DES 8/1 Propane Conversion project

[38ac]

OK, Here is some valve seat info for everyone. Please  I am not bashing the shop Tom used. Obviously the DD seat will work, going a bit larger gives a person some freedom where to place the seat on the valve.

Shown is a 6/1 valve and the Detroit Diesel 5148490 seat on top of the Qual Cast 20-1562-4 that I prefer to use.


Next is the 2 7/16 DD seat sitting on the valve. Hard to get the photo to show what I want bu the seat is smaller than the valve head. This is not terrible but causes the seat to be placed very low on the valve head, bad for flow.


Now the 2 9/16 QC seat I like to use


Here installed to give .100 valve depth in a Dursley 6/1 head


And a picture of the valve from that head. The darker ring is the placement of the seat on the valve.  A smaller seat would bring that ring toward the stem, larger seat would move it toward the margin.
 

[dieselgman]

Since this thread is basically about using alternative gaseous fuels - and more specifically LPG, I have to ask, "Are stellite (hardened) seats available from Qualcast in the correct sizes?" I know that Lister used fairly soft material in their diesel valve seats and some VERY hard stuff for the Natural Gas versions... The diesel seats are a snap to re-surface, but I have found it very difficult to resurface or cut the natural gas seats even with new specialized carbide tooling because they are so hard and resistant to tool penetration.

Thanks Butch for your clear illustrations and valuable insights! Those are some beautiful mods to the original CS heads.

dieselgman

[Tom]

I don't know which seats my shop used, I suggested the Detroit ones, but he said he'd look in the book for the best fit. I guess I should have asked. I do know that the seat area is near the middle of the valve face. Lots of good info here on parts!

[38ac]

Gary, Valve seat technology has advanced eons in the last 10-15 years. Stellite worked well and still does but is kinda old school. It is harder than hard but you cant do anything with them. Alloys that are used now allow you to work the seats after you press them in the head but work harden in use while recessing very little. Quacast has a nickle based alloy that is supposed to be the cats meow for gas fuels. Other mfgs have their own brew. I use Qual cast because they are stocked near me. Others will do same job.

[dieselgman]

Well, I guess I'm just an "Old School" sort of guy... 

Thanks for that information about nickel alloys and work-hardening... I obviously have some new research to look into.
You are the top of my list for cylinder head reconditioning resources when we can collect a large enough batch to spread the shipping costs Butch! Thankyou!

dieselgman

[BruceM]

Many thinks, again, Butch.  The Qual Cast seats look great.

[guest23477]

Hello,
I met a guy who was doing sort of the same thing, here is a link about his ignition
project of a Listeroid. I believe his goal was wood gas but he started out on LP
gas first.

Here is the link, maybe it will help you.

 http://wiki.gekgasifier.com/w/page/30448258/Spark%20conversion%20for%20Lister%20slow%20speed%20diesel%20engines

He claims he did not have to reduce the compression, but was amazed at
how much ignition advance he had to use with the large stroke ....and low
BTU value of the wood gas.

I thought it might have some value in your project.

Regards,

Les

[BruceM]

Thanks Les, I read that report fully before embarking on the project.  While woodgas, it's certainly applicable.  Points out the need for a spark retard for starting as well.  I'll see how it works out for Propane. 

[BruceM]

Does anyone have a spare hollow dipper for sale or a source for one? 

[dieselgman]

Bill W. has made up some very nice custom hollow dippers in the past and he indicated to me that he is willing to run a batch for Forum members. It is likely preferable to compile all interested parties so he can produce just the quantity that is desired and maybe can reduce costs if he does them in batches.

I will have to handle communications for the transaction. gary@dieselgen.com

dieselgman

[BruceM]

Gary, that's great about the dippers, I'd like to order 2 and will send you an email.
Progress report-
We got the DES 8/1 on Friday, thanks! Well packed and a lot less tippy without the cylinder and head on the case.

I've worked out a plan for the IMPCO CA55 carburetor mount- works best to use it downdraft on the intake manifold.  I can then extend the governor arm to the opposite side and use a straight push rod up to the CA55 throttle arm.  The stock air cleaner will fit the IMPCO inlet.  I just have to make a flange for a mount, will weldbond it to the intake manifold.  The IMPCO carb is very well designed, easy to switch the throttle arm from side to side as well as the idle stop limiter.

I've modified a COV plug to be a big smartplug (smartplugs.com).  Didn't like the RC shielded sparker for it's DC-DC converter emissions, will work up something using a Wells C1717 coil on plug unit, a hall effect switch and some simple analog circuitry.

More progress on the engine tear down when the weather goes bad again.

[Tom]

Oh boy it won't be long now. Since it won't be first smoke, what'll we call the first run on propane?

[dieselgman]

If it goes anything like our usual HRG builds - first backfire!

dieselgman

[BruceM]

Smoke, backfire.  You're ahead of me but I'm working towards that! 

[BruceM]

Talked with Tom at Central Georgia Generator about our ST3 with 240V output, AVR off of the mains instead of harmonic for better flicker reduction.  He's going to prewire it for us, which is a nice time saver.  I appreciate Tom's great service and better quality ST's as well as the price.  He's upgraded both bearings and rectifier on these, so I don't have that project to mess with.

Eaton Compressor is providing the 5hp 2 stage inline pump.  All cast iron, low speed and quiet with pneumatic unloaders and real valves, not reed. 

My friend Mark is stripping the case this weekend. He thinks we can have it hot tanked in nearby Show Low.