Too much compression?

Stephen115

Stephen115

New Member
#1
#1
I put my motor together. Gx200 with gx160 head, flat top, .265 dyno cam. And when I go to start it, it had so much compression that it broke the pull start. So I check the compression release and it really isn't working. Like the release works on the cam but it won't push down the exhaust valve. I switched the push rods to some predator ones and it didn't help. I also noticed the intake rocker arm isn't touching the intake valve all the way, just resting on the valve retainer. I think it's the lifters but I could be wrong. I'm using everything from the gx160 head along with gx160 lifters and push rods.

Any help will be greatly appreciated.
 
Stephen115

Stephen115

New Member
#8
#8
65ShelbyClone said:
Those are your problems right there. The GX160 lifters are indeed shorter.

Get some lash caps like you should have already and put your GX200 lifters and pushrods back in your GX200...
Click to expand...
There's a little confusion, I swapped blocks and cranks. I went from a built gx160 to the 200 block and crank for the displacement and put everything on the gx200. I didn't really know the lifters would be an issue. I never ran lash caps because my gx160 ran great with or without them.
 
D

davidlamb78

Member
#11
#11
are you guys suggesting that we run lash caps on both valves? I just put my motor together over the weekend, and it has a ton of compression. billet flywheel, cm1 cam, 160 head, flattop piston, 20 over piston rod, cheater carb from dover, etc. i can pull through the compression stroke, but it's pretty tough. i set the valve lash at .002 and .003 like it said. i'm using the 200 rockers because of what i read in this thread.
i can't seem to get it to fire, and i'm wondering if i'll need to use an electric starter instead of the pull start. i have a friend with an extra old starter, but i'll have to change out the rod that goes to the motor. i think i just need to get the carb adjusted, but i haven't done that. this is my first engine build. i've done some small stuff like carb jetting and cam stuff before, but never this drastic.
do you think i should run a lash cap on both valves? any suggestions on my carb? things i should check? any info would be great!
stephen115, not trying to take over the thread. i just thought i'd add to the discussion since we're having similar problems. i can start my own if needed.
 
Txpowdercoater

Txpowdercoater

New Member
#12
#12
the compression of the motor doesn't really matter if the valve lash is set properly and the assembly is working freely on the cam. I have a motor with space shuttle type compression and it is the same as starting a stock motor because the system works as it is designed and adjusted correctly.
 
D

davidlamb78

Member
#13
#13
davidlamb78 said:
are you guys suggesting that we run lash caps on both valves? I just put my motor together over the weekend, and it has a ton of compression. billet flywheel, cm1 cam, 160 head, flattop piston, 20 over piston rod, cheater carb from dover, etc. i can pull through the compression stroke, but it's pretty tough. i set the valve lash at .002 and .003 like it said. i'm using the 200 rockers because of what i read in this thread.
i can't seem to get it to fire, and i'm wondering if i'll need to use an electric starter instead of the pull start. i have a friend with an extra old starter, but i'll have to change out the rod that goes to the motor. i think i just need to get the carb adjusted, but i haven't done that. this is my first engine build. i've done some small stuff like carb jetting and cam stuff before, but never this drastic.
do you think i should run a lash cap on both valves? any suggestions on my carb? things i should check? any info would be great!
stephen115, not trying to take over the thread. i just thought i'd add to the discussion since we're having similar problems. i can start my own if needed.
Click to expand...
well, i had said yesterday that i would recheck my lash. wish i would have. the exhaust rocker had backed off a bit and i wasn't opening the exhaust valve enough. made adjustments and it fires wonderfully. now i just need to get some good gas. it was getting HOT!
 
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