General valve train issues

Hi guys.

This one is for all the 'cylinder head' guys out there.

We are having huge problems with keeping the top end of our motor together; our motor is currently eating pushrods, lifters, valves and destroying valve seats in our heads.

My crew chief and dad (who have been racing 30 years) have always installed valves the same way (checking spring pressure at 2" with a retainer and then shimming as necessary to get the right pressure) and we never used to think this was a problem.

However we bought a new set of valve springs and found they weren't the spring pressure we needed so we took them back. When we did, we were corrected on how to properly measure valve installed height and the method of the chap we bought it off measured the spring pressure correctly with these new springs (He used a 100 thou shim to act as the retainer and then shimmed from there). He then measured the spring pressures using our method and it read way more pressure than rated. With that, the seed of doubt has been planted; have we been building our heads the incorrect way? The only thing which throws the doubt in is that before this motor we've NEVER had valve spring problems, and we talked to a few other of the other teams cylinder head tech's and they all say our way is correct.

As you can imagine i'm desperately seeking a solution, the damage we are sustaining is ridiculous, which of course is triggering other problems down the line (damaging oil pumps from lifter breakups, damaging cams, mag driveshaft spindles snapping etc).

I want to sort this before the engine goes nuclear from the damage and ends up destroying the motor, or worse, damaging the car or even myself.

Thanks for reading.
Joe

 

Checking spring pressure

The shop that assembles my heads checks the spring pressure the same way you discribed, using a retainer, but what im wandering is where are you measuring your 2.000, I also use a 2.000 installed hight.. thats from the spring pocket to the bottom of the retainer...right... if your checking from the top of the retainer your spring at 2.000 you will a have alot more spring pressure, but will loose coil bind clearance.

Another thing, I dont see how a flat shim can replace the retainer for testing, I dont know about yours, but mine have a step for the small spring, so it runs at an installed hight of say...1.900, if you use a flat shim the little spring or springs (for triples) are not at there correct installed dimension.

I dont know your setup but if it was me I would go back to what worked for me in the past, or a tougher spring maybe.

Just my thinking... does this make sence???

 

Moparious:

We are measuring it from the pocket to the bottom, so i'm guessing our method is correct. The flat shim method actually fits in that step for the smaller spring, so the pressure is then tested on the bigger outer spring (The way I saw it done was using a 50p peice, which is a british coin that fits on top of the middle spring, so the top of that shim sits in the step so that it fits flush with the top of the outer larger spring. Our retainer has that same step, i'm not 100% but I think they are Manley retainers?

 

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Joe, the damage sounds like valve train out of control due to insuffient spring pressure. If dad was doing it before and it worked, that sounds like a no brainer to turn dad loose on it again.

Spring installed height means just that. To duplicate as close as possible what it will see when it's at home in the head.

I always use the retainer that I'm going to run with the springs. On my springs they are triple and the installed height is 2.100. The retainer is machined for the length of each spring, which are slightly different lengths. So when measuring the spring pressure at 2.100 if you don't use the retainer the two inside springs will give you slight incorrect actual in engine read. (hope that makes sense).

When I'm measuring spring pressure at installed height I set up a large drill press that I have with an old valve chucked up. I set the spring scale below that and then set the spring to be tested between them with the proper retainer installed. When I compress the spring to the 2.100 height (first one setup with sliding mic) the scale underneath tells me if the spring is proper or needs shimming.

In the head the mic that Mike Canter showed you is what I also use. With the valve in place along with retainer and keepers I measure how much distance there is from the retainer to the spring cup. Shim accordenly to get desired installed height that puts spring pressure were you want it.

Anyway......that's my story and I'm sticking to it.
PS..I'm in a bit of a hurry and hope I didn't confuse you.

Blessings..........Ron Clevenger

 

also goodson tools sells a great spring height mic..all steel..Dave Lowe
www.myspace.com/daveloweswr

 

You don't say what pressure you are looking for and what RPM you are shooting for. I would also want to make sure your end play is still correct. Roller lifters can't deal with endplay and maybe it is coming from the camshaft end of the valve train. I would still be interested in what seat pressure you have.
thanks
Dale

 

Thanks for the replies. Got some questions to those who replied.

Ron C: Yea my dad is setting up these heads too, I haven't changed who builds the heads, the only thing which has changed is the set of heads we use (We have gone from early AJ heads to '03 BAE fuel heads). It sounds like we are installing the valves the correct way (or at least that sounds like the general consensus) I did understand, thanks for getting in touch and sharing what you know!

Dale: We are looking for 340lbs of spring pressure at 2.00. As for rev range, in comparison to some blown motors it's quite a low revving engine, with the shift light set at 7800 with the motor just tripping the light going through the 1/4.

As for end play, i'll ask about that too!

Thanks everyone for getting in touch. For those who want to know, the valve springs we bought are Ferrea triple springs, I believe the part number is simply P1000.

 

this is how i do it, in your vice with aluminum jaws compress the spring with the retainer on it till it coil binds, measure the compressed spring, then add the actual lift of your cam, (that is total lift ) minus the valve lash, now add .060 and thats your installed hight.

 

Eli's method is a good one but don't forget your rocker arm ratio will change the total valve lift. Actual cam lift+ rocker ratio = total valve lift.
Total valve lift+coil bind+ .060=a good place to install the springs at. I always measure the actual installed height at each individual valve with the retainer and locks with one of those little valve spring checkers. I have yet to find a set of heads where every valve had the same installed height. Shim them as needed to get the correct installed height, don't just put them at the factory recommended installed height. Its amazing how many different ways there are to do this job. Dave Germain

 

Hi Joe,
Now we are getting somewhere. I personally run 450 on the seat and throw them out at this range. Now that is at much higher rpm. This may still work fine for you depending on how big your cam is. More importantly, running external oilers into the intake rocker shaft is very important. I had to add them to the brad 3's I worked with back when. Do you have external oilers. The lines should run up to a -3 fitting from the side gallery or oil pump. Brad 3's were very intolerant to lack of oil. I recommend when putting the pushrods in a mixture of anti-seize and 60 wt be brushed on the pushrod cups. then make sure the engine is free wheeled (plugs out) the first start of the day to make sure oil has traveled up to the rail.

Next, you need to turn the motor with a bar like setting the valves. Look with a flash light down the pushrod sleeves. Make sure the push rods are not touching hard. You may need to add extra shims or grind the rockers to relocate the pushrods if they are rubbing hard in the tubes. Not at all is great but light touch is more realistic. You will see the rub marks depending on the pushrod brand. Just move the rocker sideways back and forth at lash and you will see what I mean. It is a big time compromise where the rocker sits on the lash cap and the pushrod in the tube.

This may give you ideas as to what the head change has brought. Also do the new heads have bigger valves (heavier). Also might need more spring. Hope these are thought starters for you. Too expensive and dangerous to have this go on very long.
Dale

 

Hi guys, thanks again for all your replies. I'll answer more of what you've asked.

Mike:

When we ran our old motor (JP1 432ci with AJ heads) we didn't have any issues with the damages we are currently sustaining to our heads and valvetrain, yet we built up the heads the same way we used to with our current setup. I will find some cam grind numbers and get exact figures on that too. As for damage on either intake or exhaust, it seems to be across the board on both intakes and exhaust.

Dale:

Thanks again for your help. I will get some grind numbers for our cam which should give us more information about it on here. We don't run external oilers in our block, it's a plain Stage V KB block, but we do apply oils and graphite grease to the pushrod cups. As for warming the car through with the plugs out we keep the bridge on the MSD points box and the fuel off while we get oil pressure through the system before firing.

You mention about pushrod clearance, this weekend we were installing fatter pushrods into the heads and painting the pushrods and installing them to see where on the block or heads they touched. They did a few places and we've been machining very slight reliefs in the block and heads to allow more clearance.

The heads are ex nitro heads with slightly bigger valves over the old heads (2.375" in the old heads to 2.4" on the intake) but the exhausts are the same size (1.95"). Thanks for reading; it's wearing thin the damage we are causing (both mentally, physically and on the wallet).

Eli and Dave: I will definitely go back to the drawing board with our lift calculations and see if it comes up with anything different.

Also finally; I hope none of this sounds contradictory and not make sense, I'm still learning how to build these engines so if anything doesn't make sense i'll find more information.

 

Ok here is a question i have a turbo motor with AJ billet sbc heads 2.200 installed height i use a manly spring that is 350@ 2.200 with 1.058 coil bind cam is only 780 lift.i have had people say to use the 2.200 that on the box and others say use the coil bind+.060+lift to get the height if i did that i would be shiming about a 1/4 inch!!!! i would think a 2.200 spring with the lower lift would live better than a 2.00 spring. Guess i need to check my open pressure at .800

I drove a super chevy nitro coupe a few years ago it had a brad 5 ran a 2.200 spring but the cam was around 825 or so because we ran 30% nitro he did the coil bind+.060+lift deal and we were pulling the centers out of the retainers.pulled about an .125 of shims out and the problem went away.