200 Big Red High Compression

[rugman316]

Just wondering if someone can answer a question for me. I picked up a 1984 Big Red a few months got it running fixed it up a little that sort of thing. It runs pretty well but still seems a little off. I finally got around to borrowing my buddys compression tester and its testing around 190 I am thinking thats pretty high considering I think its supposed to be somewhere in the 150 range. Anybody have any idea what could cause this is? Could the top end have been redone with some sort of different piston or done completely wrong? Any help would appreciated.

[oscarmayer]

that's actually normal compression. that's a 8.8:1 piston in there and that's stock.
I run a weisco 10.5:1 in my big red with ported head CNC valve job, web stage3 cam and hardened rockers and titanium retainers and performance springs. basically a hot top end and performance clutch. runs like a scalded ape!!!! my compe is 228 so your about right for yours. may have a little bit of carbon buildup bumping it to a 9:1 rating from the stock 8.8:1 but that's still ok.

[rugman316]

I might take the head off just to see what its like in there for carbon build up or am I just wasting my time?

[lndy650]

get a light and look down the plug hole. you can also inspect the valves this way by looking on the exhaust stroke and intake stroke. carbon never hurt anyone ive never seen enough to raise the comp ratio significantly. maybe 9:1 at the most. you can also tell what piston you have by looking in the plug hole if it has a dished top its stock if its flat its a 200x piston and if its domed its a 10.5:1 or a 12:1

[rugman316]

Ok looked down the plug hole the piston has a pretty thick layer of black on it. I think I am going to take it apart and clean it up in there. I needed something to do tonight anyway. Should the two back studs come put fairly easy if I double nut them.

[lndy650]

youll probly need a new head gasket if you do take it apart. they usually rip.

[daniel_250r]

i would run some engine cleaner in it and call it a day, once you get into it you mine aswell put in new rings, lap the valves. if shes not smokin leave her be

[oscarmayer]

i agree the carboin will NOT hurt a thing. don't touch it unless you have too. it actualyl gives you better performance. more power is not a bad thing.

[rugman316]

I decided to leave it alone. Another question would a bad plug wire or coil give you a miss at high rpms or would it not fire at all?