engine advice needed

[danny]

first off i will tell you what i am running. bronco of course. 289 bored .060 over ,edelbrock performer cam, roller rockers,edelbrock performer 289 intake, quadrajet carb, headers with dual exhaust,turbo mufflers,stock 3 speed. now is where i think i might have the problem. 1970 351 heads. they have been professionally rebuilt by a reputable machine shop.i have matched the springs to the cam, all new parts.the problem is the engine turns up slow.i did not cc the heads to see what kind of compression ratio i have. but i think it is low.it runs on regular pump gas fine.i have about 3500 miles on the truck since the rebuild.it puts out lots of power and sounds mean. it does not fire up real fast,and is very sluggish until warm.

 

[bronko69er]

"very sluggish until warm" makes me think its a choke issue.....
might want to check cyl pressures just so you know

 

[Socal Tom]

What is your ignition setup? Is the EGR hooked up? Do you have the stock air cleaner with the air heater setup on it?

I would check the compression, and if its good, then I would have it dyno tuned. My quess is that the carb/ ignition timing need to be dialed it.
Tom

 

[danny]

What is your ignition setup? Is the EGR hooked up? Do you have the stock air cleaner with the air heater setup on it?

I would check the compression, and if its good, then I would have it dyno tuned. My quess is that the carb/ ignition timing need to be dialed it.
Tom

no EGR , i have a 4" tall air cleaner not stock. as for ignition it has a pertronix flame thrower distributer and coil.

 

[danny]

"very sluggish until warm" makes me think its a choke issue.....
might want to check cyl pressures just so you know

the choke is not acting right. i do need to adjust that to get it working .when i start it even on warm days it still acts sluggish. when engine is up to operating temp it still does not turn up as fast as my old 73 with 302.it acts slow getting rpm's. running down the road after i get it reved up it will take the four barrels and really sounds and acts good.

 

[bronko69er]

Mine (manual choke) still acts sluggish on warm days (on a cold start) without the choke. Its probably not choking enough.

After its warm, reguarding low rpm sluggishness:
What RPM does the dizzy hit full advance?
Might want to get some lighter springs.....
Or could be the lower comp ratio......

 

[danny]

"very sluggish until warm" makes me think its a choke issue.....
might want to check cyl pressures just so you know

I am going out in the garage to get all the dirt bikes out of the way, then i will check the compressoion and get back to you.it is dark and very cold outside.

 

[broncnaz]

other than your choke issue I'd bump up the timing I'd run around 12 degrees it should pep it up a bit also you may want to check your jetting if its to lean or rich it could cause your warm sluggishness. As for the engine turning over slow it could be a worn starter or the battery is just not up to it.

 

[danny]

other than your choke issue I'd bump up the timing I'd run around 12 degrees it should pep it up a bit also you may want to check your jetting if its to lean or rich it could cause your warm sluggishness. As for the engine turning over slow it could be a worn starter or the battery is just not up to it.

the engine turns over fast when cranking, It just does not turn up rpm fast.i would think with all the high perf. parts it would turn up very fast, just not high rpm.it was built for low end torque.I think i will check the timing . it does not detonate at all. even with low octane gas.

 

[broncnaz]

Engines built for low RPM usually dont build RPM's fast. Hi performance parts dont always mean go faster. The camshafts used in 4x4's tend to build a lot of cylinder pressure. Where in a HiPo car you can use a big cam that builds less pressure and will rev quicker.
You want to get as much timing into the engine as possible with out any pinging. I'd try around 12 degrees most 302's will run pretty good at that setting.

 

[danny]

Engines built for low RPM usually dont build RPM's fast. Hi performance parts dont always mean go faster. The camshafts used in 4x4's tend to build a lot of cylinder pressure. Where in a HiPo car you can use a big cam that builds less pressure and will rev quicker.
You want to get as much timing into the engine as possible with out any pinging. I'd try around 12 degrees most 302's will run pretty good at that setting.

thanks for all advise. i will set TIMING at 12 degrees tomorrow and get back with you fellas soon.