Interesting turn of events...something grew...or shrank

Topic: Interesting turn of events...something grew...or shrank (Read 1310 times) previous topic - next topic

Interesting turn of events...something grew...or shrank

April 15, 2008, 10:23:10 PM

Well...awhile back when I was still driving the Cougar(which was recently hacked apart), I swapped on a set of Cobra heads and Pro-Form 1.7rr's. At the time, there was about .090-.120" lifter pre-load...which is unacceptable...and the valvetrain always made noise.

Started working on pulling the motor apart yesterday and something possesed me to try spinning a pushrod after I got the V/C's off...sure enough...spun nicely...all perfectly zero lashed(which is insufficient). So I checked all the pedestal bolts...sure enough, all were still tight and to spec. Pushrods aren't bent, straight as an arrow. Lifter cups were fully up against their retainer clips. Rocker arms still look brand new, valves fully seated, etc, etc. Everthing looks fine...

WTF? lol.

At first, I thought maybe the bolts stretched...but that's a lot of stretch, and if they did stretch, they wouldn't still be torqued to spec. I'm just curious as to what the deal is here, I'd like to re-use the rocker arms on the rebuild...but not if the lash is going to change that drastically in under 3k miles.

Any ideas, help, advice, or previous Pro-Form rocker arm experience is greatly appreciated.

Thanks,
Don

Interesting turn of events...something grew...or shrank

Reply #1 – April 16, 2008, 08:29:52 AM

IF the lifters have sludge/varnish build up, lash will often change after a short run in...

Interesting turn of events...something grew...or shrank

Reply #2 – April 16, 2008, 11:12:51 AM

Problem #1:

Quote

Pro-Form 1.7rr's

You may want to read this:
http://www.foxtbirdcougarforums.com/showthread.php?t=16602

Interesting turn of events...something grew...or shrank

Reply #3 – April 16, 2008, 12:06:42 PM

What thickness of headgaskets are you running??

Interesting turn of events...something grew...or shrank

Reply #4 – April 16, 2008, 05:09:42 PM

Quote from: dominator;214266

What thickness of headgaskets are you running??

Standard issue Fel-Pro head gasket set...nothing fancy...had to keep the budget in mind at the time, so a basic Fel-Pro set was called into action.

All of my rockers look identical, there are no mis-matched 1.6's and 1.7's....this issue goes for every single rocker on the motor...exactly the same.

There was an odd looking wear pattern on the pushrod end where it contacted the rocker arm...BUT, it was only on some and it didn't look detrimental...again, the issue was with all of them.

Thanks,
Don

Interesting turn of events...something grew...or shrank

Reply #5 – April 17, 2008, 09:44:55 PM

Did you measure pushrods for correct length after the head change?

Interesting turn of events...something grew...or shrank

Reply #6 – April 17, 2008, 10:21:48 PM

sounds like the bearing in the rockers are worn..

i had a set of proforms get loose in a few hours of run time..

thats why my truck has cranes now.

Interesting turn of events...something grew...or shrank

Reply #7 – April 19, 2008, 09:59:49 PM

well, the bearings all still feel pretty good...I'm thinking about getting a set of Crane's...just have to puppies off these pro-forms to some know-nothing mustang homo...lol.