Pushrod length

Hostile_1LE · 05-12-2024, 06:44 PM

I am a little iffy on if I measured pushrods correctly… and when I ran the car it seemed to run fine. No misfires or anything. If my pushrods were too long, would it run fine? What about too short?

Hostile_1LE · 05-13-2024, 06:34 PM

It actually seems my pushrods are .005” shorter than I need. I measured in-preloaded length at 7.83x” and Johnson recommends .035” +/- .010”. I have 7.850” pushrods from GPI, Is .020” preload not adequate? Would being at the limit of preload with a 7.875” be ok.

Baddawg53 · 05-14-2024, 02:39 PM

I went with a little more is better than not enough. I've read a bunch about expansion of the engines causing decreased preload too, that's why I chose to go higher rather than lower. I also read that Johnson took that into account, so short of custom lengths I went with just a bit too much rather than too little.

I have two pushrods that are 7.850 and the rest are 7.825, the 7.850 put the preload above spec, I believe they ended up being around 0.050" preload

05-12-2024, 06:44 PM	#1
Hostile_1LE Drives: 2020 Camaro SS 1LE \| Satin Steel Join Date: Jan 2022 Location: Lubbock, Tx Posts: 172	Pushrod length I am a little iffy on if I measured pushrods correctly… and when I ran the car it seemed to run fine. No misfires or anything. If my pushrods were too long, would it run fine? What about too short? __________________ GPI SS3 / GPI ported heads \| MSD Atomic / NW 103mm \| 1 7/8th LTH \| Roto-Fab CAI \| FlexFuel \| Tuned by GPI \| xxx Hp / xxx tq

05-13-2024, 06:34 PM	#2
Hostile_1LE Drives: 2020 Camaro SS 1LE \| Satin Steel Join Date: Jan 2022 Location: Lubbock, Tx Posts: 172	It actually seems my pushrods are .005” shorter than I need. I measured in-preloaded length at 7.83x” and Johnson recommends .035” +/- .010”. I have 7.850” pushrods from GPI, Is .020” preload not adequate? Would being at the limit of preload with a 7.875” be ok. __________________ GPI SS3 / GPI ported heads \| MSD Atomic / NW 103mm \| 1 7/8th LTH \| Roto-Fab CAI \| FlexFuel \| Tuned by GPI \| xxx Hp / xxx tq

05-14-2024, 02:39 PM	#3
Baddawg53 Drives: 17 hyper blue 2SS M6 Join Date: Mar 2018 Location: NorCal Posts: 624	I went with a little more is better than not enough. I've read a bunch about expansion of the engines causing decreased preload too, that's why I chose to go higher rather than lower. I also read that Johnson took that into account, so short of custom lengths I went with just a bit too much rather than too little. I have two pushrods that are 7.850 and the rest are 7.825, the 7.850 put the preload above spec, I believe they ended up being around 0.050" preload

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