Slant Six Forum :: Valve spring question

A little late to the thread....

The peanut plug heads have pretty good meat in the bowl and valve seat areas, I have had exhaust seats put in 3 heads from 1976-1979, they have never had problems even at high rpm, and with leanouts during road tunings...I think it mostly has to do with the Pre-1972 drool tube heads and the casting shifts over the 12 years of head castings.... the argument against is drool tube heads weigh less and have more spark plug options...

I have run both types of engine builder valve springs the "340" dual dampers (works great on a .55 lift cam, as long as the machinist cuts down the valve inserts so they don't get hammered out...), the "318" single springs work very well on cams up to the .48 lift Erson 280 cam lobes...

I have not had a problem with the engnbldr valves, although I know one west coast driver that lost the head off one during a run and it was a mess.

more fuel to the fire....

Author:	ProCycle [ Thu Nov 05, 2015 8:16 pm ]
Post subject:
Remove the offending valves and have them tipped. I don't know if you can get a whole 0.030" off but they certainly could be made closer to the others.

Author:	DusterIdiot [ Thu Nov 05, 2015 8:35 pm ]
Post subject:	My 2 cents...
A little late to the thread.... The peanut plug heads have pretty good meat in the bowl and valve seat areas, I have had exhaust seats put in 3 heads from 1976-1979, they have never had problems even at high rpm, and with leanouts during road tunings...I think it mostly has to do with the Pre-1972 drool tube heads and the casting shifts over the 12 years of head castings.... the argument against is drool tube heads weigh less and have more spark plug options... I have run both types of engine builder valve springs the "340" dual dampers (works great on a .55 lift cam, as long as the machinist cuts down the valve inserts so they don't get hammered out...), the "318" single springs work very well on cams up to the .48 lift Erson 280 cam lobes... I have not had a problem with the engnbldr valves, although I know one west coast driver that lost the head off one during a run and it was a mess. more fuel to the fire....

Author:	spacecommander [ Thu Nov 05, 2015 9:10 pm ]
Post subject:	Re: My 2 cents...
Quote: A little late to the thread.... The peanut plug heads have pretty good meat in the bowl and valve seat areas, I have had exhaust seats put in 3 heads from 1976-1979, they have never had problems even at high rpm, and with leanouts during road tunings...I think it mostly has to do with the Pre-1972 drool tube heads and the casting shifts over the 12 years of head castings.... the argument against is drool tube heads weigh less and have more spark plug options... I have run both types of engine builder valve springs the "340" dual dampers (works great on a .55 lift cam, as long as the machinist cuts down the valve inserts so they don't get hammered out...), the "318" single springs work very well on cams up to the .48 lift Erson 280 cam lobes... I have not had a problem with the engnbldr valves, although I know one west coast driver that lost the head off one during a run and it was a mess. more fuel to the fire.... Drool tube head. The 340 spring/damper is on the head now, think I'll revert to a new set of standard springs for now with the hydraulic cam until the cam gets swapped out for a new one (mechanical). Awwww CARP. Now another question - I have to drill out the head to accept the deeper hydraulic rocker arm bolt. Will I be able to change back to a mechanical rocker arm assy when I eventually install the mechanical cam?

Author:	Reed [ Thu Nov 05, 2015 9:51 pm ]
Post subject:	Re: My 2 cents...
Quote: Now another question - I have to drill out the head to accept the deeper hydraulic rocker arm bolt. No, you won't. You use the rearmost rocker arm bolt that matches the head. If you are installing a hydraulic camshaft and valve train system on a pre-77 (ish) head, you will need to drill out the bottom of the rearmost hole in the rocker arm SHAFT. If you do that, you will be fine. You can swap back to the mechanical assembly whenever you want. If you are running a drool tube head, you run the rearmost rocker arm shaft bolt for the drool tube head.

Author:	Joshie225 [ Fri Nov 06, 2015 7:31 am ]
Post subject:
Regarding lifter preload. http://slantsix.org/forum/viewtopic.php ... vel#302032

Slant Six Forum https://slantsix.org/forum/

Valve spring question https://slantsix.org/forum/viewtopic.php?t=58649	Page 3 of 3

Author:	spacecommander [ Fri Nov 06, 2015 7:50 am ]
Post subject:
Quote: Regarding lifter preload. http://slantsix.org/forum/viewtopic.php ... vel#302032 Thanks. I doubt much material can be removed at all from the valve stems. Won't have the head redone as sinking the other 10 seats 0.030" isn't the way to go. Presuming I can shorten those 2 pushrods the required distance of the head cut plus ~.020. This whole thing is starting to look like a science project. Would love to figure out some way of making the mechanical rocker arm assy usable with the hydraulic lifters & cam so the valvetrain would be adjustable. Wondering that if at this point it would be cheaper to install the dang mechanical cam. This "simple" project is turning in to a mess - the previous slants I worked on 20 years ago luckily had mechanical cams so shaving the head went virtually unnoticed other than backing out the rocker arm adjusters upon installation then re-adjusting.

Author:	sandy in BC [ Fri Nov 06, 2015 8:11 am ]
Post subject:
Smith Bros Pushrods They are incredible to work with. I takes a little science but I think you already know what you need.

Author:	slantzilla [ Fri Nov 06, 2015 8:46 am ]
Post subject:
Mock it up as is and see where you are. You may not be in bad shape at all. 2 long valves is not nearly as bad as a couple way short. 340 springs wouldn't scare me at all either. They are not any kind of monster spring pressure.

Author:	spacecommander [ Fri Nov 06, 2015 11:43 am ]
Post subject:
Quote: Mock it up as is and see where you are. You may not be in bad shape at all. 2 long valves is not nearly as bad as a couple way short. 340 springs wouldn't scare me at all either. They are not any kind of monster spring pressure. Should be ok with hydraulic lifters and won't bleed them out at idle or such?

Author:	SirSlaughter357 [ Tue Dec 22, 2015 12:31 pm ]
Post subject:
when yall say 318 and 340 what are those numbers in measurement of? is that the spring rate in lbs per sqaure in?

Author:	sandy in BC [ Tue Dec 22, 2015 12:44 pm ]
Post subject:
Its the size of the motor the springs originally came on. The 340 was a higher performance build and has larger valves,,,bigger cam ....and stronger springs.

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