Inline-four crankshaft

[Jack Gifford]

My initial view of the air/fuel log seemed to show acceptable (if slightly lean) ratio of about 5.8:1. But it turns out the 5.8 was during warmup. After a ten minute break the log of the run begins- and shows A/F at 12:1- ouch! Sadly, I was at fault, not the engine. I failed to fully open the fuel shutoff, which I use to lean it out during warmup. And I failed to even glance at the air/fuel meter during the run. In short, I FAILED.

[sabat]

The road to records is paved with broken parts. Don't beat yourself up too much, I bet you'll never have a similar brain fart again.

[Jack Gifford]

Joe- one reason I said "soft" is that SCTA's B/PP record is 196 mph, while LTA's B record is 115.

[Jack Gifford]

Detonation is truly ugly.
Although the head appears to be junk, I'm considering dropping down to H/BFL- rebuilding the four as a twin, using just cylinders #1 & #4 for 91 c.i. Question- would it make sense to bolt bob weights (same weight as used when crank was balanced) to unused throws #2 & #3?

[jacksoni]

When I first built my streamliner, having no idea really what I was doing nor how fast it might go out of the box I pulled two pistons from my 4 cyl to run as a 1 liter. I probably should have pulled the 2 and 3 as you did but regardless it worked. I made up bob weights with bearings for proper clearance and oil control. I think you need to do this though I have seen people talk about just using two rod caps bolted together but I think for proper balance and protection of the crank you should have proper bob weights. Someone with real machining/engine balancing expertise may opine about this. Anyway it worked for me. However  you do it you must control the oil flow.

First year out with my car it was wet, short course only, geared for well over 200 so my runs got me to second gear (of 4) only. Record. Tore engine apart, put the other two pistons in, replaced the valves in the head (DOHC), went 50 mph faster, and got to 3rd gear. Record.  Just short of 200 club speed so we went to junk yard back when Wendover had one, found a gear set and were in the process of changing the R&P hoping to accelerate better off the line when it rained again. Embarrassingly slow by todays standards but that was 1984 (after '82 and 83 rained out. El NIno) Turbo after that bumped things up but that's another story.

[Jack Gifford]

Evidence of the violence of detonation. I never thought I'd see a BME rod destroyed like this.

[jacksoni]

I believe you run methanol, correct? My reading over the years has suggested many people seem to think methanol doesn't detonate. It is resistant and the tuning range is wider/safer in that respect. but when it does detonate, it is violent and much worse than gasoline.

[Jack Gifford]

It's now time to end this long-running thread, since the "Inline-four crankshaft" will become part of an "inline twin".
Thank you all for the half-million views and thousands of posts to the thread, which have been very helpful.
I'll start a new build diary "Speed Queen II with 92 c.i. twin".