TheSamba.com :: View topic - 2332 Stroker broken case stud flat cam 6K mi. what happened?

Tue Jan 28, 2014 6:44 am

Have CB Builders Choice 2332 Stroker with CB F.I. in street legal rail with 6K miles on it. Seemed to be running ok but oil started leaking from sand seal, valve covers, and front of engine so I did not run it. Took it in to get checked. Verdict: broken case stud, 3 lobes almost flat on cam. Shop says get new case, cam, etc. etc.
Make no mistake I run it hard, that's why I built it and went as beefy as possible with parts. Oil 20w50 changed every 1000 miles and valves tightened. Have spent thousands on this engine AFTER build - always something. Kennedy Stage II is shot too apparently. My builder is a solid experienced guy. What happened and what do I do now? New case, line bore, what? My guy says it will be $4K to get engine rebuilt. Love the 200HP +/- but this seems crazy to keep dumping money in...

Tue Jan 28, 2014 9:27 am

with all due respect, why the hell are you running 20W-50?!?!?!?!

Tue Jan 28, 2014 9:33 am

LOL. Well I was told that is would be best for the big engine, high rpm runs, high engine temps and I live in the south so cold weather is not a concern.Supposedly didn't thin out and break down like 10w40 or SAE 30 would. Used Swepco for a long time. No offense taken!

Tue Jan 28, 2014 9:42 am

What cam were you running? We're you using an oil with added zinc or a zinc additive? Did you follow the break in procedure to the letter for the cam/lifters? Did you check the cam lifter clearance? What stud is broken?

Unless something seized there is no reason you shouldn't be able to use the case again. The kits come with new ones that should last a long time unless you grenade the motor. Why does your builder want to replace it?

Stage 2 clutch is way overkill in a buggy. Use a stage 1 and a Daiken disk or an ACE copperhead disk from Blackline racing.

Nothing wrong with 20W50 oil, my buddies have been running it for 30 years in everything they own and I run it in my street engines. The only difference I see is cold start pressures. No temp or pressure difference hot when compared to my big engines.

brad

Tue Jan 28, 2014 9:45 am

Ditch the 20/50.... Cam failure would be a bad or improper break-in process.

Tue Jan 28, 2014 9:53 am

we see 110 here in the summer regularly... I run 10W30 and have never had a lubrication problem... 20-50 is just too thick in my humble opinion for vw with tight tolerances compared to my harley with roller bearings and low pressure system... just a thought i guess. and I'm not chewing your butt it just struck me as a wth moment :lol:

Tue Jan 28, 2014 10:05 am

Cam is CB2289. Broken Case Stud (Head Stud) was one closest to trans. by #1. I didn't do the build but was told break in was followed to the letter and this guy has done plenty of engines so I take him at his word. Have heard about the Zinc and believe the 20/50 I use does not have the Z in it. Have also heard that it doesn't matter, not sure what to believe. I do run this balls-out every time I drive it. Launch, WOT each gear to 100mph, etc. Just a blast. Previous clutch kept slipping so my builder suggested Kennedy II.

Tue Jan 28, 2014 10:29 am

To answer the other question, "Why does he want to replace the case?". He tells me the case is whored out on the ends basically and he is concerned that a line bored case is highly likely to have low oil pressure. He is also concerned that using the case as is will fail. AS41 Supercase. Again, it only has 6k miles on it and it really was running pretty well. Only issues I had were the idle being higher after it warmed up, which was a new symptom and the opposite of what was normal - high idle cold, normal 1k idle when hot. Also, oil started leaking from sand seal, valve covers, and front of engine. I do have a full breather set up working properly. Did not drive it when I saw the oil leaking.

Tue Jan 28, 2014 10:44 am

Don't take this the wrong way, but basically you abused your engine for 6000 miles, needn't look for any more reasons your engine didn't last more than that. No zinc in the oil = flat cam. It's not an option, you NEED proper oil for flat tappet cams to live. Big HP is fun but it doesn't last when driven balls to the wall all the time.

As long as the case isn't warped you can line bore the case with no oil pressure issues. The local ACVW shop I used to work at has line bored THOUSANDS of engines in the 30 years they've been in business and have never had oil pressure issues on a case that was sound to start with.

As I suggested before, step down to a stage 1 clutch and run a good disk and you shouldn't have any clutch problems.

If you do go for a new case I would suggest stepping up to a CB aluminum 3.5mm deck case. I have them for both my 2332s and they are STOUT and will probably handle your driving style better. Full flow, shuffle pinned etc.

brad

Tue Jan 28, 2014 10:59 am

Ok. Duly chastised, and you are right! I'll talk to him about align boring it. The Gene Berg article on line boring scares everyone who doesn't cook the case in an oven at 2500 degrees three times during boring. Hey, thanks for the input. Open to any other suggestions on oil, better sand seal for scat serpentine set up, etc., anything I can do to minimize the damage I self inflict. I did post a pic of the rail in the gallery if you want to see what it looks like. posted today 2332 stroker. I'm addicted....

Tue Jan 28, 2014 11:09 am

Agree with Slalombuggy on the zinc. No zinc = flat cam, especially with hard driving. Oil grade not bad for here in NC, depends on clearance on the internals, but could have benefited from an oil additive. If everything on the case checks out, align bore it....

Tue Jan 28, 2014 12:47 pm

I use 5-20 in the fridged weather of florida yearound, driven hard yearound.driven mildely on rare occassion's. Cam could be oil related, or could be foot related, or could be zinc related, or could be builder related,or spring related, or detonation related or shit happens related. the broken stud I would think would be 1 of 2 things possiably 3.bad stud,over torqued, combo of 1&2. clutch could also be foot related or rong disc.
I used zinc for breakin then syn oil after the first week(4th or 5th oil/filter change) also cam needs to have the lobed deburred/chamfered on all edges. my cb 2250 cam has about 70,000 miles on it, in 2 diferent engines's.
I dont know weather detonation could help the stud faliure or not.but it does effup a lot of parts.

Tue Jan 28, 2014 12:58 pm

Use Brad Penn 10-30 or 10-40. Lots of zinc.

Tue Jan 28, 2014 5:00 pm

Gene Berg was a good saleman who lived during the time of $100 new engine cases. There is a lot of truth in his writings but a lot has been passed by with time (low compression engines :roll: ) He was also building engines to last 100K miles, you're not looking for that.

brad

Tue Jan 28, 2014 6:17 pm

With valve springs/rockers that are putting 400+ pounds force on the cam it's not unusual to have a cam going flat. I'd be using oil such as valvolene VR1 20-50 or other similar oil geared toward flat tappet racing engines, but even if you do nothing wrong it still can happen when pushing the limits of this stuff.

Just since you mentioned this is a buggy..........I'll mention that the gauze filters do not stop fine dust very effectively. If your leakage/blowby wasn't caused by whatever killed the case it my next guess would be due to driving in dusty conditions.

Tue Jan 28, 2014 7:17 pm

Maybe roller cam next time? Tool steel?

Tue Jan 28, 2014 7:27 pm

Back a bit to what you said about no zinc being OK. It is true these days we have oils with other additives and synthetics can probably hold up OK with less zinc after break in, but zinc is vital until the engine is fully broken in. I use break in oil for the break in and first change and found engines aren't so fussy on modern oils afterwards, But I've never needed to run anything quite as thick as 20W50 except on an extremely worn engine.

Tue Jan 28, 2014 10:46 pm

On solid-lifter motors zinc is as good as it gets. Why re-invent the wheel?

Tue Jan 28, 2014 10:46 pm

I got a box of Brad Penn in my garage now, so I'm totally on board with the zinc-phosphate thing, buuuut that stil may or may not be the reason the cam went flat. Before I knew anything about oils, I broke in all of my engines with just regular Chevron or whatever was on sale. The engines that I've kept track of are still running and being used. My engine still runs awesome. Most old school builders around where I grew up don't even use good oil for their break ins and they last. There's got to be more to it than just the zinc additive.

Tue Jan 28, 2014 11:08 pm

I'm not talking about just break-in. I'm talking about running a good zinc-rich oil all the time. :)