Firewall datum ?

[ratc]

Here's the story so far, I'm having a 4 into 1 exhaust made for my RV-4,
0-320D3G. The engine is currently not on the aircraft but on a stand so I need to construct an accurate template of the firewall in order for them to form the exhaust.
Does anyone have the datum positions from the engine to the firewall in order for me to construct the template ?
As always, thank you in advance.

[fixnflyguy]

The RV-4 has very limited space for anything, and you really need engine on, and cowling fit before you spend your money. I would suggest when you get to that point, make one from PVC plastic pipe that fits, then send it to him for a template. My Vetterman 4 pipe just clears the lower cowl and is very tight to the engine..I'd hate to design one from prints only.

[ratc]

Hi Bill, thank you for the heads up. My intention is to send the maker my engine with "dummy" firewall and ancillary
Parts attached ! If no one has a datum I'll fit the engine mount to the engine with dummy firewall and send it, since that's what he has asked for. It seems he likes to work directly rather than with template plastic pipe work.

[Christopher Murphy]

Just curious why you dont just use a vetterman set.

Cm

[BillL]

Originally Posted by Christopher Murphy

Just curious why you dont just use a vetterman set.

Cm

It sounds like the OP wants a 4 into 1 exhaust. I did some research on that, and IIRC, Mr V has spoken against that configuration. He tested some but got no better performance, and the collector alone is quite expensive ($100s). So, I am assuming that, he saw no benefit for the cost increase and did not offer.

[Christopher Murphy]

Unless you plan to install a muffler or a turbo charger why bother with the trouble or expense of a 4 into 1 system.

Cm

[ratc]

Cm, I admit it will be more expensive AND it might not produce any extra performance but having heard several RV-4's with the 4 pipe system I feel the 4 into 1 solution will be less harsh ! Environmental impact for me is and always will be a consideration, sometimes compromised but nonetheless considered.
Still looking for answers before I complete the dummy firewall build.

[ratc]

One final try, if anyone building an RV-4 with an 0-320 is at the engine on/cowl off stage and are happy to give me their datum measurements from a "known point" on the engine to the BOTTOM edge of the firewall I would (as always) be very grateful.

A simple right angle, back (x) and down (y) measurement would suffice.

I'm fast approaching my exhaust build slot but don't have the engine hung yet.
I know it may seem counter intuitive but there is method in my madness.

Thank you.

[HFS]

Andy -

Check your PM's



HFS