ok well i have posted here time to time about my project car i have been tinkering on in my freetime, it is a '71 ford maverick (my first car) that i got back when i was 15, it has since been stripped of its 170 6cylinder and the shock towers have been shaved and modified to fit a 351w in the 350-400hp range....so says the machine shop. well i have been having nothing but fits breathing life into this thing and blew a head gasket on initial break-in, i got ahead of myself and didnt bleed the block, it was my fault i should have noticed it only took 2gallons of water. got the gasket replaced and fired it up again, it ran rough at first, i revved it a couple times and it made a tink and smoothed out perfect. ive got over $3000.00 into this motor and the tink sound i heard was making me nevous, i pulled the valve covers to find that i had bent the #2 cylinder intake pushrod. i replaced fired up again, ran rough, revved and same noise, frustrated i pulled the cover off again to find a broken rocker arm on the same valve, i figured it was something to do with my EBAY heads i got for it. i pulled it and took it to the machine shop, they said the valve was slightly bent and binding, new valve, valve guide and off i went, re-installed and still could not get it right, adjusted the rockers, in frustration i had set the torque wrench too high and stripped 2 studs. I went and bought a new head from the parts store, installed and ran worse than before, changed plugs,wires,cap,rotor and coil and swapped carbs and a new dizzy, still nothing it would run, but not smooth and would backfire on revving. pulled the plugs and noticed 2 of the cylinders were full of gas well i stuck the plugs back in and fired it up to the same thing, i figured i better check the firing order AGAIN, well i couldnt find my Haynes manual, and found an old chiltons instead, well it appears that 3 of the wires were out of place, i fired it up and it ran WAYYY smoother, i revved it a couple times and it backfired and popped, i have always timed by ear and all the sudden BOOM the loudest backfire i have ever heard, i was assuming the 2 plugs mentioned before being soaked with gas finally sparking. well after that it was not running smooth again, i have replaced all the plugs to no avail. i stuck a compression tester and am not getting equal compression out of all of them ranging from 130-180psi, but playing around with the rockers will make it lose copression or gain a bit more. i am starting to think i may have toasted my cam during break-in? anything i should check before putting in a new cam? Sorry for the long read, but i figured to get an accurate answer the whole story needed to be out there PS-the Haynes manual is going in the garbage, i have since found it and it has mis-typed the firing order in the book
Dude you have way more patience than me! Sorry you are having all that trouble. Good luck with fixing it.
yes, playing with the rockers will most certainly affect compression. Like valves opening, or not opening. You are affecting the spring rate. Yeah, all of us have been in your shoes. Stop, find top dead center and start over with your valve train adjustment. Pay attention to the chiltons manual, it explains the correct procedure for STOCK engines. Is yours a stock setup? I feel your frustration, been there myself. And I dont think your cam is ruined. I just think you are way out of spec on your valve train and you are now lost. Top dead center is your start, next is distributor. Is it on time or 180 out? K, that is all I can lend, I paint cars lol. And as a disclaimer, I have forgot more than I ever knew. Dan
the motor is not stock, it has a shaved crank, 10.1 flat tops, balanced, i will call summit tomorrow to find out what cam is in it that will probably help, i think it is a comp cams and it has the 351w firing order for sure, it is supposed to have torqued rocker arms so i dont know if the adjusting them is gonna work to well, im afraid that they will just move out of adjustment, it has the stock cast iron 5/16 head rockers on it and stock pushrods, with stock heads and gasket porting.
k, good info, yes there is a torque on the heads, but I think you need to start over and find top dead center. Keep us posted. Dan
Are you using a 351 cam or 302 cam? They are same-same, you just need to use the firing order for the cam grind. Find TDC and rewire to match the cam used when the engine was built. Hope you didn't wipe the cam, good luck. Dave
it is a 351w cam for sure, i think i may have found my problem, i had 3 pushrods that were 1/4" longer than the rest and were slightly bent, on the other 2 cylinders that i am having problems with i cant get compression in them unless i back the rocker nut way off then it is almost too loose and wont stay in place, i think i need to grind a little off the valve stem?
Here is a trick to make your non adjustable rockers adjustable. Go to the hardware store and get 16 grade 8 3/8" washers, and 16 5/16" fine thread nuts. Remove the rocker nuts from the rocker arms and leave the pivot ball in place. Put the 3/8" washer down on top of the pivot making sure the washer is centered on the povot and install the stock nut on top of that. Make shure the lifter is setting on the heal of the lobe ( the bottom, closed) turn the push rod with your fingers and adjust the nut untill the push rod has tension on it (zero lash) then turn the nut 1/2 turn more. Then thread the new nut down on top of the stock nut hold the stock nut and lock the top nut into the stock one. This will be easy due to the fact that the stock nut had a 9/16" head and the one you get from the store will have a 1/2" head. Hold the stock nut with a box end wrench and lock the nut with a ratchet. (this is a poor mans adjustable valve train) I have done this several times with stock heads and aftermarket cam. Works very well. I know you are saying that sounds a little fishy but it works and your engine needs to have the valves adjusted and it is a whole lot better than tearing them apart and having some ground off the valves. That adds another twist to the whole thing, How much do you take off. This is a quick and easy way to get the proper lifter preload and will get the valves where they need to be and not open. You will have to do one at a time but the outcome will be well worth the time. Good luck Don
hey that is some good info, i will be picking the stuff up tomorrow ill let ya guys know how it goes....thanks again!!
Yeah, gotta watch out for those Haynes manuals. I've had three seperate ones for three different kinds of cars, all listed the wrong firing order and caused me hours of work and alot of $$ needlessly spent. I'm never buying another Haynes manual.
Assuming that your replacement head is the same as the ones that were on the motor, and that the cam has less than .5 lift, you need to identify what valves you are running and what rockers you are using. If you have the extended valve tips then you need the rail type rockers (they have sides that keep the rocker on the valve) if you are not using rail rockers then you should have guide plates to keep the rockers on your valves. Do you have hydraulic or mechanical lifters? Mechanical lifters should be adjusted BEFORE you start the motor. If you have hydraulic lifters there is a preliminary adjustment that should have been made before the engine was run the first time and you should have adjusted the valves during the initial break in run. check to see that you have the right stuff for your valves and then start with the distributor pulled out and the spark plugs out of the engine but gapped and ready to install. If you are running a Holley Carb, you will need to replace the power valve - you can suck a lot of fuel through one that has been ruptured with a back-fire. Double check your compression - with 10:1 compression you should have 180 PSI and with a new engine it should be within 5 or 10 psi from cylinder to cylinder. If the compression isn't even then you have problems - fix that before you start the engine. After compression is right then put the distributor in. Start by timing the distributor on #1 TDC. Double check your firing order and wire it up. To time the distributor you roll the engine over by hand with your finger in the #1 spark plug hole. As you roll it over you should feel the compression escaping from the #1 hole - se the engine to the NEAREST TDC by the hamonic balancer. Rocking the engine back and forth 1/2 rev (1/4 each way) should put a suction and pressure against your finger in the #1 hole. Set it to TDC again and put in the distributor. Make sure that as the distributor is set in place the rotor is pointing to the #1 plug wire on the cap. DOUBLE CHECK this! Put the wires on the plugs and then on the distributor in the firing order. When you finish be sure to double check it. After it is buttoned up crank it over. if it backfires you have something wired wrong - go back and check it again. (make sure you are using the choke - a lean mixture can cause a backfire) Start it up and let it run at 1200 or so while you make any final adjustments. Put a timing light on it and time it to the specs - your ear is not good enough to time a cars engine - especially after installing a cam and high compression pistons. Once it is timed then take it around the block nice and easy. If it back fires you still have a problem.
ok well i installed new pushrods and used the above mentioned trick with the stop nuts to make them adjustable, i checked compression and all were right at 180psi so i stuck my finger on the #1 plug hole and waited till it blew off and dropped in the dizzy, i had to hammer it down slightly to get it to sit flush with the block, well i fired it up and it ran great, nice and smooth i revved it a few times then was letting it idle and it died, i figured it was because of the alternator issues i have been having so it is currently not hooked up, and my battery is shot i have to put the charger on it just to start it. i let it sit on the charger awhile and still no fire, i just installed a new battery today and no fire, i pulled a wire and plug, grounded it and no spark, i pulled the cap and bumped it over with a screwdriver, the rotor dosent turn? i pull the dizzy and it is missing half the teeth? what gives?
That's what happens when you hammer a distributer into the engine. You may have locked up the oil pump as well. You might wanna get this towed to a prefessional shop and have them get it sorted out for you.
Any ideas what? i refuse to take this thing to the mechanic, it is personal now, and i want to figure this out myself!!!!
