Help - Rocker, push rod, hyd lifter issue?
Help - Rocker, push rod, hyd lifter issue? Ok guys need some LS valve train help
I made a pressure pot & installed 6 quarts of oil in the my brand new LS 408 on the engine stand while turning over the engine slowly w/ a wrench on the crank to make sure the oil passages had oil upon fire up, then installed it in the car and cranked it over for the first time with the starter to build oil pressure w/ the spark plugs out, then I put the plugs back in it tried it again and it sounded just like it did w/ no plugs, it sounded like there was no compression….
FYI, this engine is still a roller hydraulic lifter, 7.100” push rod, and Harland sharp “Adjustable” rockers - So I took off the valve covers and backed off the rocker adjuster lock nut & the adjuster that was previously tightened to 1/2 turn for lifter preload. Anyway, turned it over again and it seemed to have compression.
The weird part is, with the adjuster backed out 100% so there should be slack or space between the top of the pushrod and the adjuster some of them still have preload on the lifter, it acts like the pushrod is too long?
I marked the tops of the valves and reinstalled everything and the roller marks are right the middle like they should be throughout the travel.
So my main questions are,
1. Do I need shorter pushrods or can I just shim up the rockers pedestal to achieve zero lash then proper preload on lifter?
2. Is there even a problem? I mean, since this engine has never even fired up to properly build up the lifter with oil, maybe I’m just over thinking this?
Let me know what you guys think. Thanks!
I made a pressure pot & installed 6 quarts of oil in the my brand new LS 408 on the engine stand while turning over the engine slowly w/ a wrench on the crank to make sure the oil passages had oil upon fire up, then installed it in the car and cranked it over for the first time with the starter to build oil pressure w/ the spark plugs out, then I put the plugs back in it tried it again and it sounded just like it did w/ no plugs, it sounded like there was no compression….
FYI, this engine is still a roller hydraulic lifter, 7.100” push rod, and Harland sharp “Adjustable” rockers - So I took off the valve covers and backed off the rocker adjuster lock nut & the adjuster that was previously tightened to 1/2 turn for lifter preload. Anyway, turned it over again and it seemed to have compression.
The weird part is, with the adjuster backed out 100% so there should be slack or space between the top of the pushrod and the adjuster some of them still have preload on the lifter, it acts like the pushrod is too long?
I marked the tops of the valves and reinstalled everything and the roller marks are right the middle like they should be throughout the travel.
So my main questions are,
1. Do I need shorter pushrods or can I just shim up the rockers pedestal to achieve zero lash then proper preload on lifter?
2. Is there even a problem? I mean, since this engine has never even fired up to properly build up the lifter with oil, maybe I’m just over thinking this?
Let me know what you guys think. Thanks!
Shimming rockers is for geometry not push rod length and if your swipe pattern in small and in the middle you don't need to shim further. Your pushrods sound extremely short but it may be what it is. You can only get on base circle, use an adjustable rod and then measure for what you need. If 7.1 is the length plus preload then it is right.
I agree on the shimming, I ordered an 6.800-7.800" adjustable pushrod to verify. Yes I agree they are short from the standard 7.400" but I'm running morel link bar lifters and adjustable LS3/L92 style rockers so I'm assuming this is why.
I thought about the comp tester but I figure I didn't need to considering its the same sound whether the plugs are in our out so I know the compression is escaping, I'm going to redo everything I did last night with a fresh look at it and see what I can come up with,
Thanks for the help!
I thought about the comp tester but I figure I didn't need to considering its the same sound whether the plugs are in our out so I know the compression is escaping, I'm going to redo everything I did last night with a fresh look at it and see what I can come up with,
Thanks for the help!
IIRC Morels are only .050 taller. That means you are losing .350 with the rockers. Anything milled off the heads? Did you actually measure the adjustable rod or go off turns or something? Your comment about some still having preload is odd too.
Good info on the Morels, didn't know what the difference between them and stock.
Not 100% sure on the milling of the LSA heads, I just sent in my LSA heads with my race ready LS3's that were set to 10.5:1 CR and told TEA (Total Engine Airflow) to match the same comp ratio, no I didn't use an adjustable pushrod, I assumed I could use the same 7.100" that the engine builder used for the LS3 heads. But now with the LS9 gasket, LSA heads and same parts as before the pushrods seem long but a little bit since some of the exhaust rockers still have preload on them with the rocker adjuster back 100% out.
I've got .020" shims coming today along with an adjustable pushrod to verify all this - I'll post back up my findings.
Not 100% sure on the milling of the LSA heads, I just sent in my LSA heads with my race ready LS3's that were set to 10.5:1 CR and told TEA (Total Engine Airflow) to match the same comp ratio, no I didn't use an adjustable pushrod, I assumed I could use the same 7.100" that the engine builder used for the LS3 heads. But now with the LS9 gasket, LSA heads and same parts as before the pushrods seem long but a little bit since some of the exhaust rockers still have preload on them with the rocker adjuster back 100% out.
I've got .020" shims coming today along with an adjustable pushrod to verify all this - I'll post back up my findings.
Good info on the Morels, didn't know what the difference between them and stock.
Not 100% sure on the milling of the LSA heads, I just sent in my LSA heads with my race ready LS3's that were set to 10.5:1 CR and told TEA (Total Engine Airflow) to match the same comp ratio, no I didn't use an adjustable pushrod, I assumed I could use the same 7.100" that the engine builder used for the LS3 heads. But now with the LS9 gasket, LSA heads and same parts as before the pushrods seem long but a little bit since some of the exhaust rockers still have preload on them with the rocker adjuster back 100% out.
I've got .020" shims coming today along with an adjustable pushrod to verify all this - I'll post back up my findings.
Not 100% sure on the milling of the LSA heads, I just sent in my LSA heads with my race ready LS3's that were set to 10.5:1 CR and told TEA (Total Engine Airflow) to match the same comp ratio, no I didn't use an adjustable pushrod, I assumed I could use the same 7.100" that the engine builder used for the LS3 heads. But now with the LS9 gasket, LSA heads and same parts as before the pushrods seem long but a little bit since some of the exhaust rockers still have preload on them with the rocker adjuster back 100% out.
I've got .020" shims coming today along with an adjustable pushrod to verify all this - I'll post back up my findings.
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FYI guys, the adj pushrod hasn't shown up yet but the .025" shims did so here's what I've come up with.
The first pic is the adjustable rockers I've been talking about
2nd pic is the pattern on top of valves with morels, 7.100" and these rockers - nice and centered but still preload on some of the lifters w/ adjuster backed out
Last pic is same setup other than .025" shims under the rocker pedestals. It fixed the preload on the lifters, now I can get to zero-lash then went 1/2 turn more, I don't see that it even moved the pattern? I'm calling it good what do you think?
The first pic is the adjustable rockers I've been talking about
2nd pic is the pattern on top of valves with morels, 7.100" and these rockers - nice and centered but still preload on some of the lifters w/ adjuster backed out
Last pic is same setup other than .025" shims under the rocker pedestals. It fixed the preload on the lifters, now I can get to zero-lash then went 1/2 turn more, I don't see that it even moved the pattern? I'm calling it good what do you think?
