Hot Rod Forum : Hotrodders Bulletin Board

Hot Rod Forum : Hotrodders Bulletin Board (http://www.hotrodders.com/forum/)
-   Engine (http://www.hotrodders.com/forum/engine/)
-   -   another vortec question (http://www.hotrodders.com/forum/another-vortec-question-226076.html)

oldworldnewtoys 11-14-2012 08:23 AM

another vortec question
 
hay guys im flip flopping on how i want to proceed with establishing proper installed spring height on my vortecs i all ready have a new set of valves with a height of 4.911 placing the spring installed height around 1.685 my new springs have a installed spec of 1.750 my question is do i get different valves as close to the right height (about +.050) as i can and cut the rest out of the seat (about .015) or do i get +.050 keepers and is that likely to cause problems with the roller tip rocker i have with the retainer and yes i know about the retainer to seal issue

thanks for the thoughts and wisdom you guys and this site are the best!!!!

ap72 11-14-2012 08:27 AM

go have your spring seats and guides cut down and run the parts you have. You can also switch to .530" seals which means you'll have a better selection.

engineczar 11-14-2012 09:14 AM

There are also several options depending on what type cam you're running. What style cam do you have? Solid, hyd, roller. What spring are you trying to squeeze in and how much seat pressure do you need? Also what are the actual measured spring pressures at the two different heights 1.75 and 1.685. Often the springs measure out different than what is advertised.

MouseFink 11-14-2012 09:36 AM

The V6/V8 Vortec heads have valve spring pockets that are thinner than older heads. I would avoid cutting those seats any amount and make up the difference with longer valves. Machine Vortec spring pocket depth at you own risk.

Your set up may vary but my 4.3L V6 engine as-built spec. would be a good guideline:

Used Manley 1.94" #11860-1 int. and 1.600" #11863-1 exh. valves x 4.951" long, 11/32" stems, with a .290" tip length for extra .020" clearance (total of .040") between the locks and the self-aligning roller rocker arm rails. Stock Vortec valves have .289" tips.

Used standard Comp Cam 613 locks on the exhaust valves and 614 + .050" locks on the intake valves.

Used Alex's Parts 1.255" OD x .875" ID shims to achieve 1.750" +/- .010" assembled height for 144 lb. seat pressure. Different shim stacks were required on the exh. and int. seats after eliminating the exhaust valve rotators.

Used a Comp Cams #4721 seat cutter to enlarge the spring pockets to 1.350" OD seat x 0.775" OD spring locator boss to fit 1.310" OD x .885" ID Comp Cams #26918 beehive valve springs.

Used Comp Cams #4726 guide cutter to cut intake and exhaust valve guide from .562" OD to .530" OD to fit Comp Cams 518 Viton .530" ID x .575" OD seals.

Reduced valve guide height by .200" with fitted .060" between the Viton seal and the lower spring locator boss. .

lmsport 11-14-2012 09:47 AM

Use the +.050 locks, UNLESS, you are using rail rockers.

ap72 11-14-2012 10:07 AM

Quote:

Originally Posted by MouseFink (Post 1611119)
The V6/V8 Vortec heads have valve spring pockets that are thinner than older heads. I would avoid cutting those seats any amount and make up the difference with longer valves. Machine Vortec spring pocket depth at you own risk.

Your set up may vary but my 4.3L V6 engine as-built spec. would be a good guideline:

Used Manley 1.94" #11860-1 int. and 1.600" #11863-1 exh. valves x 4.951" long, 11/32" stems, with a .290" tip length for extra .020" clearance (total of .040") between the locks and the self-aligning roller rocker arm rails. Stock Vortec valves have .289" tips.

Used standard Comp Cam 613 locks on the exhaust valves and 614 + .050" locks on the intake valves.

Used Alex's Parts 1.255" OD x .875" ID shims to achieve 1.750" +/- .010" assembled height for 144 lb. seat pressure. Different shim stacks were required on the exh. and int. seats after eliminating the exhaust valve rotators.

Used a Comp Cams #4721 seat cutter to enlarge the spring pockets to 1.350" OD seat x 0.775" OD spring locator boss to fit 1.310" OD x .885" ID Comp Cams #26918 beehive valve springs.

Used Comp Cams #4726 guide cutter to cut intake and exhaust valve guide from .562" OD to .530" OD to fit Comp Cams 518 Viton .530" ID x .575" OD seals.

Reduced valve guide height by .200" with fitted .060" between the Viton seal and the lower spring locator boss. .

I take it you get your valve train parts for free? Obviously cost isn't a concern.

hcompton 11-14-2012 11:32 AM

ok this is a question i get a lot but never have an answer cause i rarely use stock castings.

Can't vortech heads use beehive springs? I always see the cam mfg. suggest two types of springs and they always have there heavy dual springs listed first. But I have used beehive type springs and they work good for many applications.

Sorry not trying to hijack your post. I got a feeling beehives are your answer. It seems like they probably sell a set that are direct fit. but nto sure figured someone on here already has it figured out.

engineczar 11-14-2012 11:56 AM

Yes Vortecs can run Beehives and work well for higher rpm's if you need to run a single due to the lighter weight of the retainers as well as the reduced mass of the spring itself. Also the variable spring rate helps with harmonics.

The downfall is that they're roughly double the price of a comparable conventional spring, that along with the cost of the mating retainers.

MouseFink 11-14-2012 12:07 PM

Quote:

Originally Posted by hcompton (Post 1611162)
ok this is a question i get a lot but never have an answer cause i rarely use stock castings.

Can't vortech heads use beehive springs? I always see the cam mfg. suggest two types of springs and they always have there heavy dual springs listed first. But I have used beehive type springs and they work good for many applications.

Sorry not trying to hijack your post. I got a feeling beehives are your answer. It seems like they probably sell a set that are direct fit. but nto sure figured someone on here already has it figured out.

Beehive valve springs or dual standard valve springs will not fit a Vortec heads without machine work. The Vortec valve springs are 1.241" OD and the Vortec heads have spring pockets that are 1.248" OD with a inside spring locator boss that is .750" OD - .775" OD. Beehive valve springs are 1.310"" OD x .885" and require a pocket that is machined to 1.350" OD x .775" ID with the seat cutters that are available. Dual valve springs are at least 1.300" OD in order to accommodate the inner spring.

Most beehive valve spring failures can be traced back to the bottom coil because they were fitted on Vortec heads with re-sizing the spring pockets.

engineczar 11-14-2012 12:15 PM

CompCams 26981-16 will fit with no machine work.

MouseFink 11-14-2012 01:46 PM

Quote:

Originally Posted by engineczar (Post 1611190)
CompCams 26981-16 will fit with no machine work.

My error....those Comp Cams beehive valve springs fit will Vortec heads without machine work. They would be good to use with a milder camshaft with less than .460" valve lift.

The Comp Cams 26981 valve springs are the ones I used on my first set of 1993 L35 4.3L V6 heads two years ago. . My fresh heads are 1995 L35 heads and are being finished now have Comp Cams 26918 valve springs. I up graded to 344 lb. open pressure at .500" valve lift.

ap72 11-14-2012 03:31 PM

Quote:

Originally Posted by MouseFink (Post 1611188)
Beehive valve springs or dual standard valve springs will not fit a Vortec heads without machine work. The Vortec valve springs are 1.241" OD and the Vortec heads have spring pockets that are 1.248" OD with a inside spring locator boss that is .750" OD - .775" OD. Beehive valve springs are 1.310"" OD x .885" and require a pocket that is machined to 1.350" OD x .775" ID with the seat cutters that are available. Dual valve springs are at least 1.300" OD in order to accommodate the inner spring.

Most beehive valve spring failures can be traced back to the bottom coil because they were fitted on Vortec heads with re-sizing the spring pockets.

There are MANY different beehive springs out there, some will fit, some are too large in diameter for stock seats, and some require a different installed height. Like any other spring you need to check the info for each different part number.

oldworldnewtoys 11-14-2012 07:09 PM

Quote:

Originally Posted by engineczar (Post 1611111)
There are also several options depending on what type cam you're running. What style cam do you have? Solid, hyd, roller. What spring are you trying to squeeze in and how much seat pressure do you need? Also what are the actual measured spring pressures at the two different heights 1.75 and 1.685. Often the springs measure out different than what is advertised.

you guys might hate me but im building this block around this cam and on the cheep so my options are slightly limited. but im a machinist so free machining!!
I have a lunati 60103 flat hyd cam. add durr of 268/276. at .050" of 227/233 with a lift of .489" and .504". i recently got all my parts and there sitting in my closet lol. i have not checked the actual spring rate. i went with the spring they recommended for the cam. spring number 73943 they stopped making it after i ordered them. that kinda worried me. it has a closed pressure of 108# and an open height at 1.250" and 339#. coil bind at 1.060". inside dimensions (with wire damper) .765" and outside of 1.266"

cobalt327 11-14-2012 07:38 PM

Quote:

Originally Posted by engineczar (Post 1611190)
CompCams 26981-16 will fit with no machine work.

Sure will. There are other drop in springs for the Vortec heads that allow more lift w/o any machining needed, despite what you may read.

Two beehive springs from Comp are p/n 26915 and p/n 26918.

Another spring that works w/o machining and is recommended by GM is the Crane Cam p/n 10309-1 drop-in valve spring/retainer kit which is good for .550 lift (this allows about 0.025" between the retainer and seal).

More here.

hcompton 11-14-2012 07:45 PM

Free machining! Where do you live and can i buy you a beer.

Cam seems fine. Those are pretty heavy springs i wouldnt want to cut the head too much if its weak in that area for those springs.

Might be better to get the correct springs lunati can tell you if they have a set that will work on your heads. They usally will not recommend another compaines product but maybe they know a gm part number that will work.

If they stopped making them they may have been replaced with another part number sometimes compaines will free exchange if the part number is superseeded by another one. Might want to call just to see if they have a better option or found a defect in that design.


All times are GMT -6. The time now is 07:34 AM.

Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.