Engine questions 500
 

Im going to be going through the heads on a 500efi.
To my knowledge is based off of the ram jet 502 motor correct? What generation would a motor built in 03'?
Also, is the entire valve train Crane? I need to replace a lifter.
Do I need to retune this motor after doing the work, I am going to keep it stock for the most part.

I had a push-rod break apart, so I am going to rebuild the top end. I was right around 325 hours. Lucky for me all the pieces stayed in the valve area.
I'll keep posting the progress.

i would replace all the springs,lifters and get a good valve job. i would also take a good look at all the rocker arms&pushrods.03 is a gen6.i think most of the valvetrain is crane but not the lifters.

Im going to go pro comp steel rockers, inconel exhaust, stainless intake and all associated hardware and springs, Smith brothers push rods.

Pics of the damaged parts
https://www.dropbox.com/sh/oabrhxq1y...R0VT-KZxa?dl=0

i personally would not use pro comp rockers,the crane golds are pretty hard to beat.i also like the scorpian endurance rockers and they are american built by american workers.your engine already has inconal exhaust valves and stainless intake valves so if they check out ok they can be reused.the valve springs mercury uses are not the best and i recomend something like the isky springs.

Is there any disadvantage to replacing the one damaged crane gold that I have vs the whole set? Why no to the pro comp? I was looking at the Ultra pro magnum XD just FYI.
Also I still need help identifying the lifter that came in the motor.
Thanks for the support!

IF your doing all this, I wouldn't run used rockers, 500 bucks for two new sets of rockers is piece of mind...

I just checked Summit, their a bit more than I thought

Massive shortage of crane golds lately. Seems nobody has them anywhere.

I would stay away from the procomps. Just about everything from pro comp is questionable. The comp ultra pro magnum XD looks like a nice rocker arm , and its steel. The older comp cams steel rockers, i dont like. Im going thru my tops ends currently, and going with crower enduro stainless rockers.

the crowers are nice but pretty pricey.agree on the pro comp stuff,pure junk.they now go by the name SPEEDWAY.

Agree as well, I would not use any of the Pro comp stuff either nor any used stuff.

Ok, I might have spent too much time in the motox world. pro comp are junk, but comp cams are not? Are they the same company or am i missing something.
Just a little slow today

pro comp[speedway] is a chinese company that makes junk and floods it into the american market,the people who buy it soon realize the did not get such a good deal when the parts break and trash their engine.comp cams is an american company that makes good quality parts.their is no connection with the two company,s.

Im so glad you said this :cool-smiley-011:

We re-used our crane gold rockers. It was the only thing we re-used. Valves, springs, locks, and lifters got replaced. People that talk about fatigue don't know material or structural analysis. Parts are designed to 10x6 cycles. That's 2500 hours at 4000 rpm. Sure there are pre-mature failures on used parts but there can also be premature failures on new stuff too. Just my 0.02.

not sure if i follow,are you saying a crane rocker arm is designed to go 2500 hrs at 4000 rpm.that equils 300 million cycles.NO WAY!

Sorry long night at the office. Typos and bad math. Fatigue life is designed to 10x7. That's roughly 500 hours at 4000 rpm. Id imagine that's 1000 hours or more of real time running.

So based on those #'s with an average rpm of 3500-4000 its time to replace the whole set. I'm sitting at 325hrs now. Where does one find that information? Or do you have the numbers for other rockers?

i don,t know the cycle life on the crane gold 1.7 ratio rocker arm but bob madera mentioned to me that the aluminum shaft mounted rockers on a mercury marine sc1075 has a life of 11 million cycles,they translate that to 80 hours.

These are typical design values commonly used not hard numbers. Nothing is 100% when it comes to mechanical parts. In my field we design for 10x7 fatigue as do most companies. We always derate material allowables accounting for temperature. Usually it's a -3 sigma 99%. Obviously all this math goes out the window when there is mis-alignment, higher than designed spring forces, etc. likely the contributing factors to early failure.

I highly doubt your average rpm is 3500. Read your ECM and I would be willing to bet 75% of your run time is at idle. Just trying to point out that many people replace things way before they should be replaced.

It's conceivable that they use 10x6. I'd be a little surprised as there would be a lot more failures out there.

i believe they did a cycle test and had first failure at 11 million cycles.i am not telling you what to do but when i error i do it on the safe side.a new set of rocker arm,s is peanuts compared to xtra damage when a rocker takes a chit at 5000 rpm.

No argument here.

You guys are just running the wrong stuff. Im running a special set of matched unbreakium rockers using a proprietary unobtainium alloy for the roller bearings. I have a friend who was a rocket scientist for Nasa and he hooked me up.

yea that new alloy pro comp uses is the BOMB,lol.

Just dont let china know the secret is depleted uranium,,,,

Are those specially staggered so you can pass him on the outside in turn 4? :party-smiley-004:

So one of these bear claws should work for me then.
Seriously though, thanks for the help on this one.

http://www.landoverbaptist.net/wordp...5/11/putin.jpg

I don't think the "cycle life" thing is that cut and dry. Theres guys out there running crane gold rocker arms in boat engines that have been thru quite a few hours. I changed mine out in 2010, and they were stamped from 1985. They had lots of time on them. out of 32 Rocker arms, 1 had a cracked Trunnion. What gave up, wasnt the aluminum body, but it was the steel part of the rocker arm!

Mercury used those crane gold aluminum rockers on everything from the old 370hp 454's, to 420's, HP500s, 500EFI's, 600sc's, 800sc's, 575sci's, 525efis, 525sc's, and so on. Granted those were not extreme engines, and none of them were running big spring pressures or extreme cylinder pressures.

I'd be willing to bet, take that rocker arm that goes 700 hours on a 420hp merc, and stick it on a blown engine making 2hp per ci, lots of spring pressure, and the exhaust rocker has to open the valve against extreme cyl pressure, and its not going to go nearly 700 hours. Throw in a jerky cam, and it might go 50 hours before eating chit.

Yes, a time bomb :)


Ryan

on my friends 1075s in a big OL,were just a little past that on hours.so far,185hrsish and we plan on another 75 this summer.I check them and the lash every 25.lash hasn't moved all that much.