Pushrods?

[wrench1]

Whats the opinions on using 5/16 x .105 pushrods in roller motors. I know some are using 3/8 & 7/16 but clearance is an issue.

[sj valley dave]

What kind of spring pressure are you running? We run 245lbs @ 2.020 and 740 lbs over the top and we run 3/8" .080 pushrods at 9.000 and 8.950 lengths...Would not trust a 5/16" in our situation...

[stockcar5]

do whatever you can to make the 3/8 pushrods fit.

[hogracer3d]

Go to a high seat roller,which shortens the pushrod, then a .120 wall

[let-r-eat]

Remember you only need .010 clearance. To me with a roller 3/8 is a must or possibly the right tapered wall.

[parrot69777]

All the roller engines we had.....used Trend .080 wall, 5/16 pusrods, with the 210 degree end, Isky tool room 9995 springs... 260lb on the seat - 750lbs open - .721 lift - 8200 rpm. Never had any issues.

I also do the maintenance on an open mod with a Mullins engine. Full roller, Jesel shaft rockers, etc. and it has 5/16 pushrods. They turn it over 8000 without a problem.

I hear all the time about push rod flex. But even on the stock car engines I build with 5/16 pushrods...the only marks I see on them are from the guide plate.

Now from what I have seen due to other issues. Would rather have a bent or broken pushrod than have a valve drop and ruin an engine completely.

[let-r-eat]

parrot:

Do you think pushrod flex is a myth?

[parrot69777]

Everything has flex.

[stockcar5]

a stable valvetrain is huge..and worth hp. there are no downsides to running larger pushrods..no reason not to unless they physically wont fit.

[stock car driver]

All the roller engines we had.....used Trend .080 wall, 5/16 pusrods, with the 210 degree end, Isky tool room 9995 springs... 260lb on the seat - 750lbs open - .721 lift - 8200 rpm. Never had any issues.

I also do the maintenance on an open mod with a Mullins engine. Full roller, Jesel shaft rockers, etc. and it has 5/16 pushrods. They turn it over 8000 without a problem.

I hear all the time about push rod flex. But even on the stock car engines I build with 5/16 pushrods...the only marks I see on them are from the guide plate.

Now from what I have seen due to other issues. Would rather have a bent or broken pushrod than have a valve drop and ruin an engine completely.

What other marks would you see on a pushrod?

Whos stock car engines do you build? What are their names, tracks and cell numbers?

Whos Mullins motor are you maintaining, whats his cell number?

I call B.S.

[parrot69777]

Not really sure what your hard on is......

Alex Buffington - A mod - CJ Raceway/West Liberty, Farley
Darrin Ealey - IMCA Stock Car - CJ Raceway (sometimes 34/Lee County/ WL)
Blaine Dopler - IMCA Stock Car - CJ Raceway/34
Brodie Dopler - IMCA Stock Car - CJ Raceway
Rod Staats - IMCA Stock Car - 34/Lee County
Rod Staats - Sport Mod - 34/Lee County (sometimes Boone)
Kenny Foor - IMCA stock car - CJ Raceway
Danny Daggs - Sport Mod - Memphis, Mo
Dean Kratzer - Sport Mod - 34/Lee County
Brian Holmes - IMCA stock car - CJ Raceway/34 (sometimes Marshtown, Lee county, Boone, Indy)
Brian Tipps - Hobby stock - CJ Raceway/34
Scotty Pratt - Street Stock - WL, Tipton, East Moline, Farley
Brad Ewart - IMCA stock car - CJ Raceway
Shane Richardson - IMCA Stock car - CJ Raceway/34

I also use to build all of our own engines for our late model up until I quit racing last season.

When I first started doing professional work back in the early 90's...I worked for B&J Auto Parts in Muscatine, IA. Helped build engines for a new kid running pro stock called Brian Birkhofer and Dave Birkhofer's late model. In 1998 I worked for Robert Yates Racing in the cylinder head department doing head work for Cup and Craftsman truck engines.

What's next....you want a DNA test too?

[parrot69777]

a stable valvetrain is huge..and worth hp. there are no downsides to running larger pushrods..no reason not to unless they physically wont fit.

Your right on this. If you have the room to put in larger pushrods.....silly not too. 80% of the stuff I work with....mostly 23 degree stuff.....stock heads, dart iron eagles, bowtie's, World Products, RHS, etc. don't have the room to put anything larger in unless you want to go to quite a bit of work. Now if you talking 18 degree, SB2, etc. Whole different ball game.

[sj valley dave]

Ya Parrot, you are right regarding tight fit...We have SB2.2 heads on a standard block so the valve train geometry is a little starnge and the 3/8's fit, but some of the teams are now running tapered 7/16" to 1/2" stuff which would not fit for us....I like running the biggest diameter that you can with a thinner wall, .080 or .065 as it is stronger than a smaller diameter pushrod with a thicker wall, and lighter!! IMO

[stockcar5]

i've never had any trouble..even using non offset rockers. offset rockers do help a ton though and it's not what i consider "quite a bit of work".

[runyou-2]

It sure was quite a bit of work for me.Using 180 offset roller lifters and .550 offset jesel rockers,9" x 3/8 tappered pushrods,i still had to HAND FILE about 1/8-3/16" out of the sides of the pushrod holes to get em' in there.Then had to hand grind on the rods because they HIT the cam lobes.Thought i'd never gett'er done.Been a year now and she turns 8 grand twice a week.