install height 452s xe274h

[70challengerdane]

im putting my 383 back together and im super scraping on cash as always, and it turns out i need valve springs.. so far my best choice was the $90 440source springs but then i found $55 BBC (gasp) trickflow springs on summit ( http://www.summitracing.com/parts/TFS-15117/ ). the issue with the trickflows is the 1.9 install height. standard mopar being 1.86 from what ive read. so has anyone tried something like this? ive been trying to find threads and such all over the place and i gotta go to bed and get up for school so im starting a thread of my own.

basically,
will + .040 install height be enough to cause problems?? either with bind or seat pressure?

i know it raises seat pressure but im having a hard time getting ahold of an equation to figure out how much etc.. anyways if anyone has any ideas let me know!
i have a link about to the springs, the cam is gonna be an xe274h with .488/.491 lift and standard rockers.

 

[70challengerdane]

also, did i do my math right here? 1.9 install height - 1.110 bind would be good to .790 lift?? or did i do that wrong?

 

[moper]

You really want to use the pounds per inch rating to figure out how high the pressures will be over the nose. Lift means little. It's all about the pressures. That cam wants about 150 on the seat and 330 over the nose. I think that TFS spring will be too much over the nose and you run the risk of wiping the cam. Not to mention that the cam is not meant to be broken in on that high pressure. Normally it's broken in with the outer spring of the dual assembly only. So it has less chance of wiping during break in. By running the heavier single you really increase the chances of failure during break in. I would run a weaker set to break it in, then add the TFS spring if you feel you have to run them. Personally, I run exactly what the cam maker specs for parts so the heads would have been set up for dual springs and you'd be running the 926-16s.

 

[70challengerdane]

You really want to use the pounds per inch rating to figure out how high the pressures will be over the nose. Lift means little. It's all about the pressures. That cam wants about 150 on the seat and 330 over the nose. I think that TFS spring will be too much over the nose and you run the risk of wiping the cam. Not to mention that the cam is not meant to be broken in on that high pressure. Normally it's broken in with the outer spring of the dual assembly only. So it has less chance of wiping during break in. By running the heavier single you really increase the chances of failure during break in. I would run a weaker set to break it in, then add the TFS spring if you feel you have to run them. Personally, I run exactly what the cam maker specs for parts so the heads would have been set up for dual springs and you'd be running the 926-16s.

hmmm ok. so, i have stock springs (208 at 1 something or whatever) but i think they are gonna bind. so i dont think i can use those to break the cam in. and theres a procedure to break springs in too... how do you break your cam in when you have to do the opposite for the springs? my auto teacher was saying the .040 is probably gonna add about 5 to 7 lbs, and with the stock springs the tolerance is about 12 lbs so he was saying it would be ok. thanks for the help too!

 

[70challengerdane]

and this may be a stupid question. but how do you change springs with the heads on the motor? i used a tool that pushed against the valve which wouldnt work with the head on the motor... argh i HATE being on such a tight budget

 

[70challengerdane]

so it says 127lbs on the seat in the description at 1.9 if you take 368lbs/inch x .040 thats 14.72 if you add 14.72 to 127 you get 141.72. wouldnt that be almost right where i want my seat pressure?
for open pressure, the open height would be 1.369, and would be at 322.408
OH and i forgot until i did it again, when you look at the cam http://www.summitracing.com/parts/CCA-CL21-224-4/SuggestedParts/?prefilter=1
the suggested parts include these springs! haha so... i think it would be ok.. the comp springs it suggests are also 1.9. ok i feel better now... but im still curious as to why theyre 1.9 and not 1.86

 

[moper]

There's a tool that bolts to the rocker shaft saddles to compress the valve springs on Mopars... I have the Comp Cams one but you could prob find them elsewhere. I think my math was a little off. You're math is correct. It will leave you light on the seat, and light over the nose., and you still have the issue of finding a sset of lighter springs with which to break in the cam. You could prob get some cheap BB CHevy springs for that. BB Mopar factory springs will not be tall enough to install at 1.9. Normally the taller installed height has to do with getting a spring to fit or more lift at the valve although other heads use longer valves for port design reasons. I still wouldn't use them..lol. But it's your engine. We're all on budgets. The trick is to figure out when it makes sense to compromise in parts, and when it makes sense to wait and earn more...lol. I'm still working on that last one.

 

[70challengerdane]

yeah i know the feeling haha i would wait and save but in mid june i graduate and lose all my recourses and would have to finish the build in my side yard with no specialty parts.. so its getting done now regardless. but the install height is going to be 1.86 cause im not changing the valves so the old springs will work i just dont know if theyre gonna bind at .491 lift or not. i was gonna check at school today but i was busy polishing my crank and discovering all the lines in it :/ but it is what it is. down the road when i have a job ill try to do one right but for now i just want to take advantage of my resources and learn as much as possible while i have the opportunity. and get the challenger on the road too haha

 

[70challengerdane]

well little update here.. i got a job and finally have the ability to save for parts.. which is good cause i did in fact wipe my cam out upon break in.. however it ran for probably 15 minutes while trying to tune it and also finding a bad distributor cap in the mix but either way, took the cam sprocket guide pin thing out so its time for a new cam.. i guess what im wondering here is do you think the springs were too much for the cam all together? cause i was worried about wiping lobes out but i didnt really think about the cam guide pin.. if i can get my hands on something to do the springs i might try to get the correct ones this time haha or ill find a cheap used cam and reuse these lifters and see what happens haha

 

[moparleo]

What condition are the heads in ? Rocker ratio, valve seats, guides, valve faces , head surfaces ? Like what someone said before somewhere, why is it that we don't have time/money to do it right the first time, but always manage to find the time and money to do it over again ? Do your self a favor and don't try to go "cheap". If the cam is gone, stands to reason that the lifters won't be in good condition either. It is more economical to talk to the mfg of whatever brand of cam that you are choosing and he will ask for all the questions that need to be answered by you to recommend the correct cam, lifters, springs, installed advance or retard of the cam, rocker/ratio to work best for your engine/ car combination. Remember that all of the parts have to be matched to work together, not work against itself by damaging the rest of the engine parts. You should not be playing with timing and ignition problems when you are doing a cam breakin. Follow the cam makers recommendation. No body knows better that the people that make it as to how to do it for their parts. You will get a lot of good advice on this site but you need to know when to follow all the advice/opinions given and when not to. Just because somethiing worked for someone elses build doesn't mean it will work for you.

 

[70challengerdane]

so it looks as if the cam bolt worked itself lose because i didnt put any thread sealer on it which is what broke the dowel pin... and theres also a crack in the front cam journal now so the cams done for but i havent inspected the lobes yet or checked for bent valves.. the reason i have money and time now is because i was unemployed the first time around and was basically mowing lawns to build the engine and had 3 months to do it before school got out and i had to take it home haha so anywhere i could save a buck was very important lol but now that i have the ability to save money, within reason, ill buyy the same cam i just ruined haha and the valve seats were good i had to toss the heads that were on the motor originally cause the seats were cracked in a few places, i did a valve job on it, checked the guides and they were ok, ported the heads, factory rockers, deburred the oil drain back areas and cleaned the oil gallies, got a high volume cause i didnt have enough money for machine work and the steel crank i was putting in was a little on the scary side of tolerance after polishing it but i had good oil pressure when it was running so hopefully it wasnt just clogged somewhere. sorry im just kinda rambling haha i need to go to bed haha

 

[70challengerdane]

oh and the cheap cam/reused lifter wasnt as a permanent thing, it was more for getting the rest of the motor square away without ruining another $250 cam in the process and then once everythings sound, get the same cam i had before... if that makes sense

 

[moparleo]

I really am glad that things are going good now for you. Most advice comes from experience. I, like most guys that will admit it, we did dumb things when we were young and just want to help the next generation.

 

[70challengerdane]

once again another update, got a new cam and lifter kit as well as pushrods and timing gear set. but long story short cracked the already crappy shortblock haha so now in the process (finally after sitting for 4 months lol and im getting married in august so that doesnt help my time factor haha) of putting everything on a good 65 383 shortblock