Stroker Renewal?

I don't doubt that they'd have some valuable input, Frank, but even if they did, that's another couple weeks of me working on this instead of other house/trailer/work/kid projects that really should have my attention. As always, I have more time than money, but I really think I'm going to bite the bullet and let a pro iron out this one.:eye:
 
If you need a truck/trailer to haul your rig to the shop you choose, lemme know Chris. I'm tending to my wife's after-surgery care this week, but we could work it out......
 
YELLAHEEP said:
If you need a truck/trailer to haul your rig to the shop you choose, lemme know Chris. I'm tending to my wife's after-surgery care this week, but we could work it out......
Click to expand...

Thanks, Yella - it runs well enough to get downtown to a mechanics -- thanks for the reference, Frank, I'll shoot him a note...
 
you, my friend, are a glutton for punishment -- you finally sell your stroker after uncounted tales of woe, and now you can't keep your hands off of mine -- seek professional help man (not the same kind I am :roll:)... thanks for the offer, I'm turning in my wrenches on this project.

Had the boriellos already tonight, may pick up a sixer so I can really jack up my plumbing project...:peace:
 
minor update -- Leonard pegged my noise down to upper end, cylinders 2 and 3 in about 2.5 seconds. Said diagnosis has now been confirmed by a couple of his machinists as well. Compression test showed 35lbs in #2, 65lbs in #3, and some pressure bleeding between them. The head is at the machinists getting checked for warpage, etc., should know more by Monday. SOOO, its appearing Frank and I managed to get everything right, except for the one thing we took for granted and didn't check -- figures don't it? :sunshine:


more to come....
 
Ok Fellas -- need some imput from you all, particularly any of you who are more than shadetree mechanics...

Leonard over at Tinkers (trialrunner on NAXJA) is looking through the engine for me, trying to track down the problem. As previously mentioned, his trained ear and that of a couple of machinists he uses all put my noise at cyl 2 and 3, top end -- those two cylinders failed their compression tests miserably, showing only 35 and 65 lbs of pressure, respectively. Further, there was evidence of pressure bleeding between the two cylinders...

The head is off and has been inspected by the machine shop -- it is warped 0.0014, which I believe is still within factory spec, but the warpage is focused on the front of the head, in their opinion resulting in the compression issues in #2 and #3. Further, while the valves were all seating well enough to pass the water test that Frank and I put them through (Leonard did as well), they did not fair as well under pressure in a leakdown test at the machine shop, both cylinders #2 and #3 showing significant leakage. The machinist recommends planing the head and a valve job, and it is difficult not to agree. FWIW, all springs tested at 240lbs, which is what these aftermarket Crane springs should be at (also allow for additional lift).

So, some progress - However, it does not answer the question as to why I am repeatedly getting bent pushrods - several were bent again when Leonard disassembled the engine, and that is with approximately 15 miles on them. Leonard is somewhat at a loss, as am I. Measurements from the machine shop, and mine, indicate that stock length pushrods should have been appropriate. There is no signs of any valve contact with the pistons. The lifters all appear in fine shape... WTF??

I really don't want to get the compression/head issue resolved, put it back together and end up with a bunch of pushrod related damage -- what say you oh wizards of jeep??:peace:
 
Dunno if any of this you've already seen, but figured I'd post up these links:

Stroker exclusive website:

http://www.jeepstrokers.com/forum/viewforum.php?f=34

Another webpage by a guy with quite a bit of knowledge on jeep strokers:

http://www.jeep4.0performance.4mg.com/index.html

Taken from the above webpage. Bottom of the page discusses performance push rods, pre-load and lengths:

http://www.jeep4.0performance.4mg.com/valvetrain.html

Fourwheeler Magazine's stroker build article:

http://www.fourwheeler.com/techarticles/engine/129_0711_1987_2006_jeep_40l_inline_six/index.html

HTH.
 
Thanks, Yella, but all of those have been in my "favorites" for years -- nothing new for me there. :cool:
 
Figured as much.

Have you considered PM'ing "Dr Dyno" here? He seems to have a wealth of knowledge with strokers........ :dunno:
 
YELLAHEEP said:
Figured as much.

Have you considered PM'ing "Dr Dyno" here? He seems to have a wealth of knowledge with strokers........ :dunno:
Click to expand...

he does, and I might... hoping some of the ASE-type guys might chime in with their experiences, stroker or not. Seems to me that bending pushrods is simply an internal combustion engine thing, not necessarily a stroker thing, since the mechanicals are all essentially the same... Is it 5pm yet? I'm parched.:o
 
240# seems high to me.

Yep, just looked at my FSM.

Valve Springs
​
​
Free Length (Approx.) . . . . . .47.65 mm (1.876 in.)
Spring Tension—Valve Closed.271 to 307 N @ 41.656
mm
(61 to 69 lbf. @ 1.64 in.)
Spring Tension—Valve Open . . .818.5 to 871.9 N @
30.89 mm
(184 to 196 lbf @ 1.216 in.)
Inside Diameter . . . . . . . . . .21.0 mm to 21.51 mm​

(0.827 to 0.847 in.)
Click to expand...
 
I was just looking up some valve spring specs as well. I saw 'Grin's posting of his being at 240 lbs and I haven't seen any other spec close to that on the internet links on stroker builds that I looked over.

The only article I found was this guy's over-the-top stroker build where he's using chromoly hardened pushrods, roller rockers and pushrod guides:

http://www.maizekustoms.com/pages/jeep-4.0l-to-4.6-stroker-build/stroker-build-continued.php

"I am using dual springs not because I am planning on reving the motor high, but because it cuts down on valve train harmonics. If you will observe the spring pressures in my last post, closed pressure = 100lbs, open = 235lbs. That is pretty close to stock pressures. Stock springs were rated at 105lbs closed, and 245lbs open."

Not sure where he got the stock spec being 235 lbs...... :dunno:

Edit: Finished reading his article...... I guess the push rod guides were a bad idea........... :eek:

jeep89.jpg
 
Last edited:
Yella, if you read down the page there is a picture of the tag that came on his "Australian fine wire" springs -- not stock. I was aware that stock was around 200# (196 per Frank's FSM) and Leonard and I talked about that -- his machinists thought 240 shouldn't be a big deal and was typical of an aftermarket spring for a stoker, your link kindof confirms that. Crane's website blows and is having a hard time loading, but I found several applications before their site locked up with 300+ lbs of spring rate... :dunno:
 
Yeah, after doing some further reading on other sites...... there really is no consistency with a particular "recipe" for the perfect stroker. Seems everyone has success with various spring rates. Some saying they're doing fine with stock springs and a Crane 231 cam, others saying they get bad valve float with the same set up after 4K RPM.......

This link seems to have some real good valve spring rate specs based on the different manufacturers. I also realized that there are two spring rates involved - actual spring rate until the coils are compressed completely, and then the spring rate installed when the spring is compressed with the valve open to max spec...... big difference.....

http://www.jeepstrokers.com/forum/viewtopic.php?f=5&t=343

I'm gonna bow out now....... my brain is angry with me. :wierd:
 
mild update and correction -- I mistyped in my last real update, the head was warped 0.014, spec being 0.006 - significant and is being planed, along with a 3-angle valve job. that should clear up the compression issues, but doesn't seem particularly relevant to the push rod bending issue...

Exchanged some PM with Dino today, who suggested checking the same ususal suspects we have been working through -- lifter pre-load, spings, etc. I made sure the machine shop is checking on stem height, valve height, etc., so we'll eliminate those as an option...

Anyone have any other thoughts as to causes for push-rod bending? Leonard suggested perhaps over oiling due to worn cam bearings... they appeared fine when disassembled but its a thought. frustrating as hell.:anon:
 
bastid.




















































although I have to say I noticed the full rebuilt 5.2L drivetrain for sale at Colorado4x4.org... :skull2::thumbdn:
 
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