SMasterson

I have a TPI engine with zero deck, Trickflow 23 degree heads, stock hydraulic roller lifters and Harland Sharp roller rockers. I have 7.150 length pushrods now and the rollers run from the center toward the outer of the valve stem. It's nowhere close to coming off but it just doesn't look correct.

I belive stock is 7.250 but I could be wrong. Since approximately .025 was milled off the deck can I assume I probably need 7.225 pushrods? (I haven't seen ANY that length) But, I can assure this, with shorter ones the roller on the rocker is NOT going to start at the intake side of the valve face, travel accross the center line of it, and back again at full lift. I don't see how that geometry would be possible!

Does anyone else have a similar setup and if so, what length pushrods are you using? It appears I need shorter but can't find the locally and I'm almost ready to fire this thing up!

I've read for two hours on the NET on how to check/do this but was just wondering if it's common to have to change the pushrod length this much.

I really need to get an adjustable one and check it but. . . everyone I know only has the longer ones. 7.5 inch or so.

Oh well, my head hurts from thinking about it and it's getting late!

Thanks in advance.



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SMasterson

Ski89Z28

7.200" length actually, I think the measurement is 7.198" on a stock engine.
Any how I used these in my setup in the signature below.

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89 IROC 350 Auto
MSD 6AL
Custom DUAL Exhaust
Edelbrock Performer 6085 Aluminum Heads
ZZ9 Cam
TPIS Level 5 Chip
And Free mods.
(stock intake, runners and suspension)

13.879 @ 98.90 mph (with 2.77 gears!)


Moderator of http://www.iroczone.com



[This message has been edited by Ski89Z28 (edited August 09, 2001).]

chiefz28

I too am using 7.2 I running AFR heads.but was originally going to go with Trick Flow I called them to find out and it was 7.2 for those also.If your still not sure I would just call them ask they'll be able to help

Damon

TrickFlow heads, and especially the newer G2 heads require different length pushrods than stock by a LOT. Go to the Trick Flow website and dig into it. They have a chart that tells you what length you need with what type of cam and what type of rocker arms.

I just built a flat-tappet engine with the FTF G2 heads and Crane Gold full roller rockers. I also built one with the same rocerks but with a stock GM roller cam motor a few months ago. The flat tappet motor required 8.600" pushrods. The roller cam pushrod length I can't remember off the top of my head, but it was longer than stock.

In my experience, Trick Flow's recommended pushrods are too long. You can EASILY subtract .100" from whatever they recommend. In fact, I recommend that you do. I start from setting up CORRECT ROCKER ARM GEOMETRY and that determines correct pushrod length. What they recommend is too long. Yes, it's drop right in and work just fine, but if you're into details, measure for yourself and I believe you'll agree with me.

BTW- make sure your centerbolt valve covers don't contact any of the valvetrain. We found that the larger 1.43" valvesprings provided with the G2s would actually rub against some of the inner webbing of the stock centerbolt valve covers. That's BAD!

One last thing- don't sweat a few hundredths of an inch in pushrod length due to milling, especially with haydraulic lifters. It's not a race engine you're building and it's not THAT critical a measurement. But TENTHS of an inch- you gotta get those right!



[This message has been edited by Damon (edited August 09, 2001).]