hydraulic lifter problems

[bruce4268]

iam running a comp cams hydraulic flat tappet cam in my 360 i purchased the cam kit with the high engery lifters iam running the mopar performence 1.6 roller lifters the motor would not rev over 5500 rpms i called comp they recamended the pro magum lifter they want 2" to 4" pre load with the engine hot hard to set perfect with intake on but i think iam closer to 2" now the engine breakes down at 6100 rpms iam running the 995 springs should be enough spring has enyone run into this problem with this combo

 

[dodge freak]

Well I have Comps. HE268 right now and it stops pulling at 5200-5400rpm's. I put adjustable rockers on in Sept. and now its good to 5500rpm's. All I know is my next cam is going to be soild. Comp. told me the [email protected] would be just like my HE268 at idle but rev. higher, can't wait for spring. I would say 6100rpms with a hydraulic is not bad. What type of oil are you running? Call Comps and tell them the type of oil and maybe they could tell you what might be better. Problem with stronger springs is cam wear. One more thing could be your valves sticking, remember theres no lead in this gas today, I hear some trans. oil in the gas helps sometimes

 

[fishy68]

What cam are you running? You didn't say. There are a lot of flat tappet comp cams. Unless it's a really big one that's about all your going to turn with a 360. 6100 RPM is spinning pretty darn good for a 360. Why do you need to rev higher? Are you running forged pistons? It's not a good idea to spin much over 6000 without them.

 

[dgc333]

My 360 with a Comp XE268H hydraulic flat tappet will rev right to my self imposed redline of 6500 rpm. Normally don't rev past 6000 but it will when I ask it to.

FWIW, I am using Melling lifters and magnum heads with the factory 1.6 ratio stamped steel rockers.

 

[340mopar]

Do I read this right you put roller lifters on a flat tappet cam? The reason it won't rev is because the duration is probably about 160 deg @ .050

 

[Dusterb318]

I think he means 1.6 roller rockers.....God I hope that's what he meant. I think you have some bad lifters there.......

 

[bruce4268]

they are flat tappet lifters the cam is thexe275hl gross lift is 525 with the 1.5 rockers 561 with the 1.6 rockers they are cast pistons i have 4.10 gears and 26" tires with the old lifters it would not make it to the traps i had to let of the gas at at about the 1000 foot mark i dont want to rev any mor than i have to if you bring it up slow it will go to 6400 ithink i can get thru around 6100 but that is when it starts to break down i went from the ld340 to the tm5 it revs quicker now on the dyno the ld fell off around 5000 the heads are ported i think it should be good to 6200 but with this cam and 1.6 rockers the valvetrain may be unstable

 

[Dusterb318]

Can you go to a taller tire? like a 27 or 28" tire....that will get the trap RPM down. Are your pushrods the right length giving you the right pre-load? I used to run an Edelbrock RPM cam with th eEdelbrock lifters and my 318 would run up to 6300RPM without a problem. You might be having a problem with coil bind with the 1.6 rockers....have you check for that.....that's a lot of lift to be running with stock valveguides and retainers.

 

[bruce4268]

coil bind is at 1.100 iam at 1.160 at max lift bronze guides comps retainers i only go to the track twice a year its mainly a street car iam running groodrich drag radials my best time with old lifters was 12.5 at 104 i was 89mph at the 1/8 i had to shift at 5400 and still could not make the traps i could run a taller tire but first i want to make shure its not the lifters i saw a 440 build in a mopar magizine same cam 1.7 rockers it would not rev past 5500 they tried new spring did not help so just as test they thru in soild lifters it went to 6400

 

[Dusterb318]

I think you are having lifter problems and getting some coil bind.....you need to get the coil bind problem fixed before you go winding it up again....crashing stuff into each other is not good. Just because that mag used 1.7 rockers doesn't mean they didn't clearence the guides for the lift. I would call Scott Brown and look at getting a new solid lifter cam if you are wanting to run it up in that RPM range......I know you are only going to the track a couple of time a year but you are sounding like you need a solid lifter cam. I run a solid on the street two and if you have good valvetrain parts valve adjustments are far a few between.

 

[bruce4268]

sorry i misunderstood what you were asking about the guides yws they were cut for clearence the springs were installed at 1.722 with max lift the springs are at 1.160 at .562 max lift comp wants + .60 to coilbind the spring chart say coilbind at 1.100 that puts me in spec if there is no lifter pump up my pre load is .002 this may be to tight of a window didnt know if anybody else had this problem

 

[BJS racing]

I know but this is and example of a chevy motor. But my old man was having the exact same problems with his race car. We replace the springs rechecked the valve lash. It ended up being a fuel delivery problem. nothing to do with the motor. He had a weak pump and a stuck float. It would run out of fuel at the top end but when we were checking it in the pits it looked fine. Just food for thought.

 

[dodge freak]

Hey, that might be it. You did say if you take it easy it go to 6400rpm's. This is what so great about these sites, something that nobody thinks about untill one poster brings it up, then it starts to make sense.

 

[Dusterb318]

Good call BJS....very well could be the problem especially if he's running a mechanical fuel pump. A bunch of people looking at the same problem at different angles will always come up with a correct fix.....