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Tech / General EngineIs your car making a strange sound or won't start? Thinking of adding power with a new combination? Need other technical information or engine specific advice? Don't see another board for your problem? Post it here!
I am trying to select new valve springs and need some advice. I'll try to keep this short.
The problem: I have had two sets of lifter/pushrod/rocker failures and now a broken valve spring.
The choice: Should I go with a better, somewhat stronger dual spring or a beehive spring?
The combination: SBC- Comp hydraulic roller 229/239 @ 050 .600 lift w/1.6. QNX lobes which are fairly intense. About like XFI lobes with a little more lift. Cam was ground with a .950 base circle. Short travel race retro roller lifters, Ultra pro roller rockers, magnum pushrods. AFR heads w/8mm valves and 8019 springs. 140 seat @ 1.810 410 open @ 1.210 450# rate. Pushrod length/geometry good.
The plan was to go with Comp beehive 26918 LS spring setup with 125 seat @ 1.800 348 open @ 1.200 372# rate. I figured the beehives are supposed to be better at controlling the valve train with less pressure and that would relieve some of the stress on the valve train.
Comp is recommending a 26526 spring with 146 seat @ 1.800 449 open at 1.200 505# rate. A stronger spring. This does not relieve valve train stress from a static standpoint. However, if some of the problems I have been having is due to float, or loss of control, the better, stronger spring set may be the answer.
Either way I am going with a tool steel retainer to reduce weight and will double check geometry etc. Any thoughts?
You only need a spring similar to what's recommended for the camshaft but it doesn't end there.
The heads need to be set up for that specific spring. Depending on the diameter, the spring pocket may need to be enlarged. The springs need an install height. Depending on your valve lengths, the install height may not be enough. Spring closed height depends on lobe lift/rocker ratio. Depending on how compressed the spring is at full lift, there still needs to be roughly 0.060" between the coils. Also a full lift, the bottom of the retainer may be hitting the top of the valve guide/seal causing problems. If you're not using a roller rocker, the slot in the rocker may hit the rocker stud at full lift also.
0.600" lift is a lot of lift for a SBC. Since the springs you want are very similar to what you already have, I think the broken springs, pushrods, rockers are not cause by the valve springs. What pistons are in the engine?
Sounds like a harmonics issue or geometry problems. Also valve control to break rockers and pushrods. As said above, sure the valves are not hitting piston? If it floated it might.
Float can be caused by lack of spring pressures and harmonics or wrong geometry.
Are the 8019 springs installed at stock afr height? Not shimmed?
I think the 8019 springs should handle that cam. But i would shim them to .060-.070" to coil bind, for seat pressure closer to 180.
Coil bind is listed as 1.080". Install height should be near 1.80-1.81" from afr. A .650" cam would be .080" from coil bind. You are far from bind so you might be suffering spring surge. Running closer to bind helps fight surge.
Seat pressure is 155 at 1.81". Shim .030" will give you 1.78" height and 169 lbs seat. 0.100" from bind.
.045" shim would put you at 1.765" height and 175 lb seat. 0.085" from bind. I would start here and use a titanium retainer.
I would also recommend 3/8" pushrods if you can fit them. Go over length again to verify geometry
The 210 heads are cut for large springs (1.60 I believe) and locators from there. Open pressures given were based on 1.800 install and .600 lift not catalog dimensions. The heads are basically LS in valve stem size and I believe length.
Yes, the current springs are 8019's factory installed at 1.800. I haven't measured the shim under the locator but it is .030+ just from feeling it. I can shim it up more to get closer to bind at lift.
I don't necessarily think the springs "cause" the problem except for the pressures they exert on the valve train. I do think loss of control is very likely a problem. I guess the question is what is the best approach to correcting it, more pressure or finesse. I am sort of confused about all the hype regarding the beehive springs. Comp tech said if I had an LS he's recommend them but since I have SBC he recommended the 26526's. He sited the heavier lifters, longer pushrods and bigger(?) valves as the reason.
These may be unrelated but a couple of things I noticed. The past few times I went to the strip I was having to pull fuel (VE) from 4800+. Not a ton but it was going rich where it was ok before. Could this be a clue regarding valve float? About a year ago when I was on the dyno the operator asked if I had hit the rev limiter. I had not but I wondered later if his ear was picking up something, possibly valve float?
Between these and the issues I have had with the valve train I am trying to take a different approach. I agree the 8019 seem to fill the bill but possibly going with a different spring would better match harmonically.
I can certainly shim closer to bind and increase the pressures. If float, not too much spring is causing the wear issues then that certainly sounds right. I was just thinking in the opposite direction. But I am not an expert and that is why I am asking for advice from others I trust not just whomever answers a tech line.
I dont like beehives as if the geometry is wrong or the valve continues to float and spring breaks, you drop the valve. Takes out the piston and head. Double spring usually does not break the inner springs at same time
What did the dyno curve look like? If he heard what sounded like a limiter it might indicate float.
I really think you need to put those springs in at a 1.76-1.77" height. The spring pressure will help but closer to bind will help fight any surge/harmonics
Ls valvetrains arent much lighter here. Lifters and pushrods are similar. You already have 8mm stems. Ls has advantage in shaft rockers
do you have 7/16" rocker studs?
The 8019 springs are PAC springs. Very good stuff. Should not be breaking parts and springs unless something is very wrong
... had two sets of lifter/pushrod/rocker failures and now a broken valve spring.
Pushrod length/geometry good.
Either way I am going with a tool steel retainer to reduce weight and will double check geometry etc. Any thoughts?
Breaking a rocker. Breaking a spring. Breaking a pushrod. Sounds to me like there's contact somewhere.
Coil bind.
Piston to valve.
Poor geometry.
As for the geometry, what is your testing method?
As for the others, that's a measured value. What is your P/V clearance? What is your clearance at max lift between coils?
While I'm not at .600", I have successfully run the 26918 spring with tool retainer to 7000 RPM (often) with lifts of .575" using an XFI lobe. That spring offers more control with less pressure as you point out. They also offer more lift capability with greater clearances (with respect to coil bind) due to their design.
The dyno curve peaked at about 5700 and was still pretty flat. Didn't go beyond 6k but no fall off was seen. Yes, 7/16 studs.
The rockers and PR didn't break but galled at the joint, created lash and then the lifter plunger was beaten out. At least that's the theory. Lifter could have gone first due to float beating it.
Based on install height and spring specs there shouldn't be bind although I haven't had a spring tested. The piston to valve clearance was listed on my build sheet as .100+ but I didn't measure it.
Geometry. Have tried a few things and currently am using Comps method of intake side of valve cross the mid at mid lift and exhaust side at max. Leaves a wide contact (short pushrod) Have used the mid lift @ 90* but the contact patch is reaalllly close to the edge. I know the contact location shouldn't matter but I was persuaded by Comp to use their method after the second pushrod/lifter/rocker issue. The motor was delivered this way and I had tried the longer pushrods (1/2 lift) after the first pushrod/lifter/rocker issue. I have had the problem with both geometry setups.
I am interested to know you have run the 23918's. That is the PN I am considering along with the tool retainers.
I also hear the caution regarding the single spring. The inner spring is likely why there wasn't piston damage. In fact I probably ran a few runs and drove home with the broken spring. The only reason I checked everything is because it was idling a bit rough and the VT was a bit noisy. It was not catastrophic.
Last edited by antman89iroc; 04-06-2017 at 11:04 AM.
One other thing I want to point out. This is a true daily driver. Not every day but every dry day that I don't have to haul someone or something. It spends a lot of time in the 1800-2500 RPM range. Most of the time in fact. It's only at the track I can really let it stretch it's legs. This is a factor in my thinking the beehive springs may be a good choice. But in the end I want the best for the combo. If replacing the rockers & springs every 20k is what it takes then fine but I would rather get more miles out of it. The real bummer is the unexpected problems. I know I am pushing the limit on cam lift for a daily driver and possibly that is my downfall.
At this juncture my choice is between the 26526 springs (very similar to the 8019 AFR's) or the Beehive 26918's. Cost is about the same with the beehives being about $100 less for everything. The 26526's are hi-tech springs with a lot of treatment/peening to make them last longer but still dual brute springs.
Its not so much a pressure issue with longevity. Its valve motion from aggressive cams.
Sounds like not a spring related issue. This is a dart shp block? What lifters are you using? Galling the pushrod cup at the rocker and lifter sounds like lack of oil. Is it getting oil thru the pushrods?
Small base circle cam could have the lifters fall down in the lifter bore below the oil band. You should have the plus .300" tall body designs.
I never heard of the comp method of sizing pushrods that way. You certainly dont want a wide contact sweep. Sounds more like a geometry issue here
And for a daily driver i would have went with a different lobe for sure and also largest base circle that fit
Mine is a daily driver (more or less) as well. The difference being mine sees red-line every day, several times a day. It's also made several cross-country trips of 5-6000 miles (return) and has plenty of hours.
That said, after a half dozen engine iterations and literally more than 100 000 miles with several sets of 26918's, I had my first failure. Fresh top end. Springs had about 10,000 miles. That day saw no engine abuse however I returned home to an engine idling poorly. I had at most about 500 miles on the reassembly (with the 10k springs). No rhyme or reason for the failure. Geometry was set like it should be, using the mid-lift method to get the narrowest possible sweep across the valve tip, and then went so far as to order Crower's offset trunnion rocker arms which pulls the contact patch away the valve tip edge.
The only difference with this engine combination and the one previous is that this cam is advanced 4 degrees and puts my intake valve to piston clearance at slightly more than .100". That, as I understand it, is a close as you want to get. Did I have contact? I sincerely doubt it but...There's no evidence of a bent valve.
The single spring failure didn't result in the valve dropping into cylinder. I still had to use a spring compressor to remove it. Your results may vary.
That your pushrod tip galled at the rocker arm suggests a couple of things. Separation as you point out is likely. Poor angularity is another although you say you've done the geometry more than one way with similar results.
Best guess here is that there's a loss of valve control with the result being the lifter is lofting off of the cam lobe. The other loss of control, with the valve bouncing off of the seat, may produce the same results.
You're probably aware of David Vizard's testing of the Beehive springs vs conventional. I've attached a screen shot of one of his articles. (I hope he doesn't mind).
I never heard of the comp method of sizing pushrods that way. You certainly dont want a wide contact sweep. Sounds more like a geometry issue here
I'm tending to agree about the geometry although the oiling is an interesting insight.
I lost several hydraulic roller lifters due to oiling. In my case it was because that particular shortblock, having ingested a flat tappet cam once before and after the rebuild, it ate up the fuel pump lobe on the cam (it was literally milled completely from the cam core), put a lot of metal in the engine and I suspect the lifter bores were whacked. Not to mention that the lifters themselves were put back into service after the pump lobe failure and the internals looked to have been sandblasted (but that's a different story).
I've seen too many failures and know now how critical this geometry measurement is. Hence the $500 Crower rockers.
And with an aggressive lobe like you have, along with the other contributing factors, suggests that this needs to be readdressed.
Out of curiosity, how many miles do these heads have on them with this particular configuration?
Once again, thanks for the input. Lot's to digest/address.
SHP block. About 30k miles total. Lasted approx. 18k before the first issue. Then around 2k and now 10k or so. I don't have my notes with me so this is from memory.
The first cam (and first issue) was ground on .860 BC. The second cam is .950 BC. Small yes and if I ever do another it will likely be with less lift and larger BC.
I am very aware of DV and his tests. That is one of my sources. I am also aware of the centerline rockers and on my "wish list".
I accept the geometry plays a big role. There are so many varying methods and I just haven't had a lot of problems in the past so my experience is limited. I "like" the 1/2 lift @ 90* method (mid-lift) the most and it would require off set rockers to get there. I am currently running 7.400 pushrods but have used 7.650 and that got the pattern width down to about .040" but the contact patch was very near the edge of the valve. I use lash caps because the rockers beat up the valve tips and the extra width helped. I may go back to them upon reassembly even if I don't get the back set rockers yet.
Oiling could be an issue. In fact that is how I found the first lifter failure. On the last (current) assembly I did prime assembled until I saw each rocker get oil. When it is running there is oil dribbling at each rocker but not shooting out like a stocker. I did verify the lifter to oil passage alignment by measuring from the dist hole and it was good. The second cam brought the lifters up ~050 too which was perfect.
Last edited by antman89iroc; 04-06-2017 at 02:06 PM.
On the oiling topic, what weight oil do you run? I am currently using Valvoline 20/50 and that may have been too heavy for winter cold starts. I think once it warm up it is fine but I am thinking about going back to 15/40 Rotella. Since the second pushrod/rocker issue I have been adding Comp zinc additive every oil change.
The contact patch ended .030-.040 from the edge of the valve stem. It was probably .100 from the edge of the lash cap. This is from memory but I can check my notes later.
Your description of the problem sounds to me like typical spring harmonics, strong enough to make the coils boioioioioioinnnnng against each other. Guaranteed to indiscriminately trash just about ANYTHING that gets in the way.
The 1219; Comp 787 retainers; keepers to match your valves.
Don't worry about "where" the contact patch is. (within reason... your description seems OK to me but I'd need to see it to be sure) Look for the narrowest possible, then choose the next shorter push rod than that, which will slightly "bias" the error in favor of occurring while the pressure is less (at lower lift). Remember, there is ALWAYS error; you need to plan it out so that the error is on the side that works in your favor if you can make it do that, or at the very least, so that it has the least severe consequences. Getting it "perfect" is less important than making sure it doesn't explode if something happens over the course of time and reality, and it becomes "less perfect".
They make dual springs too, if you're worried about dropping valves. http://www.texas-speed.com/p-5040-pa...l-springs.aspx Haven't researched that for a traditional SBC, not sure whether there's any retainers in existence for that combo. I suppose you could www.emachineshop.com (the 2nd coolest site on the Interwebz) some titanium ones if it really came down to it. Won't be cheeeeeep but will be exactly what you need, if you engineer it right. You may need longer valves.
Its not so much a pressure issue with longevity. Its valve motion from aggressive cams.
Sounds like not a spring related issue. This is a dart shp block? What lifters are you using? Galling the pushrod cup at the rocker and lifter sounds like lack of oil. Is it getting oil thru the pushrods?
Small base circle cam could have the lifters fall down in the lifter bore below the oil band. You should have the plus .300" tall body designs.
I never heard of the comp method of sizing pushrods that way. You certainly dont want a wide contact sweep. Sounds more like a geometry issue here
And for a daily driver i would have went with a different lobe for sure and also largest base circle that fit
What he said. Without proper lubrication, your camshaft & lifters cannot survive, and
oil cools the valve springs. Guess what happens without it?
Are your push rods rubbing on the outer walls of the intake ports?
Last edited by NoEmissions84TA; 04-06-2017 at 08:26 PM.
Look for the narrowest possible, then choose the next shorter push rod than that, which will slightly "bias" the error in favor of occurring while the pressure is less (at lower lift).
GREAT advice.
I will go out on a limb here - he has a lack of oil problem to the valve train.
Oiling could be an issue. In fact that is how I found the first lifter failure. On the last (current) assembly I did prime assembled until I saw each rocker get oil. When it is running there is oil dribbling at each rocker but not shooting out like a stocker.
It's probably due to those short travel roller lifters.
I seriously doubt spring surge. He's only turning <6000 rpm. Sure, it's possible. But he also does not have the heaviest valve train setup like a BBC.
Is this only happening on 1 head (pass side), or both.
If it's only happening on the pass side, then your lower distributor shaft housing is either causing a massive oil leak to that lifter bank, or it is cutting off the oil supply somehow.
If the screw in plugs at the rear if the block (for each lifter bank) were screwed in too far, this would reduce or cut off the oil supply to the lifters.
Last edited by NoEmissions84TA; 04-06-2017 at 09:06 PM.
Ok again great discussion.
I do understand (and have seen some utube videos) on spring surge. It seems to be worth addressing.
Yes, no broken parts other than one spring and galling. Funny thing is the problems is on the passengers side only. Lifter/pushrod/rocker on the same valve, #2 cyl exhaust. Broken spring on the #4 intake. I checked oiling with lifters out (priming) and the oil came from the front of the block (SHP priority main oiling) so the #2 gets oil first. Now the distributor could still drop pressure for that bank. Both banks "seem" to be getting about the same dribble of oil at the rockers. It oozes good at idle but never squirts. (I didn't rev it much with covers off though)
I agree I need to go over it all again and check pushrod length/geometry. Good rule of thumb Sofa and pretty much what I did to get to the 7.650 long set.
Rechecked my specs and the lift measured on the motor (lifter) nets .616 Intake .600 exhaust. Measured duration was 226/239 against a 229/237 card. My measurements could have been off a degree or two I guess but non the less it's a lot of lift for the duration.
I really like the beehive design but still felt hesitant. With all the advice here and talking with a couple of techs at Comp I ended up ordering this spring with tool steel retainers and the appropriate keepers and seats.
It is supposed to be the latest and greatest spring for this application. It ain't cheep and is a really strong spring at 505#. I'm now figuring out my installed height to get as close to bind as necessary to mitigate surge. Anyone want to chime in here?
Last edited by antman89iroc; 04-07-2017 at 09:48 AM.
Reason: Duration mis typed
I have been through this before!
The problem is your lifters.
If you want to read about my adventure, I can direct you to a post.
Here is how you can prove it to yourself:
Put a SBC SOLID flat tappet lifter in any hole you choose. Or you could use a KNOWN GOOD hydraulic flat tappet lifter. Have the rest of your roller lifters in the other 15 holes. Run the oil pump with your preluber shaft.
You will see the the appropriate amount of oil come out of the top of the flat tappet lifter, and the pathetic dribble out of the other 15.
Don't argue. Do the test.
Last edited by NoEmissions84TA; 04-07-2017 at 01:18 AM.
Did you use a solid lifter for measuring pushrods or sub in a light tester spring?
I always use a solid lifter i made out of spare ls7 lifters. Take internals out and fill with small nuts and washers to take up the space and put the cup back in
What is the cam card specs for that cam? Cam card says 239/237 and you say it measures like 226/239? Lift suppose to be .600 each but one is .616?
0.100 from end of lash cap sounds bit close but could be ok. Maybe back off pushrod length next size down and see what it gives
Fwiw i used ls7 regular lifters with Afr 195 heads with the 2.050" valves. Afr 8019 springs shimmed to 1.77". Ran a comp magnum high lift lobe, 286:230 .603 intake and a 306:245 .613 exhaust. Turned 7k rpm no problem. Oem 4 bolt block. Base circle was 1" or so
I used the hydraulic lifters for the pushrod test. I had primed them first but could have lost some lift for the test so there may be some error. I could not detect that the plunger receded into the lifter much at all.
I mistyped the specs. Card states 229/237 and I measured 226/239. Lift on the card was .385/.387 (616/619) and I measured .385/.375. (616/600) I only measured cyl 1 during the degree process.
If I keep having problems or if the "oil comparison" shows what NE84 found, I may just swap lifters too.
Lifter likely collapsed when turning motor over while checking pr length. Have to do it with a solid or light checkin spring
You are right. I now have 16 light springs (inners) which should work ok. lol.
And not to 'jack my own thread but here was my thinking on not using a light spring.
When attempting the 1/2 lift method the way I went about it was to establish rocker at 90* from the valve stem and adjust the nut to that point. Then I screwed the nut down exactly 1/2 of the expected lift and adjusted my checking pushrod to that length.
I happened to have a few different pushrod length and one close to that length. Even though the lifter may bleed down some it is still valuable to check one length against another to see which one gives the narrowest patch. Now let's say the lifter bled down .020. That would reduce valve travel .032. but since we're doing the 1/2 lift method that .032 would come off of the last 1/2 of the valve's movement. The width of the contact patch would still be the same even though the rocker didn't make the last .032 of movement. Right? I know this is going to get some push back but it's how I rationalized it.
With my combo the closest to being perfect is the longer pushrod. When it approaches the right length the contact patch is getting close to the exhaust side of the valve and almost off of it. So most of the time the pushrods are too short rather than too long. I think my above logic only falls apart when the pushrod is too long which I haven't been able to do without the patch rolling off the edge of the valve stem.
Last edited by antman89iroc; 04-07-2017 at 11:05 AM.
Now let's say the lifter bled down .020. That would reduce valve travel .032. but since we're doing the 1/2 lift method that .032 would come off of the last 1/2 of the valve's movement.
If you know exactly how far it moved then yes maybe you can do it this way and add it back in to account for length
I just dont know how far down the lifter cup will go
I use a valvespring height mic and set it to half lift at valve. I use dial indicator to set cam lifter to half lobe lift. Then setup rocker to 90 deg, use adj pushrod to fill the difference. Add lifter preload. Should be it
If you measure the valve train geometry using the mid-lift method, then a special lifter isn't needed. Neither is a light weight checking spring. In fact the rocker just sits on the valve tip and pushrod with no adjusting nut and no pre-load. Measurements are taken with the cam at half lift. Same lifter that's to be used. Same spring too. All of the other stuff is completely unnecessary and leads to these errors.
Tools required: A straight edge and machinist's ruler.
I went so far as to make a jig that allowed for easier measurements of the roller tip axis and the trunnion axis.
Originally Posted by antman89iroc
When attempting the 1/2 lift method the way I went about it was to establish rocker at 90* from the valve stem and adjust the nut to that point.
What points on the rocker did you use to establish the 90 degrees?
Some mistakenly draw a line from the trunnion axis to the point where the roller tip contacts the valve. That is incorrect.
Last edited by skinny z; 04-07-2017 at 06:20 PM.
Reason: edited to omit the need to place the lifter at half lift
Its ideal to check sweep afterward under full load to verify alignment of components and account for some valvetrain flex but you are right. Technically it isnt required
If that's what is felt to be necessary, then the solid lifter made out of the same hydraulic lifter would be needed. The running spring is also needed to ensure accuracy. Problem is that a link-bar style lifter can't be disassembled. At least not the Comp versions that I've worked with. The rivet that attaches the bar to the lifter body prevents the cup from being removed.
Kind of a catch 22 situation.
For what it's worth, if the mid-lift method is used as it's been developed then the amount of sweep is a moot point because it will be at it's smallest. Guaranteed. The point of contact with the valve tip can be observed and that can be done at zero lift because again if the geometry is correct, then the sweep isn't going to be any more than .030". You'll easily see how close to the valve tip edge the rocker roller is.
You can "solidify" a hydraulic lifter for this exercise by submerging it in hot molten petroleum jelly or the like and allowing it to fill, then chilling it. Trans-Jel works great. Nice thing about this is, you can just put the lifter into the motor afterwards without further effort, and within a couple of minutes of running, it's back just like all the others. Will require re-adjustment but that's a minor inconvenience at most, you'd probably be doing that regardless.
Ok you have re-sold me on the 1/2 lift method. I always thought it made the most sense but when problems started to crop up I tried different things. Pushrod length, oil weight etc. Probably made things worse.
I used the centerline of the trunion and the centerline of the roller tip to align the 90* off the valve stem. There's a pretty good utube video showing a simple method. Once 90* is found the adjuster nut is brought up against the trunion. Then, you calculate how many turns are needed to equal 1/2 of the total lift and turn the nut down that amount. Now you can extend the checking pushrod to the rocker cup, remove it and measure it. Simple really. No indicators are really needed. It may not be 100% but it will be very close. Especially if you are going to back down to the next shorter pushrod. It's probably a good idea to check it anyway but as skinny said, if it is at 1/2 lift it will be the narrowest contact patch.
I've seen that method but I still prefer the measurement approach. Then there's no eyeballing the 90 degree part.
You may know this one but I'll run through it quickly for anyone reading this later and would like the information. I had mentioned earlier that the lifter should be at half lift. That is incorrect. The lifter is on the base circle of the cam and all measurements and calculations are made from this position.
Using an adjustable pushrod, place a rocker over the stud. It will rest on the valve tip and the pushrod. No preload needed.
Using a straightedge across the retainer, measure up to the centreline of the roller tip and down to the centreline of the trunnion. The difference between the two values should equal exactly half the lift once the pushrod has been adjusted to the proper length.
No need for a solid lifter or checking springs. The procedure is done with all of the components used for the running engine.
As for the point at which the rocker roller contacts the valve stem tip, concern yourself with that once you have pushrod length determined. Off centre is OK. Dead centre is best which is why I went for the previously mentioned offset trunnion roller rockers.
Red dot to red line is the roller tip measurement. Green dot to green line is the trunnion measurement. Red minus green equals half lift. (The green line and the red line are actually the same line. Typically the top of the retainer.)
The hardest part of this whole deal (in my case) is that my retainer has no flat surface on which to rest a straight edge. I ended up using a "jig" that fit between the retainer and the spring. The jig being an old ruler in this case. Then is was easy to measure from the "jig/ruler" to the axis' centres. It doesn't matter where your reference line (the point where you're measuring from) is as long as you use the same line for both measurements.
Very interesting. I am double checking everything I can.
I just primed the engine and did notice the driver's side got oil before the passengers. Now this is with the priming tool and it does have a smaller lower end (about .010) so it may be allowing more leakage.
Going back to the cam/spring combo. Let's say for argument the cam change lowered peak rpm by 500 to 5200. If everything in the valve train is correct I should still be able to rev to say 6000 without expecting damage right? I was recently shifting at 6k and wondered if I may just be over revving the engine. Just a thought.
Maximum engine RPM before component failure and engine peak horsepower RPM are different things. While you need the RPM capability of the hard parts to at the very least satisfy power production requirements, any reasonable selection of quality hardware will surpass what's really needed (with respect to the case in point). Aftermarket lifters, rocker arms, push rods, etc, (and I'm discussing reputable brand names here) if assembled correctly will more than meet your RPM needs, vis-a-vis power production.
Short story version, from what you've listed as valve train parts, I'd think you're good to go.
I will say though, that's a helluva lobe profile. I thought the XFI's were aggressive....
I was running a custom cam spec'd with Comps XFI lobes. 224@.050" with .575" lift and 1.6 rockers. I not only wiped out valve guides in a hurry when the valve train geometry (VGT) was off, but I also ruined a low mileage set of intake valves. This is why I'm such an advocate of the VGT deal. Funny thing is, getting it wrong doesn't really show itself until you find it many miles later. Broken parts. Worn guides. Oil consumption. Bits of valve guide seal floating around...Then it's generally expensive to repair.
Maximum engine RPM before component failure and engine peak horsepower RPM are different things. While you need the RPM capability of the hard parts to at the very least satisfy power production requirements, any reasonable selection of quality hardware will surpass what's really needed (with respect to the case in point). Aftermarket lifters, rocker arms, push rods, etc, (and I'm discussing reputable brand names here) if assembled correctly will more than meet your RPM needs, vis-a-vis power production.
Short story version, from what you've listed as valve train parts, I'd think you're good to go.
I will say though, that's a helluva lobe profile. I thought the XFI's were aggressive....
I was running a custom cam spec'd with Comps XFI lobes. 224@.050" with .575" lift and 1.6 rockers. I not only wiped out valve guides in a hurry when the valve train geometry (VGT) was off, but I also ruined a low mileage set of intake valves. This is why I'm such an advocate of the VGT deal. Funny thing is, getting it wrong doesn't really show itself until you find it many miles later. Broken parts. Worn guides. Oil consumption. Bits of valve guide seal floating around...Then it's generally expensive to repair.
I hear you. I was asking about the rpm in case I was causing the problem by shifting at 6k. The valve and guide wear problems are what I was trying to avoid in the first place. Interesting, the guides have been good. Last time I had the heads off I took them to my shop expecting to need guides and/or valves but they were ok.
I agree the lobes are probably too much for daily use but I'm tying to make it work as well as possible. The engine makes good power for what it is and has been great except for these valve train issues. The power numbers it made was in full street trim with all accessories, exhaust and street tune. I haven't had it dyno'd since the cam change but it didn't loose any performance at the track and may have picked up a hundredth or two.
I just got the springs in and am getting it set up now. I am having a little trouble getting the valve seals off since I don't have a puller but have always just pried them off in the past. Do you know if AFR has anything special on the stem seals?
6000 RPM should be very doable with your selection of parts.
That the guides weren't worn (not certain of the mileage interval) is a good sign. It didn't take long for my new heads to be wiped out. About 6000 miles with the same heads on two different shortblocks and different lifters. I had left the pushrod length the same and it was obviously wrong for one of the two iterations as the stack up of measurements was at least .25" difference between the two assemblies.
The last set of AFR heads I worked with (195 Eliminators) needed nothing special to remove the seals. I do remember that AFR has their own seal spec.
My engine has right at 30k on it. Last time at the shop was at 24k so about 6k since. Mostly street miles.
I was able to get the seal off. The guide is grooved, almost looks threaded. It took so much more effort I wanted to be careful.
They do have their own seals but I got LS seals and so far they measure out ok and look like they'll work fine. The body is about .080 longer but the AFR seals don't go down all the way and have about the same gap. I will double check everything first to make sure.
How much clearance to bind should I leave? The current springs had .099/.115.
The new springs have a taller min height so think I need to change it. If I install it as is it will have .046/.060 clearance. I can pull out a .034 shim and leave .078/.094. What do you recommend?
Last edited by antman89iroc; 04-08-2017 at 07:43 PM.
Reason: Wrong original numbers
I had figured the "original" height with the new retainers.
I took out a shim to end up at .079/.095 clearance. Too many numbers lol.
When I re-read my cam card specs it should be 619/603 even though I measured less. So, to be conservative and give a little more room for error I left more clearance than the min.
Last edited by antman89iroc; 04-08-2017 at 07:52 PM.
Seat Load: 129 lbs @ 1.835''
Coil Bind: 1.100''
Clearance: .060"
At 1.835" there's room for .675" lift.
They are installed at 1.795". I had to remove a .032 shim to get there. The AFR retainers are taller which required more shim to get about the same height. I almost left them in but it would have been under the recommended min.
Everything went pretty well until the last valve on the last cylinder. Seems Comp packed 15 of the correct locator and one different. I was bummed on Sunday afternoon but that's the way it goes sometimes.
04-06-2017, 07:46 AM
