Lifter bore clearance?

[wyrmrider]

comp shows the 200 duration as 156/254 and intensity as 13.8/ 15
281 MM series 173@200 12.3 13.3 from .904 lifter
271 gets 169
you can go as short as 265 and still have more at 200
why use an old chevy grind?

MP series 274 @20 162 @200
284= 166

 

[bherman]

comp shows the 200 duration as 156/254 and intensity as 13.8/ 15
281 MM series 173@200 12.3 13.3 from .904 lifter
271 gets 169
you can go as short as 265 and still have more at 200
why use an old chevy grind?

MP series 274 @20 162 @200
284= 166

wyrmrider, I'm sorry you have significantly exceeded the knowledge base of your intended recipient. Would you please school me. Please speak slowly, loudly and use small words...LOL. Thanks Brian.

 

[wyrmrider]

Hi Brian
we've sorta moved from lifter bores to questions on the clearances etc
How did you come up with the comp FT cam and do you own it?
Without knowing all the details on your build and usage can't make any but general hopefully informative comments.
Which Indy heads and what type of chamber do they have- do you have a pic?
can you get head flows? cc's
what intake, carb, exhaust
compression and quench or squish
gears, trans weight usage
what fuel
etc.
I'll post on flat tappet trade-offs later
some great posts by challenger above
some things he suggested was habit and he explained it so I could even realize that I had not been clear.

 

[wyrmrider]

Brian
did anyone suggest to use IHC .997 hyd lifters seat height is about right but do not know about oil band IDK if there is a solid in this size or for the big olds lifter
I know we have the BHJ tooling and some older one and bore for 1"+ lifters and more than 1" for bushings so boring for .997 plus clearance should be doable

 

[bherman]

Hi Brian
we've sorta moved from lifter bores to questions on the clearances etc
How did you come up with the comp FT cam and do you own it?
Without knowing all the details on your build and usage can't make any but general hopefully informative comments.
Which Indy heads and what type of chamber do they have- do you have a pic?
can you get head flows? cc's
what intake, carb, exhaust
compression and quench or squish
gears, trans weight usage
what fuel
etc.
I'll post on flat tappet trade-offs later
some great posts by challenger above
some things he suggested was habit and he explained it so I could even realize that I had not been clear.

wyrmrider, I didn't understand what you were telling me in the post with duration and intensity, that's what I was asking you to explain. As far as moving from lifter bores to bearing clearances that was Challenger340 being thorough about possible reasons for my low oil pressure condition other than lifter bore clearance. I'm still on lifter bores I took Challenger340's advice and contacted lifter manufactures, Trend can produce a tool steel lifter @ .907 out of their existing blanks. I will bush the bores if I can't get the bores round and straight @ .908-.9085. Thank you for your replies and suggestions, Brian

 

[wyrmrider]

I'll get to it today Brian
thanks for the reminder
something to ponder
motors with large bucket lifters have shorter duration cams than cars with small diameter lifters.
this is the chevy .842 vs the MOPAR .904 - same reason as above

 

[wyrmrider]

Brian

I started with your “straw man” cam

Comp Cams part# 23-232-4 Extreme Energy series

Comp show this with a seat duration (.020) of 282-290

and they show the valve Timing @.015 tappet lift and you can factor in lash

you can use this to compute Dynamic Compression Ratio

Duration at .50 is useful for degreeing in a cam and a rough cam comparison tool

I looked it up in the master lobe catalog under EE lobes and found one that matches

and posted data from that in post 41

“comp shows the 200 duration as 156/254 and intensity as 13.8/ 15 “

which is how many degrees the cam is doing really useful work filling the cylinder while the piston if really pulling on the air/fuel “mass”



I then posted a similar duration profile from Comps MM series of Mopar grinds

to show that for the same (close) seat duration you get 173 degrees @200 or 17 more

dropping the seat duration by to degrees to 271 still gives 169 degrees @200 13 more

shortening up the duration is very useful if your compression is not maxed out and has a similar effect to advancing the “straw man” cam or squeezing the lobe centers without increasing overlap

as I said I'm working with a “straw Man” cam and doing some “what ifs'

I have no idea if 282 is the correct number- compression and air flow and usage come into play



I then said

“you can go as short as 265 and still have more at 200 “ that's 17 seat degrees you have to play with

 

[wyrmrider]

Brian also asked about "intensity" asking " I have no idea how aggressive the lobe profile is."
If you look in the Comp master lobe catalog they give the M.I which I take as Major intensity as 13.8/ 15 which I'm guessing is the opening and closing sides from .020 to .050 and back to .020 Others can chime in but it looks like smaller numbers are more "intense" not exactly the way Harvey Crane- who AFAIK started "intensity" or at least promoted it so have at me guys.
Comp MM series 12.3 13.3 from .904 lifter but the MP series
has a couple of comparable lobes (there was a typo in the exhaust 200 above but we're not doing exhaust )
MP series [email protected] with 166 @200
MP series 274 @.020 with 162 @200
less intense than the MM series but still give greater 200 for the same seat as the XE chevy series 156
COMP Catalog does not give intensity for MP but does say similar to chevy TL Tight Lash Series

"The MP Series uses a design similar to the TL Series except these have more area due to being designed with more velocity for a .904" minimum tappet diameter"
"TL Solids-- shorter seat timing and more area than other similar designs"

now the Mopar Performance Soild series would be even less intense and the factory cams even less
so you can use the larger Chrysler lifter for MORE or you can use it for easier on the valvetrain and still have more "area under the curve" for which we are using .200 duration as a proxy

I wonder if you could get away with less spring with the MP series?
Are you going to EDM you lifters?

I'm not recommending COMP- just examples based on the cam number brian posted
several other good sources for off the shelf mopar solids
T0 me 10 degrees is BIG

 

[bherman]

Brian also asked about "intensity" asking " I have no idea how aggressive the lobe profile is."
If you look in the Comp master lobe catalog they give the M.I which I take as Major intensity as 13.8/ 15 which I'm guessing is the opening and closing sides from .020 to .050 and back to .020 Others can chime in but it looks like smaller numbers are more "intense" not exactly the way Harvey Crane- who AFAIK started "intensity" or at least promoted it so have at me guys.
Comp MM series 12.3 13.3 from .904 lifter but the MP series
has a couple of comparable lobes (there was a typo in the exhaust 200 above but we're not doing exhaust )
MP series [email protected] with 166 @200
MP series 274 @.020 with 162 @200
less intense than the MM series but still give greater 200 for the same seat as the XE chevy series 156
COMP Catalog does not give intensity for MP but does say similar to chevy TL Tight Lash Series

"The MP Series uses a design similar to the TL Series except these have more area due to being designed with more velocity for a .904" minimum tappet diameter"
"TL Solids-- shorter seat timing and more area than other similar designs"

now the Mopar Performance Soild series would be even less intense and the factory cams even less
so you can use the larger Chrysler lifter for MORE or you can use it for easier on the valvetrain and still have more "area under the curve" for which we are using .200 duration as a proxy

I wonder if you could get away with less spring with the MP series?
Are you going to EDM you lifters?

I'm not recommending COMP- just examples based on the cam number brian posted
several other good sources for off the shelf mopar solids
T0 me 10 degrees is BIG

wyrmrider, thank you for taking the time to explain this to me. You provided a lot of information to assimilate. I will have to do some research on cam profiles. I'm not looking for maximum performance so I will probably look more at "easier on the valve train" aspect of things. Great info, guys like you, Challenger340 and many others on here make this site a great resource, Thanks again, Brian.

 

[wyrmrider]

how's it going?

 

[bherman]

how's it going?

wyrmrider
Hi wyrmrider, thanks for checking on me. After checking several blocks and finding one that I thought had acceptable bore thickness to work with, we measured the lifter bores and found them to be a little large .9064-.9067 before any clean-up. I checked into bushing the lifter bores and discovered that the vendor that we have a good relationship with (and has produced excellent results) was tied-up for weeks. Based on your recommendation that I use tool steel lifters for the spring pressures we had, I ordered a set of Trend tool steel lifters @ .906 diameter. Comp cams recommended that the cam be Nitrited for this application. I felt that .001 lifter bore clearance might be tight so I asked the machinist to hone to the low side of .0015. The bores are very consistent @ .9074-.9075 almost no out of round or taper. I did use a Nitrited version of the "straw man" camshaft as I had no idea how to select a cam lobe and was not really concerned with making maximum power. I'm hoping this configuration will be easy on the valve train and to that end I purchased 1.5 ratio rocker arms (one of the 1.6 rockers was damaged and I couldn't get a replacement). Because I'm oiling rocker shafts anyway I elected to stay with the Mopar configuration ball and cup push rods, not oiling through the push rods. The engine is assembled, just have to set push rod length and button-up the top end. I hope none of my (possibly poor decisions bite me on the butt. The engine shop is going to dyno the engine so I guess I'll find out. Thanks again, Brian.

 

[wyrmrider]

using roller rockers
set your shaft height and backspacing
read these if you have not b 4 ordering the wrong pushrods
http://www.b3racingengines.com/techpages/MoparRockerArmGeometry1.asp
oiling the rocker adjuster balls through the pushrods helps
if not make sure the lifter oils the tip and adjuster directly- under the arms- not just splash from a hole in the top