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Posted by: crash914 Oct 29 2019, 03:17 PM

So blew up my #3 rod. wondering what caused this. lack of oil, due to rpm? poor return? oil pump sucking air?

last time it was #2 rod. I really don't want to live with this again.

Motor specs,
Dual oil coolers with full flow plumbing
102 bore by 80mm stroke
long rods,
ham heads and valve train.
Running to 6800 rpm
g loads to 1.5
windage tray modified at pushrod tubes for oil flow
tuna can with 1/2 extra oil

Pics of horror below. First are this failure, then old failure.

Posted by: Chi-town Oct 29 2019, 04:38 PM

What kind of rod is that? Looks aftermarket?

Odd that it's snapped in half and the cap bolts are snapped

Posted by: HAM Inc Oct 29 2019, 04:57 PM

Man that sucks!
I think the rod bearing seized on the crank. I see micro-welding on the journal. That happened before the rod broke.
Any warning? Weird vibration, change in engine tone? Anything?

Is the oil pressure stable in corners?

State of tune? Detonation can cause bearing failures. Bearing failures can break con rods.

Posted by: crash914 Oct 29 2019, 06:14 PM

I did get some warning (that I ignored) running hotter than normal, low oil pressure at idle, knock, etc.

I heard something happen part way through a run. but nothing visible outside. I knew better than to run it, but only 2 runs to finish the season....No detonation, running 100+ octane at 12:1 afr. this was a really fast motor. revved quick and put the power down. I figure close to 200hp and also 180ish torque.

Posted by: Superhawk996 Oct 29 2019, 06:28 PM

Not trying to be a jackass . . . but sometimes it is what I do.

And we're discussing how/why this happened?

It does suck but when playing at those power levels and racing, this sort of failure shouldn't be a surprise. Especially when combined with ignoring the warning signs.

You have my utmost sympathy though. This is an expensive failure. But . . . racing is an expensive hobby. Ask me how I know.

Posted by: Superhawk996 Oct 29 2019, 07:12 PM

On a more constructive note.

Play with this centripedal force calculator.

https://www.engineersedge.com/physics/centrifugal_force.htm

In this specific case, RPM's have increased from 5500 rpm to 6800 rpm. RPM is directly related to the velocity term.

The force on the rod bearings is going up as the SQUARE of velocity. Said differently, the force increase isn't linearly proportional to the crank journal velocity, it is increasing exponentially.

Double the velocity term in the calculator and watch what happens to Force, it goes up by way more than double.

Bottom line, although the top end was likely beefed up to control the valve float, the stock lower end rod bearing journals are getting overloaded. This squeezed out the very thin oil film that separates the rod bearing from the journal and prevents metal on metal contact.

First part of this occurs as dramatically increased bearing material wear. Eventually it results in steel on steel contact and the micro-welding Lew mentioned.

If you are going to run this type of engine at these elevated power levels I'd recommend that you do professional oil analysis after every race. If you establish a baseline immediately after engine break in, you WILL be able to tell when the bearing material is being shredded off into the oil more rapidly than usual.

At that point, you need to stop running the engine and replace the bearings at predetermined intervals. Ultimately you will likely get a crank failure in the long term after some unknown number of bearing replacements.

Posted by: wndsrfr Oct 29 2019, 07:31 PM

With the stroker crank, do a really thorough inspection/magnaflux of the crank, especially if it's a DPR or other built up then machined OE one. If it's a new forging it might have survived, but I'd be wary of a reworked OE. Had two DPR's fail on me due to the resulting closeness of the oil channel to the web after offset grinding. Went with FAT performance new forging crank after that.

Posted by: Chris914n6 Oct 29 2019, 11:14 PM

I can't think of a motor with nearly a 4" bore that turns more than 6k.

Posted by: falcor75 Oct 29 2019, 11:46 PM

Pushing an engine with low oil pressure and knocking sounds. Sorry but thats just dumb. As for what caused the failure I think Superhawk is onto a good lead. Sure a T4 can push 200 hp with some reliability but it will always need alot more attention and preventive maintenance than a less high strung engine. Changing the oil after every race with an oil analysis is a good start. Measuring is knowing. To me this isnt as much an engine failure as an maintenance/owner failure, the signs were there and you saw them and chose to ignore them.

Posted by: crash914 Oct 30 2019, 10:53 AM

I accept the responsibility for the failure. No need to run it in.
What I would like to generate is what to do to have a high rev engine live more than 20 hours? Bearing coating? Super secret windage tray mods? Better balance? Lots of folks build big bore motors, hopefully we can help them with longevity.

Posted by: mepstein Oct 30 2019, 11:33 AM

Regarding bearings, I’m curious why 6800 is high revs on a 4 and normal for a six. Are the bearings loads or stresses different! I always thought valve train was more the limiting factor to revving a four.

Posted by: crash914 Oct 30 2019, 11:50 AM

Exactly what I thought also. That the valve train was the weak point. I did address that. Let the high revers chime in.

Posted by: johnhora Oct 30 2019, 11:50 AM

Herb..

20 hours is pretty good for MTTF
were both engine failures at the 20 hr mark?
I see a sheared rod bolt...that is definitely a failure point on a high rev engine.

Posted by: jd74914 Oct 30 2019, 12:28 PM

Dry sump with a few suction points...

It would be interesting to measure and log gallery oil pressures at high speed and see what happens in relation to lat./long. acceleration. As noted, there is likely a story on the bearing overload side which is related to oil pressure.

Posted by: crash914 Oct 30 2019, 12:40 PM

I will know more after the post. Engine is ready to drop. I should have it apart Saturday. Small thin bearing material in the sump. Correct on 1 sheared rod bolt. The other is ok, I haven't found the rod cap yet

Posted by: ClayPerrine Oct 30 2019, 12:59 PM

Use a 1.7L crank and bigger bore to increase the displacement. Shorter stroke/bigger bore allows more usable RPM with the same displacement.

For example... a 76 930 engine with a 70 911S counter-weighted crank and 906 cams gives you a motor with about 2.5L, but will rev to 10K. AS explained above, it lowers the stress on the rod bearings. It is a screamer of an engine, but not very streetable.

So get a 1.7L crank with counterweights, and bore it as big as possible. you can probably get 7K out of the motor.

I would suggest asking Jake Raby about this. He knows more about it than I do.

Clay

Posted by: sixnotfour Oct 30 2019, 01:55 PM

Clay that's a 66x95 2.8....76 911 66x90 2.5+...but get your point...

Posted by: ClayPerrine Oct 30 2019, 01:56 PM

HEY!! Give me a break. I am doing this from memory.

Posted by: sixnotfour Oct 30 2019, 02:01 PM

All I Know is; Type Four Sale

Posted by: HAM Inc Oct 30 2019, 07:35 PM

Herb, you can't assume that because you have a fat AFR that you aren't experiencing detonation. Indeed, because a fat tune takes extra time to react completely in the combustion chamber it's common to have elevated temps around the exhaust valve and higher egt's since the fuel burned at the end of the cycle does so around the valve. That concentrated heat can definitely contribute to detonation.

You said it was running hotter than normal. CHT's, EGT"S, oil. . . what was running hotter?

You may need an accusump. Your rod failures might be a combo of state of tune and inadequate oiling. Could just be oiling alone.

Posted by: crash914 Oct 30 2019, 07:45 PM

oil temp was elevated due to the rod bearing failure. symptom of low oil pressure at idle and temps of 220 oil temp.

normally I run around 180 degree oil temp and 30 psi pressure at idle.
Also running 100+ octane race fuel at 12:1 full throttle and about 9:1 compression.

Posted by: jd74914 Oct 30 2019, 08:16 PM

Thinking out loud here...Why are you running high octane fuel with a mild CR? With such low hours are your rings totally seated or are you pushing some fuel into the oil?

Posted by: yeahmag Oct 30 2019, 09:30 PM

I had to rebuild two motors before switching to a dry sump due to rod knock. The CB Performance pump has pretty poor idle pressure, but is fine at anything about 1200 RPM. I did do a bit of work to open the ports in it...

Evan and I beat the piss out of the motor now (7000-7250 RPM) and it doesn't bat an eye.

Posted by: crash914 Oct 31 2019, 05:18 AM

actually my CR is higher, more like 10:1. I hate fuel knock. I would get some with running 93 so I just used 100 in this motor from the start.

How does the dry sump perform better if the oil is trapped in the heads and the issue is return flow? I guess you could tap a port in each head to help the return?

Posted by: HAM Inc Oct 31 2019, 06:21 AM

Don't vent the heads. Oil pools in vented T4 heads. The higher the revs the more pooling.
https://newsite.hamheads.com/2016/12/10/type-4-crankcase-breathing-system-tests-analysis/

Posted by: crash914 Oct 31 2019, 08:29 AM

Good read. Thanks Len.

For things to note, I did see my dip stick extend after runs. Seems to indicate excessive crank case pressure.
I did have the heads vented to a breather box that drains back. The dry sump and no vents sounds promising.

Posted by: yeahmag Oct 31 2019, 08:43 AM

I employed Lens and Jakes work on the current motor. Heads are not vented and a -10 AN welded to the chimney that leads to a breather tank.

Posted by: VaccaRabite Oct 31 2019, 09:57 AM

There used to be pictures of the test engine with modified valve covers with glass windows where you could see the oil pooling. Those pics were very convincing and had me pulling my head breathers out.

Zach

Posted by: HAM Inc Oct 31 2019, 03:56 PM

Herb, if you're just AXing then a dry sump system would probably be overkill. A lot goes into converting a wet-sump engine into a properly designed dry sump engine.

Keep the tuna can. Dump the head vents and add an Accusump.

As for the possibility of detonation, one easy tell-tale sign you can look for during disassembly is if top and second ring gaps have lined up. That's a classic sign of detonation.

Posted by: crash914 Oct 31 2019, 03:59 PM

Len, just so I am clear, plug the head vents, don't cross connect?

Posted by: GregAmy Oct 31 2019, 04:10 PM

Totally taking this off-topic a bit further...last few races I experienced unhappiness with my 914 regarding vented rockers.

Last summer with my 2L I was taking a nice long left-hander at Thompson (under the bridge) and the pressed vent tube in the right head came out. Dumped shad-ton of oil all around the bend, causing a couple cars to spin and one to hit the wall (I strongly apologized and ensured he did not buy beer or dinner that night). Field-fixed it by slightly swaging the tube, tapping it back in tightly, and gooping it with silicon. Held for the weekend.

This September at the Lime Rock Labor Day historics, using a borrowed 1.8L. The valve covers have welded 1/2" tubes coming off the valve covers with oil hose secured by hose clamps. First session out, driving through Big Bend and the left hose came off the tube....dumping a shad-ton of oil all around the bend, causing myself and several other cars to spin (no contact, thank goodness). Field-fixed by cleaning it all up, screwing it on as tight as I could, then drilling a hole across the hose, clamp, and tube and putting in a cotter pin, sealing it with silicon. Held for the rest of the weekend.

I'm also running a CB Performance dry sump pump.

I'm really getting tired of that. If I don't need these rocker vents then I'll just drill/tap/plug the holes on the 2L engine I'm building now and be done with it.




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Posted by: cuddy_k Oct 31 2019, 04:10 PM

Curious...could unbalanced components accelerate the bearing wear and lead to this sooner?

Posted by: HAM Inc Oct 31 2019, 05:02 PM

Yes. Just plug them.

Basic engine theory: Place the oil sump pick up at the engines lowest point in the crankcase and vent the crankcase at its highest point. Keep it simple.

Posted by: HAM Inc Oct 31 2019, 05:20 PM

Greg you don't need anymore oil incidents! Your last one ought to hold you for the rest of your driving career.

Posted by: yeahmag Oct 31 2019, 05:23 PM

Greg,

Just make sure that you increase the chimney vent some. I went with a -10 AN weld-in bung and a catch can to ensure good breathing.

-Aaron

Posted by: GregAmy Oct 31 2019, 05:39 PM

Jeebus! That's not even https://www.youtube.com/watch?v=wO6TwYRFS74 Toss in the "https://www.youtube.com/watch?v=FcFhn71Ek1s" in early 2018 and it's been an "interesting" 18 months...I really do need a boring hobby...

Fantastic meeting you and your dad at VIR. Hope that happens again soon.

I think I'm'a gonna plug those head holes.

Posted by: GregAmy Oct 31 2019, 05:42 PM

That shouldn't be a hassle. I've modified the "stack" there to both vent and accept drainback from the can (kinda see it in this photo); it would be easy to toss in a larger vent tube on that block-off plate.





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Posted by: HAM Inc Oct 31 2019, 06:20 PM

Damn Greg! You've had a hell of a year and a half. That VIR shit was scary and such a suck ass way to end up considering how hard you guys worked to make the race.
The NOLA "Jackie Stewart" commentary is gold! I have to ask, how did you handle the post race de-brief with the dive-bomber? Was a jack handle involved?

Dad and I had a really good time at VIR. We sure did appreciate the passes and we enjoyed meeting your guys. Wish we could have socialized more. Maybe next time you won't have to work so hard!

Posted by: GregAmy Nov 1 2019, 05:08 AM

Oh, it did not go well AT ALL. The short version is I was tossing paper as I was climbing out of the meat wagon, and when the SOM decision went against him, he and his dad yelled and cursed at the stewards and flipped them the bird. Then started yelling at us, claiming we were damaging his chances for his future racing career. At the time it was kinda surprising; in hindsight it's freaking hilarious.

I DO NOT like thrashing at the track (or, really, at home). But I seem to surround myself with people that are all like, "dude, we're here, let's fix that s**t" and it makes for good stories. I need more less-motivated friends.

But last weekend at NJMP was nice: good weather, 914 ran all weekend without a hitch, boring video, pretty car goes back on trailer as pretty as it was when it arrived. Need more of those.

Now to decide what to do in 2020. I am becoming more attracted to that limited prep HProd 1.8L option...know anyone that could build a Micro/Megasquirt using the stock throttle body...?

Back to our regularly-scheduled "toss a rod" discussion. In that vein, here's what happened to me the weekend before the Lime Rock Historics 2019 (remember what I said about needing to be more boring...?)

Knitting. That's the ticket. Or crochet or quilting. Though they get pretty serious about that stuff...


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Posted by: rick 918-S Nov 1 2019, 06:49 AM

check your connecting rod ratio to assist in cakculating you approximate RPM range. The long rods should allow for higher RPMs but the size of the Piston may be causing the inertia to jerk the bolts apart.

My BMW 2002 had a con rod ratio of 1.6875 which translates to 6875 RPM's at an extended 7200 the harmonics and piston inertia would pull the rod bolts apart. Ok for short bursts but really a grenade waiting to happen.

Posted by: GregAmy Nov 1 2019, 07:00 AM

Did I miss something in this thread, or did the OP note that he ran the car despite a noticeable rod knock and low oil pressure?

Seems a pretty easy answer...no?

Posted by: crash914 Nov 1 2019, 07:14 AM

I did run it to failure. Before this last event there was no indication of potential problems. I also had a couple of runs that were normal. From first indication, it was a quick failure.

I think my rod ratio was good, but will review my that was one of the changes with this motor. I had shorter rods previously.

Posted by: Mark Henry Nov 1 2019, 12:46 PM

To me 6800 rpm is really pushing the limits of a stroker T4.
You have a number of fail points that can be happening all at the same time, below I'm only addressing crank flex.

Crank flex the crank actually bending at/near the center main journal, as well the 2" "chevy" rod journals. Having 2 throws without support in between the rod journals is another weak point. the higher the RPM the more flex.
This flex is why a 1.7/1.8 case is a better choice over a 2.0 case, as the crank flexes even in a stock engine and it's hard on the center main case bearing saddle. VW knew this, basically stating a 2.0 couldn't be done reliably and it was Porsche that designed/modified the 2.0 crank for the '73 914. VW didn't use the 2.0 engine in the bus, till the 914 proved it was satisfactory reliable enough, for the 1976 model year.
With a longer stroke, in this case a 80mm, at high rpm you are amplifying all the bad, the crank flexes, causing bending stress on the rods, points of the bearings begin touching the crank journals, side loading, heat begins to spike, add into the mix events high RPM downshifting causing mechanical over rev, etc.
All of these stress points begin to cascade as RPM increases until the weakest point fails, in this case the rod.


I'd choose the 78mm crank with T1 rod journals just because the bigger T1 journal has more strength. I'd also lower my redline to no more than 6500rpm.

Hope this makes sense, I've got a L5 herniated disc back issues and I'm whacked out on pain meds.

Posted by: crash914 Nov 1 2019, 01:38 PM

Thanks Mark, I was hoping to get your insite.
Try whiskey? It helped with the pain of losing this engine.

Hope you get well soon..

Posted by: dirk2056 Nov 1 2019, 02:23 PM

When I had my heads reworked the machine shop closed/weld the breather vents is that a good or bad idea??

Posted by: crash914 Nov 1 2019, 02:41 PM

It sounds like it was a good idea.

Posted by: HAM Inc Nov 1 2019, 07:35 PM

Pretty funny the guy accused the racer he dumped of ruining his career. If he keeps driving like that he'll get more than paper thrown at him eventually.

I don't think you'll have too much trouble finding someone to build your MSquirt. What about DIY in Atl? I'll bet a post on the Sandbox would flesh out sources fast.

Greg your broken crank is kind of unusual for a stock crank. They're actually nice chilled forged German steel. I think case flex and or shuffling may have something to do with your failure. I have heard of them breaking in the center main before, but like I said it's not common.

I broke a 1.8 crank on the FP 914 at the #1 journal, just in front of the flywheel. But we had lightened the shit out of that crank and I was turning around 8k at W.O.T. in turn 9 at Roebling. Caused a momentary rear wheel lock up. It was exciting.

For our race engines I used to drill the 6 main bolt bores for 1/2" bolts. They fit snug in the case and that totally eliminated shuffling. I torqued them down good and that eliminated any separation of case halves. I line-bored the case with the new big bolts. This process was waaaaay cheaper and easier than installing shuffle pins and buying ARP case hardware.

I would spend in the neighborhood of a 100 hours prepping our dry sump race cases.

Posted by: Superhawk996 Nov 2 2019, 01:53 PM

@HAM Inc

Love the fact that you're using the 1/2" bolts to effectively shuffle pin it without all the work and machining associated with shuffle pins. Colin Chapman would be proud.

“…simplicate, and add…lightness" has been attributed to Colin Chapman. To paraphrase his lightweight philosophy, each part should serve multiple functions. Your creative solution achieves that goal. Nice way to work smarter not harder.

Great job Len!

Posted by: GregAmy Nov 3 2019, 06:15 AM

Dat's purdy work up there...if you're bored and want to do another one...

Not sure that I want to pursue the Limited Prep HProd route. I already have the chassis at LP (it's an ex-ITA/ITB car) but the induction regs require using the stock, unmodified throttle body. That's a lot of development that has to be done around that one piece.

Posted by: HAM Inc Nov 3 2019, 08:50 AM

Colin Chapman was a genius. He would have gun drilled those bolts. I did at leat lop off the extra threads I considered using Jet Nuts to save some more weight, but didn't want to spend the money.

Greg, you ought to talk to Blake Meredith. He ran a ITB 914 and considered switching it over to HP. IMO it would be an expensive exercise in

The case work was a labor of love. And it worked great. That bottom end never gave a minute of trouble and ran 11 double weekends plus test days. Oil samples always came back perfect and hot idle oil pressures never changed one bit from new.

When I sold the car that engine was in it. Kip sold it to a guy in CA. I'd love to be a fly on the wall when he tears into it.

Posted by: type2man Nov 3 2019, 12:21 PM

One thing no one else has asked is how were the other rod bearings. If they all looked really worn, then you should have a lack of lubrication. If they all looked fine, then you have another issue.

Posted by: crash914 Nov 3 2019, 07:53 PM

Engine is out, I won't have a chance to split the case until the weekend. Lots of copper in the filter along with thin pieces of bearing.

Posted by: HAM Inc Nov 4 2019, 07:10 AM

Herb, based on the picture of your crank I'd bet money your issue is oil starvation related.

You've probably had a lot of momentary oil starvation episodes that eroded the bearings over time till you suffered a seizure and failure.

Posted by: GregAmy Nov 4 2019, 07:29 AM

FWIW, the prior owner of my car kept losing rod bearings due to oil starvation. It was an Improved Touring car, built in the late 90s. He said the problem began to manifest itself as Hoosier moved the (vastly improved) R3S03 tires...and ITx does not allow dry sump.

So he parked it in his basement garage with a spun rod bearing, built an ITS 944, and I bought the 914 from him 15 years later...

Posted by: crash914 Nov 4 2019, 07:34 AM

Oil starvation makes sense. More to come. The question will be how to address it without breaking the bank..damn, I was real strong this year. Keeping up with all the Caymans and gt's.

Posted by: GregAmy Nov 4 2019, 12:29 PM

Well, if one were to work on the baseline assumption that it is actually oil pickup starvation...

- Slightly Improved: Tuna can. Didn't see above if you're running one now.
- Better: https://www.pelicanparts.com/More_Info/SCAT50020.htm?pn=SCAT-50020&bt=Y&fs=0&SVSVSI=978. Watch for ground clearance, though.
- Best: dry sump. The CB Performance bolt-in dry sump pumps are not hatefully-priced, all you'd need to do is engineer a tank someplace in the chassis/engine compartment and plumb it. And it doesn't have to be 10-12 quarts, I'd suggest 4-5 should be more than enough...

Posted by: HAM Inc Nov 4 2019, 06:52 PM

Herb are you running an accusump?

I'm of the opinion that an AX car doesn't need a dry sump system. A good tuna can and some mods to the windage tray are a big help.

Blocking the head vents will help keep oil from accumulating in the valve covers. That's a quart and half or more right there.

There are a bunch of little mods that can be done to improve the wet-sump function.

Properly engineering a dry-sump system is more complicated than just adding a dry sump tank and the plumbing. This is especially true if you are using a two stage pump, like the CB, which is a simple plug and play pump and adequate if proper prep is made, but not if you don't as the scavenge stage is not substantially larger than the pressure stage.

The mistake a lot of people make (I made it too) is to think that by adding the tank you can give short thrift to the scavenge aspect of the case prep. The reality is, you still have to prep the scavenge capabilities the same as if you were running a wet-sump system.

If you don't, when you corner and oil moves away from the pick-up you stop pumping oil out of the engine, but you don't stop pumping oil into the engine. This extra oil wraps around the crank and sloshes around in the case. With every significant corner you end up transferring oil from the tank into the crankcase.

At best this condition just robs power, but at worst it foams the oil so badly that even baffles in the tank can't de-aerate the oil fast enough. And if you vent the crankcase directly into a breather can and bypass the tank the oil that transfers from the tank to the crankcase will transfer out to the breather can.

The case mods I made to our dry-sump engines radically reduced the case-sump capacity with expoxied in place panels. The panels were arranged to direct oil to the pick-up which was down in my home made tuna can.

I also removed the goofy stud that runs through the pick up and cut off the restriction where the o-ring fits into the case. I welded a bung to the pick-up and sealed it to the case with a bead of silicon. The pick-up was secured to the bottom of the case with a bolt that went through from the bottom.

The stock by-pass circuit was sealed off with epoxy and an external regulator put in line.

[attachmentid=717974] [attachmentid=717977]

Posted by: GregAmy Nov 4 2019, 07:08 PM

Nice, Len!

I, too, have been thinking about that sloshing problem, coupled to the fact that the CB scavenge pump isn't very much bigger. I've noticed that even when I let the engine run without cornering, there's always a lot of oil left in the case before I do an oil change. This goes toward explaining why.

Thanks for sharing this stuff; it's giving me a lot of thoughts.

Edit: Just walked out to the gaage to measure the CB pump: the pressure gears are 20mm long and the scavenge side is 26mm.

Posted by: HAM Inc Nov 4 2019, 07:33 PM

The CB pump is okay, but it has an internal cross over that can cavitate at high revs.

I used a Bugpack pump that came with 3 30mm gear sets and had the same cross over. I eliminated the cross over and one gear set. I did this by separating two gear sets with a hardened steel plate and shortening the shafts. This way the scavenged oil exited the engine through the cases original pressure circuit that originally lead to the stock oil filter.

With the external regulator I was able to dial in the pressure to a steady 50psi. That's not as much as most people run, but it's plenty of pressure. Observing the bypassed oil going back to the tank on the chassis dyno and comparing it to the scavenged oil returning to the tank I was able to estimate that ~ half of what was drawn from the tank was bypassed back, meaning that ~20mm of pressure side gear was plenty to generate a constant 50psi at 240* oil temps.

The modded Bugpack pump is on the left, the CB on the right. Once finished it fit behind the fan housing with only a slight bit of clearancing to a rib on the housing.

And yes, in case you're wondering, the old 10psi for every 1000rpm's is old school overkill. We ran 8300rpm's with 50psi for two years with zero issue. And on the dyno the difference between 60psi and 50psi was in the neighborhood of 5hp over 7Krpm's.

For a few years I circle tracked a 2.3 Ford mini-stock and ran over 8500rpms with 40psi and 275* oil temps. Never hurt a bearing though the oil temps did shorten valve spring life.

Posted by: HAM Inc Nov 4 2019, 07:46 PM

Some more pics.
Opening the scavenge port in the case to port match it to the Bugpack pump.

A better angle of the modified pick-up and the channel opening to direct oil to the tuna can.

Posted by: Superhawk996 Nov 4 2019, 07:53 PM

Laughing at all the work that that goes into making a Type 4 hot rod. Truly a labor of love.

I live in a world where electric vehicles are quickly becoming more common. They don't have much soul as far as I'm concerned but they can be crazy fast and put internal combustion to shame in a street car drag race. Sad but true.

I have to wonder if someday folks will be swapping out IGBT transistors in an attempt to hot rod their 50 year old EV's as inverter technologies evolve. I have to say I doubt it.

Labor on and fight the good fight guys.

Love watching this post evolve and seeing Len's creativity at work!

Posted by: GregAmy Nov 4 2019, 08:25 PM

I'm amazed at the work that went into this development...while simultaneously clearly understanding why Limited Prep Production is so attractive.



Engineering an EFI system around the stock throttle body suddenly ain't so unimagineable.

Posted by: crash914 Nov 4 2019, 09:18 PM

I do have and run a tuna can. I do not have an accusump. I like the ideas on the process of dry sump engineering! Not sure of my next steps, depends on what I can salvage. Don't think I will use a 80mm crank though.

Posted by: Superhawk996 Nov 5 2019, 05:55 AM

Good call. Generally speaking, stroker cranks are great for making more torque but have limited use in a T4 at high rev's for all the reasons Mark Henry pointed out. Also recall the crank stroke radius works against you by increasing bearing forces per the centrifugal force formula:

Centrifugal Force=1227 x Weight of piston & rod assembly x Radius of revolution (in this case 80mm) x RPM^2 (RPM squared). In your case, you increased all three terms. Piston weight is probably up due to big bore. The radius of revolution is higher. And finally, the RPM is 25% higher but is going up exponentially as the square of RPM's. All these are working against you.

Also don't forget the formula above is only centrifugal force which is acting on the bearing all the time. Your cyclical combustion force on the the rod bearing also has increased as a result of the increased combustion forces (Mean Effective Pressure x Piston Area) acting on the piston downward during the combustion stroke.

Not saying you don't have an oiling issue too, but, none of the stuff above is working in your favor even with proper oiling.

Posted by: crash914 Nov 5 2019, 06:31 AM

But what a fun motor! Light up the tires whenever at full throttle. Pulled great out of corners, lots of lateral acceleration. I could finally keep up with all the modern cars, except the Tesla on autocross tires. Tesla's suck, but man do they accelerate fast!

Posted by: HAM Inc Nov 5 2019, 07:20 AM

Thanks Greg. When I was finished with the Level 2 914 (not to say it was fully developed to my idea of its full potential) I became a big fan of level 1 prep!

All of this same crazy effort went into redesigning the suspension, the shift linkage, the cockpit, the pedals and on and on. I ended up with a great handling, great shifting and great braking 914, yet after all of that a Spec Miata on the same tires we ran was a bitch to keep up with.

Posted by: Superhawk996 Nov 5 2019, 06:27 PM

Depends on the definition of fun.

The ability to light up the tires whenever really means you have too much power for the tire you're running.

If you truly want to be fast, the ability to ground power without lighting up the tires is key to being fast. Lighting up the tires means you've lost both longitudinal grip and lateral grip. That isn't a good thing. . . . but many consider it fun. If you can light up the tires that easily, I'd ask you to do some soul searching about how much power you really need to maximize your lap times. You may find less power, or conversely, more tire, is actually faster.

To use an extreme analogy. If I put 2" wide hard compound motorcycle tires on a 914, I could light up the tires at will with something on the order of a 1.7L's power. It may be fun (i.e. burning rubber and/or drifting) but I assure you it won't be fast.

The reason a Tesla P100D in Ludicrious mode is so fast (in a straight line) is because it can ground the power (via AWD). It isn't losing grip, and, therefore losing longitudinal acceleration (and by default) lateral grip. Not much drama, but the Tesla P100 D ludicrous mode launches with about 1.4G of Longitudinal Acceleration. Very hard to match that with production car running an Internal Combustion engine.

Personally, prefer the sound of an air cooled motor (especially a six) any day the week over the silence of an EV.

Posted by: crash914 Nov 5 2019, 07:05 PM

The tires I light up are 225 45 15 Hoosier A7's.. it is a really sticky tire.

I am able to modulate the throttle to get the limit of grip.. They give up at 1.5 or so G's.

Posted by: crash914 Nov 10 2019, 03:43 PM

Motor is disassembled. See below for some pictures. Damage is not too severe, cam is ok, heads and lifters are ok. Case is a loss, 3 piston/cylinders look ok. crank is toast.

Posted by: crash914 Nov 10 2019, 03:45 PM

A couple more pictures.

Posted by: crash914 Nov 10 2019, 03:46 PM

case GA000277 is history..

Posted by: VaccaRabite Nov 12 2019, 08:41 AM

I have a 2L case you are welcome to.

Zach

Posted by: crash914 Nov 12 2019, 08:45 AM

Thanks Zach! I might take you up on that offer. I have one to tear down. Depending on what shape it's in I will let you know... Now if you only had an extra -6 oil tank.