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Discussion Starter · #1 ·
OK.
Basically, rotator eliminators maintain the original spring seat height when removing factory rotators for high spring pressures.

But.
What would it due to rocker geometry and stem contact sweep, if one was to just install a shorter valve when removing rotators to achieve proper spring installed height eliminating both the rotator and eliminator?
 

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First of all I am not sure if you could find a valve that short without it being custom. Then like you said your rocker geometry will be way off and would require a lot shorter pushrod. Then there is a good chance the pushrod would bottom out on the stud. Etc etc etc. Not worth the trouble. The eliminators are only $30 or so.
 

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Discussion Starter · #3 ·
Would like to go to 11/32 stems over 3/8 with close to the original 2.06/1.72 valve size in a set of Peanut ports for a torque engine to tow the Lemans with.

429/460 exhaust valves come 1.71 and 1.76 with an overall length of 5.042 where the BBC are 5.350
(Close without the .300 thick rotator eliminators)

Intakes are easy some 2.08/+.300 for a SBC.
 

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Would like to go to 11/32 stems over 3/8 with close to the original 2.06/1.72 valve size in a set of Peanut ports for a torque engine to tow the Lemans with.

429/460 exhaust valves come 1.71 and 1.76 with an overall length of 5.042 where the BBC are 5.350
(Close without the .300 thick rotator eliminators)

Intakes are easy some 2.08/+.300 for a SBC.
My 2nd set of peanut port heads had the 11/32" valves in them 2.19 and 1.88. The performance was fantastic with almost no compression.
 

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Would like to go to 11/32 stems over 3/8 with close to the original 2.06/1.72 valve size in a set of Peanut ports for a torque engine to tow the Lemans with.

429/460 exhaust valves come 1.71 and 1.76 with an overall length of 5.042 where the BBC are 5.350
(Close without the .300 thick rotator eliminators)

Intakes are easy some 2.08/+.300 for a SBC.
Whatever, but that seems like a lot of crazyness just to save on buying the eliminators. To be honest with you on a towing engine I would just leave the rotators on. Most of the lower hp Mercruiser engines have them on all 16 valves. They purr along just fine for 1000 hours or more. Not even sure why you would want to waste the money on 11/32 valves for an engine like that ???? It probably will never see 4000 rpm and spend 99% of its life below 2500.
 

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Discussion Starter · #7 ·
Whatever, but that seems like a lot of crazyness just to save on buying the eliminators. To be honest with you on a towing engine I would just leave the rotators on. Most of the lower hp Mercruiser engines have them on all 16 valves. They purr along just fine for 1000 hours or more. Not even sure why you would want to waste the money on 11/32 valves for an engine like that ???? It probably will never see 4000 rpm and spend 99% of its life below 2500.
Here we are yet again digressing and completely off the original topic.

But

I'm not trying to get out of buying eliminators, I'm trying to stay away from the machine shop.

I'll be buying valves no matter which way I go.
So, valves from the same manufacturer for example. (Rounding to an even 5 bucks)

2.06/1.72 w/3/8 stems $285 plus guide work cost and eliminators.

2.19/1.88 w/11/32 stems $315 plus seat cutting cost and eliminators.

OR

2.08/1.76 w/11/32 stems $325, no eliminators and doing all the machine work at home.
 

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I'm not trying to get out of buying eliminators, I'm trying to stay away from the machine shop.
I don't understand. The eliminators don't require any machine work.

2.08/1.76 w/11/32 stems $325, no eliminators and doing all the machine work at home.
Do you have the ability to put the 11/32 guides in at home and then do the valve job ? If so then I guess go for it.

Something you might want to keep in mind in your application is there might be an advantage to the 3/8" stem, especially on the exhaust. If you have ever been next to a big block Chevy in a truck while it is towing its not uncommon for the exhaust manifolds to be almost glowing from the heat. The 3/8 stems can dissipate more heat into the head casting.
 

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Discussion Starter · #10 ·
I don't understand. The eliminators don't require any machine work.



Do you have the ability to put the 11/32 guides in at home and then do the valve job ? If so then I guess go for it.

Something you might want to keep in mind in your application is there might be an advantage to the 3/8" stem, especially on the exhaust. If you have ever been next to a big block Chevy in a truck while it is towing its not uncommon for the exhaust manifolds to be almost glowing from the heat. The 3/8 stems can dissipate more heat into the head casting.
Yes, I set up to do SBC heads decades back when I raced them, long before swapping to a BBC platform and never got tooling for 3/8 guides.
Should probably buy a modern seat cutter and just go 2.19/1.88 with 11/32 guides.

Never seen any glowing exhaust manifolds before and not too worried about it, as it won't be a neutered 7.5-1 comp. dump truck/motorhome style engine build.
 
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