What are the better options out there? I searched a bunch old posts, most don't provide all the details. Before I start making phone calls and bugging people, I thought I'd ask here first. I'm seeing these as options: - TA Performance- Listed as 1.92"/1.55" and 3/8" stem. - Centerville Auto- someone said they were heavy, 140 g. Are these from TA? They are not even shown on their website. - SI Valves, stock-spec Portflow series. - SBC valves, such as the 1.94" Intakes and 1.6" Exhausts avail from several sources. These would need to be cut down to fit, somewhere around 1.92" and 1.55". Benefit would be they are avail with a slimmer 11/32" stem for better flow. I assume there are different valve head shapes as well... tulip vs flat, etc. Questions on the SBC valves: -These are longer than stock. 4.91" vs 4.785" for the stockers. Is the longer length (0.125") a concern? Or does one just use shorter pushrods for the difference? -Would my machine shop be the one cutting the valve head down to size, or can the valves be ordered cut to size? Costs for machining vs ordering custom valves is a concern! - There are lots of suppliers, ranging from Summit Racing brand to SI valves, Manley, Ferrea, etc. Ferrea 5000 series has been recommended. Which have a decent cost-performance ratio? - For a 11/32" stem, are the original guides reamed for a sleeve, or should one start with new replacement guides. I am concerned about the originals possibly not being concentric, but that may be a non-issue if larger valves are installed.... they'll get a new larger valve seat cut, too-deep original size seats won't be a concern. - I realize they'll need new retainers/keepers, and likely non-stock type valve springs. I read there is a beehive spring that can work well. The TA set is $300 but 3/8" stem. The Centervilles and SI Valves are also 3/8" stem, and probably stock size, and maybe heavy. Do modified SBC valves add a lot to the cost? I do see a performance advantage. This is a build for the 4 speed car I've been doing a frame-off resto on. 3.36 gears. Just building a nice street performance car. Heads are getting a home porting job, Tom's roller rockers will go on, and will get a cam somewhere in the TA-25 range of 218/228-110. I'm not looking to spend a fortune for a race build, just good performance for the cost.
to answer your easy question comp 26915 springs and 795 retainers. i would go with 1.94-1.50 valves for most power and no cutting. On first custom valves and head porting koffel's place did them. we used Manley custom valves 1.94-1.50 and 4.850 length. on 2 other sets of heads gs Bob ported and then set them to Terry's machine shop in Bridgeton,Mo. he used over the counter chevy valves and the same 26915 beehive springs he will give you some good information. for a lot less cost the stock valves with the tulip intake from Carmen or Tom might have them too are lighter then 140 grams and a stage 1 or stage 2 valve spring depending on what cam your using will work fine and now you can use the stock light weight rocker arms.
Tulip valves bring nothing to the table with these heads, in fact they bring less flow then stock to the table! Flow benches lie to you many times, and this tulip valve thing with these heads that have minimal short turn height is one of these times. Flow benches test at a steady lift point and this way of testing does not, and can not replicate the dynamic conditions of a running motor. All the tulip back side of a valve used in these heads does is actually to choke off the flow for a longer time once rpm's climb above 2000 to 2500 depending on the cid of the nail heads. Also in terms of a tulip Intake valve that gentle back angle does not help at all to shread up wet flow of fuel back into a more atomized and in turn better and more complete burnable state. Since your going for new valves anyway if you have the needed funds I would have new guides installed so you can take the flow advantage of 11/32" stem valves, and not to mention the weight savings and longer lived valvetrain parts. 99% of new valves have a .100" 45 degree seat width area. Interms of the Intake valve a 30 degree back cut should be applied so that the .100" wide seat is now down to .050" for a street motor. The Exh valve should be done in the same manor, but a .065"wide area should be left. The 3 angle valve job should be done to complement what's done on the valves. The Exh side on these heads flow miserable so I would go with 1.60" Exh valves and then Chevy 2.02" valves that you have cut down to 1.96, and then have a 30 degree back cut done to them as posted above.
i did go from the 140 gram to the tulip for weight savings on the flow bench there was no change in flow but like you said maybe in the real world that might hurt flow.the other thing to consider is on the tulip valve you will lose 4 cc of chamber volume which could be good or bad. with a 1.94 intake the biggest exhaust valve that would work was a 1.50 a 1.55 would not work with out running into problems in the long run.not sure how you can fit 1.96-1.60. you will always gain more hp on the intake side increasing flow then increasing flow the same amount on the exhaust side.
As any NA motor gets below a 10 to 1 compression the motor will need all the low lift Exh flow you can help it attain. A means to that end besides having a back cut on the valve is to increase the curtain area and that means using a bigger valve if you can. This then allows a Cam with a tad less overlap to be used which then helps to keep the cylinder pressure up .
Anyone know if Tom/Carmen have oversize valve sets that are ready to install? Preferably with 11/32" stems. Longer stems seem like they would upset the stock geometry? or will the 0.125" longer length work without issues? Steve, about what would shop costs be to have a set of SBC valves cut down to size? I would prefer a slightly oversized exhaust valve since that would raise the seat to at least new spec.
I just checked, weight of stock valves is 118g for the intake and 98g for the exhaust. With some of the stock style replacement valves reported to be 140g, that's sure a step in the wrong direction.
the 140 gram valves were from centerville auto. invoice back in 2017 for chevy valves and machine work.
When Tommy did my heads he used Chevrolet valves but he had to find ones with stem hardening of (?) .050 cause they had to be cut down quite a bit for correct installed height. i'm sure he'll chime in here. I want to say I wound up with 1.92/1.52 valves, but the exhaust may still be 1.50...
Most have hardened tips .030"-.040" deep. The ones I used were hardened .150" deep so there was enough to remove & still be hardened. You MUST remember that heat generated by cutting can damage the hardness so it's slow & easy as you DON'T want to overheat the tips. IF I remember correctly the intakes were 1.900" & the exhaust ended up at 1.52"??? Tom T.
Correct, and thanks. Had to look it up. What I dont have written down is whether we went 11/32ns (I dont think so) and what we used for springs/locks/retainers.
Thanks everybody! I figured this would be complicated (and expensive). What is recommended? I'm thinking the TA valves might be ok for the price, unless they're as heavy as the Centervilles.
So what is the factory length of a stock nailhead valve? And installed height too if someone has it handy?
The valves were 11/32nds. diameter stems. I honestly don't remember the springs/retainers/locks I used, BUT they were all readily available Chevy stuff at the time. I'm sure more are available today. These valves give you a Pandora's box of options as far as pressures, diameters, standard locks, plus or minus.050" to adjust valve heights , etc. It takes time & LOTS of research to end up with what's right for you or your combo. It can boggle your mind with ALL the combos available. You MUST write down each & very step along the way as you can easily get lost very quickly. I've got notes written down SOMEWHERE??? BUT who knows where as it's so been so long. For what I was doing at the time I would remove anywhere from .030"-.050" & as much as .080"-.090" from the tips. It all depended on what combo I was looking for or trying to achieve. Everyone is concerned with valve weight. It's not as important now because we have options available via different springs. AND, another wrong move is replacing valve guides. We now lose the original centering & have to grind the seats excessively to end up with a centered seat which takes MOST important material from the seat area. Today we have more options available as far as guides go AND they are NOT bronze/brass liners. Today cast replacement liners are more readily available than in the past. I could write for days & not cover it all. START doing your own research. What one guy does for his combo will not be EXACTLY what the next guy wants to do & it CAN START to get costly when you start "experimenting". Shop wisely. Mike Lewis in Ca. might be costly BUT he & I have done the research & worked together for about 20 yrs. now. Tom T.
So I pretty much decided to go with the TA 3/8" stem stainless valves since they are a drop-in replacement that won't require extra $$ to make them fit. Figured I'd use some beehive springs and retainers to finish it up. Then I discovered (yesterday) Buick valves use a unique 11* valve keeper/lock, unlike the 7* or 10* that is used with beehive retainers. Soooo.... do I now have to go back to using dual valve springs to go with the available 11* keepers/retainers? Or are there better options? I've read of someone having retainers machined for the 11* retainers, but again, I don't want to spend extra $$ for the machine work. I'm now finishing up the porting work so I can finalize the chamber volume specs to finally order the pistons I reserved from Tom in 2015?? I've been working on this car on/off for almost 20 years, trying to finish it up before I die!
I would just go with the TA stage 1 springs maybe even a .030 shim. plenty of pressure with the slow ramp TA cam your going to use. not much to be gained with beehive springs. why not a tight lash solid lifter cam your going be running Tom's adjustable rocker arms.
I could go with solid. Looking at Comp Cams Xtreme Energy series. Maybe go with a 218/224 duration for this 4 speed car, 3.36 rear, stock exhaust manifolds. A bit extra duration would be nice tho. And the 224/230 to replace the Isky 244/244 in my blue car, 425, 3.42 rear, headers and 2x4. Probably reduce the lobe separation from 110 to 109 deg. Would these need the TA stage 2 springs for the faster ramp profiles? Stage 1 is 90/230# Stage 2 is 105/275# I have to stop (over) thinking this and just do it.
wasn't trying to talk you out of the TA 218-228 hyd it's on a 110 lsa which is good. just throw the solid out there because you already have the adj rockers. i was trying to talk you out of the beehive springs just to keep things simple. not much if any to gain on the beehive's for what your doing.
I got the TA stainless valves, they look pretty good. Intakes are 1.915" (0.040" oversize) and exhausts are 1.55" (0.050" oversize). Intakes are a bit lighter than stock, 117.1g vs 118.8g. Exhausts are a bit heavier, 101.8g vs 97.7g. They have a nice undercut stem under the head. The dish in the valve faces, Int + Ex, total about 1.6 cc. The stock intake is about 4.5 cc, so they'll raise the compression a bit. One issue is the clearance between the valve faces in the chamber, it varies from 0.020" to 0.010". I read on SpeedTalk that 0.020" is generally recommended. Wondering if I'll need to have the shop turn the valve heads down a bit for more clearance? I did install new SBI valve guides. The SBI valve seals didn't fit in the inner springs, so I bought some 'triple spring' seals from Comp, #521-16. But they are a loose fit on the SBI guides..... guides are 0.4955" and ID of seals is a bit more, but under 0.5". So I'm going to glue, shim, or crimp the Comp seals to the guides for a secure fit. Or buy new guides and have them machined to 0.50. Unless there are other seals out there for 3/8" stems and 0.4955 guides?? What a pita. I asked about the above issues on the Nailhead FB page and Matt is being Matt..... giving me a hard time about not buying parts from him. Centerville does have several different SS valve sets, standard, HP1, and HP2. Says one of them is the same as TA's. I went with Isky Valve springs, #1005W and #1006W. Specs put them between the TA Stg2 and Stg3. 135# @ 1.600" 290# @ 1.100" TA Stg2 are: 105# 275# TA Stg3 are: 140# 300# My cams from Comp arrived a few days ago. Took about 6-7 weeks. I'll do a mock-up soon to see what length pushrods will be best. I also need to determine if my blue car has enough retainer-guide clearance for the Comp cam. I do have some adjustable 1.5 rockers if it comes down to that. I'll take some pics to post before too long...
