Well after a 10 hour shift in the O.R.....sometimes you have to rely on a calculator to think for you
-Jonathan
-Jonathan
GB feeler -- 7M Cams (new not regrinds)!
- Thread starter ma71supraturbo
- Start date
drjonez said:
Thanks Adam -- you've got PM
I just didn't want to quote stuff I didn't know would work. The 4AG valvesprings are the ones I usually sell to people now (as the TRD part numbers for singles were identical to the 7m), but they are still far more than the comp cams...
If anyone has any creative solutions to the shim issue -- I'm open to suggestion
You guys with street cars will want to stick to cams that will fit without machining the head or converting to shim under or shimless buckets. Anything over about 270 duration or 9.5mm of lift is going to kill driveability, vacuum for the brakes etc...
Jeff and I have talked about this for a sometime. If you dont plan reving past redline then something a tad better then stock will do. Just so you wont float any valves and such.
well, im using the comp cams valve springs, 1mm os ss valves, titanium retainers, and the cam grind i listed earlier, id be really nice to get them on new billets as the head i have is perfect, no scoring at all in the cam saddles. plus if i get regrinds id have to find custom shims to fit under the buckets to take up for the reduction in base circle. and the packs of 12 of the comp cams is cheap. like $32 per 12 pack so ~$70 shipped for the set. also i got lucky and got my titanium retainers off ebay brand new in the package for $255 shipped. hehehe. deals are out there, just gotta look.
Adjuster
Supramania Contributor
Not to go OT, but the Comp Cams springs work great. (I have them in my engine now.)
To adjust the valves, here is what the shop I used does. (They do this on all the head/valve jobs they do, and they do many heads a week.)
They have a grinder that removes very small amounts of material from the stem of the valve. (Effectively making it shorter.)
They measure the valve lash, and move the shims around to get it as close to spec as possible.
If a shim is too thick, and they can't use it anywhere else, they grind down the valve stem so it's the right thickness.....
So, the easy way to resolve the whole shimless bucket deal is to do the following. Buy the thickest shims Toyota sells. Then let the end user have the machine shop do the valve job, and make the specs right on each one by grinding down the valve stems to get the correct lash amount. Worked on my head, and the many others they do where shims are used to adjust valve lash. (These guys mainly do import engines, so they deal with this quite a bit.)
One other option that I don't think anyone is using, but we need to get someone to try out.
Useing stock 2JZGTE valves in a 7M head. I know they are longer. That's the benefit.
Have the stock cams re-ground to a new base circle that removes the extra height of the 2JZ valves. Keep all you can on the cam lobes, and you could pick up a few thousands on the thicker shimless buckets too. (Using the thickest Echo buckets for example.)
The net result would be a higher lift, longer duration cam out of stock used blanks, not much money spent on this for the gains you would have. Also your going to get better flow from the larger valves, and Manley sells 2JZ valves pretty cheap right now if you want new ones.
Perfect budget combo:
Manley 2JZ valves.
Comp Cams BBC inner springs.
Thickest shimless buckets from the Echo.
Re-ground stock cams to a smaller base circle with a higher effective lift and duration as a result.
Just a thought.
The same would hold true for the other option, new cams from new blanks, wtih radical lifts and specs. Just would cost you more for the blanks and machine work to get everything right. (Cutting the CPS and such is not needed when your using existing cams.)
Sorry for the long post, but I think these are good ideas, and nobody else is doing it.
To adjust the valves, here is what the shop I used does. (They do this on all the head/valve jobs they do, and they do many heads a week.)
They have a grinder that removes very small amounts of material from the stem of the valve. (Effectively making it shorter.)
They measure the valve lash, and move the shims around to get it as close to spec as possible.
If a shim is too thick, and they can't use it anywhere else, they grind down the valve stem so it's the right thickness.....
So, the easy way to resolve the whole shimless bucket deal is to do the following. Buy the thickest shims Toyota sells. Then let the end user have the machine shop do the valve job, and make the specs right on each one by grinding down the valve stems to get the correct lash amount. Worked on my head, and the many others they do where shims are used to adjust valve lash. (These guys mainly do import engines, so they deal with this quite a bit.)
One other option that I don't think anyone is using, but we need to get someone to try out.
Useing stock 2JZGTE valves in a 7M head. I know they are longer. That's the benefit.
Have the stock cams re-ground to a new base circle that removes the extra height of the 2JZ valves. Keep all you can on the cam lobes, and you could pick up a few thousands on the thicker shimless buckets too. (Using the thickest Echo buckets for example.)
The net result would be a higher lift, longer duration cam out of stock used blanks, not much money spent on this for the gains you would have. Also your going to get better flow from the larger valves, and Manley sells 2JZ valves pretty cheap right now if you want new ones.
Perfect budget combo:
Manley 2JZ valves.
Comp Cams BBC inner springs.
Thickest shimless buckets from the Echo.
Re-ground stock cams to a smaller base circle with a higher effective lift and duration as a result.
Just a thought.
The same would hold true for the other option, new cams from new blanks, wtih radical lifts and specs. Just would cost you more for the blanks and machine work to get everything right. (Cutting the CPS and such is not needed when your using existing cams.)
Sorry for the long post, but I think these are good ideas, and nobody else is doing it.
Using the thickest available shims is counter to having good valvetrain performance. The same applies to lash caps and other methods used to take up the excess lash from regrinds. Lighter = better.
Adjuster
Supramania Contributor
Ok, so get the thinnest ones you can, grind the cams for the difference of the shims and the longer 2jz valve stems, and go from there. (And hope that you don't need to add anything to get proper lash adjustment, or your screwed at that point.)
Heh, you missed my point Adjuster! I meant that is a big reason why new cams are better than regrinds. They maintain the appropriate base circle hence no added valvetrain weight over factory installed cams...
I'm definetly interested in a mild set of 7M cams, all I have is a little Gt35R. I don't really want to spend 600-800+ just for shimless buckets for a radical grind. Same goes for the 1200+ rpm idle. Thats why I didn't buy the last 2 set of Group A cams for sale recently. BTW is everyone that wants a radical set of cams on aftermarket EFI? I didn't think there were that many out there. I don't really see any way to keep the idle up high to prevent stalling on the later 7Ms.
Adjuster
Supramania Contributor
Ok, unless I'm missing something, let's go over this again.
The 2JZ valves are longer than the 7M ones. (Same stem diameter, and the stock valves are 1.5mm larger in diameter, so an upgrade for the 7m using stock 2JZ ones.)
The Comp cams springs will work with either valve as the difference is pretty minor as far as the spring is concerned.
Stock 7M retainers and locks work fine with the 2JZ stem size. (As far as I know.)
So, the only difference is the larger diameter, and longer stem.
You can do one of two things to resolve the stem. Cut them down to 7M size, which is a pity since we are looking for ways to increase lift and duration on the 7M cams,,,,
Or, reduce the base circle of the STOCK 7M cams, and leave as much of the lobe height and duration as you want. (Also leaving the important hardened steel on those lobe alone and grinding off the less important base circle where wear is generally never a problem.)
A mild grind like this would retain the stock buckets and shims, a good thing for street motors since the shims turn when the engine is running, spreading out any wear across the entire shim. (They rotate some with every cam lobe passage from what I can see.) I would imagine that shimless buckets would also rotate, but they have more drag taking the skirts into account, so you have more chance of getting one stuck, and creating a wear issue down the road. (Just a possibility.)
For 99% of us, the extra lift from the difference between the 7M and 2JZ valve stems would add some measurable power gains, and be a modification that is easy to afford.
If someone wants to make new cams that take advantage of this, or if there are other valves out there with 6mm stems and the right size valve diameters, you can even pick up more lift/duration by further reducing the base circle. (At least down to the point where we need taller springs, but then you come into a spring coil bind issue, and other problems like having the shims spit out by the lobe side forces. (Not likely using the 7M/2JZ height difference.)
Discuss. I know that Defiant was having this looked into, but I've never seen what came of it.
Perfection would be valves with 1.5mm longer stems, and stock cams re-ground to new specs with the base circle reduced by the 1.5mm, and corresponding added 1.5mm of lift and longer duration as well.
The 2JZ valves are longer than the 7M ones. (Same stem diameter, and the stock valves are 1.5mm larger in diameter, so an upgrade for the 7m using stock 2JZ ones.)
The Comp cams springs will work with either valve as the difference is pretty minor as far as the spring is concerned.
Stock 7M retainers and locks work fine with the 2JZ stem size. (As far as I know.)
So, the only difference is the larger diameter, and longer stem.
You can do one of two things to resolve the stem. Cut them down to 7M size, which is a pity since we are looking for ways to increase lift and duration on the 7M cams,,,,
Or, reduce the base circle of the STOCK 7M cams, and leave as much of the lobe height and duration as you want. (Also leaving the important hardened steel on those lobe alone and grinding off the less important base circle where wear is generally never a problem.)
A mild grind like this would retain the stock buckets and shims, a good thing for street motors since the shims turn when the engine is running, spreading out any wear across the entire shim. (They rotate some with every cam lobe passage from what I can see.) I would imagine that shimless buckets would also rotate, but they have more drag taking the skirts into account, so you have more chance of getting one stuck, and creating a wear issue down the road. (Just a possibility.)
For 99% of us, the extra lift from the difference between the 7M and 2JZ valve stems would add some measurable power gains, and be a modification that is easy to afford.
If someone wants to make new cams that take advantage of this, or if there are other valves out there with 6mm stems and the right size valve diameters, you can even pick up more lift/duration by further reducing the base circle. (At least down to the point where we need taller springs, but then you come into a spring coil bind issue, and other problems like having the shims spit out by the lobe side forces. (Not likely using the 7M/2JZ height difference.)
Discuss. I know that Defiant was having this looked into, but I've never seen what came of it.
Perfection would be valves with 1.5mm longer stems, and stock cams re-ground to new specs with the base circle reduced by the 1.5mm, and corresponding added 1.5mm of lift and longer duration as well.
Since I've left HPF, I passed on all the information to Ron. You can reach him on AIM at HPFronW or by calling (866) 473-5600 x 103 Things are progressing, and I think he'll have an update within a few weeks for everyone
Adjuster said:
Agreed, mostly. Installed height is a critical factor in having proper valve spring seat pressure. This should be checked and shimmed if nessicary.
Longer valves are heavier. This will require a heavier spring to maintain proper valve operation over a stock height valve for any given RPM range. If you maintain the correct base circle on the camshaft (by using a new one), you don't need to build a tower of sprung weight up to reach the now miniature base circle. This will allow for lighter valvesprings and less frictional loss, wear etc...
Shimless buckets do not have wear issues. They are in service in many newer model Toyotas. The only drawback to shimless buckets is that the camshaft(s) must be removed to adjust valve lash.
You lost me here. Extra lift from taller valves? How does that work?
You can only reduce the base circle so much. It can't get any smaller than the O.D. of the cam casting. I have a set of mild regrinds sitting here and the base circle is just slightly larger than the casting. There isn't any room for more grinding down. That is why all regrinds that do not include welding of new material (whole new set of problems there) have very mild lift.
Longer valves and ground down cams are both going in the wrong direction as far as valvetrain performance is concerned.
Adjuster
Supramania Contributor
Unless I have this wrong, and it's possible, the stock 7M valves are shorter in stem length than the stock 2JZ valves. They are also 1.5mm smaller in dimeter at the face, but have the same stem diameter.
When installed with stock 7M retainers and locks, the 2JZ valves would be too "tall" so you would need very thin shims to make them work.
My idea is to use the thickest shims you can get, the BBC inner valve springs which are taller than the 7M stockers anyway, but actually have a better compression distance before coil bind occurs.
The extra "Height" of the valves installed in the 7M head could be used to re-profile and reduce the base circle of the cams by that amount. (So, your stock cams are left alone at the tall part of the lobes, but the base circle is reduced so you are close or dead on clearance wise with the thicker shims, and longer valve stems.
The effect would be that the lobes would then open the valves longer, and with more lift than stock, yet retain the stock hard faced lobes etc.
I don't have the figures here, but using the thickest JDM shimless buckets in conjuction with the longer valve stems would allow for some very nice base circle reduction, and a mild cam with higher lift and some longer duration that requires no other machine work to the head for it to work right. (Well, the valve seats would need to be re-cut, and then blended to take advantage of the 1.5mm size increase, but the flow from the added lift would contribute as much or more I'd think than the larger valves. (Flow data supports that our heads would flow much more with more lift v/s the stock setup.)
When installed with stock 7M retainers and locks, the 2JZ valves would be too "tall" so you would need very thin shims to make them work.
My idea is to use the thickest shims you can get, the BBC inner valve springs which are taller than the 7M stockers anyway, but actually have a better compression distance before coil bind occurs.
The extra "Height" of the valves installed in the 7M head could be used to re-profile and reduce the base circle of the cams by that amount. (So, your stock cams are left alone at the tall part of the lobes, but the base circle is reduced so you are close or dead on clearance wise with the thicker shims, and longer valve stems.
The effect would be that the lobes would then open the valves longer, and with more lift than stock, yet retain the stock hard faced lobes etc.
I don't have the figures here, but using the thickest JDM shimless buckets in conjuction with the longer valve stems would allow for some very nice base circle reduction, and a mild cam with higher lift and some longer duration that requires no other machine work to the head for it to work right. (Well, the valve seats would need to be re-cut, and then blended to take advantage of the 1.5mm size increase, but the flow from the added lift would contribute as much or more I'd think than the larger valves. (Flow data supports that our heads would flow much more with more lift v/s the stock setup.)
