[IMG]imgp2340[/IMG] I'm building a 383 stroker using the LT1 Trick Flow Heads with the Crane Gold stock LT4 1.6 ratio roller rockers.

Does anyone have experience with what Pushrod Lenght will work with this package??

Thanks in advance.......G

 

Bump...

 

Only way to know will be to either outright measure or at the least check with a stock one and see if it is close.
Besides head choice, valve length comes into play, as does how much has been machined off the head and block mating surfaces, how thick the gasket is. Way too many variables to say they will be "X" length.

 

Yep, gotta check um.

 

im running trickflow assembled heads with 1.6 rr's, i did no machine work on either mating surfaces and im running the stock length (7.2 in) trickflow hardened pushrods. a quick check is to look at the mating surfaces between the rocker arm tip and the valve stem, with the valve fully closed the rocker arm should rest very slightly off center of top of the valve stem towards the middle of the engine. also if your rocker arms are self aligning then you dont use guideplates, this will also be a factor...

 

I did all of the above and this is the issue i'm haveing now.

Just completed the Pushrod check using the stock 7.200" lenght pushrod of which i got a good .080" wear pattern in the center of the valve stem for both intake and exhaust. I machined up a solid insert for one the the stock hydraulic lifters as the test has to be done with a solid lifter. In that configuration the locknut for the crane gold 1.6 ration roller rockers is just about hitting the rocker in the non lift position. The contact would be at the slot edge. Maybe only .010" from hitting. Crane tech says i need taller pushrod to cause the rocker to rise more off the rocker stud. I set up the test rod to 7.350" and found it better but it was moving the "contact pattern off center so i beleive the 7.200" is the better lenght.
Now.....What do i do about the crashing condition of the hex portion of the locknut to the rocker?? Crane tells me they only make the one lenght locknut. Does anyone sell small diameter hardened washers in different thicknesses that i can put under the locknut to rolloer rocker 'trunion face' ?? What about longer locknuts??

 

I have heard the Crane Golds needed machining in a few areas but I always thought that was just to clear larger springs. I havent heard of anyone doing it but if you needed a longer rocker nut you could always go with the stud girdle ones which are longer to accept the girdle in between the rocker and the rocker nut.

 

Here is a pic of the condition i am haveing with both the Crane Rolers.
Last nught i mocked up the old stock head with stock lenght eod and i have the same issue.

This can't be normal can it?

Just seems like its way too close to the top of the rocker.

 

First thing I would do is dump them SA rocker arms. I have seen nothing but problems with them.

 

Whats SA??? You mean the Crane Golds? If they have been around for over 25 years and GM purchased them for the LT4 , i thought they have been one of the most reliable. What issues have you with them??

 

SA is self aligning and non-SA is usually preferred for high lift high rpm usage.
The GMPP rockers are different from the Crane Golds too because GM speced a shorter slot which limits lift capacity which is what you are seeing. Also true stock LT4 rockers are for a metric stud.

I have seen guys wear out the GMPP/Crane aluminum rockers with high pressures and three speed trannies(no OD no lockup so high rpm all the time) run on the street would not call it common and it did take 20K, they are a good rocker just definitely not the best.

Since you did not understand SA I have to guess you are getting in a little over your head on this project and only did half the research.
Please give us a more complete rundown of the total setup and we can be of more help. Your ability to check the rocker pattern on the valve tip does indicate some experiance, maybe just more oldschool???

 

Ahh! Got it.
Over my head?...........Hmmm? Well maybe regarding the application of these rockers and there idiosyncrasies to the LT1 motor,but not to engine building.
Yes this is my first LT1 build but have SBC and multiple engine builds with other makes over the years. I have a tool and Die and machining background so have a good grasp at that stuff but always learning.
Trick Flow LT1 assembled heads ( no add. machining)
Block decked to clean @.006"
Crane Gold 1.6 ration LT4 rockers
Solid mock up lifter @ stock lenght
Timing = Factory settings
First if you look at the pics closely you will notice that this condition is at no lift but on base circle when valve is at .000" lift. The Comp Cam XFI 280 i am using has .571" intake lift and there is no issue at full lift as there is plenty of clearance to the locknut.My first reaction was to increase the pushrod lenght to 7.350" as the Crane Tech suggested. Upon mocking that up i found a little better clearance(but not much) but the wear pattern was noticeably "off center" of the valve stem(getting worse not better).Trick Flow spec sheet showed 7.350 as a possibility with comp cam and crane configuration ( but not written in stone)
I then had the idea to mock up the stock head and see if it would be the same condition and it is. The hex portion of the adjuster nut comes very close to the edge of the slot (.010") in the closed (off ramp_on base circle) position. These are stock LT1 heads and not LT4 so there may be some variable there as well. My 1996 LT1 heads and the LT1 Trick Flow heads have a 3/8-24UNF thread and not a metric thread. The bore in the Crane rocker is .378" and would not accept a 10mm stud, but this really has nothing to do with my issue
The distance from the flat surface of the trunion of the rocker to the hex portion of the adjuster nut seems to be too short if i try to use the 7.200" pushrod which seems too be best for .080" wear pattern position in center of valve stem tip. The Crane tech confirmed the oal of locknut @ .860" and no hardened washer between the locknut face and the trunion flat face.
Hope this helps. Seems like my only option would be to find some hardened washers around .030" thick to ull the hex portion of the nut away from the slot edge. I really do not want to releive material from the rocker if at all possible.

 

i sent you a pm before checking your new posts...+1 for non-SA...im not very familiar with SA rockers but if it comes down to the point everything is installed correctly then 0.010" clearance is fine....just as long as they dont touch...