ftpiercecracker1 wrote:Thats all fine and dandy, but those guys, savvy & currie, probably have gobbs of money to throw at their motor, so a complete teardown/rebuild + hesco stroker and custom aluminum head after every event means nothing to this thread. If i had all the money in the world i could probably build a motor to spin 10000 rpm, but hey i only have to rebuild the hole thing after every pull. :roll:
When i first saw this video, i was stunned, dumbfounded. I watched every video the guy has on youtube fearturing this particular XJ, he does the same thing over and over again, with presumably the same motor. I started this thread to see what it takes to build such machine, be it either how its geared, some kind of high quality bearings, or secret african voodoo.
lets see what we can come up with. :rockout:
From your comments you are obviously over your head. With enough air flow, spark, fuel and exhaust you can make any engine rev.
It is not rocket science. The key is to how long it can sustain said rpm.
The XJ ? High numerically gears coupled to a ignition and fuel system that supports it. My own stroker at 5300 doesn't sound much different.
Dont know where i went wrong, but i'll be the first to admit that i dont know jack sh*t about strokers/performance compared to the most of the guys on here. My apologies if i came across like i had my head up my arse. I was just trying to get the thread back on track. I dont really care if somebody else has a stroker that can do 7000 rpm, unless that is they can provide information as to how they did it, reliably. I just wanted to hear what folks thought this guy had goin. Because from my experience, our motors arent designed for such prolonged "high" rpm. But then again what do i know.
I have done a few things over the years that were just done out of desire and want but mainly there is no SECRET to my motor.
CRANKS=12 cw crank for me. I tried a lightweight 4cw and broke three main caps, won't do that again. Been racing this six stuff 39 years (my dad raced amc sixes for 15yrs) and never had an issue like that before. (Reason for the 4cw crank venture was to reduce spinning weight, a 4cw crank is 15lbs lighter) Balance job was just done by normal standards. Rods balanced over all and end to end. NEVER remove any more material than needed to balance rods. Overlightening the small end can result in rod failure. Replace stock rods bolts with an aftermarket set like ARP and chamfer oil holes in crank. If I had the money I would try a few other things to the crank to try to increase durability like cryo, or nitrate.
Rods=I used a stock set of rods for 17 yrs, SAME SET! Engine machinist treatened me so I did buy another set. ARP bolts a must. Using Eagle H-beams now in N20 motor, just felt like I was pushing it!
Crank girdle=never used one until the two years before the 4cw failure. I am not using one now I just bought a stud kit after the crank failure. Before that I used stock main cap bolts for 20 yrs.
Timing chain= I used to use a cloyes double roller until 1987. After that I used a gear drive then switched to a belt drive. Nothing wrong with the gear drive. Despite what I have heard neither one of the gears drives I used whined at all. I did understand that I was probably giving up a little HP but to me it was worth it in piece of mind. BIGGIE here. NO matter what type of timing system you use replace spring loaded bolt with a torrington bearing instead using the spring. Take a normal 1/2-20 bolt and machine a small flat indentation into the head about .060 deep, this will be used as your cam bolt so use a grade 8 bolt. Locate and drill hole in timing chain cover to coincide with cam bolt. Weld a piece of Alm round stock over hole about 3/4" tall and tap to 1/2-20. Reinforce round stock with gussets to increase strength. Take a 1/2-20 bolt and machine the tip to accept a torrington thrust bearing and besure the bolt only protrudes through the torrington .030 after it is installed. Cut off head of bolt and slot for a screw driver and install in cover with a 1/2-20 nylon lock nut on outside of cover. Install cam using machined grade 8 bolt. Apply grease to inside tip of bolt where it was machined for torrington. Put torrington thrust bearing on inside of cover on machined screw driver bolt. Grease will help hold torrington to "screw driver headed" bolt. Install cover carefully. Then hold nylon nut and screw in bolt with screw driver until torrington hits the cam bolt then back off just a touch. A couple of thou will do. Cam walk at high RPM will kill any timing chain and ruin dist gears in a heartbeat. I think most people who have seen dist gear problems have had some kind of cam walk causing the problem. HV pumps, thicker oil, tight tolerances, cold engine revs can all increase load on the cam thrust causing cam walk.
Valve springs= not rocket science here. Until a few years ago I had never used anything other than quality solid lifters from Comp Cams. I never have broke in a single camshaft with lighter springs either. Mistake? Maybe. I just have never done it and have not had a cam failure doing things "wrong". That being said, I usually had 150-160lbs seat pressure and about 350-360 open. Follow Cam manufacturer recommendations. Be sure to check for coil bind, retainer to valve guide clearance with seals installed and follow common install practices.
Pushrods= I have allways used 3/8ths Comp Cams or Jesel pushrods. Besure you have enough head to pushrod clearance when pushrod goues through head into the block! Machining will be required.
Rocker arms= I have had Jesel roller rockers since 1989 and it has been the single best investment I have EVER made for the motor. Pricey? Yes. Reliable? Still using them today!
SIXPAK wrote:Timing chain= I used to use a cloyes double roller until 1987. After that I used a gear drive then switched to a belt drive. Nothing wrong with the gear drive. Despite what I have heard neither one of the gears drives I used whined at all. I did understand that I was probably giving up a little HP but to me it was worth it in piece of mind. BIGGIE here. NO matter what type of timing system you use replace spring loaded bolt with a torrington bearing instead using the spring. Take a normal 1/2-20 bolt and machine a small flat indentation into the head about .060 deep, this will be used as your cam bolt so use a grade 8 bolt. Locate and drill hole in timing chain cover to coincide with cam bolt. Weld a piece of Alm round stock over hole about 3/4" tall and tap to 1/2-20. Reinforce round stock with gussets to increase strength. Take a 1/2-20 bolt and machine the tip to accept a torrington thrust bearing and besure the bolt only protrudes through the torrington .030 after it is installed. Cut off head of bolt and slot for a screw driver and install in cover with a 1/2-20 nylon lock nut on outside of cover. Install cam using machined grade 8 bolt. Apply grease to inside tip of bolt where it was machined for torrington. Put torrington thrust bearing on inside of cover on machined screw driver bolt. Grease will help hold torrington to "screw driver headed" bolt. Install cover carefully. Then hold nylon nut and screw in bolt with screw driver until torrington hits the cam bolt then back off just a touch. A couple of thou will do. Cam walk at high RPM will kill any timing chain and ruin dist gears in a heartbeat. I think most people who have seen dist gear problems have had some kind of cam walk causing the problem. HV pumps, thicker oil, tight tolerances, cold engine revs can all increase load on the cam thrust causing cam walk.
Just my .02!
Exactally!
Why doesn't someone market this as a kit, all machined, and with a new cast/machined cam cover?
CobraMarty wrote:Why doesn't someone market this as a kit, all machined, and with a new cast/machined cam cover?
I don't think there is enough market for it. Plus on the XJ the serpentine belt goes right in front of where it would be, so it can't stick out more that the stock cover.
ftpiercecracker1 wrote:He says in a description or comment he has been running the same motor going on 3 years, not sure when he posted that comment but its still three years.
Just because he says he is using the same motor for 3 years does not means he does not tear it down frequently and rebuild. you would have to if you were doing this very often. no matter how much the motor cost.
I was just trying to get the thread back on track. I dont really care if somebody else has a stroker that can do 7000 rpm, unless that is they can provide information as to how they did it, reliably. I just wanted to hear what folks thought this guy had goin. Because from my experience, our motors arent designed for such prolonged "high" rpm. But then again what do i know. 
