truckmann

iTrader: (8)

Ya I know you don't have an actual z06 cam if you did I would suggest getting the 7.450 Pushrods. From my research I'm not even sure how to properly measure the cam base circle and I couldn't find much info on what a stock cam base circle is. Hopefully someone who is a cam guru will see this and enlighten both of us.

On a side note what I am thinking is that you can probably get away with running the stock size 7.4 pushrods either way. I saw many reference that people have used stock length pushrods with the z06 cam and the hydraulic lifters appear to be able to handle the difference. Of course to always have the proper pre-load and avoid possible valvetrain noise you should use the proper length pushrods.

My guess is that with that cam you are going to need pushrods somewhere between the stock of 7.40 to 7.45.

I just wish I could be more help. This seems to be kind of a gray area that no one has a definite easy answer.

truckmann

iTrader: (8)

This looks like some good info.
https://ls1tech.com/forums/showthrea...e+circle+stock

If you assume that your stock cam base circle is the same as an ls1 cam then by the math in that post.

Stock diameter = 1.552 ish / 2 = 0.776 base circle
your cam diamter = 1.417 / 2 = 0.709 base circle

Difference 0.770-0.709 = 0.067

Assuming this is all correct I would say the 7.450 pushrods will work.

RotaryResurrection

iTrader: (24)

Here's a good link I found, but I havent tried it yet because I dont have winzip on this computer (shop computer) yet. https://ls1tech.com/forums/showpost....59&postcount=1

here's a good thread I've run across...

https://ls1tech.com/forums/showthread.php?t=268011

truckmann

iTrader: (8)

Is windows the operating system on your shop computer? I though a basic unzip utility was built in to windows these days.

Anyway I checked it out and the spreadsheet figures it the same way that I did. It adds the dimension of cylinder head milling and gasket thickness so if you ignore that it comes up with the same answer that I got!

Well the same difference anyway. The spreadsheet uses 7.38 for stock instead of 7.40

RotaryResurrection

iTrader: (24)

Yes I have w2k on my basement computer but it did not open the .zip file so I DL'd winzip and opened it. Using 7.4 and 1.617 values for stock pushrod length and cam base circle, and 1.420 for new cam base circle it predicts a 7.466 pushrod.

After a limited amount of searching and reading it seems that a few others have used stock length pushrods with similar setups and had it run okay, but reported additional valve train noise. I guess I will get the new cam in and then use the pushrod length checker, and order/overnight some custom pushrods rather than taking the chance, because you never know who you can or cannot trust on these forums, especially when searching older threads.

Thanks for your help so far, btw.

truckmann

iTrader: (8)

No problem. Glad to help and try to learn something new for myself too. Sounds like you have a good plan and we are thinking along the same lines. It seems the best way to find out what you need is just going to be to measure it.

RotaryResurrection

iTrader: (24)

I have to admit that I'm a little disappointed in the turnout on this forum as far as help and comments. Obviously nothing is owed me, but at the same time, 98 people have viewed this thread and only one has seen fit to offer any serious help. I've started several technical question threads now and seem to get very few helpful replies. Perhaps it's because I am a new user and not "one of the guys" or perhaps I ask dumb, or difficult questions?

RotaryResurrection

iTrader: (24)

Got my passenger side head off and found that both lifter trays were cracked and one lifter is stuck in the block.

This is the result of 3 bent pushrods a couple months ago, the truck would not start due to a bad tank of gas and I tried to use starting fluid to help it get going but instead it backfired through the intake a couple of times which is when the damage must have happened.

I have tried to pull on the lifter with a magnet, pliers, and vise grips, and it just sits in there. It will move down but not up, so I figure the roller must be busted and the cam ground a flat spot on the bottom of the lifter which is catching on the underside of the hole in the block.

So now I figure the only thing I can try is to get the cam out and use a magnet to pull it downward while using another magnet to guide it from the top, and try to work it out the front without dropping it. Unless anyone has any more suggestions.

...And people say rotaries are a bitch to work on and tear up a lot. (rotary engine mechanic and builder since 1999 here)

truckmann

iTrader: (8)

I would say help seems to be hit or miss on here. Since in general people are lazy, one thing that migh help your posts get more attention in the future, is keep it initially short and to the point. I think you will get more peoples interest that way because they are more likely to read the post if it is only a couple of lines long.

As far as the lifter goes I can't offer up any good ideas on that one since I've never had to deal with anything like that. You might try posting another thread simply asking for help on how to remove a broken lifter and include some pictures. We like pictures here!

Lesson learned by me in this ... Starting Fluid BAD...

RotaryResurrection

iTrader: (24)

Since you all like pics.

got it all torn down...



That's gonna leave a mark...



Won't be needing that cam anymore...