Valvertrain noise, loose rocker, port matching... need help from guys in the know!

[Michael Yount]

I'm with Rick - if you're in a very tightly contested rules-limited racing class where every 1/2HP makes a difference - then port match things. But to pay $200 to have it done - no way I'd do it. It's simply not worth it -- you won't gain much from it at all.

In my old SCCA ITC racer, we blueprinted the engine. Competition was EXTREMELY close, and with a small engine to start with (1620 cc) I needed every advantage I could get. But that's the only one I've ever had port matched. For street cars, you'd be MUCH better off spending your $200 on something else.

Let us know what happened with the car once you get it figured out. If the pushrod is bent, I'd want to know WHY before I put it back together.

 

[Rick 91GT]

If you find that pushrod is bent I'd check the lifter and cam...and look everything over.

You definitly need to figure out why is bent if that is your issue.

 

[roush69racing]

If you find that pushrod is bent I'd check the lifter and cam...and look everything over.

You definitly need to figure out why is bent if that is your issue.

I agree with rick ( he seems to know ) you really need to find out why your pushrod bent< IE loose rocker?? are you using pushrod guides? are the pushrods hardend?, anyway, if your going to get them gasket matched, spend the extra cah and get them decked, (depending on your pistons) stock?? there will be a much better increase in power, (compression = HP)
umm oh yea my drafting picture coming soon..........(your gonna love it)

 

[jb89coupe]

Honda Land? U dont know who your talking too!! Listen to me, Iv been majoring in alterative fuels in college for sometime now, and my college professors TOLD me what to do. Are you calling my professors idiots?

If you'd just keep taking your medication your "college professors" would stop telling you what to do.

 

[astronut1885]

Yes, the pushrods were hardened. My mechanic said that the rocker being turned would cause the pushrod to bend. If it's bent, I'm going to put one of my stock ones in it's place until I get some FRPP ones like the ones there now from Summit. The rocker was fine, and the cam is new. I assume a loose rocker being off from it's alignment would **** the pushrod enough that it could bend. This all happened the night after I missed a shift and revved it hard to 5 grand, but I don't know if a small rev like that would cause this.

Mike- I'm about out of bolt on power parts for my car. I'm not going to change my H/C/I setup for a few years now. Once I get out of college, I am going to build a 331 combo with all new stuff. A friend who ported his heads out to gasket sizes said he felt an increase. My exhaust ports are so small that I don't see how they couldn't benefit from an increase. He's not going to just open the ends of the runners up, he's going to work the whole head to get better flow. It's more of a home done porting that uses the gaskets as a guide. I don't see how opening up airflow in the intakes and heads can be bad...
This is what they look like now:

 

[Michael Yount]

"said he felt an increase" -- you don't really want to spend hard earned money on a testimony as weak as this do you?

If you're talking about actually doing port work on the heads - that's another thing. But even then, have your 'porter' flow test before and after so you've got documentation that things actually improved. Just getting in there and removing material may not be much helpful if the person doesn't know what they're doing. Alternatively, I've seen amazing gains in flow just from a little bowl work, and a nice 3-angle cut on the valves. But just port matching - I'll promise you, it's only worth it if things are WAY off. And unless there's been major cutting of heads or block, they're not misaligned enough for port matching to make much difference.

I was gonna ask if you'd missed a shift recently. Did you check p to v clearance when things were put together? Was it an exhaust-side pushrod that bent? If so, it's possible you had a valve hit a piston and that's what bent the pushrod. Just a thought.....especially if you didn't measure p to v.

 

[ImportEater98]

Hey Rob! Good to see you posting again....long time no chat. Sorry to hear of your recent misfortune, but please take my advice:
If you want your NASCAR to make 8900 horsepower you need a college proffessor in semi trucks to mount 3 intercoolers, and he can't be a hater.

 

[astronut1885]

My P to V clearance is fine, so I don't think I smacked a piston into the valve. The rocker on this valve was off like 15*, so I'm thinking that caused it. When I missed the shift, I only revved to maybe 5k RPM, so it's not like I tached it out or anything.

 

[Michael Yount]

What was your p to v clearance?

The question remains - why did the rocker come loose/get cocked?

 

[astronut1885]

The nut on it had backed out. I don't have an exact measurement on the P to V, I wasn't there the night the heads were mounted, but my mechanic said I'd be all set.

 

[Michael Yount]

Was the allen-head locker for the nut still there but just loose?

 

[Rick 91GT]

If the spring is weak or not correct for your cam and the valves floated it is very possible that it hit the piston.

When the valves float anything can happen.

I like to loctite the poly locks on the rockers, ensures nothing backs out.

 

[astronut1885]

Allen head locker? The bolt that holds it in is an allen bolt. I pulled the rocker, and it was fine except for the rear corner, it looked like it had rubbed the valve cover. I pulled the pushrod, and while it didn't appear bent, it had alot of scoring in a swirl pattern. I put a stock one in it's place, put everything together, and fired it up. It's still screaching. I can't find where this is coming from. Any help would be great here.

 

[crunchie12268]

what about taking the valve cover off, and the with the coil wire off have a friend turn it over a couple times? push down on the back of the rocker to see if the lifter is squishy. Good luck

 

[astronut1885]

Well, I think I've narrowed it down to a lifter. Everything is all in good shape, and the lifters are 130k miles old. I never replaced them when I rebuilt the motor. I didn't have enough money. A friend just sent me some info on hydro lifters, and it explains why on cold starts my car misses and has no power. The lifter is shot and is not opening the valve. Looks like new lifters are on the chopping block.

 

[Michael Yount]

Astronaut said - "The nut on it had backed out. " I assumed because of that statement you had stud mounted rockers held on by nuts. Those have allen head lockers to hold the nut in place so they can't 'back out'. Sounds like you have pedestal mount rockers - so, it's the "bolt" that backed out, not the nut.

 

[astronut1885]

Yeah, my bad. I ordered new lifters tonight, and hopefully bu Thursday I'll have this wrapped up. I want my stang back in true fighting form already...

 

[Michael Yount]

Make a note to yourself (save it in 'favorites') to come back in and add to the thread - let us know what happened.

 

[astronut1885]

Will do Mike.

 

[astronut1885]

Well, I found the problem. I took the lifters out, and one of them is marred. The roller has a flat rough spot on it about 3mm wide across the width roller where it looks like it may have seized and the cam rubbed it when it tried to open the valve. It's not too deep, maybe 1mm. There are a few small nick marks on the roller as well around the edges. I'm going to try and take a look at the camshaft through the roller hole, but atleast I found the culprit. I hope I don't have to pull the cam out due to damage.