Reusing pushrods

[tealcherokee]

You do not want to use old pushrods,(unless you know exactly witch rocker they were on and which valve,)I could give you a bunch of reasons why not to do it but they are so cheap to replace and for the peace of mind alone replace them with new. Good Luck

id love to hear these reasons

 

[Dr. Dyno]

You do not want to use old pushrods,(unless you know exactly witch rocker they were on and which valve,)I could give you a bunch of reasons why not to do it but they are so cheap to replace and for the peace of mind alone replace them with new. Good Luck

What you said certainly applies to reusing lifters (each one must go into the same lifter valley that it came from) but if your pushrods are in perfect condition, there's no reason not to reuse them. It doesn't matter if you mix them up either. Just make sure they're clean and that the oiling holes are patent. You can blow compressed air through them to clean them out.
I agree that new pushrods are cheap ($30-40 per set) so you could just replace the old ones anyway and keep them as spares.

 

[Cjmartz2k]

Then MAKE DAMN SURE the lifters either go back into the holes they came out of, or just don't move to begin with. Mixing lifters can destroy a cam in about five minutes flat...

You Have Been Warned.

5-90

That's why I was asking if he swapped cams :wave1:

 

[XJING]

id love to hear these reasons

When doing a swap and something gets mixed up (like both sets of pushrods ) the last thing you want to do is put them in and have the possibility of a even a very slightly bent pushrod throwing everything out of whack, Yes this happens more than most would think, its a no-brainer... Even with using the old lifters... IMHO.

 

[tealcherokee]

just as dyno and 5-90 said, if they're in perfect cond, it doesnt matter what hole they go in and there no reason NOT to reuse them....

im still waiting for LOWTECH to get back about grinding valves....

 

[Mike1331]

I thought grinding a certain area of each valve head is part of a valve job.
I hope so cuz mine were

 

[Mike1331]

Slight milling to straighten a head should not affect the valve train geometry enough to worry about it. Infact, you can easily make up that distance by using a fatter head gasket if you are worried about it; though you shouldn't be. Most heads are trued sacrificing a small amount of metal. Since you are changing years of head, you may want to at least compare lenght between the 83 and 93 pushrods. Using used pushrods is not an issue unless they are not straight (roll them on a flat table, if they go "thump, thump..." then they are not straight), or the ends are gauled. Hydrolic lifters are forgiving within a range. If you want to examine the valve geometry, you will need to take an old lifter apart and make it solid, then take your readings, both intake and exhaust.

Besure to use assembly lube or a bit of gear oil on the pushrod ends, yes both ends, the rockers and the valve stem to "preoil" them. It makes one hell of a squeeking noise if you don't (don't ask how I aquired this knowledge)

If you decide to have the heads fluffed, just go with a basic 3 angle valve job. Make sure when you get the heads back that all the valve stems sit at the same level. Unleaded seats are much tougher than their leaded counterparts and require less maintance.

Ron

Thanx zuki man


Thats some good stuff, Why can't they include this in chiltons. Nope they make us pay for info most of us really need and give us the crap we don't. I smell jewery amongts us.

 

[tealcherokee]

I thought grinding a certain area of each valve head is part of a valve job.
I hope so cuz mine were

lapping, or grinding the valve seats is a cover up for a bad valve job, or a just something a know nothing engine machinst does to ruin your valve job

 

[5-90]

Grinding a valve and seat should be done if:
A) new seats are installed
B) new valves are installed
C) a slight mechanical defect is noted in the valve seat
D) a slight mechanical defect is noted in the valve "margin" (the part that seals against the seat)
or
E) if the valves are pressure/vacuum checked, and it is noted that they will not seal.

After grinding, valves should be "lapped" to their respective seats, and NOT MOVED FROM THAT SEAT to another - or you're lapping valves again.

Grinding valves/seats "just on account of 'cause" is a good way to help put your machinist's kid through school - if you don't have them checked first. There's nothing wrong with doing it to correct a known or suspected defect, but I'd not do it just because I was there. I've pulled heads and just re-lapped valves, put the head back on, and everything was just ducky.

Why did I re-lap the valves? Because that's also a very good way to clean the valve margin and seat of carbon deposits and the like, and it only requires about a minute per valve (beyond time spent for disassembly and reassembly, of course.)

5-90

 

[tealcherokee]

grinding or lapping a valve should NEVER be done

im going to post this, and let me first say that anyone that beleive that a valve should be ground will not care or beleive me because they are too thick headed to understand, thats the end result every time this happens. If you would like to speak with someone who has about 30 years expierence as a good engine machinist, PM me and we'll set something up

grinding a valve seat is a crappy way to do a valve job (hense the need to lap the valve)

valve seat seats should be cut, with precise carbide cutters, weather its a 3 angle, 5 angle or radius cut (race app only).

Lets just say you get the normal 3 angle valve job done, the TYPICAL angles are 30*, 45*, and 60*. the angle of the valve is then set to 46*, one degree steeper, why? its called an interfearance angle, its to allow a rock hard seal between the valve and head for engine break in, that 1* will be gone in 100 miles or less giving you your normal seat of .060 for intake and .090 for exhaust (usually thats about the norm). anyway, so now that you have your freashy cut angles on the head and valve, you test the for concentricity put the valve in and NEVER rotating it, slap it into the head 4 or 5 times. Remove the valve, there should be a perfect pencil line going all the way around it, this proves that the seat is within the .002" tolerance, if the line doesnt go all the way around, the seat has a high or low spot. Spinning the valve if you have a high spot will give you the same (but misleading results)

now back to lapping. you now have a perfect, in spec valve and seat, and you take this "compound" that has the consistancy of tooth paste, with some rock mixed in (litterally rock, most of them use pumice), you smear it on the valve and literally grind this shit into the head and valve, therefore destroying your interfearance angle, and once beautiful valve job. so now you start up seal is shot, lets see what else we can ruin.
Theres now a layer of this stuff permently embedded into the head, what do you think displaces heat better, your steel or alum head, or pumice toothpaste...you guessed it, the metal of the head, so now your valves are running hotter.....so your 300k mile engine now starts burning valves at 100k.
Lets go beyond the head, see if we can ruin some more of the motor.... lets say you do a pretty good job cleaning up the head after lapping the valves....even still, some of its going to stay there, guess were that goes, into the combustion chamber..... rocks do real well at scrating up the cross-hatch you put in your cylider walls when honing it. the cross hatching is what keeps the rings spinning and oiled, so now you have a screwed up cross hatch, so your rings are getting unnecessary wear. Then this stuff could get into the oil, tears the hell out of the crank and bearings. There .001 clearance between the bearings and crank.....thats small, real small, 1/4 of the thickness of a piece of paper, not really room from rocks in there.

but go ahead, lap your valves if you want to....

again if you wanna hear it from someone w/ more expierence than most of you have been alive, or read it in writing, let me know

usually i get told to fuck off because i'm just some 20 year old kid....im not expecting anything more this time

 

[XJING]

TealCherokee, I am surprised that with all of your experiance being a machinist that you would "over the internet" with a guy "that obviously doesn't know much" tell him to reuse his pushrods. I guess I am on the side of caution when I can't be there to check each end for galling (no matter how slight) & roll them all on a piece of granite to test for trueness. Let alone the fact that all these pushrods come out of tired motors. My father operated a machine shop and all he did was high performance motors. Old school imports and domestics. I learned a little, and one thing I have learned on the boards. Don't let some newb go and save a few bucks when the potential is there to cost him more... Ok..... now I am off my soapbox too.... Good Luck

 

[tealcherokee]

i supose your right, but i took mine out of my 190k motor, and put them into the stoker, i checked them, and they were all fine, so i didnt see a prob w/ it.

if you dont know what your doing, new ones would be your best bet

 

[Slo-Sho]

So about cleaning all the carbon formations off the valve face...How should I go about this? Berryman's doesn't even phase it. Can I lightly take a wire wheel to it?

 

[CanMan]

So about cleaning all the carbon formations off the valve face...How should I go about this? Berryman's doesn't even phase it. Can I lightly take a wire wheel to it?

I wouldn't use a wire wheel. You may take off too much on the face of the vavlve, the stem, ect. I did all 16 of my in my SBC with steel wool and scotch brite. Also carb or brake cleaner sprayed on while cleaning, helps too.

 

[5-90]

Got a drill press? I've had good luck with chucking the valve stem in a drill press, spin it on a fairly low speed (~300-500RPM,) and touch a pad of Scotch-Brite gently to it. It might take a while, but it isn't going to remove any material, and spinning the valve should make it take things off evenly.

Just watch you don't get your finger sucked up... I haven't done that yet - I'll usually let go of the pad if I feel any pull more than I expect!

If the Scotch-Brite doesn't work, you might try emery or Crocus cloth (600 grit or FINER!) and a VERY light touch - but you'll end up needing to re-lap afterwards. Emery and Crocus WILL remove material, thus the very light touch...

5-90

 

[WB9YZU]

Valve lapping isn't neccesary. That's real old school stuff. With hardened seats and valves, it just isn't a required item anymore. If the valve job is done right, lapping the valves could actually mess it up by putting a groove in the valve face.

Cleaning of old valves can be done on a light wire wheel, I've done it lots of times. There should be no carbon on the seat itself, just the top, stem and tulip. Do not use sandpaper though scotchbright is OK with a little carb cleaner or mineral spirits.

 

[tealcherokee]

Valve lapping isn't neccesary. That's real old school stuff. With hardened seats and valves, it just isn't a required item anymore. If the valve job is done right, lapping the valves could actually mess it up by putting a groove in the valve face.

Cleaning of old valves can be done on a light wire wheel, I've done it lots of times. There should be no carbon on the seat itself, just the top, stem and tulip. Do not use sandpaper though scotchbright is OK with a little carb cleaner or mineral spirits.

none of the hard heads care.....i posted a shit load on it, no one cares, they ignore it

 

[WB9YZU]

LOL!
Yah, I suppose you get that after however many years of history that said "Lap the valves". An aircraft Mechanic I worked for ground seats as many do in that industry, and sure enough, lapped in the valves. Then again, those were not hardened seats.

When I started working on Chysler LA motors, I asked the guy doing the valve job if I had to lap them. He said "Not neccesary", then he went on to say exactly what you said about cutting the seats instead of grinding them. Same way with the valves, not ground, cut. I don't know of any mechanic who laps valves on hardened seats. Any shop up to speed with the last 20 years should be cutting and not grinding the seats.

As I mentioned a few posts back. Hardened seats just don't require the maintance they used to anyway, so this is all moot unless you want a "race" valve job done, or nicked the seat when you were enlarging the area in the bowl below the valve -ouch!-

 

[N20Jeep]

i have NEVER reused pushrods in ANY motor ive ever built....i dont care how good they look or how flat they roll...any time i pull old ones out of the block, new ones always go in

its cheap insurance, and theres no reason not to do it