Engine and Transmission Tech

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, 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.



Edited 1 time(s). Last edit at 12/15/2022 01:49PM by mgb260.

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.

I believe RV-911-16 is an Elgin spring. Maybe NLA.

This spring has same specs to what I ran with the 300 heads. My Crane springs are no longer available too. Jim B said 300 valves are 1/16" taller.

[www.ebay.com]



Edited 1 time(s). Last edit at 12/15/2022 02:33PM by mgb260.

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.

RV-943X is an Elgin spring.

Isky valve spring specs:

[iskycams.com]

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

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

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.

[www.taperformance.com]



Edited 1 time(s). Last edit at 12/15/2022 05:51PM by mgb260.

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.

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

I have never run dual valve springs.

PAC racing springs catalog

[www.racingsprings.com]

Dual springs use a special retainer like these:

[www.ebay.com]

Here are the stock retainers and seats:





Jim

These from Pac will work but, aren't +.050.

[www.summitracing.com]



Edited 2 time(s). Last edit at 12/17/2022 04:26PM by MGBV8.

Jim, are you talking about the PAC-1231X mod motor spring? I actually think that might work fine with the standard offset retainer. No room for a steel washer under the spring and it'd be .015" tighter but I think that works out OK. No issue with coil bind. It raised the spring load by about 4.4# on both ends to 124 and 284#. It sort of amazes me that they can do that with a 1.083" diameter spring.

Need to see what sort of prices I can find on that spring but this does sound like a possible solution. Also will have to get the price from TA for a V8 set of keepers (32ea.)

Jim

Jim, The stock springs didn't have a steel shim under them? The small diameter beehive would set on the step around the guide? TA also has +50 keepers. listed for the V6.

[www.taperformance.com]
You may want to call them to see if they will work with the Rover valves.



Edited 2 time(s). Last edit at 12/17/2022 10:53AM by mgb260.

The stock (post 1980) sintered retainers are known to break up with prolonged high RPM, with that in mind I wouldn’t want to be running high rpm with a higher spring load….
The pre 1980 retainers are machined and reputed to be almost indestructible. The comp retainers posted earlier are easily available, but are slightly heavier than the pre 1980 retainers.
This pic shows the very obvious visual machined appearance of the earlier retainers. Very obvious vs the smooth, rounded edge appearance of the sintered units.