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Author Topic:   Engine timing / Valve timing
BB46
Dirt Roller

Total posts: 6
posted June 25, 2001 07:53 PM
Engine won't time. I'm guessing valve timing is way off. SBC 406 10.5-1. (Alky) Probably not enough compression. Roller cam. 630 lift. Needs to be WAY advanced to run at all. When timing gets to around 40 BTC the engine dies. You can hear it struggle on its way there though. That advanced it won't run high rpm either. (Spits, flutters, caughs, and when you punch the throttle it falls TOTALLY on its face.) At 40 degrees it also turns exaust bright orange at 2500 rpm in about 1 minuit. Do you think valve timing is retarded, advanced, OK, or something else? Tried 2 different duel points, 1 HEI, 2 carbs, plus trick gas with the second carb. Has same problems with all above. How much differance will a few degrees make in valve timing when you degree a cam in? Thought I would let the PRO'S think about this one. I'm stumped and frustrated.

Pickel
Dirt Freak

Total posts: 239
posted June 25, 2001 08:48 PM UIN: 25419780
Check your harmonic balancer. If it's spun it will throw everything off. We've run into that problem before.

BB46
Dirt Roller

Total posts: 6
posted June 25, 2001 08:56 PM
Crank Top Dead Centered on timing marks. If not exactly perfect was within 2 Deg. (FluidDampener)

dirtracer14
Dirt Maniac

Total posts: 128
posted June 25, 2001 09:36 PM UIN: 23443678
Hey butch we just ran into that same problem befor we blew the good motor at yakima. It was the balancer it was brand new and it was slipping from the outer ring,not sure if the fluid dampner is solid or 2 peice. Might want to check for a vacum leak also just tring to help, Glad to see ya out there but it would be better to see you back!! Email me if you need anything.18436572

[This message has been edited by dirtracer14 (edited June 25, 2001).]

BB46
Dirt Roller

Total posts: 6
posted June 25, 2001 09:55 PM
Craig,
I thought you puked your motor Friday at Nationals. You did run Saturday didn't you? Also,, I have heard that about balancers before. This always checks out TDC.
Just thinking,, I'm sure Leroy will let you borrow his "BIG BERTHA" motor. (I've never talked to him when he actually has had it IN his car.) hehehehe.
Thanks again Craig. Keep thinking. Valve springs on the FT 406 are at 180lbs. I would imagine thats borderline isn't it? Other motor (377)they were 220lbs.
BB46
Thanks again for the pic.

dirtracer14
Dirt Maniac

Total posts: 128
posted June 25, 2001 10:20 PM UIN: 23443678
We lost the 377 at state fair 2 weeks befor the nats and couldnt get parts in time, the motor from friday was the same motor we lost last year at the nats we tried it again and we had balance problems, and leroy lost the big gun this sat.I run about 150s with my flat tap cams ( cant afford rollers ).I hope you can get it figured out the car looks real nice,not much time to look around we were kinda busy hope to see it out there soon! Just give it a check i have over looked it many times is firing order? Is the water getting real hot lots of pressure on the hoses, Do you have a flow restrictor in it? If you want ill be on the live chat here for a little bit!

[This message has been edited by dirtracer14 (edited June 25, 2001).]

booting left
Dirt Roller

Total posts: 10
posted June 27, 2001 11:13 AM
we have come across this problem also
check the harmonic balancer to see if the outer ring has moved.we always mark the front of the balancer to quickly check for problems,if the marks move away from each other change the balancer

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