Esslinger SVO head spark plugs and adjustable cam gear

[mthibbitts]

Hi All,



I just got my new BoPort short block and new Pimpx ECU installed and drove it last weekend in my rock crawler. The current tune was set up for 93 octance but we only have 92 here. I noticed it would ping so I backed boost down and stayed out of the skinny pedal.



Got it dyno tuned yesterday and the tuner thinks the ignition system is weak as the engine sounded loaded up in higher rpms with boost. In order to prevent it from pinging they also altered the fuel and retarded the timing as much as possible. I can only able to run 14lbs before it starts pinging. The only thing that changed from before is the cam gear has been advanced or retarded by Bo. I can't recall which direction but it's for torque. Could too much advance/retard of the cam gear cause detonation? (all new within the last 6 months, TFI, cap and rotor, coil, wires, plugs).



The tuner pulled a spark plug and its gapped at 26 thousands. This Esslinger head uses 12mm motorcylce plugs. I currently am running the autolite copper 4132's. Do I need to reduce gap? Is the spark plug too hot causing detonation? Any recommendations on a good plug to use for this head with stock ignition?



Specs:

Boport short block with cp pistons and HD rods.

Esslinger aluminum head

Boport 2.1 torque cam turbo and solid lifters

Stock IHI turbo Manual boost controller

Stock injectors

Adjustable fuel pressure regulator

Stock upper and lower intake manifold with some port matching

Ported polished exhaust manifold

PIMPx ecu

C4 auto

4 spd transfercase

14 bolt rear axle





At 14lbs of boost it only made 140 hp and 160 tq. Seems to be on the low side but I dont know for sure how much drivetrain loss I should be considering. The tuner did mention that there is a fair amount of slippage int the transmission due to not having a locking torque converter.





Any insight is appreciated.

[Stinger]

Is the head milled? If so what's the chamber volume?

Dished or flat top pistons?

What ignition system?

Plugs are one step colder than stock so that shouldn't be the issue. Gap should be fine as well.

Cam timing certainly affects detonation limits as cam timing changes cyl pressure. Targeting torque with cam timing will increase cyl pressure in the midrange. Knowing what the cam timing is would certainly help.

Does it feel as slow as the power would indicate? Trying to figure out how much of that power reading is slip and how much is "real". That's significantly less power than a stock SVO so it would be quite slow if it's "real".

What RPM was tq peak and hp peak on the dyno (this is likely the most helpful piece of info I'm asking for)?

Are you 100% sure the cam isn't off a tooth? This is a common issue on these engines, will run "ok" but be way down on power, and it will make it prone to detonation without pulling a ton of timing out of it (like pulling 8-12 deg from our base tune).

[mthibbitts]

Head is not milled and is 62.8.

Dished pistons.

Stock motor craft ignition.

Just checked and Cam is advanced 4 degrees.

This is a rock crawler and I have only really driven it on the trails a few weekends ago. It has 43'' tall tires, 5:38 gears in the axles and a 4 spd transfer case. So needless to say, I have not driven it in high. I drive with the transferase in low gear. So it's hard to say how it drives in this configuration. Obviously in low gear (2.7:1), the turbo would spool up and it felt powerful.

Peak hp was 4700 and peak tq was at 4200.I will email you the dyno graph and you can see it fluctuating. They seem to think I have an ignition issue but everything is new.

Boport degreed the cam when he assembled my short block and head together. That obviously doesn't mean it did not get bumped when installing the cam belt but I marked the location of the cam gear to the valve cover. I could always recheck. Do you guys use the flat metal block to put it at zero? Do you sell that piece?

[Stinger]

For verifying the cam gear is on the right tooth (rather than doing fine adjustments), and assuming the cam gear is not marked in some way to give you a reference point like the stock cam gear does, you just turn the engine to TDC on the compression stroke and verify the cam keyway is pointing straight down. Unfortunately, you've got to loosen the belt tensioner (and potentially move the belt) to check this when the cam gear doesn't have a "stock timing location" mark on it. This is why we mark our gears before we ship them, it makes future diagnosis easier.

The 2.1 cam would "normally" get peak HP around 6000 or a bit higher. I wouldn't expect there to be enough adjustment in the cam gear to be able to move the peak power down by ~1500 rpm. Have you asked Bo about this detail?

[wesk]

The HP and torque peaks are true rpm, and not calculated from roller speed (but with an auto)? If so the cam timing is absolutely off IF boost is relatively flat with rpm. Logs from dyno would help a lot (or just stick with the tuner you are using and let him "fix" it). "Flat" with boost/rpm generally is not what an ignition miss sounds like. Extremely advanced cam timing does.

[Stinger]

Forwarded dyno sheet email to Wes.

[mthibbitts]

Thanks. I reached out to Bo. This cam has lobes ground in different location to the dowel he said so I can't put the dowel straight down as its not tdc on cylinder 1.

He suggested advancing the cam 2 degrees to see how that does. 

Based on the dyno curve the power is not smooth and all over the place. I just changed the plugs after the dyno tune. They had been fouled out on the old ecu. Hopefully that a contributor to the power.

[Stinger]

I certainly wouldn't be on a dyno with old fouled plugs so replacing them is certainly a good idea. Your "not smooth" portion is only changing about 5-7hp from peak to valley which is minimal enough that it could "disappear" with smoothing applied. If it's got massive misfire issues causing massive power loss, you'll hear it, often in the form of popping/backfiring, and power will fall off a cliff, not just level off.

Moving the cam timing 2 degrees is only going to move power peak a few hundred rpm so I wouldn't expect much from that minimal change.

The "e-bar" timing method doesn't require any "special" piece of material to lay across the lobes. It doesn't even have to be steel, it just has to be flat, stiff, and be narrow enough to not hit the next set of lobes.

The bottom line is your peak power is lower than even a stock 2.3T engine (which has super long intake runners, a tiny cam, tiny turbo, etc., all of which are designed to make power from 2500-5000ish rpm) but yet you've got upgrades that should shift peak power up significantly (not necessarily losing power down low relative to stock, but peaking higher) but your engine is not doing that at all. So it's either got a MASSIVE restriction, or cam timing is off.

[mthibbitts]

Thank you for your insight I greatly appreciate it!