225 promax with one piece adapter plate

[PanRonnie]

you have to pamper yourself from time to time
the rounding of the end was my insperation for the best bellmouth
now this would be about the intake pulse but i figured this
might be beneficial and put the rounding on it as it might help with the reflection wave going back up and possible creater a better cyllinder filling
http://www.profblairandassociates.co...mouth_Sept.pdf

if you check out EGT 8 and EGT 7 at the bottom of the graph you see the temp,s
EGT 8 and EGT 7 are from the engine with the SST 200XS poppet spring
EGT 5 and EGT 6 are from the engine with the flow cooling like the old 260 and 280
and apperently a 36-1 is no problem for megasquirt you see the spinup when i get loose
was a bit rough today

[NZ Sidewinder]

Those two EGT comparisons are great.
Where are your Pyros fitted?
Im only familiar with EGT's in light diesel trucks which need to have the pyros before the turbo and dont exceed 700 degree C or bad things can happen.
As for reinforced gaskets, yes my Gasket maker informs me he can cut .060 inch stainless steel mesh reinforced graphite paper so that will do me.

[PanRonnie]

on the 2.5 it,s very easy
the 2 lower exhaust cover bolts stick into the exhaust
you can order these predilled holes from mercury but they are 1.5mm
i drill them to 3 mm and 1/8 donkey/horse thread to fit these from RS components
these are twin tipped so 2 channels
one for a gauge on the dash and one for logging
https://nl.rs-online.com/web/p/thermocouples/3971359

[NZ Sidewinder]

on the 2.5 it,s very easy
the 2 lower exhaust cover bolts stick into the exhaust
you can order these predilled holes from mercury but they are 1.5mm
i drill them to 3 mm and 1/8 donkey/horse thread to fit these from RS components
these are twin tipped so 2 channels
one for a gauge on the dash and one for logging
https://nl.rs-online.com/web/p/thermocouples/3971359

If you were to lean out just one cylinder would this system see that in time to back off

[PanRonnie]

If you were to lean out just one cylinder would this system see that in time to back off

noop only complete bank average is what you read
i have been thinking about this
if you look at the exhaust cover there bolt holes over every cylinder
you could install same cover bolts made with the 1.5mm hole which would also be drilled into the block bolt hole
it should exit into the exhaust cavity
this might give the ability to tune on a cylinder by cylinder basis depending on how much the egt probe is getting exhaust from the other cylinders
in general EGT,s are slow but if they are somewhat shielded from the exhaust pulse from the other cylinders by their placement it might just work

[NZ Sidewinder]

Difficult to say.
It could be one of those cases where data makes more questions than it answers .
Would the data be consistent across the rev range and would there be a wide variation in temps from top to bottom?

Has anyone measured measured spark plug hex temps?
Im not a 2 stroke mechanic.

[NZ Sidewinder]

Ok Ive been looking real hard at this one piece on a Pro max issue and have some ideas.
First thing I did was to write down a description of what I reckoned was happening through a two piece adapter.
It was pretty straight forward until the part where I had to work out what the relationship was between the 3/16 hole in the water duct and the cylinder head dump ports at the bottom of each bank.
That hole in the water inlet still has me stumped for a definitive answer.
Its probably not just a drain because a drain would be better drilled in the floor of that cavity into the eyebrow ducts
So it must be some sort of balance duct.
So I decided that my one piece mod would include that balance system.

Im planning on getting a Pan plate cut with zero dump holes
That allows the dump cavity in the one piece to act solely as a poppet drain duct.
This new poppet dump duct will drain through two 1/4 pipe fittings to the exhaust port just above tuner, well below the portion of the exhaust port that warms the infeed water.
This piping route is shown in the photo of the underside of the one piece.

Then the new Pan plate with no dump holes in it will have a 4mm hole drilled to match the 4mm hole in the water infeed duct as shown in the photo.
This connects the water infeed duct to the head dumps.
The tolerances on this hole are fine but doable.

The Stats water will go to a tell tail and maybe to the 2 exhaust port holes in the front of the one piece.
The reason for the focus on using spent water to cool tuner is that the tuner that came off the one piece was cooked.
The gasket was baked, the web between ports was blown through and the bolts were all seized.
No fun to fix.
Ill reluctantly drill the midsection at the eyebrow ports to relieve the back pressure at idle.


This plan could change.

[NZ Sidewinder]

edited out

[NZ Sidewinder]

Stay focussed bunnymeister. Dont forget the hose from the top of the block that is connected with the poppet cover. The poppet cavity gets feeded at all RPMS. Also at lower speed when the poppet is closed. Even the the tuner gets cooled. Thats why I think mother merc goes from the full footprint poppet size to a smaller hole. It works restrictive and pushes water in the channel to cool the tuner.

With my 2 piece plate I disconnected the fitting at the rear of the adapter with a running engine. Actualy water was comming through the fitting. So in other terms with the fitting it might spill more water than pushing through the tiny holes to cool the tuner.

The fitting at front of my PM is fed from the stats and feeds the water jacket that wraps around the front and sides of the exhaust ports in the lower half of the 2 piece.
Then there is an upwardly sloping duct leading to the poppet dump to atmosphere.
Id say the upward slope of this duct is to ensure that the 2 small holes that drain to the front face of the tuner get priority over the eventual exit of this water through the poppet dump.

[LakeFever]

Yes, create a popet cavity with a water dump passage straight out the bottom. Plug up the existing water drain holes and drill 2x 1/8" drain holes to allow powerhead to completely drain.

This method is good to go yes? This thread went some distance and i read every post a couple times this method is attractive but the discussion seemed to get complicated for no good reason if this method works ok?

[Greg G]

Steve has not been around for a bit but you could PM him to see if he would come back to the thread and comment given it was years back.

[NZ Sidewinder]

The dumpless pan as described here, has worked well for me on a 80mph circuit race boat.
It might have been big boy who cracked it with the info about the special pan that turns a 1 piece into a 2 piece.
It all got covered elsewhere on the site from memory.

In a nutshell, block up the dump holes in the pan plate but leave a drain hole in the center of one of the blocked up holes.(this ensures there is no gasket covering the drain hole.
Do what you like with the factory holes in the bottom of the one piece just don't block them up because the poppet water needs them to dump through.
I didn't run diverters in the block but have put them in and haven't tested yet.
There was talk about creating a poppet duct and I did this but it only real purpose is to support the pan plate and gasket.
On mine, that wall has holes in it so the poppet water can be directed into the cavity below the pan plate.
Sounds complicated but it's head banging simple.

[Steve Pope]

Yes a dumpless pan as used factory on 15 inch promax's or the method I have used does the job

[PanRonnie]

looking at the data from last sunday
the temps on the poppet motor look much better than on the flow cooling system
i do want to mention that that particular motor has an original head and a replacement head wereby the gives more piston carbon
i think there is a compression difference between the 2 but both heads should be 225 promax heads
anyway easy fix to close the plate and choose what spring you want to use

and use high performance gaskets as these have metal reinforcement in them

[PanRonnie]

i have an EGT gauge from the sensor connection
you hear the buzzer go off at 3.12
it does have a reading difference between what the CAN-EGT is measuring and the gauge so i have the alarm threshold at 1150 fahrenheit and warn at 1125 fahrenheit

http://thesensorconnection.com/gauge...-gauge-display

very usefull as you are way to busy at the water