Same cam, new heads, pushrod length question
Thread Starter
Joined: Oct 2002
Posts: 523
Likes: 58
From: Winnipeg, Manitoba, Canada
Same cam, new heads, pushrod length question Local shop says to use the same pushrods. I checked the length with the comp cams pushrod checker. 7.400 is where there is no play and the bolt is finger tight (11 turns on the pushrod checker). My old pushrods were 7.400. Using Johnson lifters and Yella Terra rockers btw. Johnson lifter preload is 0.035.
So the question is:
Should I get 7.435 pushrods or should I stick with the 7.400 pushrods because it won't make much difference?
Local shop said no. My old pushrods were 7.400 on this cam. But I have TFS heads and Yella Terra rockers now. I was surprised they were still the same length. But my car buddies here say I should get longer rods.
So the question is:
Should I get 7.435 pushrods or should I stick with the 7.400 pushrods because it won't make much difference?
Local shop said no. My old pushrods were 7.400 on this cam. But I have TFS heads and Yella Terra rockers now. I was surprised they were still the same length. But my car buddies here say I should get longer rods.
Last edited by Gripenfelter; Apr 9, 2018 at 09:55 AM.
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Verdad Gallardo Thread Starter
Joined: Oct 2002
Posts: 523
Likes: 58
From: Winnipeg, Manitoba, Canada
I'm gonna re-measure mine in 1/4 turns. I did 1/2 turns before. Also I'm going to colour the tips of my valves with a black marker and look for wear marks after I turn the motor over a few times with 7.400 pushrods installed. That will tell me where the rocker sits on the valve and if it's too short.
Last edited by Gripenfelter; Apr 13, 2018 at 09:10 AM.
I don't use the turn method as it's not relevant. Run the rocker bolt down while spinning the pushrod with your fingertips. Once the pushrod begins to tighten in rotation, that is zero lash.
Add your preload and that's the size pushrod to use.
You don't mention which lifter part number, rather .035" of preload. If the lifter is indeed the 2110 then set the preload at .050" which will be fine. I'm thinking they have .150" of plunger travel.
Another thing I didn't mention is the fact I'm using Harland Sharp rockers. The TFS heads need a quality roller rocker to reduce guide wear as introduced by the factory rockers.
Add your preload and that's the size pushrod to use.
You don't mention which lifter part number, rather .035" of preload. If the lifter is indeed the 2110 then set the preload at .050" which will be fine. I'm thinking they have .150" of plunger travel.
Another thing I didn't mention is the fact I'm using Harland Sharp rockers. The TFS heads need a quality roller rocker to reduce guide wear as introduced by the factory rockers.
Thread Starter
Joined: Oct 2002
Posts: 523
Likes: 58
From: Winnipeg, Manitoba, Canada
If I use your method of spinning the pushrod I would probably get different results. I'll try tomorrow and post my results using your way and the marker tip way.
I'm using Yella Terra roller rockers to reduce guide wear.
The lifters are Johnson 2116LSR (slow leak down).
I'm using Yella Terra roller rockers to reduce guide wear.
The lifters are Johnson 2116LSR (slow leak down).
Given the fact you have procured nice expensive parts. Take the time measure each and every I/e and call Manton with the requirements.
As others have stated if zero lash is at 7.4 then you don't have enough preload to suffice the plunger. If ordering Mantons is not a viable option I would order a set of 7.450", most generics will be .005" shorter than advertised.
My statement on the rockers was more of a blanket for future reference. I killed a set of valve tips with stock rockers in 2007.
As others have stated if zero lash is at 7.4 then you don't have enough preload to suffice the plunger. If ordering Mantons is not a viable option I would order a set of 7.450", most generics will be .005" shorter than advertised.
My statement on the rockers was more of a blanket for future reference. I killed a set of valve tips with stock rockers in 2007.
Last edited by brobinson216; Apr 13, 2018 at 11:03 AM. Reason: Left out info
Thread Starter
Joined: Oct 2002
Posts: 523
Likes: 58
From: Winnipeg, Manitoba, Canada
I feel really dumb making this post. The pushrod was caught up on the lip of the lifter so it gave an inaccurate measurement. Actual length of pushrod came out to be 7.650” with lifter preload.
I borrowed a 7.650” from a buddy and installed it at 22 ft-lbs. Coloured the tips of the valves with a marker to see where they would wear. The wear line is pretty much in the middle. If it was closer to the center of the motor it would mean the pushrod was too short. If the wear line was closer to the fenders it would mean the pushrod was too long.
I borrowed a 7.650” from a buddy and installed it at 22 ft-lbs. Coloured the tips of the valves with a marker to see where they would wear. The wear line is pretty much in the middle. If it was closer to the center of the motor it would mean the pushrod was too short. If the wear line was closer to the fenders it would mean the pushrod was too long.
http://i329.photobucket.com/albums/l...sengl2li3.jpeg
Last edited by Gripenfelter; Apr 15, 2018 at 09:11 AM.
I feel really dumb making this post. The pushrod was caught up on the lip of the lifter so it gave an inaccurate measurement. Actual length of pushrod came out to be 7.650” with lifter preload.
I borrowed a 7.650” from a buddy and installed it at 22 ft-lbs. Coloured the tips of the valves with a marker to see where they would wear. The wear line is pretty much in the middle. If it was closer to the center of the motor it would mean the pushrod was too short. If the wear line was closer to the fenders it would mean the pushrod was too long.
I borrowed a 7.650” from a buddy and installed it at 22 ft-lbs. Coloured the tips of the valves with a marker to see where they would wear. The wear line is pretty much in the middle. If it was closer to the center of the motor it would mean the pushrod was too short. If the wear line was closer to the fenders it would mean the pushrod was too long.
I feel really dumb making this post. The pushrod was caught up on the lip of the lifter so it gave an inaccurate measurement. Actual length of pushrod came out to be 7.650” with lifter preload.
I borrowed a 7.650” from a buddy and installed it at 22 ft-lbs. Coloured the tips of the valves with a marker to see where they would wear. The wear line is pretty much in the middle. If it was closer to the center of the motor it would mean the pushrod was too short. If the wear line was closer to the fenders it would mean the pushrod was too long.
I borrowed a 7.650” from a buddy and installed it at 22 ft-lbs. Coloured the tips of the valves with a marker to see where they would wear. The wear line is pretty much in the middle. If it was closer to the center of the motor it would mean the pushrod was too short. If the wear line was closer to the fenders it would mean the pushrod was too long.
http://i329.photobucket.com/albums/l...sengl2li3.jpeg
Pushrod length will not change the wipe pattern of a fixed fulcrum rocker like the stock LSx or the Yella Terra. Only way to affect the wipe is with shims or material removal depending on where the wipe pattern resides and its width.
Personally, that pattern should be redone to get a better wipe so you can gauge both position and width. You shouldn't do this by turning over the motor as the hydraulic lifter will skew the results. Once you have an accurate wipe pattern determine if the rocker height needs adjustment to obtain the correct wipe, then measure and purchase pushrods with the correct rocker height.