Sorry to hear you are having grate problems ( pun intended ) What size engine is in the Cadillac?? TomC
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Hi Tom,
Hope you’ve had a great (no pun) summer. The Caddy has a 4.9 liter, a somewhat unusual engine in that it has an aluminum block and cast iron heads.
Rick
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I have NO experience on a WK gasifier so I should not speak out, and I would hope that Mr. Wayne would jump in here for you. In the meantime, I think you are running an engine that is on the smaller size for a WK. My work with the Imbert would say you are not getting enough “heat” down to the reduction area. Raise the restriction up a ways and go from a 6" restriction to something smaller to speed the gas up going through it. Close the grate up like you have been trying to do, but I’m not sure how will that has worked so far. Finally, the reduction zone is too big. Start by making the grate just a little smaller than the fire tube, and mount the grate so it is in the fire tube and can be adjusted like the restriction.
That should stir some of the other WK guys to jump in and probably on me. TomC
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Check out Herb Hartman’s Caddy build, it was also a 4.9 L. Might compare notes with him on how it’s running.
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Hello Mr. Rick .
Keep us posted on your latest try on the grate .
I have never had a problem with slipping too much char so don’t know what to advise .
Because of the bouncing of the trailer may have to make some adjustments but I’m not sure what. Will sleep on it tonight and maybe can think more clearly in the morning . I just drug in from the hay field and the ole brain seem to be shot 
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that 4.9 is not that far off a 5.0 ford (302) and that puts it close to the 318 dodge so he should be fine tom. I know I’m down to close to 1/2 inch grate gap I was having the same slip problem.
rick if you have another tear down give a call always up for a field trip . if all is going good I hope to see you soon good luck .
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Hi Tom and Chris,
First off, I did check the ash dumps and the grate now seems to be working correctly. I had maybe two cups of mostly fine ashes and char after a 14 mile run. Hopefully the stainless steel mesh holds up.
I have studied Herb’s Caddy, it is very similar to mine and is also working with a WK based gasifier. I have corresponded with Herb about my Caddy, I believe his is running well but that he has sold it. The most obvious difference between mine and his is that his gasifier is mounted on a trailer hitch luggage rack and mine is on a small trailer.
Tom, I generally have better performance with the Caddy than I had with my GMC truck. I have better hill climbing ability and idle and low speed performance is smoother and more reliable. This is not to say that I don’t have occasional stalling problems but they seem to occur mostly before the car is warmed up or with other problems.The large reduction zone combined with low gas velocities in the firetube compared with Imbert styled gasifiers seems to create a large reserve of woodgas. So far I have seen no evidence of tar past the filter. The 6" restriction is considered a little small for WK gasifiers powering V8 engines but is recommended as a good size to start with to avoid tar issues while becoming used to running them. Actually my 4.9 liter engine is only 19 cubic inches smaller than the 318’s that most WK’s are run with. While much of the WK design does not use Imbert parameter values, I like how it works.
Thanks,
Rick
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Good morning Rick .
Even though you are slipping a lot of char it may not be a waste . You can add it back to the hopper and use it.
Keep us posted .
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Hi Wayne,
That was my modus operandi while trying to fix the problem, I would empty the char, screen out the fines and then dump it back in the gasifier. When my ash pit filled up with char (sometimes within 14 miles of driving) I noticed reduced performance, probably due to gas flow problems. Has this been your experience as well?
Thanks,
Rick
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Hello Rick .
I will drive my truck until the ash and char builds up around and under the grate . At this point the ash and char purging will stop and the vacuum reading at the cooling rails will show a higher reading and I have to hold more throttle and adjust the air mix down also.
This happen today so I pulled up by the garden ( I put the ash and slipped char in the garden ) and dump the ash bin. I was careful not to disturb the ash and char above the grate . The first few miles back on the road the fire tube was a little constipated but I had enough power to stay with traffic so I didn’t hit my shaker ( I would have wasted char by slipping it ) . After 3-4 miles the vacuum reading came back to normal .
It seems the vacuum readings ( cooling rails vs hopper ) of about 3 to 1 the gasifiers are performing well. As the ratio gets higher the performance will suffer . You will still be making good gas but not as much of it.
Today before I dumped my ash I noticed the reading was about 10 to 1 but I was on a back road and didn’t need much performance. If the ratio gets down below 3 to 1 you may have good performance but the gas starts getting dirty . If the reading go on down below 2 to 1 you may get weak gas and end up with a sticky throttle .
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3 to 1 is my favorite. 10 to 1 is a joke, but it will drive. Just requires a lot of attention.
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Hey RickB
Trailers can hammer/crumble, compact and, excessively shake down the reduction zone char.
Solutions?
Soften the trailer with wider, higher profile LOWER pressurized tires.
Switch to a tougher char out of a true hardwood versus a softer fragile char conifer wood.
Try to never road operated the trailered gasifier without it fired up, and flow-drawn to keep the char in Brownian-like motion particle separation.
Regards
Steve Unruh
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Thank you Wayne, Carl and Steve.
Currently I only have vacuum gauges connected to the rail and to the piping just before the intake manifold. You may have inspired me to install another to the hopper, until now I wouldn’t have considered it. I only worried about the filter clogging before with my Imbert style LaRosifier, never had the char plug.
All my fuel now is hardwood, mostly hard maple, ash and beech with a little ironwood and cherry. So if I have problems with the char compacting (I don’t now as far as I know) due to excessive trailer bouncing I will try lower pressures in the tires first, if that doesn’t work I might have to install spings and maybe shocks.
Rick
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I think it was Carl Z who advised me to not remove char until you notice a plugging problem
I have gone over a 150 miles now without touching the clean out and it is still working well
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hey rick I hope the rest of your trip went a little better and you had a good visit with your sister. I haven’t seen any posting wasn’t sure if you made it home 
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Hi Paul,
I made it home but it wasn’t easy. Unfortunately being almost out of gas wasn’t the only problem the Caddy had. I made it to my sister’s OK but it wasn’t running right, almost stalling sometimes. Felt like it was surging, a few seconds of running well followed by almost stalling. Made me nervous waiting for the flagmen to let me through at the construction areas on 104.
Then it got worse after leaving my sister’s. When I got to Jordan, I could barely drive uphill. Ended up leaving the trailer with a farmer near Elbridge, limping on to my mother’s house in Skaneateles and then having AAA flatbed me and the Caddy home from there. Then I took the Caravan back to the farmer near Elbridge and retrieved the trailer. So everything turned out OK in the end.
So on the Caddy I believe I need to look at the fuel pump and replace the battery. I need to look at the gasifier grate situation again, too. I haven’t looked at anything on either since I got home, maybe I’ll get a chance in the next week or so.
It was great seeing your place and projects as well as riding around in your truck. Hopefully I’ll get the Caddy back in shape before we head south.
Rick
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well I’m glad that you got everything back home even if it took a couple of trips . I enjoyed the visit till next time .
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After last months debacle of a run where I couldn’t operate on woodgas alone and the car stalled and lost power on gasoline to the point I had to be flat bedded home, I looked into the Caddy situation this week after a county mechanic friend of mine loaned me a fuel pressure gauge and gave me a battery out of a county truck that was rotated out of service but still functional. Contrary to what I expected, the fuel pressure was fine but I noticed that the accelerator was sticky. Removing the air duct and looking at the throttle plates revealed lots of my old nemesis, TAR! It seemed to be concentrated at the plates, I didn’t notice any in the piping from the gasifier to the engine. I did not look in the intake manifold underneath the plates yet. I am not sure what led to this condition, I can think of three possibilities:
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It accumulated gradually over many runs as a result of using the blower during startup until my temperatures at the grate were 450 F - 500 F, then using hybrid mode until grate temps were at 650 F when all woodgas operation was possible, typical cruising temps being 800 F - 900 F.
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It accumulated gradually over many runs as a result of the excessive bouncing of my springless trailer breaking down the char into fine pieces making it difficult for the air to reach the middle of the reactive zone resulting in tars forming and not being broken down. I know the extreme depth of the WK firetube and reactive zone compared to a typical Imbert gasifier usually prevents tar formation.
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It built up suddenly during my last run when I was not successful in switching to 100% woodgas operation. This possibly was due to trying to switch over when I was driving up and down steep hills and could not operate with WOT except when driving up steep hills when I needed to use gasoline anyway.
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Combination of some or all of the above.
So in the near future I will probably unbolt the thottle body and try to clean all the tar out. I did drive the car locally up and down hills and at least no valves seem to be sticking and it seemed to have adequate power although there still was a hint of surging.
Then, probably next season, I will alter my startup procedure and first try to warm up to a higher grate temperature, maybe 700 F, before shutting the blowers off and driving in hybrid mode. I will inspect the throttle plates regularly for tar buildup.
If tar still is a problem I will either increase fuel chunk size and/or reduce bouncing of the trailer by using softer tire pressures or adding springs.
Rick
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Sorry to hear about your problems!! I assume you are getting ready to go south so you have limited time to work on it. That to me would really be a bummer. How many miles have you driven on wood with the Caddy? I’m sure some WK drivers will comment, but I have heard Mr. W say his manifold “burns itself out” from time to time. Could you go to a smaller restriction to maybe force the gas to go through the char instead of going maybe down the middle where the char is not so hot? Anyway good luck. TomC
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Good morning Rick and Tom.
Once you get some tar on the throttle plates it keeps showing up as a stuck throttle each morning or cold start up . Even if the gasifier is making clean gas or running on gasoline.
If the throttle plates are stuck and once the motor heats up the throttle will break free and operate well but if left over night the throttle will be stuck again . This will be the case even if run on gasoline.
With the multi-port fuel injection systems it seems to be very easy to correct with a quick burn out with a hand held torch.
If the motor is a TBI you may have to pull the throttle body and clean manually .
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