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tips, technology, tools and techniques related to vehicle driveline components

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BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6470 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Adjustable rockers for the late Rover (rollers?)
Posted by: BlownMGB-V8
Date: December 23, 2022 11:12AM

I've decided to resell these rockers on ebay and order the TA rockers and guide plates. The cost is $135 higher (plus I'll lose a bit on the resell) but the rocker angle should be correct (I will check), but the single most important consideration is that these rockers do not hit in the center of the valve tips. They are offest to the outside. Now this might not be a real problem with a standard setup but because I'm running titanium valves I'm installing lash caps and as a remnant of the old application the valve tips have a small groove around the tip which theoretically could allow the lash cap to cock a bit if the roller is far enough off center. I don't think it is that far off and it would probably work, but at high speed with that stuff all bouncing across hell's half acre who can say? So I'm going to do the safe thing. It's not a huge price to pay compared to the rest of the investment in this engine.

Now, with that problem solved, it's back to the original topic of this thread and the use of the Procomp rockers on the Rover heads. The shafts I have do have a little wear, about .0015" so I'll be breaking down the other rocker shafts I have on hand to see if there's anything better at hand. Then I can decide if new shafts are justified.

Next I will be checking the rocker arm angle to get some idea of how far it deviates from stock.

Then I'll look at setting up to bore the rockers. More on that later.

Jim


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6470 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Adjustable rockers for the late Rover (rollers?)
Posted by: BlownMGB-V8
Date: December 23, 2022 02:22PM

It's possible to use the Procomp rockers if certain concessions are made.

IMG_0031.JPG

The adjuster needs to be run out to about the limit of it's adjustability to match the rocker angle of the stock rocker.

IMG_0032.JPG

It will be using a plain bore bearing with the rocker body as the bearing material.

IMG_0034.JPG

And the biggest issue, the distance from the rocker shaft to the valve tip is a bit far. and puts the roller off center on the valve stem. Some of that can be corrected by moving the enlarged bore off center but it will still be past center. Maybe not enough to matter, I will probably go ahead and use them. But there may be better prospects out there.

IMG_0035.JPG

For me, this is a refresh on a good engine. It will get new bearings and a different set of heads with the piston dish deepened to match, but it isn't a fresh build. If it was I think I'd be looking for some rockers that were a better match.

Jim


mgb260
Jim Nichols
Sequim,WA
(2465 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: Adjustable rockers for the late Rover (rollers?)
Posted by: mgb260
Date: December 23, 2022 02:40PM

Jim, On the push rod cup you could use longer pushrods.


DiDueColpi
Fred Key
West coast - Canada
(1367 posts)

Registered:
05/14/2010 03:06AM

Main British Car:
I really thought that I'd be an action figure by now!

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Re: Adjustable rockers for the late Rover (rollers?)
Posted by: DiDueColpi
Date: December 23, 2022 02:44PM

The rover rockers are offset Jim. Can you accommodate that with some machining to the procomps?
Also moving the shaft bore around is going to change your ratio. It might be better to move the pedestals.



Edited 1 time(s). Last edit at 12/23/2022 02:49PM by DiDueColpi.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6470 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Adjustable rockers for the late Rover (rollers?)
Posted by: BlownMGB-V8
Date: December 23, 2022 04:18PM

Yeah, I don't think moving the pedestals is going to work. You're right, the ratio total lift will take a hit, I'm not too worried about that. The procomps are also offset but not the same. I hope I can get them to line up good enough though.

On pushrod length, that adjuster position was the point at which the pushrod angle was about the same, so a length measurement with it in that position should give the closest geometry to the stock rocker. In that location the adjuster does move a little below the trunion centerline so it also has a very slight negative affect on the ratio. But again I think I can live with that. I am not that married to the current lift figures.

Jim


gsjohnny
john gudaitis

(13 posts)

Registered:
06/07/2010 01:09PM

Main British Car:


Re: Adjustable rockers for the late Rover (rollers?)
Posted by: gsjohnny
Date: March 17, 2023 09:48PM

been a long time for me.
don't know how much difference between 350 and other sbb rockers.
but i run 1.65 rollers. with the 350 casting for lack of room, i didn't want a bigger cam, i wanted more rocker ratio.
i bought some stud roller1.6 and 1.7 sb fords. i took one apart and reamed the hole to 350 size, only issue
with the ford vs sbb is shaft c/line to valve roller. the fords are about .050 longer. i could move the hole over,
but the 1.7 ratio would diminish. don't know how much. but its all doable.
i bought some 1.7 shaft rollers. this would require a new shaft with different o.d. spacers. still working on how to make it work.
one other idea, which i have lots of 350 heads, is to adapt ford 390-428 shaft rockers and stands. i can machine the stands
to whatever dimension that will work with the fords. looked at them, just have to buy them.

btw, those who try other parts to work, how much junk have you made and keep? i know i have a bunch of scrap. lol


mgb260
Jim Nichols
Sequim,WA
(2465 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: Adjustable rockers for the late Rover (rollers?)
Posted by: mgb260
Date: March 17, 2023 09:57PM

Johny, Welcome aboard!



gsjohnny
john gudaitis

(13 posts)

Registered:
06/07/2010 01:09PM

Main British Car:


Re: Adjustable rockers for the late Rover (rollers?)
Posted by: gsjohnny
Date: March 18, 2023 12:36PM

being a scatter brain doesn't help. look for something, i end going all over the world. lol
the 350 whines for me. i may have to expand my r&d to the little engines. got 3 340's, have to find a 300.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6470 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Adjustable rockers for the late Rover (rollers?)
Posted by: BlownMGB-V8
Date: March 18, 2023 03:18PM

Only really two reasons to use a 300 over a 340. One is if you don't have room for the 340 (the MGB falls into this category) Two is if you want a better intake than the stock factory cast iron 340 4bbl intake and aren't willing to either use spacers on a 300 intake or to fabricate one. Other than that I don't really see an advantage and with the larger mains the 340 crank should be a little stronger. There is only 2lbs difference in the weight of the blocks. I modded an MGB to accept the 340 and fitting the 455 turned out to be almost exactly the same except for the exhaust. By contrast the (RB) MGB needs no body mods to fit the 300, making it the logical choice.

Jim


MGBV8
Carl Floyd
Kingsport, TN
(4517 posts)

Registered:
10/23/2007 11:32PM

Main British Car:
1979 MGB Buick 215

authors avatar
Re: Adjustable rockers for the late Rover (rollers?)
Posted by: MGBV8
Date: March 18, 2023 04:26PM

#3 If you want a smaller displacement V8. ;)


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6470 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: Adjustable rockers for the late Rover (rollers?)
Posted by: BlownMGB-V8
Date: March 18, 2023 05:16PM

So true.
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