Vacuum or Timing issue

Moistbois

Member
Dec 20, 2021
6
1
13
32
Pittsburgh, PA
Hello,

Just for the motor infor it is a new built 289 bored .040 with Wiseco pistons(part # pts500a4). Ford racing timing set. It has melling hydraulic roller lifters, and a bullet cam (see photo for specs).I have afr 185 heads, with upgraded springs. I am using trickflo 1.6 rocker arms and 6.300 comp push rods. I have a edelbrock dual plane intake. I am running Holley efi with hyperspark distributer with coil driver. Coil igntion. C4 trans with 2800 stall. Ford racing balancer.

The car idles decent but once it is in gear it bogs and exhaust backfires at low throttle. The distributer is phased and verified TDC with a piston stop. I have verified static timing with timing light. I have about 11" of vaccum. I could not find any vacuum leaks. and plugged all vaccum ports to verify. It says its reading a late timing issue? I am going to advance the standard timing to 22 degrees to day to see if this levels it out. Here are a few questions and concerns.


When adjusting the rockers there was a half turn of preload, the rockers have no up and down play but side to side play is evident. After running. No ticking clicking sounds can be heard. Is this okay or should there be none?

Is that vacuum okay for my cam specs. Its a bit aggressive but nothing crazy?

Could my timing be off? When I used the piston stop it was about 1-2 degrees off from the 0 degrees. This needs re verified as my bolt couldn't be locked down. (got longer bolt) Would this cause the lower vaccum and bog? and is this a problem?

When throttling my vacuum seems to be dumping out. causing a stall. I can show EFI logs if needed. Any ideas why?

Is 15 degrees a good start with this cam or should i go to say 22 and limit WOT to 36?

When I measured pushrods they were within spec. Does the 6.300 sound about right for this setup? I will verify the top pattern. again to make sure.

Any other ideas on why the car is bogging out/running low vacuum at light throttle?

Any help or knowledge is much appreciated.
 

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Moistbois

Member
Dec 20, 2021
6
1
13
32
Pittsburgh, PA
Hello,

Just for the motor infor it is a new built 289 bored .040 with Wiseco pistons(part # pts500a4). Ford racing timing set. It has melling hydraulic roller lifters, and a bullet cam (see photo for specs).I have afr 185 heads, with upgraded springs. I am using trickflo 1.6 rocker arms and 6.300 comp push rods. I have a edelbrock dual plane intake. I am running Holley efi with hyperspark distributer with coil driver. Coil igntion. C4 trans with 2800 stall. Ford racing balancer.

The car idles decent but once it is in gear it bogs and exhaust backfires at low throttle. The distributer is phased and verified TDC with a piston stop. I have verified static timing with timing light. I have about 11" of vaccum. I could not find any vacuum leaks. and plugged all vaccum ports to verify. It says its reading a late timing issue? I am going to advance the standard timing to 22 degrees to day to see if this levels it out. Here are a few questions and concerns.


When adjusting the rockers there was a half turn of preload, the rockers have no up and down play but side to side play is evident. After running. No ticking clicking sounds can be heard. Is this okay or should there be none?

Is that vacuum okay for my cam specs. Its a bit aggressive but nothing crazy?

Could my timing be off? When I used the piston stop it was about 1-2 degrees off from the 0 degrees. This needs re verified as my bolt couldn't be locked down. (got longer bolt) Would this cause the lower vaccum and bog? and is this a problem?

When throttling my vacuum seems to be dumping out. causing a stall. I can show EFI logs if needed. Any ideas why?

Is 15 degrees a good start with this cam or should i go to say 22 and limit WOT to 36?

When I measured pushrods they were within spec. Does the 6.300 sound about right for this setup? I will verify the top pattern. again to make sure.

Any other ideas on why the car is bogging out/running low vacuum at light throttle?

Any help or knowledge is much appreciated.
It is a 66 block, and has 351W timing. MSDS spark plugs.
 

Moistbois

Member
Dec 20, 2021
6
1
13
32
Pittsburgh, PA
For anyone with similar problems...I ended up adjusting the fueling to make it richer and this cleared up most problems. I need to take it to a tuner to get it fueled completely right. Seems its a large cam for a 289 and needs alot more fuel at idle...