehive retainers and custom rocker setups .Not much performance stuff for the Buick/Rover and if there is seems to be way too expensive.

MGBV8

#66
December 15, 2022, 02:46:32 PM
RV-943X is an Elgin spring.
Carl

BlownMGB-V8

#68
December 15, 2022, 03:25:38 PM
Only beehives on that list were 1.8" IH so no help there.
On the Procomp rockers fitted to the Rover shafts, I don't know why I couldn't just use the springs that were original. Depending on how things line up I may get away with the existing spacing. But, not much point in doing anything until I get the springs sorted out. I'll try to call Dustin tomorrow and see if he has any ideas. I also need to see how hard the stock retainers are if I'm going to try turning them down.

Don't know about a cottage industry, I seem to have too many irons in the fire already.

Jim

BlownMGB-V8

#69
December 15, 2022, 03:53:02 PM
The OEM retainers are quite hard so it looks like the beehive springs probably aren't going to happen. Too bad but sometimes you just have to punt.

So... the specs still hold, maybe there's a single spring that will do the trick:

1.240" dia
~120# @1.560 I.H.
>300# @ 1.010 open

Have to just keep looking.

Jim

mgb260

#70
December 15, 2022, 04:13:07 PM
Jim, this may be a solution for the beehives. TA has 10 degree keepers for the Buick valves so you would need 10 degree retainers for the beehives.

http://www.taperformance.com/proddetail.asp?prod=TA_V1434C

mgb260

#71
December 15, 2022, 04:16:35 PM
On the rocker shaft springs. May be ok if you use hardened shim between the rockers so the spring doesn't wear into it. Spacers are better at high RPM for rocker alignment.

BlownMGB-V8

#72
December 15, 2022, 04:51:07 PM
The Isky 4005 might work but here's the question:
Since it is a dual spring will the inner spring be OK sitting on the step in the retainer and the seat? That size is .852", the outer spring ID is .925" and the inner spring ID is .690" which means there's .073" of slop and the inner is sitting on .062" of the pilot. A little less than ideal I'd say and it might dance around a little. What do you guys think?

Jim

MGBV8

#73
December 15, 2022, 05:10:15 PM
I have never run dual valve springs.

PAC racing springs catalog

https://www.racingsprings.com/media/wysiwyg/2020_Master_Catalog_FINAL_Web.pdf
Carl
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