After new jugs and heads.... Problems with full rpm

[xymox]

Okay after installing new heads and jugs/pistons on the right side I'm able to get to about 3, 000 RPMs.
Was previously pulling 3200 static RPMs on the ground. When I apply Full Throttle it actually bogs down a bit and I need to throttle back to have it stabilized at the 3000. all else remaining equal what would need to be adjusted? And or checked?

Regards

[marsolgp]

Pushrod lengths.... rocker arm adjustment? Maybe......

[tom0nex74]

Installed Mahle 90.5 cylinder assemblies and reconditioned heads at 220 hrs. During the last 20 hrs of flight, picked up 100 RPM at take-off power. Break-in seems to take a long time on the Aero-Vee
0nex 74

[SonexN76ET]

Tom Onex is there some reason you went with smaller cylinders than the 92mm standard size for the Aerovee?

Jake

[xymox]

I jsut realized I never paid attention to which way the arrow was pointing on the new pistons. so Ill need to disassemble and check.
Question, what difference does it make what direction the pistons are pointed towards, they look symmetrical.

In any case I wanted to document what happens currently when I try and apply wide open throttle (on the ground)

SO she runs smooth until about 2900 rpms, at which point advancing the throttle to full only seems to foul out number 2 and 3. (I have egt probes on all exaust pipes BTW so am able to tell they are not firing.) During this excersize I only have the primary ignition switched on. I then back down the throttle (only running on 2) and its barely able to run of course.

I switch on the secondaries and she kicks back to life apparently burning off the carbon on 2 and 3 at which the whole test could repeat itself.
Doing a standard compresion test (non-leak down) I get about 175 psi on each cylinder.

My setup:
aerovee and aerocarb with a 2.5 needle (stainless)
1 mofoco rebuilt head
1 EMPI New head
2 new cyl/pistons on 1 and 3

[boosted0ne]

Generally speaking, the piston pins are offset to one side of the piston or the other by a small amount. The arrown indicates the front of the engine so the offset is on the correct side for the direction of engine rotation. This helps to prevent side loading.

This is general information not specific to the arrived or any other VW based engine.

[Klimek]

TomOnex,
On all VW aiecooled “Type 1” engines the rod had a casting in the side marking the direction the rod should be installed on the crank, that is installed with the cast “bump” facing up. The pistons have arrows that should be installed pointing in “the driving directions” (toward the flywheel) which in our case is pointing to the flywheel or tail of the airplane. The original pistons and rods were designed with a 1mm offset (not sure of the exact dimension) and when installed properly kept piston “slap” to a minimum when the piston changed direction of travel at or near TDC and ignition took place.
The rods supplied with the AeroVee kit have no markings but the pistons do. Make sure the arrows are pointing toward the flywheel. As far as the rods are concerned I just compared the General shape of the rods to an old VW OEM rod and installed them as if they had the “bump” on the side of the casting/forging. (Side being on the edge of the rod, not in the web)
Bla, bla; bla. I seem to rattle on a lot.

Capt. Frank B. “call the tower” Klimek
ONEX090
Unit Room Trained by Gerd Beetz, President VW service and Erwin Loheneiss, VP Training, VWMA.
Aeroinjector
Tail dragged
Steam gauges
2180 AeroVee
Paint not polish (in my right mind and not a gluten for punishment)
Going flying today!

[Area 51%]

In lieu of a casting mark on the rod, the bearing anti-rotational notches are the go-to indicators. Check the manual...but I think they go down.

[tom0nex74]

I went with the smaller pistons and more robust Mahle cylinder assemblies for more reliability. After 15 hrs I am able to gat 3350 rpm smoothly with good cht's and egt's. I need 3350 to keep the 0nex up on plane. It gets 130 mph (true) at 3500 ft 3350 rpm with my 150 lbs and 5 to 8 gallons of fuel. At lower rpm's the engine runs smooth and cool but I have to raise the nose to hold altitude and it looses 15 to 20 mph in cruise.
Tom 0nex 74

[lutorm]

Okay after installing new heads and jugs/pistons on the right side I'm able to get to about 3, 000 RPMs.
Was previously pulling 3200 static RPMs on the ground. When I apply Full Throttle it actually bogs down a bit and I need to throttle back to have it stabilized at the 3000. all else remaining equal what would need to be adjusted? And or checked?

When playing with the mixture adjustment, it seemed to me that the "full throttle bog down" appeared if the mixture was a bit on the lean side and went away if the mixture was enrichened further. (However, this was with my custom plenum, which has much larger volume than the standard intake, so it's expected to see more of a transient lean-out when the throttle is opened. The standard intake may not behave the same.)