Reactive as opposed to proactive solution to PTV clearance problem...?

Topic: Reactive as opposed to proactive solution to PTV clearance problem...? (Read 6193 times) previous topic - next topic

Reactive as opposed to proactive solution to PTV clearance problem...?

December 23, 2010, 03:58:22 PM

As the title admits, I was not proactive about this and you can beat me up over it, whatever. Lesson learned. I seemed to recall a member here having had GT40 heads on top of a flat-top pistoned 5.0 and so I went ahead, bought 'em threw 'em on, got everything sealed up and painted and I REALLY don't want to tear this fresh thing apart again and either a) screw the GT40s and use my E7's like I had originally planned way back with this engine bay teardown or b) flycut the pistons.

I have .045" of clearance on intake, and .085" on the exhaust. I took the spring off, bolted the rocker back down, held the rocker tight against the pushrod, and with the valve sitting against the piston, used a feeler gauge in the gap above the stem.

How hard and fast is this ".080 on intake, .100 on exhaust" rule? How close is "close enough"? What does it account for? So that the worst case scenario won't cause destruction, AKA the engine is grossly overheating while being spun at 6 or 7 grand? These cars' tachs redline at 5 grand. The electronic limiter is 6150 or 6250 depending on who you ask LOL. The red car has then naturally seen that limiter numerous times, through donuts and burnouts. It's never gotten rough or made any weird noises during that time. Always sounded like it wanted to be there honestly. Would that mean no [significant] valve float happened?

A chart I have says that F3ZE heads like mine have 60-63 cc for the chamber. 60-64 for E7TE. What's the difference? Just the design? Milling it? Or is the only PTV issue with GT40's because of the bigger valves? If I wasn't going to work in an hour I'd sit down the do the trigonometry and find out what my clearance might have been with the E7's.

I found these, shockingly: http://cgi.ebay.com/ebaymotors/Ford-stud-302-1-5-Scorpion-roller-rocker-arms-1080-_W0QQcmdZViewItemQQhashZitem43a388c131QQitemZ290506457393QQptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Assuming of course I can get the right stud blah blah valve covers etc...might these help the clearance enough? If the motor isn't going have the piss wound out of it (which is how I intended to treat the thing *anyway*, the silver cat is the whipping boy), could this work?

I know I'm going to get a lot of "only way is to check" responses. At least that's my gut feeling. Can't hurt to try though, right? If I have to buy them and test them and possibly flush $300 down the toilet, at least I'd have a 50/50 shot as opposed to nothing.

Reactive as opposed to proactive solution to PTV clearance problem...?

Reply #1 – December 23, 2010, 10:35:21 PM

Wow. Tough not to give a cryptic answer here. Some people learn by others mistakes, some by their own.

If you'd like to learn by your own, fire it up and see what happens. The most likely result will cost far more than some paint and a set of gaskets.

If you'd like to learn from the mistakes of others. Pull the heads and measure.

How hard and fast is the guideline for valve clearance? The pistons are pretty hard on the valves really fast! The valves, guides and maybe pistons become junk.

Putting studs in a stock head to use those roller rockers is a waste of $. Besides, you'll have to pull the heads and send them off to the machine shop to have studs installed. Not what you'd call a simple solution to the problem...

Hope you have good luck, which ever route you choose:D

Reactive as opposed to proactive solution to PTV clearance problem...?

Reply #2 – December 24, 2010, 12:23:41 AM

I had ported E-7 heads and an E303 cam with aftermarket double valve springs and no issues with the other engine before the GT40-P. BUT,each engine is different.Personally,I'll bet a set of head gaskets,that with good valve springs and an H.O cam with those heads you'll be fine.

Reactive as opposed to proactive solution to PTV clearance problem...?

Reply #3 – December 24, 2010, 12:39:32 AM

Okay, didn't realize machining was required to put those rockers on. I guess I'll cut the pistons. I just don't have much confidence in not getting metal shavings where they shouldn't be :(. I'll have to plan out a creative way to contain it.

I do have the H.O. cam vinnie. Definitely no intention of a high profile cam in this motor, ever. I could also just clean up the old E7's it had, now sitting on my bench, paint them and then put em back on and sit on the GT40s for something else or try and sell them. Does anyone make thicker head gaskets or is that just another stupid idea? LOL

Reactive as opposed to proactive solution to PTV clearance problem...?

Reply #4 – December 24, 2010, 05:29:37 AM

I would not use those scorpion rockers. I have just heard alot of bad things about them, and that their machine work is not always up to par. For less the $100 more you could have very good rocker arms. You will need new springs, if you have not already. Use the GT-40 heads, tape the top of the pistons, or you could try cutting foam out and put it around the piston. Maybe shaving cream?

I personally would not use thicker head gaskets. But yes you can get them.

Reactive as opposed to proactive solution to PTV clearance problem...?

Reply #5 – December 24, 2010, 05:46:39 AM

Read here.

http://sbftech.com/index.php/topic,57.0.html

Reactive as opposed to proactive solution to PTV clearance problem...?

Reply #6 – December 24, 2010, 08:12:19 AM

Quote from: Haystack;346881

Read here.

http://sbftech.com/index.php/topic,57.0.html

How many times have I quoted the original post from that thread on this board? A lot. Not worth converting to stud mount FWIW. Buy stud mount heads if you want stud mount. Otherwise get RR's in pedestal mount for those heads if yer set on keeping them.

Reactive as opposed to proactive solution to PTV clearance problem...?

Reply #7 – December 24, 2010, 08:22:56 AM

I have roller rockers in the classifieds.They are SVO 1.7 roller rockers. The E-7 heads,1.7's and the H.O cam would really make you happy. Have some port work done on the heads as well. If not,it would still be a fun car.

Reactive as opposed to proactive solution to PTV clearance problem...?

Reply #8 – December 24, 2010, 11:14:00 AM

I wouldnt even consider the rockers anymore. I thought they would just bolt on. I was surprised I even found that ratio at all. Chebbies use 1.5 stock, we're 1.6. I fully understand why max lift isn't what's important, I have seen you quote that thread those many many times V8Demon

But my thinking was that the bigger ratio made it open faster as well, sounds like that's not the case. Even still, I'm not going to change anything with the valvetrain. If I go back to my E7's I'm just gonna leave it with what it had, because I know that worked and would make me feel most comfortable.

How touchy of an issue is flycutting with the overall balance in the rotating assembly? I read in more than one spot that if you take off too much you'll upset the balance. It looks like I'd only need to grind a reaaaally small amount off for each relief...about .050 - .060 and I'd be golden for both valves.

Reactive as opposed to proactive solution to PTV clearance problem...?

Reply #9 – December 25, 2010, 11:29:19 PM

there isnt any way you could fly cut by hand and have the same amount of weight removed unless you have a jig that guided a dremal to do the work. IE- like have a piece of ply wood cut to allow the dremal to follow a curve / depth while the piston stays stationary.

hard to explain but you get my point. I wouldnt ever consider doing a fly cut by hand and know all my pistons weight remained the same. Not to say it hasnt been done free hand, its just that free hand would not be my best suggestion.

Reactive as opposed to proactive solution to PTV clearance problem...?

Reply #10 – December 25, 2010, 11:32:14 PM

wait, wtf am i talking about.. it lmao

REedit..

it's easier to just spend 100 bucks on a set of speed pro pistons.. their valve reliefs are deeper than the stock HO's

Reactive as opposed to proactive solution to PTV clearance problem...?

Reply #11 – December 26, 2010, 12:05:48 PM

But, with new pistons your going to upset the balance anyways. Could be more or less then flycutting. Unless your going to pull it all apart anyways to balance it, just pull the valves out of your e7's, and use them as a guide. Do some reading on that SbFtech. You will learn alot.

Reactive as opposed to proactive solution to PTV clearance problem...?

Reply #12 – December 26, 2010, 08:38:38 PM

At this point I would just pull it apart and put in new bearings and pistons. The engine is already out of the car so you might as well do it now.

Reactive as opposed to proactive solution to PTV clearance problem...?

Reply #13 – December 26, 2010, 08:41:13 PM

Quote from: thunderjet302;347173

At this point I would just pull it apart and put in new bearings and pistons. The engine is already out of the car so you might as well do it now.

you're not building a full blown race motor where the correct pistons aren't available, they're plentiful so i would just go new.. not to mention, it's nice knowing you have a fresh set in there with zero miles

Reactive as opposed to proactive solution to PTV clearance problem...?

Reply #14 – December 26, 2010, 08:55:03 PM

Get some Trick Flow heads... No valve reliefs necessary and are far better than any cast iron Ford head...