If using Champ 8 bolt GN1's the following facts are in play; 1) Champ has a specific P/N for GN1 valve C/L offset ( think it was 0.052") rocker , 2) Champ did not open up pushrod holes (maybe due to water jacket break out / porosity )- I would suggest a dry fit prior to install to review pushrod position in the hole, 3) absolute minimum 0.005" from any shim to any rocker , shim, pedestal must be observed for oiling, 4) bottom tap shaft bolt holes for best depth into casting to reduce pedestal cracking, 5) get shims from T&D to get flat of rocker roller over flat of valve tip, 6) MOST IMPORTANT; observe valve tips and pushrods through full motion of cam, (7) push rods will get very close to the casting in couple of instances & #3 exhaust roller tip will be the worst to get the rocker roller tip over the valve tip. This took a lot of trial and error but in my case everything lines up.
Gn1 heads t&d rollers?
- Thread starter bpman1234
- Start date
thanks I thought I was going to have to sell these so if I call champ they will get me the correct rocker with 00.52 offrset all iwould need olny 2? or more ?then call t&d and get the shims and then play with it till its good? and bottom tap shaft holes so I will have to take it to the machine shop to bottom tap?
This is the last time I will post in this thread. The T&D rocker assemblies,made for Champion GN1 heads,use the same rocker bodies as the T&D rocker assemblies for iron heads. You currently have these same rocker bodies. If you try to move these rockers over with shims and tubes and new longer shafts,you'll hate yourself when its over and won't like the results. The good news is that you will still be able to buy the T&D rocker assemblies for TA SI heads.
I beg to differ but the T & D rockers that I have which were purchased from Tom @ Champion have a rectangular body and a different valve centerline / pushrod centerline offset. The rockers which were purchased from Champion could very well be the TA/SI rocker asm's. I can only suggest to you that my system works fine. What causes a lot of pain with the GN1 system is the reluctance to open the pushrod holes slightly?? Champ should have notified their customers of this condition in their instructions so a dry fit observation can be made and the pushrod holes reamed as needed. These holes may only need 0.025" at the rocker pedestal deck of the head down 0.100" deep. The pushrod needs to clear the pushrod wall through all cam phases.If the pushrod casting tube is compromised by 0.025" by reaming then other problems exist. I'm sure a concern exists about a newbie grabbing a dye grinder and possibly hitting porosity and breaking through. I know my info is supported because I had to purchase additional shims from T & D and the P/N was dependent on the shaft O/D. Also I use 0.032" cometics at 8.6:1 with a 46 cc chamber and 8.025" pushrods (0.80 wall). I don't have a problem with my setup but it was a lot of work. I should let you know that I have been through 2 identical setups.
Thanks for all your replies love the info new I wasn't the only one that did this but glad to get real world answers from guys that been there done that and taking the time to post there experience and there remedies to my problems I also have comedics head gaskets to install just had not gotten there yet that would be the next after this .
I would dry fit everything first (oil your cam) so you can see your valvetrain through all 4 cycles. Do not tighten up your rocker oilers more than about 3/4 of a turn since you can shut down your oil supply to the rocker fulcrum and valve roller tip. I bought the rockers from Champion and they supplied a couple of shims. I purchased shims from T & D for about $25 for 0.020" thickness (maybe 20 shims-what a rip off). I purchased Trend 0.080 8.025" pushrods for around $80. You will need rocker studs (about $20), a bottoming tap,feeler gages & calipers. I believe the rockers were close to $500 from Champion. I think people are of the opinion that these heads will work with a stock rocker & I remember that being said in some Champion instruction. I don't have the nerve to try stock rockers on these heads.
turbo nasty
Turbo Dojo / MNTR
- Joined
- Jul 19, 2001
http://www.tdmach.com/pn-05940.shtml
What is that adjuster specification?
We never recommend turning the adjuster more than 2-1/2 turns down. Pushrod length is determined by the following: (1) Turn the adjuster all the way up into the recess in the rocker body until it stops. (2) Turn the adjuster down one full rotation. (3) This is the initial adjuster position. (4) Once the engine is fully assembled, this will be the starting position where lash will be set, and the adjuster should NEVER be turned one full turn either up or down. For general information, the hole in the adjuster that feeds oil to the pushrod cup shuts off flow completely when the adjuster goes just past two turns down from the initial adjuster position.
What is that adjuster specification?
We never recommend turning the adjuster more than 2-1/2 turns down. Pushrod length is determined by the following: (1) Turn the adjuster all the way up into the recess in the rocker body until it stops. (2) Turn the adjuster down one full rotation. (3) This is the initial adjuster position. (4) Once the engine is fully assembled, this will be the starting position where lash will be set, and the adjuster should NEVER be turned one full turn either up or down. For general information, the hole in the adjuster that feeds oil to the pushrod cup shuts off flow completely when the adjuster goes just past two turns down from the initial adjuster position.
- Joined
- Aug 1, 2003
you can forget those instructions .they are wrong .for one the adjuster will never stop ,it will turn out and you can remove it before it will stop
i just went through this after tearing into a friends motor that was way off on the combos expected hp ( track times) and finding T+D 1.55 iron set adjusted with four + threads above the adjuster nut ..i knew this was wrong just looking at it and the instructs on the T+D site arent correct either
so i removed the adjuster (backed out the threaded section ) and measured into the rocker from top to the center of oil hole and then set the adjuster nut on the adjuster the same distance centered on the oil slot provided in the thread .what i had was about 1/4-1/2 thread above the nut.. then threaded the assembly back into the rocker arm and had 1 thread extended from the underside . with the adjuster centered in the oiling hole theres is at least two turns (.100") up or down before oil will be impeded , they recommend no more than 1 turn either direction but there is more
so ..turn the adjuster down until its level with top of adjuster nut , turn it back half a turn . ( i usually start with adjuster flush on bottom )now get your pushrods measured with a tool and zero lash and you have enough window to adjust for for more or less preload or even for a rod thats ordered from a stocked size within +/- .050" (1 turn up or down)
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turbo nasty
Turbo Dojo / MNTR
- Joined
- Jul 19, 2001
Good catch I should have read it through. Biggest thing is the turns up/down before blocking oil flow
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- Joined
- Aug 1, 2003
turbo nasty
Turbo Dojo / MNTR
- Joined
- Jul 19, 2001
Cometics
