[matt1840]

Before ordering pushrods...... OPINIONS!!!

so im about to order pushrods since i got some extra cash and i have a question...


I used converted stock hydrolic lifters to solids by filling them with jb weld to measure the length.. They are off by .006 from the hydrolic lifters im using from comp cams. My pushrod measured out to be 9.900 adding the .025 for preload and the .006 for the difference in the lifter i come up with 9.931... Considering they dont made rods in the length should i bump it up to a 9.950 or drop them down to a 9.900. Either way im going to lose geometry and gain or lose some lift.

Any opinions before i order???

 

[Moneypit]

Stockers

so im about to order pushrods since i got some extra cash and i have a question...


I used converted stock hydrolic lifters to solids by filling them with jb weld to measure the length.. They are off by .006 from the hydrolic lifters im using from comp cams. My pushrod measured out to be 9.900 adding the .025 for preload and the .006 for the difference in the lifter i come up with 9.931... Considering they dont made rods in the length should i bump it up to a 9.950 or drop them down to a 9.900. Either way im going to lose geometry and gain or lose some lift.

Any opinions before i order???

Just get stockers for a hyd cam unless you have some sort of aftermarket heads/valve length difference. GM heads, stock valve height, hyd cam= stock push rod length....Ray

 

[matt1840]

Just get stockers for a hyd cam unless you have some sort of aftermarket heads/valve length difference. GM heads, stock valve height, hyd cam= stock push rod length....Ray

The stock pushrods are way to short.. I changed over to harland sharp 1.6 rockers, and screw in studs. The stock rods allow the rocker to sit on the stud base, not to mention the rods dont even come into contact with the rockers till about 1/4 lift.

Longer rods are deffinetly needed for proper geometry and valvetrain operation.

 

[Moneypit]

Change

The stock pushrods are way to short.. I changed over to harland sharp 1.6 rockers, and screw in studs. The stock rods allow the rocker to sit on the stud base, not to mention the rods dont even come into contact with the rockers till about 1/4 lift.

Longer rods are deffinetly needed for proper geometry and valvetrain operation.

Is that all you changed? Why the 1.6 if I might ask? Most aftermarket manufacturers stress that stock components will work with their product. I am not familiar with the H/S rockers and studs. Crower rockers on 990s use the standard stuff, as do Crane Golds..........Ray

 

[matt1840]

Is that all you changed? Why the 1.6 if I might ask? Most aftermarket manufacturers stress that stock components will work with their product. I am not familiar with the H/S rockers and studs. Crower rockers on 990s use the standard stuff, as do Crane Golds..........Ray

I got a really good deal on the harlands and the 1.6 ratio is all they make for the olds. I wanted to upgrade the valvetrain from stock. With my cam choice i had to upgrade springs, change to screw in studs add guideplates and comp highly suggested an adjustable valvetrain. So i went with that i had. Considering i got the HS rockers for $150 brand new i took em.

The cam i chose is the comp xe274h
int .520 exh .523 lift
.230/.236 @ .050
110 lobe sep.

Its supposed to be real strong in the mid range which is where i usually cruise.

As for the pushrods no option if i should just jump to the 9.950??? Harland sharp doesnt suggest anymore than .025 of preload otherwise id just add .050 for it.

 

[Jetaholic]

My build with Performer RPM heads needed pushrods that were 0.050" shorter than stock. However, the block was decked 0.010", and 0.005" were taken off the heads when they were resurfaced.

Not sure what the pushrod seat height is on the lifters, but they are the Comp Cams Pro Magnum hydraulic lifters so if anyone has that spec for them please post it up. The rockers are Scorpion rollers.

I figured with aftermarket heads, rockers, pushrods and cam along with the block decking and head resurfacing plus the fact that I'm running aftermarket lifters probably was the cause for this. Not sure if the base circle of the cam lobes is the same size or larger than stock, but a larger base circle and/or lifters with a taller lifter bottom - pushrod seat height would also cause this.

 

[matt1840]

My build with Performer RPM heads needed pushrods that were 0.050" shorter than stock. However, the block was decked 0.010", and 0.005" were taken off the heads when they were resurfaced.

Not sure what the pushrod seat height is on the lifters, but they are the Comp Cams Pro Magnum hydraulic lifters so if anyone has that spec for them please post it up. The rockers are Scorpion rollers.

I figured with aftermarket heads, rockers, pushrods and cam along with the block decking and head resurfacing plus the fact that I'm running aftermarket lifters probably was the cause for this. Not sure if the base circle of the cam lobes is the same size or larger than stock, but a larger base circle and/or lifters with a taller lifter bottom - pushrod seat height would also cause this.

the stock 455 lifters are .291 from top of lifter body to bottom of cup and the comp cams lifters are .253 from top to bottom of cup. Right off the bat im gonna need shorter rods... BUT thats if i was using the stock rockers. The HS 1.6 rockers sit higher thus changing my rod length even more.

 

[Moneypit]

Olds, duh....

OK, that explains a lot. An Olds..........You failed to mention Olds in your first post............Ray

 

[matt1840]

OK, that explains a lot. An Olds..........You failed to mention Olds in your first post............Ray

nothing wrong with these engines as long as the main problem is taken into consideration..

Im not out racing this boat like the rest of you guys this is a weekend warrior, 461 olds with all the bells n whistles lol.

 

[sleekcrafter]

Smith Brothers will make the exactly the length your looking for, no in between guessing.

 

[scott foxwell]

the stock 455 lifters are .291 from top of lifter body to bottom of cup and the comp cams lifters are .253 from top to bottom of cup. Right off the bat im gonna need shorter rods... BUT thats if i was using the stock rockers. The HS 1.6 rockers sit higher thus changing my rod length even more.

Your measurement will only work if the overall length of the lifters are the same...the critical dimension is from the face of the lifter (that rides on the cam) to the bottom of the cup. If the overall length of the lifters is different, it makes no difference what the distance form the top of the lifter to the cup is.

 

[scott foxwell]

Just get stockers for a hyd cam unless you have some sort of aftermarket heads/valve length difference. GM heads, stock valve height, hyd cam= stock push rod length....Ray

Unless the valve job is sunk, the heads have been milled, and/or the decks cut.

 

[matt1840]

Your measurement will only work if the overall length of the lifters are the same...the critical dimension is from the face of the lifter (that rides on the cam) to the bottom of the cup. If the overall length of the lifters is different, it makes no difference what the distance form the top of the lifter to the cup is.

Both lifters (the new comp and the stocker) are the same overall length.. And not that i think of it you are correct in what your saying.. I was more worried about the cup depth than the overall. Good call on that.

Both lifters are 2.000 so just do the math jetaholic. These are same size as chevy bbc lifters as well according to summit racing. Considering i can order rods in .010 increments im going to doble check my measurements and see about pricing on these rods.. They are 5/16 i believe and ball end.

Steelcomp where do you get the rods from??? Im not needing "high performance" unless you feel that length will be prone to bending at high rpm... I was just gonna order the comp cam rods until i realised they didnt sell in the right length... GRRR another wall lol nothin can be easy with this engine lol

 

[Jetaholic]

Both lifters (the new comp and the stocker) are the same overall length.. And not that i think of it you are correct in what your saying.. I was more worried about the cup depth than the overall. Good call on that.

Both lifters are 2.000 so just do the math jetaholic. These are same size as chevy bbc lifters as well according to summit racing.

I'll look into that. I don't trust Summit's tech help line. Had a friend that bought a bigger cam kit (I think it was for a .550 lift or somewhere around there) for a Ford 460, and Summit told him that even with the stiffer springs and higher lift that all the stock rockers and pushrods were compatible with the cam kit! Needless to say, he bent a couple pushrods and lost a couple lifters.

Always better to go with info direct from the manufacturer rather than the supplier.

 

[Moneypit]

Hyd......

Unless the valve job is sunk, the heads have been milled, and/or the decks cut.

I doubt there would be enough difference too matter. This is a hyd application. A hyd lifter will compensate for a lot.

I'm really surprised there is such a problem simply because the rocker pivots were changed to single rocker arms...How can H/S sell stuff for an Olds that doesn't fit an Olds? Something smells fishy..........I realize the Olds valvetrain leave a lot to be desired, but why the major change for a hyd cam???.......Ray


PS I do find this interesting as I am planning on some Olds valvetrain mods myself........I built one a while back and remember the oil restrictors and the adjustable push rods...However, I did use the existing rocker pivots. As I recall that engine was bullet proof in a jet ski boat owned by a guy that destroyed everything he ever owned prior to that.......

 

[matt1840]

I doubt there would be enough difference too matter. This is a hyd application. A hyd lifter will compensate for a lot.

I'm really surprised there is such a problem simply because the rocker pivots were changed to single rocker arms...How can H/S sell stuff for an Olds that doesn't fit an Olds? Something smells fishy..........I realize the Olds valvetrain leave a lot to be desired, but why the major change for a hyd cam???.......Ray


PS I do find this interesting as I am planning on some Olds valvetrain mods myself........I built one a while back and remember the oil restrictors and the adjustable push rods...However, I did use the existing rocker pivots. As I recall that engine was bullet proof in a jet ski boat owned by a guy that destroyed everything he ever owned prior to that.......

Only reason i changed the valvetrain is comp recomended it with the cam kit i purchased. It specifically said not to use any stock components.

 

[Moneypit]

1000s

Only reason i changed the valvetrain is comp recomended it with the cam kit i purchased. It specifically said not to use any stock components.

I'm willing to bet there are thousands of Olds powered boats with hot cams in them running the stock valvetrain....Didn't the Hardin Marine engines come with the stock set up?.....I could see major changes if you went solid or solid roller, but I believe the weak link will be the hyd lifters........BTW, I doubt any of the cam manufacturers actually produce their own hyd lifters......Ray

PS Did you purchase valve springs from comp with the cam kit?

 

[FastRat]

Smith Brothers will make the exactly the length your looking for, no in between guessing.

x2...they will also make u 1 piece & hardened for the guide plates...i have run there pushrods for years in my dragster etc with n/p ever...i would go with 3/8" ...i think they are still located in Irwindale, Ca...just my .02 cents

FastRat

 

[Moneypit]

Oregon

x2...they will also make u 1 piece & hardened for the guide plates...i have run there pushrods for years in my dragster etc with n/p ever...i would go with 3/8" ...i think they are still located in Irwindale, Ca...just my .02 cents

FastRat

Smith Bros.

800 367 1533 in Medford Oregon

 

[Boat 405]

Smith Brothers will make the exactly the length your looking for, no in between guessing.

x2