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Need some advise, 79 302 bored .060 over. in a 79 F100
Edlebrock Perfomer intake, Edelbrock 650 carb, elec choke, MSD 6ALN box, Crane WG1144 cam.
Truck seems to lay down on me during heavy acceleration, I tried to advance the timing a bit and I get bad spark knock.
I turned the diaphram out on the vacume advance as far as I can and put in as much timing as I can get and it's at 7 degrees.
Anyone got any ideas how to cure it?
Is it getting enough fuel? you might want to check the fuel pump pressure,there are testers available to hook inline and check with motor running. I have one from snapon,those pressure testers you use while only cranking the engine wont help you with a above idle pressure problem. Jeff
You can only get 7 degrees of advance at idle, or you can only get 7 on top of the base advance? Because you say you get spark knock so it would seem as if you're getting plenty of advance. If you can't get past 7 degrees, I'd say you should pull the distributor out of the hole, then rotate it enough so it will engage the cam shaft 1 tooth earlier. I would also check the accuracy of your timing marks by finding tdc on the number one cylinder and checking what your timing tab says. If that doesn't get you anywhere, your fuel mixture might be off or your carburetor is too large. 650 cfm on a truck cammed 302 might be kind of big. 600 cfm was plenty on the cars with the 80's h.o engines.
Fuel pressure is good, was a bit high in the begining but Weber likes 2 to 3 lbs, so I had to add a regulator.
Got a question on moving the dist to one toothearlier, what is that going to acomplish? Still using the timing light to set 7 degrees. Seems that it just moves the distributor around a bit.
Right?
Hit the button too early........
The 7 degrees is at idle. run it up to 2k or 3k and it goes another 10 to 15 degrees.
Another note, when I installed the cam, the card said the intake opens 3 degrees BTDC on the intake. I set the cam dead on, no preset on the cam. A fellow told me that I didn't need to index it since it was such a mild cam. WRONG????
Ok Craig ;A few things we need to talk about like how heavy is your truck, is this the same motor you had before you cammed it, If so how did it run before? Next I would get away from vacume advance and put the weight kit in your distributor for mechanical or new distributor. Next where is the power band on this cam,you see all these things plus more come in to play here. We will try to help if we can but we need a little more history on your truck. I belive that you have picked the right carb size for you truck, I think the problem is else where, how about your trany,is it automatic or manual, maybe the kick down is not working see you can get in to a lot of other things.
Vegas
The Truck is a standard 79 "Explorer" F100, long bed. This is the original engine, I rebuilt it 6 months ago due to 165,000 miles.
It had to be bored .060 over to clean the cyl. walls. As far as running before the rebuild.... well, smoked like crazy on start up, power was awful. The power band on the Cam is 2000 to 4800.
I had a valve job done on the standard heads. No shaving. Original Distributor, new cap,rotor button, new wires, plugs. Timming mark @ TDC was dead on when I assembled the engine. Like I said earlier, I did not index the cam, I set it just like normal cam. Bottom end, new pistons, rings, bearings, ARP rod bolts, new HO pump.
What else????
I think I got it all.
I like the idea of switching out the vacume advance for weights, don't know if it means much but the vacume hose from the distributor is connected to the carb on the passenger side of the Edelbrock/Weber. Oh, one more thing, all holes in the heads for the polution stuff plugged with freeze plugs.
Wehn I rebuilt the motor I was expecting a bit more HP than I have, I don't expect much but just a dab more than I wound up with. I love the truck, it's a grocery getter, neighbors use it etc.
Thanks for taking the time to help guys!
Ok Craig ;this helps me some, I thoght it was going to be a heavy truck! I did a ford with a cab a few years ago and it had a 302 in it to.Is this a automatic trany and at what RPM"S do you have this flat spot at thanks. Oh what kind of cam is it or who made it?
Vegas
Automatic, flat spot is from 2,500 up under WOT
The cam is Crane WG1144 Grind # 284H
Lift
intake @cam 3027
Wrong button..
Intake @ cam 3027 @ valve 484
Exhaust @ cam 3027 @ valve 484
Cam timing @ .050 intake open 3 BTDC Closes 33 ABDC Max lift 105
Looks like you've made all the right selections.the duel plane manifold edelbrock Performer is idle to 5500 good,650 edelbrock carb good,, headers good. You've done good on your selection of all the parts, there all in the right RPM range of each other. What size air cleaner/filter are you running.This will make a differance as well.
It was a Mr Gasket Chrome abortion. It had a real thin element in it and I replaced the element with a Fram element that is 14" in diameter.
Craig; what is the engine compression you know 8 to1 or not? I don't want to depress you but these 79 302's with 8 to 1 were only about 130 H.P. with a 2 barrel carb. Now your a little more with the intake and 4V carb an cam/headers all this helps.But you've got a heavy truck and with out more horse power it will probable will bog down a little, I would have told you to get some early 289H.P. heads for more compression of 10 to1 with about 230H.P. plus what you've added probable 280hp.But you've just done your heads. We had the same problem with the one that I worked on too. It would bog down under a heavy load, those trucks are very heavy for that 302 especialy if it has low compression of 8 to 1.
Vegas
To tell you the truth I haven't tried to figure the compression, it probably is 8 to 1 since I didn't touch the chambers or the deck on the block or heads. As usual, if I had it to do over I would have done a little porting on the heads. Ford heads for these small blocks are just awful. I have a little 1971 Triumph Spitfire that is just beggin for a transplant. That little 302 would do just fine in the 1,200 pound Spitfire.
vara4 thanks very much for looking at this for me, I think I sort of knew the answer when we started but I didn't want to admit it unless someone else agreed.
Too much truck not enough motor!
I'll tell you some thing If you do put that 302 in the other car. Go and get one of them old 351windsors it will bolt right up to your trany and motor mounts, 1969 was the best year. They had 290H.P with 4V carb stock and 10 to 1 compression,good engine.
And they used them in the Mach 1's hope this helped.
Vegas
hey there try going to fordmuscle.com for a step by step ignition tuning and distributor curving guide for fords great tips good luck
. . and that thread was 3 months old.
And I am STILL subscribed to it.
You never know, good stuff this forum!
Make sure your vacuum diaphram is good. Have the vacuum hose hooked up with the timing light connected and watch the timing advance. Also check your accelerator pump on your carb. You can enrich it or lean it. If it is sputtering on takoff its probable too lean. Also is it not good from a dead stop or is it bad from a moving stop. The reason I ask that is my 75 truck with a recent 429 build was chugging from a moving stop, but I took off good from a stop, stop. I played with a lot of stuff. But I figured out that the tranny (C6) was not shifting down to 1st unless I was almost stopped. Also It had already shifted into 3rd gear by 35mph. Maybe your tranny is doing the same. I think the ford guys were trying to save fuel? If I want power I shift manually now. I think a good shift kit its in the works. Also I noticed the more I drove it the more power. It needs time to break it. Especially with molly rings. Good Luck, Rick