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Old 09-08-2001, 06:00 PM   #1
lcvette
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Default HELP..Valve adjustment for new LT4 hot-cam Kit

Just installed the LT4 hotcam and 1.6 GM roller rockers on my 95 lt1..
Do I tighten the rockers all the way to the stops the same way as LT4 or
do i take the lash out and go additional turn. Please let me know since we are in the process this minute. Thanx a lot for any info.
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Old 09-08-2001, 06:53 PM   #2
Stratocaster
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Default Re: HELP..Valve adjustment for new LT4 hot-cam Kit (lcvette)

I did the same upgrade myself on same year C4. I found good results at 1/2 turn passed lash-out and did not have any chatter. I did open one of the the valve covers about 5000 miles later to give one rocker an additional 1/4 turn.

Now 15k mi into the upgrade and still noise free. Pulls very hard. Huge torque difference mid to high...
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Old 09-09-2001, 10:04 AM   #3
RichS
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Default Re: HELP..Valve adjustment for new LT4 hot-cam Kit (Stratocaster)

If you are using the stock non adjusable 10mm LT4 rockers they just get torqued down. If you have the 3/8 adjustable ones they need to be set around 1/2-3/4 turn from 0 lash. If you bought the 3/8 GM rollers they have a sheet in them with the adjustment procedures.
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Old 09-10-2001, 01:57 AM   #4
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Default Re: HELP..Valve adjustment for new LT4 hot-cam Kit (RichS)

Rich and Strat,
they are theadjustable 3/8", i turned mine to 1 turn past Zero lash, should i back off? wil this effect my power at all? or rev capability? your wisdom here is appreciated. the sheet recommended 1/2-1 full turn past zero lash. so i opted for the full turn due to a couple of them feeling loose at 1/2 turn. thanks again guys! also, Rich and strat what other mods were done to your 95's and what kind ftires etc ereyou running to get your best times, launch rpm's etc... just for a starting place this thursday at the track,i will adjut per tracion and response as needed, that first un is always kinda differnt ater some mods as these! tanks again guys!!

chris :smash:
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Old 09-11-2001, 02:18 AM   #5
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Default Re: HELP..Valve adjustment for new LT4 hot-cam Kit (lcvette)

Youre safe... Basically you are working withing the range of the hydraulic piston in the lifters.. you should be ok at one turn. I just stopped when I felt I went passed the point where the hydraulic piston was first actuated.. It is important that the slack is removed, but doesnt really matter as long as you are in the range of motion for the piston so that it doesnt bottom out. At 20 threads per inch, your additional half of turn is miniscule relative of what that piston can handle. what happens if you torque it down too much is the potential of the piston bottoming out is increased. if it ever were to do this, you will end up bending a rod at high rpms..

I run my redline/rev lim at 6500 now... of course higher compression valve springs and a roller timing chain set is recommended to do this. Otherwise valve float comes into play and the potentiality of a timing chain failure with the non roller chain at higher rpms. I have programmed the 1/2 shift at 6300 rpms.. at this rpm the car drops right into the sweet spot of the torque curve for second gear.... if i want to manually shift, i can take it to the brink of 6500 before rev lim kicks in. I run a 3:07 rear end which is kinda long for the track, but decent for street. these higher RPMs really helps the times out big.. also, when you run the higher rpms, you will notice that others who have to shift before you do will tend to fade as your motor keeps pulling/spinning (provided you have sufficient torque). take for instance two cars with the same torque and weight, but one red lines at a lower rpm than the other.. what happens is the one that raps out keeps pulling after the other has had to shift into the next gear (thus applying less torque to the ground) and ends up winning the race.

tires? Ive only used two sets. The OEM GSCs and SZ50s. I cant say enough about my contentment with the SZ50s. Very sticky at all speeds, both linearly and laterally.

chris, after your cam install, have the PCM programmed.. It will net you nearly as much as the cam install does. Reason being is the stock fuel trims were design for the mild OEM cam and emissions. Stock fuel trims are rich and poorly timed. A good tuner will take your cam specs and leverage retarded timing and lean mixes to get you another 30-40 horses depending on your other mods.. I would endorse Ed Wright (FastChips by Ed). He is extremely knowledgable and accessable.

chris, also while you have the car apart, it would be good for you to investigate underdriven pulley set and electric water pumps... these are good for another 20 horse at the flywheel.

good luck Chris!
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Old 09-11-2001, 09:33 AM   #6
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Default Re: HELP..Valve adjustment for new LT4 hot-cam Kit (Stratocaster)

strat,
thanks for all the greeta advice! the car is back on the road! the program was done by Ed Wright for the hot cam, sent it to him while the car was in for surgery. at this stage though i have yet to try a 1/4 mile blast. i am not excatly finished with the exhaust. i have about a 2.5' gap between mt 3" headcer collector and the 3" SLP system, i bought a 5 foot length of exhaust flex pipe from advanced auto and slid it into the headers and exhaust sytem to temporarily take some of the noise from the straight header sound out. this was done last night and tonight i will be taking her on a two hour venture to greenville to have some work done to get the correct pipe placed in and finally have the rest of the system welded instead of u-bolted together. right now i opted to stay away from the pulleys. i instead went with the electric waterpump and didn't want to take away from the alternator due to concerns for powering the new elec pump.
i will probably recheck the head torque wednesday after she has been driven and also back a half turn off on the rockers. i think this may help keep her from pumping up too soon at higher RPM's. i am loving the cam and heads i did so far and can't wait hear what she sounds like without the huge leaks in the exhaust, i can already tell she has some cackle and lope to her!! :yesnod: :yesnod: :yesnod: :yesnod: :yesnod: and i am very pleased with that! just a few more small things, wednesday i will also change the oil in her and filterjust to get some of the assembly lube out of the system and get under the car to inspect everything and hook up the O2 sensors. i am runnning without them right now, gotta have bungs welded in tonight. so she is running a little on the rich side to say the least. it will be nice to get everything straightened out wednesday nigth and know shes finally completely finished! thankyou for the advice and insight very helpful and welcome to forum, i noticed your post count was kinda fresh! keep up te great posting and watch those stars multiply by your name!!

thanks again strat1
chris :cheers:
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Old 09-11-2001, 09:33 AM
 
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