Author Topic: Inline-four crankshaft  (Read 477107 times)

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Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #375 on: April 15, 2018, 02:22:50 AM »
It went... tediously and stressfully. I had never dyno'd an engine before; the shop had never run such a small engine; the mounting and driveline hardware that I had prepared beforehand needed rework (different dyno 'cart" than the one I had measured); the dyno computer and my crank sensor weren't "happy"; zoomies had to be modified to connect to the cell's vent duct; etc.; etc. On the first startup in the dyno cell I forgot hearing protection and was literally deaf for the next 24 hours. Adding to the stress was the hour and a half commuting to the shop each of four days, plus the cost- $85/hour/man, usually two guys working with me.

Positives: engine is still in one "lump"; dyno data for pressures (bottom end oil, top end oil, fuel) and coolant temperature were fine.

Negatives: first attempted full-throttle "sweep" (3,000-7,000 RPM, 600 RPM/sec) ended quickly (about 3.5 seconds in, 4,430 RPM) with a bang (not severe enough to blow the burst panel).

The manifold pressure data clearly identifies the culprit. My guess at blower drive ratio (80% of crank speed) was totally "out of the park". This billet 14-71 is WAY more efficient than I knew. I was shooting for no more than 30 PSI of boost at around 9,000 RPM; the dyno recorded 25 PSI boost at 4,300 RPM! :-o Since the fuel setup was configured for a slower rise in boost, the mixture was going rapidly lean.

A quick engine check showed compression low on two cylinders, so I need to pull the head and hope it's repairable.

« Last Edit: April 15, 2018, 02:57:05 AM by Jack Gifford »
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Offline jacksoni

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Re: Inline-four crankshaft
« Reply #376 on: April 15, 2018, 11:33:44 AM »
Shucks, Jack, sorry to hear. I have no experience with supercharges but seems a 14-71 is awful big for a 3 liter. They put them on big V8's don't they? Anyway, hope any damage is small. Have you had anyone really versed in the big blowers help with set up, pulley ratios etc? ( sorry if that be you, not meaning to put anyone down)
Jack Iliff
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Offline wobblywalrus

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Re: Inline-four crankshaft
« Reply #377 on: April 15, 2018, 04:12:47 PM »
Would a manifold pressure release valve be a fix?

Offline Milwaukee Midget

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Re: Inline-four crankshaft
« Reply #378 on: April 15, 2018, 04:51:05 PM »
the shop had never run such a small engine;

I feel your pain there.

Orphan and custom engines are always a PITA getting properly hooked up to a dyno.

In most shops, you can get an LS or BBC bolted in and ready to go in an hour.  It's rare to find a shop that will tackle anything but a common drag motor, or a roundy pounder, and tougher to find a dyno operator with the patience and experience to even touch a combination like this. 

But when you do get this dialed in, it is going top be so much more impressive than any Bow-tie.

It's always better to find the problems before you run it on the track:  It's quicker to diagnose, you've got easier access to the problem not having to pull it out of the car, and you're not under the pressure of trying to get it together before the event closes down.

With the engine back in the shop, you can fix it on your own terms.

Sometimes, a dyno failure is a blessing - a track failure is always a headache.

Press on, Mr. Gifford.  I'm looking forward to seeing this thing go.



"Problems are almost always a sign of progress."  Harold Bettes
Well, I guess we're making a LOT of progress . . .  :roll:

Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #379 on: April 16, 2018, 12:16:33 AM »
... Would a manifold pressure release valve be a fix?...
No. Besides at each port, fuel is injected above the blower.
There's no need for dynamic pressure relief in a Roots-blown engine, once the correct configuration is established (i.e., the dumbass who set it up should have better researched the blower characteristics)! :oops:

jacksoni- I'm not aware of anyone familiar with a huge blower on a small engine. I tend toward less-travelled paths (at my own peril). In this case, I want to explore a means of reducing heating of the intake mixture without resorting to an intercooler system. Maybe I'll learn something, maybe not...
« Last Edit: April 16, 2018, 12:31:34 AM by Jack Gifford »
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Offline jacksoni

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Re: Inline-four crankshaft
« Reply #380 on: April 16, 2018, 07:44:48 AM »
..[/quote]jacksoni- I'm not aware of anyone familiar with a huge blower on a small engine. I tend toward less-travelled paths (at my own peril). [/quote]

Well, I have to say, I am personally familiar with this syndrome.  :roll: :wink:
Keep at it!!
Jack Iliff
 G/BGS-250.235 1987
 G/GC- 193.550 2021
  G/FAlt- 193.934 2021 (196.033 best)
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Offline bearingburner

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Re: Inline-four crankshaft
« Reply #381 on: April 16, 2018, 10:02:28 AM »
Experience is a good teacher though costly.

Offline POPS

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Re: Inline-four crankshaft
« Reply #382 on: April 16, 2018, 10:06:26 AM »
Jack,
We have the solution for cooling the charge.  Our atomizing nozzles will drop the inlet temperature 40 degrees.
Typical manifold temperature drops 20 degrees. 
Power gain for alcohol drag motors is 75 for roots and 85 for screw compressors.
You will see a 1.5 gain in boost, because the case will shrink faster than the impellers. Case will be cold to the touch.
Total EGT spread at WOT in the Flashpoint Streamliner is 35 degrees. 
POPS
Don Jackson Engineering
714-269-9645

Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #383 on: April 28, 2018, 01:11:49 AM »
Head off now. Head just has one small torched spot by #3 exhaust, easily repairable. But #2 & 3 sleeves are damaged, appears to be right at the spot where their top rings sat when detonation occurred. If they were typical cast iron sleeves, I'd guess they are cracked there. But I specifically make sleeves from DOM steel tubing to avoid the cracking of cast iron. I won't know what's happened until I get it completely torn down and the sleeves pressed out.
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Offline oj

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Re: Inline-four crankshaft
« Reply #384 on: May 02, 2018, 06:49:11 PM »
I feel for you.  Learning thru experience is a tedius job, I guess thats why its called the 'bleeding edge of technology' when you can't ask anybody else how they got there.
In any event, you are an inspiration to the rest of us, for whatever thats worth.

Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #385 on: May 06, 2018, 11:16:14 PM »
Torched spot in head's chamber #3 repaired, just need to "touch" the valve seats a few thousandths. Prior to taking block apart, blocked off coolant passages to do an air pressure check of sleeve integrity- they are okay, air-tight. Apparently I'm seeing evidence of top/middle rings being "blasted" out and marking the sleeves. So it still needs to come apart to replace rings. But hopefully a careful light hone will save the sleeves from needing changing.
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Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #386 on: June 07, 2018, 12:52:54 AM »
Shortblock buttoned up. Waiting on custom head gasket from SCE to bolt it all back together. Other than sourcing a belt, blower drive is set for 40% of crank speed. The only 32 tooth pulley available was intended as the driven pulley on a screw blower, so I machined down my crank hub to match the pulley's tiny bolt/dowel/register pattern. Looks crazy with an 80 tooth pulley on the blower! While it's apart, I've been chipping away at the list of stuff to make the next dyno session less hassle (matching fittings, connectors, etc.) and a few items I wanted to do better. The first two photos are of a plate on the bottom of the blower manifold to maintain alignment of the deflector style port nozzles. Despite best attempts to not disturb the nozzles when changing jets (in cramped space underneath the manifold), I had never found them perfectly aligned on a teardown.
The final photos are a reminder to NEVER use a grade zero fastener for ANYTHING! After I exploded and rebuilt the blower manifold a year ago, I had added four 5/16" bolts as anti-balloon "struts" near the middle of the manifold, and apparently grabbed one grade zero bolt by mistake. The photo shows it stretched and stripped where the locknut had been under the manifold's 1/2" thick top plate, following this year's detonation incident. The final photo shows how the "bang" tried to separate the blower from the manifold.
« Last Edit: June 07, 2018, 01:40:27 AM by Jack Gifford »
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Offline Jack Gifford

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Re: Inline-four crankshaft
« Reply #387 on: June 07, 2018, 01:41:42 AM »
Final photo
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Offline floydjer

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Re: Inline-four crankshaft
« Reply #388 on: June 07, 2018, 02:57:12 PM »
wow...26 pages of proof that everyone should read every thread on this site. Boat load of great info. Bravo. JB
I`d never advocate drugs,alcohol,violence or insanity to anyone...But they work for me.

Offline ronnieroadster

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Re: Inline-four crankshaft
« Reply #389 on: June 07, 2018, 04:19:48 PM »
Having run GMC and now Whipple blowers on one off intakes for my vintage engine projects one thing I learned was using a paper blower gasket is not a good idea.  Now on every blower manifold I make I machine a grove so " O " ring Buna N cord stock can be installed around the perimeter of the mating surface with the blower. Using the "O" ring material I now experience no gasket leakage even if the mating surfaces become slightly warped. I realize your gasket failure was due to the manifold explosion but eliminating the gasket would be a good thing. Plus considering all the work you have accomplished yourself making the "O" ring grove will be extremely simple.  
   Just wanted to mention this about manifold sealing to. You have A great project which I have been watching as you progress along. Your in a learning curve those of us who chose to go our own way find  rewarding after the learning curve has been beaten.   :cheers:
    Ronnieroadster
« Last Edit: June 07, 2018, 04:21:53 PM by ronnieroadster »
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