I've never had an issue with oil feed holes of any kind unless the motor in question was extremely sludged up.
Since 1998 I have worked on, owned and parted at least 100 F2/F2T's 1988-1992 I have scrapped thick sludge out of oil pans, run 20/50 motor oil and w70 lucas motor oil but I have never seen a blocked rocker
Based on the fact that liquids dont compress and there is a one way check ball held by a spring I think it's safe to assume to that hlas dont compress under load in good running condition. If that is true though the only way for them to collapse would be if they had an internal leak between the plunger and body or weak spring pressure on checkball causing leak down. Small leaks may not be noticed while driving due to oil flow/pressure and the fact that on following the cam while the valve is closing there is less pressure on the "plunger" causing less seating pressure of check ball allowing oil to potentially enter the hla to keep contact with cam on next revolution. A small leak could cause the tick on start up people always hear as well for the first few minutes. I dont know if the squirters only work when that valve on that rocker is pushed or if they consistently squirt at all times. I've never watched it but I know it happens. If they only squirt upon valve movement it would suggest there is some compression of the hla helping with this. But seeing as there is nothing in the reservoir of the rocker besides an hla, a feed hole, and a squirter/lube hole I'll make another assumption and say they squirt all the time and hlas dont compress unless they need replacement. That's also how you check for a bad hla, does it compress by hand or not? Please correct me if I'm wrong on anything as I've been outta the f2t game for awhile.
Not exactly, you check the HLA's by hand for a gap between it and the rocker, if there is free play the HLA has failed. This could be a wording thing, I was using collapse as move, they do move, whack a rocker and you will see the hla springs in a bit and comes back, If they didn't move and the check valve and spring locks them in place then why did mazda use hydraulic lash adjusters in the first place. A simple test would be to take 4 or 12 HLA's and just weld the HLA in the opened position and run the 4 exhaust "Sla's" or all 12 and see how the engine runs.
The rockers only squirt oil when they engage the valve, 1 exhaust,2 intake and so on, I think it has to do with the holes in the rocker arms and rockers lining up.
Hlas are cheap to buy, easy to replace, and easily recharged in a cup of oil with out running them in a separate motor to charge them and swap them back, that would be waste of time and energy.
This is all true except this applies to a factory F2 head, once you "recharge" them in a cup of oil and reinstall them in a single valve spring head they will tap for a minute or two until they actually recharge. With a dual valve spring head they will never stop tapping thus never recharge.
Dual valve springs while never necessary per say do have there place and I think will benefit this motor at higher rpms, boost, hp figures. Could be a double edged sword though. Shims can help for less money but the stock springs in my opinion are junk. Even just the outers of the duals are way stronger and I can see just those being an upgrade over stock. Has anyone ran just the outer springs of the duals? I will run my duals and If I dont like how they are performing they are easily taken out with head on the car before real tuning begins. No big deal.
What RPM's are you aiming for?
What do you base your opinion of the stock spring on? (i'm guessing a cloud formation or star cluster).
The outers are not stronger in this thread I compare specs of B2200 8v springs to those of F2 12v springs. https://www.mx6.com/forums/1g-mx6-ot...-required.html (Dual valve spring technical help required)
Keep in mind this is info for the F2/F2T intake valve spring the exhaust valve spring is slightly longer and stiffer.
"F2/F2T intake valve spring info (for sealed power springs on rock auto) :
Max Outside Diameter 1.31
Wire Diameter 0.17
Total Coils 7.1
Closed Height 1.57
Closed Pressure (Lbs) 58
Open Height 1.17
Open Pressure (Lbs) 157
The 1992 mx6/626 Factory workshop manual states:
Standard valve spring free length IN- 1.949" EX- 1.984"
Standard setting load/height IN- 45.5-51.5lbs / 1.614" EX- 53.9-60.9lbs / 1.614"
B2200 (1991) Sealed power valve springs (intake/exhaust not mentioned):
Max Outside Diameter 1.417
Wire Diameter 0.156
Total Coils 7.2
Solid Height 1.048
Closed Height 1.45
Closed Pressure (Lbs) 59
Open Height 1.2
Open Pressure (Lbs) 96
Max Outside Diameter 0.97
Wire Diameter 0.125
Total Coils 8
Solid Height 1.06
Closed Height 1.35
Closed Pressure (Lbs) 35
Open Height 1.1
Open Pressure (Lbs) 59
The solid height would be the spring compressed to it's maximum
Closed height would be on the head with the valve closed (seat pressure)
open height would be with the valve fully opened
How thick are the upper b2200 valve spring seats, the ones that go on top and the keepers sit in.
I find the open closed height of the mx6 spring versus the b2200 outer spring quite different.
mx6- 1.57" closed, 1.17" opened, total travel- 0.40"
B2200- 1.45" closed, 1.2" opened, total travel- 0.25" The inner spring also has 0.25" travel.
MX6 spring pressure closed 58lbs, open 157lbs
B2200 spring pressure closed 94lbs, open 155lbs
Sealed power mx6 - 58lbs intake
WSM mx6 - 51.5lbs IN, 60.9lbs EX
Sealed Power b2200 - 94lbs
Mazda Powered Mx6 - 85lbs
The B2200 springs may list the same spring pressure with the valve opened as the Mx6 but that is for 0.25" travel, what is the pressure at 0.40" travel.
This longer travel is why the mx6 spring gains 99lbs over seat pressure when the valve is opened.
It is not easy to calculate accuratly because I don't know if the stiffness increase is linear.
The mx6 spring : 157/ 58 = 2.70689 X seat pressure @ 0.40" or a 270.689 % increase.
If the B2200 springs act the same as the mx6: 94lbs X 2.70689 = 254.44lbs @ 0.40" travel.
If the spring increase is linear: 155 - 94 = 61lbs / 0.25" = 244 X 0.40" = 97.6lbs + 94lbs = 191.6lbs spring pressure with valve opened."
So at a closed height of 1.57" the F2 intake spring has a pressure of 51.5 - 58 lb
At a closed height of 1.45" the B2200 outer spring has a pressure of 59lb but what is it's pressure with the spring 1/8" farther opened at the F2's 1.57" height. I bet it's less than 51.5lb.
Everything you recommended will be done and probably a few extras. Diff cams, pistons, rods, head shave and the like will not touch my motor. Although it will be getting a 3 angle valve job which these motors have stock and I find necessary to any good head job.
Well the valves have a two angle cut but only one seating face at 45%, A 3 angle valve job won't hurt and should insure proper seating but forced induction motors don't show any power improvements, charge air above atmospheric pressure doesn't behave the same as aspirated air, it doesn't care about shapes and smooth transitions it's all about area and filling it.
Since valve springs are easy to change with the head on the car (stuff rags in the oil return holes of the head to keep the keepers out of the oil pan.
I recommend starting with factory springs and shims then try out the dual valve springs. If you are hell bent on stiffer springs for the F2T why not run 8 exhaust valves springs on the intake side (taller and stiffer) and double the shims on the exhaust side. At least the factory springs are designed to hold the proper height and travel the proper distance.
I have yet to see worn valve guides or valves on a head,next time you need one let me know I have at least 20 good bone stock F2T heads and 6 F2 heads kicking around my shop and more on blocks and in cars...
I wasted time and money on engine work and head work many years ago, I hate to see people make the same or similar mistakes that I did, I have tried adjustable cam gears (have two paid 0$ both are worth 0$), run lightweight under drive pulleys (have2 paid lots worth 50$ each), fidanza aluminum flywheel paid too much (Have 1) worth having the factory flywheel lightened for100$ (have3 love them). Had an engine built 50thou over, swapped the rods, pistons where rated to take 30 psi, 7.6:1 compression.... (cost a lot, ruined a good block), some machine shop idiot took 10thou of a ported head 2times by accident but told me I would get more power this way, all I got was head lift and popping rad caps above 21psi.
To be honest polishing the exhaust ports on a F2T head is a waste of time, after porting the surface is smoothed with sanding cartridges and flap wheel sanding disks, polishing the exhaust to a mirror finish doesn't change the exhaust port carbon build up from the flap wheel fining at all, it does make it easier do clean with degreaser and a rag but who's pulling the exhaust manifold to do that?
Having the combustion chamber sanded is beneficial, it slightly increases combustion chamber size lowering compression ratios and the smooth finish has a lot less carbon build up versus the rough, porous and flawed sand cast finish.