Topic: 302 rocker adjustment problems

[paul302289]

hi everyone, i'm new here and i live in the uk.I am having some real problems with a 302 engine in my sierra xr8 (merkur built in south africa for racing) i recently pulled the motor to swap for a different one i had stored to allow me to rebuild the origional , i have been told it is a 1968 motor. The motor had been dismantled and re assembled by an engine builder for the previous owner as he had it as a spare for his gt40. I got the motor into my car and got it started but the rockers were making one hell of a noise. I pulled the covers off and found that the rockers needed adjusting, i assume the engine builder couldn't do it because the followers needed some oil in them. I had run the motor so i proceeded to adjust them . They were still not right as when i started some of the rockers had jumped off of the valves. I did them again and the same thing happened. Everytime i did them, ran the motor then checked them they had chaged and i could not get them right. In the end i did them with the motor running and seemed to had cracked it, i just wound them back untill the normal clacking sound turned into a louder tap then wound it in, i did this to all of the right hand bank then an extra half a turn, seemed to solve the problem appart from if i nail the motor a bit one of the rockers gets noisey then gradually quietens down? the left hand bank of cylinders seems to be fine and requires no further adjustment!!!! can anyone help me, thanks, Paul, ps i also own a 66 coupe!

[Soaring]

The rockers in the 302 should be hydraulic and not need adjustment if there is no wear.  My suspicion is that you need to replace the rockers with new ones that aren't worn out. 

[paul302289]

I realise that, but the slack does need to be taken up and then wound down a further 1/2 to 3/4 of a turn. I have followed this to the letter and still found them to be too loose. I have checked them for wear and everything seems to be ok. that's why i am at a bit of a loss. These motors are a bit new to me as we only have punny 4 bangers or at best a v6. Your v8's are so simple to work on wich is why i am a bit concerned i am having so many problems with it.

[Soaring]

OK, here is a "how to" article.  Check it over and see if you have followed these procedures.

http://raceabilene.com/kelly/hotrod/valveadj.html

[paul302289]

i read the article and its basicaly what i've done, i used a book called "how to rebuild small block fords" it does show a sequence to do it when you only need to index the crank 3 times. i have checked, double checked and tripple checked it, thats why i rsorted to doing it while running, seemed to be the best way so far! what really gets me is that it is only on the right hand bank of cylinders???
could the rocker studs be pulling out of the head? what keeps them in?

[Soaring]

That's a really good book.  The rocker studs have threads that screw into the head.  Try turning them and see what you get.  They should be secure and tight. 

[rmodel65]

ok i believe your following the wrong procedure there 2 types of rocker arms rail and non rail. the non rail is adjustable

this is a rail style rocker


this is a non rail



the non rail uses the procedure you have been doing














the rail type setup has no adjustment, you just torque them down and your all done, the stud has a positive stop on the rail setup with a "shoulder". (the non rail stud is the same thickness all the way down the stud) iirc the stud torque is about 22-24 ft lbs

Self Aligning “Rail” Rocker Arms
Originally the small block engine used a machined slot in the head to guide the rocker arm on the valve. It has been common to enlarge this hole and install a guide plate when switching to a high performance valve train. Later model engines utilize a small alignment slot or “ears” on the valve tip end of the rocker where it contacts the valve. These rockers must be used with long stem valves. These applications can be easily identified by a large (1/2”) hole where the pushrod passes through the head and the fact that there is no pushrod guide plate. If the head in question has either a guide plate or a slot to guide the pushrod, the rail type rocker arms cannot be used.

[rmodel65]

could the rocker studs be pulling out of the head? what keeps them in?

iirc they are pressed in and only the Hipo 289 heads have screw in studs

[paul302289]

i have non rail type like in the top pic and there are just holes for the pushrods to go through. i have a lter motor that i took out that has screw in pedestals with guide plates under them and crane roller rockers. could i pull the studs out and tap a thread to fit the screw in type? if the are pressed in is there a possabillity that they are pulling out and altering the rocker heights??

[Soaring]

I had assumed you had the adjustable type since you mentioned the book.  Stephen is right, in that the studs are pressed in. 

[rmodel65]

take a picture of your setup

[paul302289]

Ithink i know what i have now!! the motor had rail type rockers but the press in studs have no stop on them. The pushrod hole are about half inch. i thought that the studs might be faulty so i removed them and some of them came out very easily. I then taped the holes 7/16 and fitted a set of screw in studs, again no stops, just parallel. I then tried to fit the guide plates and roller rockers off of the other motor. The rockers bottomed out on bottom of the stud so i machined the underside of the hex to make it thinner and gain some more clearance, still no fit. My last thing was to install the rail rockers on the threaded studs. I know that the raised bit were the studs go in need to be machined down by about a 1/4 inch to allow the fittment of the guide plates and roller rockers, but pulling the heads was not really an option at this point, i was looking for a quick fix to keep me going so i could rebuild the origional motor i took out, something that is long overdue. Everything adjusted up nicely then clattered like crazy, checked adjustment all out again, re adjusted still bad, they seem to tight now.
Released all the rockers again tried a different set of pushrods, a slightly different lenght, still the same. removed them again, removed the inlet, fitted the followers from the old motor in desperation, still the same??any ideas? cam? throw it away? cost is a bit of an issue at the moment so just ned to get the thing on the road as cheap as possible, Paul

[rmodel65]

pics

[paul302289]

i know, got so carried away with doing the bloody things i forgot to take one. i will do it tomorrow and post it tomorrow eve,

[Soaring]

Get yourself a set of AFR 165 heads and be done with it.   

[rmodel65]

AFR 165's would be nice

[paul302289]

absolutely pissing with rain,couldn't do it. tomorrow. i have read about the afr heads and was very impressed, might get a set for my other engine that came out of the car and needs a rebuild, thats why i need to get the other motor reasonable so i can use the car.
would you recomend a 347 stroker kit or keep it tame with a 331, i have read about probs with the oil rings on some of the 347's.
i have also seen kits for less than 700 bucks? are these crap and should i spend a bit more?
should i stick to a big company like summit or jegs or are they all the same sort of thig, i'm at the mercy of you guys a bit here, regards, paul

[Soaring]

I would stick with Summit and Jegs type of companies.  You need the guarantees they offer  for their products because those Chinese made parts are not reliable.  Hey, if you are going to take the time and effort to do a project, do it right the first time. 

[paul302289]

mmmm yes i know, if i knew you before you could say i told you so! i bought the motor in good faith and even got the paperwork for a teardown, inspect and re assemble? for what motor i am not sure. i can locate the seller on a gt40 forum, i will tell him he was ripped off as he got it for a spare fore his gt, or so he says. there is nothing i can do s it was a while ago i got the motor and i should have torn it down and done my own inspection for the sake of a set of gaskets, you live and learn.
still not done the pics but did do a comp test and they are all over the place, heads of tomorrow, i'll let you know what i find, paul

[paul302289]

more developments now, pulled the r/h/head off and pistons 1 and 2 have got a load of slack, i think this could be my problem. a compression check prompted me to go down this route, 4.2,10.2, 8.7, 8.6, 8.6, 8.7, 8.7, 8.6 (bar) i don't know why no 2 is hgher than 3 and 4 as the pistons are so slack, oh well, wish i had a boat, i could use it as an anchor.