Going to a 218/218 roller w/ 1.65 roller rockers and would like to use 3/8" pushrods . how much grinding is required on iron heads to make these work ? Rather than going 3/8" , I'm thinking 11/32" (.083 wall) . I've also seen "single taper" or "dual "taper" rods that come in taper sizes of 11/32" to 5/16" , 3/8" to 5/16" or 3/8" to 11/32" . anyone know anything about these "taper pushrods" ? thanks .
Pushrod Tech question .
- Thread starter KWIKR 1
- Start date
Can't tell you about fit, but as for stiffness using a 5/16" rod with 0.083" walls as 1, here's how they rank using the same 0.083" wall for each one:
5/16" 1
11/32" 1.268
3/8" 1.748
Every little bit of diameter makes a big improvement in stiffness. Also, I'm not including those numbers here but diameter absolutely trumps wall thickness so the thinnest wall 3/8" rod beats even a solid piece of 5/16" rod by about the same margin as above ( made a posting maybe a year ago giving more numbers if you want to dig in the archves). When I finally get my new ta heads bolted on so I can measure what length pushrod I need I plan on ordering the thinnest wall 3/8" pushrods I can find, 0.065" I think, and making them fit. I can't calculate the tapered shapes (at least not without real work
) but they will fall in between the ratings for the two ends, obviously, and how close to which size depends on the lengths of the straight and tapered sections.
5/16" 1
11/32" 1.268
3/8" 1.748
Every little bit of diameter makes a big improvement in stiffness. Also, I'm not including those numbers here but diameter absolutely trumps wall thickness so the thinnest wall 3/8" rod beats even a solid piece of 5/16" rod by about the same margin as above ( made a posting maybe a year ago giving more numbers if you want to dig in the archves). When I finally get my new ta heads bolted on so I can measure what length pushrod I need I plan on ordering the thinnest wall 3/8" pushrods I can find, 0.065" I think, and making them fit. I can't calculate the tapered shapes (at least not without real work
) but they will fall in between the ratings for the two ends, obviously, and how close to which size depends on the lengths of the straight and tapered sections.well I'm thinking to at least upgrading to 11/32" w/5/16" ball ends/.083 wall) over the stock 5/16" pushrod. IMO I guess ideally a 3/8" to 11/32" taper rod should work if concerned about clearance issues in the head .
check out
Pushrods-Manton Pushrods-High Performance Pushrods some good info .
check out
Pushrods-Manton Pushrods-High Performance Pushrods some good info .
Blown&Injected
Active Member
- Joined
- May 31, 2001
I put 3/8" PR's in my engine - was not too bad at all.
Used a strip of cardboard from a large box of wooden matches as a gauge to let me know where I needed to grind. Just installed the heads, rocker arms, push rods, and then just rotated the PR with the gauge in place so I would know where the clearance problems are. Use a marker to make a note of it and then make sure the grinder is long enough to go all the way thru the holes in the head.
Used a strip of cardboard from a large box of wooden matches as a gauge to let me know where I needed to grind. Just installed the heads, rocker arms, push rods, and then just rotated the PR with the gauge in place so I would know where the clearance problems are. Use a marker to make a note of it and then make sure the grinder is long enough to go all the way thru the holes in the head.
Attachments
When I finally get my new ta heads bolted on so I can measure what length pushrod I need I plan on ordering the thinnest wall 3/8" pushrods I can find, 0.065" I think, and making them fit. I can't calculate the tapered shapes (at least not without real work
James
Just be careful when increasing the pushrod thickness. I have TA Street Eliminators on an On-Center TA Block with off-set solid rollers. The rockers are 1.75 ratio. As you can see, some of the pushrods are close to the holes. When the heads were ported, the intake port broke through to the pushrod hole, thus requiring a sleeve as seen in #4 intake (no biggie) . The pushrods are Smith Brothers 5/16 heavy wall (.083) with .030 restrictors (style 581). The reason for the restrictors was due me using the pushrods in a 109 block with roller rockers. So... I might get new pushrods with a .116 wall without restrictors due to the block lifter feed already restricted. My open spring pressure is 600lbs, so I'm undecided if I should get new pushrods.
The Smith Bros pushrods 5/16 (.083 wall) are good for 700lbs. Smith Bros (style 5116) now make a 5/16 rod with a .116 wall good for over 700lbs
Hope this helps
Billy T.
gnxtc2@aol.com
steve hughes
Well-Known Member
- Joined
- Jul 5, 2002
I' m useing Smith Bros 5/16" x .116 wall 9.450 " in my stage motor with a solid roller with 275# on the seat and 600 over the nose. I have not had any issues . I also buzz it to 7100 rpms.
Thanks for the info, Illy T. I'm hoping that with the 1/2" pushrod holes in the TA heads and stock style T&D 1.55 rockers they will center up okay and I won't have to do any grinding with 3/8" pushrods. Going from .083 wall to .116" wall 5/16" od only gains you 4.6% more stiffness (see, diameter wins big ). Oh, gorgeous motor, btw. I can't imagine how anxious you must be to get it done.
). Oh, gorgeous motor, btw. I can't imagine how anxious you must be to get it done.- Joined
- May 26, 2001
Thanks for the info, Illy T. I'm hoping that with the 1/2" pushrod holes in the TA heads and stock style T&D 1.55 rockers they will center up okay and I won't have to do any grinding with 3/8" pushrods. Going from .083 wall to .116" wall 5/16" od only gains you 4.6% more stiffness (see, diameter wins big
Unless you guys are going for LOTS of HP, we have many 9 sec. engines rev to 7000+ RPM with no problems using 5/16" pushrods.
Even Dick Kereny's 8 sec. stock block used 5/16" pushrods.
Unless you guys are going for LOTS of HP, we have many 9 sec. engines rev to 7000+ RPM with no problems using 5/16" pushrods.
Even Dick Kereny's 8 sec. stock block used 5/16" pushrods.
Thanks Nick for the Real Life answer ....
.why PR restrictors in a 109 block and roller rockers ? NICE engine !
Since I was running roller rockers which don't require much oil, I wanted to keep all the oil in the bottom end.
Thanks
Billy T.
gnxtc2@aol.com
Blown&Injected
Active Member
- Joined
- May 31, 2001
Yes, from Mike at Full Throttle. They are custom and not returnable so make sure ya get the right size.
Now get this - as if that outfit needs more praise - I called FTS on the same day I signed up for and ordered some Block Buster DVD's.
I got the pushrods before the DVD's
Yes, from Mike at Full Throttle. They are custom and not returnable so make sure ya get the right size.
Now get this - as if that outfit needs more praise - I called FTS on the same day I signed up for and ordered some Block Buster DVD's.
I got the pushrods before the DVD's
cost for pushrods ?
Blown&Injected
Active Member
- Joined
- May 31, 2001
Unless you guys are going for LOTS of HP, we have many 9 sec. engines rev to 7000+ RPM with no problems using 5/16" pushrods.
Even Dick Kereny's 8 sec. stock block used 5/16" pushrods.
What - Bigger is not better?!?!?! What type of nonsense is this?
When I ordered the PR's there was lots of talk on the board about the Spintron (I think that's what it's called). A device that checks out valve train type stuff, like finding errors in the works. It seemed like the PR's are subject to some flex even below 5000 RPM's. But then when reading the charts, the 5/16 .083 wall PR's in the length we use are well within the acceptable range for the spring pressures we often use.
Since I needed to go back in - I figured WTH
Blown&Injected
Active Member
- Joined
- May 31, 2001
cost for pushrods ?
I'm sorry but I do not recall. If they were lots more $'s I believe I would have remembered.
My main concern was the weight - but the mfr's claim weight on that side of the rocker is not important
I also became concerned about the grinding when it was towards the intake ports, for reasons shown above, would even hold my finger in the port while grinding - did not feel any heat so I should be fine
turbo nasty
Turbo Dojo / MNTR
- Joined
- Jul 19, 2001
They gave u 5 tenths in the 1/4 like everything else he sold...LOL
