1926 Buda WTU 4 cylinder -- 40 psi compression?

[Gotfredson]

Hello again!

I have a 1926 Gotfredson flat bed with a 4 cylinder Buda WTU engine at 226 cubic inches.

 

Just did a compression test and all four cylinders come back between 38 and 40 psi.

 

I am happy all the cylinders are the same, but 40 psi seems a bit low. No significant smoke coming from the tail pipe.

 

What do you think? Is 40 psi normal for this vintage engine?

 

Thanks in advance!

 

Specs:

 

 

 

[nickelroadster]

40 lbs sounds a little low but it depends on what the compression ratio is.. I didn't see that in the lit.  If it is 4 to 1 or lower I don't think that it is too far out of the ballpark.  The horsepower is quite low and if it seems to run okay , I wouldn't worry .

[trimacar]

4 to 1 would be 55-60 psi, which was common until mid-20's when leaded gas allowed higher compression ratios. 40 is low, but if it runs OK just enjoy as is....

[Gotfredson]

Thanks guys!

[Friartuck]

Agree with the others, 40 is low. Consider doing a non evasive leak down test. It may tell you if valves or head gasket are suspect. If you're not planning to do anything then use it and enjoy.

[Bud Tierney]

Some of these old Budas have their own idiosyncrasies---if you haven't already,  make an effort to locate and talk with other WU/WTU owners before engaging in any explorations; any teardown/overhaul info they have will be invaluable as to weak points, parts sources (if any) or workarounds, etc...

Granted, gaskets are available (gasketstogo or olsonsgaskets), valves can be turned from blanks, and carefully pulling the head and dropping  the pan for inspection can be reassuring, especially if considering some kind of use that will build up engine hours...

However, if only minimal running, with no undue clattering or smoke clouds, just enjoy it, as mentioned above...

 

[Rusty_OToole]

See if you can get some low octane tractor gas or mix 25% kerosene or stove oil with regular pump gas. It is made to run on very low octane fuel.

Edited January 11, 2016 by Rusty_OToole (see edit history)

[Gotfredson]

Thanks for the advice.  I am hearing elsewhere that 40 psi is normal for this low compression engine.  Apparently it only had about 45 psi brand new.

[C Carl]

Let's see. I better be careful here. What is "low octane tractor gas" ? STOP ! STOP ! STOP ! Before reading further , Google up "kerosene". Readers will have varying degrees of petrochemical expertise , but diligent reading , perhaps the relatively straightforward britannica.com link will be rather unequivocal in its implications. Please pay attention to comparisons with gasoline , and relationship to jet fuel. Now lookka here : jet fuel is about 140 octane. Remember your flight engineers training ? I remember mine. Diesel fuel is virtually the same. Has to be VERY high octane for 22:1 compression engines. O.K. , true confessions time : anyone who reads this , raise your hand if you have ever had to run pure kerosene (or stove oil , or jet fuel , or diesel) in your old 10:1 or 11:1 high compression engine in an emergency. Tell the truth , now. Remember how lousy it ran ? But smoky , it did limp along , right ? See , the octane was way too HIGH. If you had just given it a load of very LOW octane , your engine would have suffered mortal damage. Pistons would never have forgiven you. FOR THIS REASON DO NOT TRY THE REVERSE ! DO NOT EVEN TRY TO RUN A DIESEL ON GASOLINE. THEY NEED THE VERY HIGH OCTANE KEROSENE BASED FUEL APPROPRIATE FOR THEIR HIGH COMPRESSION RATIOS ! That 92 octane will break 'em.

Peace be upon you , dear brothers and sisters , I am not looking for a fight here. Not with anyone , particularly kind , generous , helpful , knowledgable 8000 posters who probabably , literally , have forgotten more than I ever will know about cars. Seriously. On the land , where rubber meets road , some degree of inaccuracy may be tolerable. Up high over Albequerque , Alberta , Antartica , or Argentina , persistent myth has no home. Ummmm , Argentina. I have an enormous amount of very high altitude driving experience in the Andes. Specific very low octane fuel is necessary to pull grades at , say , 15 , 16 , 17,000 feet of altitude. And fuel management coming back down to the Amazon jungle , or the coast must be considered. I do some of this for driving I do in the U.S.A. in the 5000 to 12,000 foot regions. Again , I mention this only to substantiate some knowledge of octane considerations. I just have to lay in a bit of groundwork before the fan driven storm about to be unleashed against me. Been through a bit of this before , so forgive my pre-emptive defensive posture.

As best I can tell so far , it is possible some old cars were set up to use kerosene. This may have been driven by commodities availability at one time. This involved pre - heaters , so the cars were running on VERY HOT KEROSENE VAPORS. A bit different from just tank up and go. You simply can't blend DOWN the octane of 87 octane gasoline by adding 130 or 140 octane. O.K. , I have to do something else. I better duck and cover for coming ridicule.

Gotfredson shown rests along with acres of automotive treasure belonging to Bernie Long , Burlington , Ca. That is East of L.A. , before you get to Redlands. He does advertise in Hemmings. Anyone feel free to P.M. if you want more info or pics. I hope all of you are having a good start to the new year ! - Carl

Edited January 12, 2016 by C Carl (see edit history)

[Rusty_OToole]

When the truck in question was built high octane leaded fuels had not been invented yet. It was designed to run on straight run, low octane fuel with no additives. This was about 50 octane and was a close relative of kerosene or lamp oil.

 

Oil companies continued to offer this fuel for years and still make a low octane gasoline for low compression engines. I live in farm country and those farms that still use gasoline tractors, have a 500 gallon tank and get delivery of tax free low octane gas which is available from all oil companies.

 

I don't know where you can get it if you don't know any farmers but I assure you it does exist.

 

A good substitute is regular gas with some heavier fuel added. Kerosene, stove oil or diesel. Diesel is easy to get but not preferred because of the smell.

 

This is somewhat of a moot point because I doubt that the truck will ever be worked hard again. But if you want to develop maximum power and avoid overheating you should use the fuel it was designed for.

[Rusty_OToole]

Here is an article on Tractor Vaporizing Oil an even lower octane fuel.

 

https://en.wikipedia.org/wiki/Tractor_vaporising_oil

 

I wouldn't suggest using such low octane fuel but it does give a good explanation of using low octane fuels in low compression tractor and similar engines.

[Stude Light]

I won't get into what you should or shouldn't do but there is a need for some clarification here.

 

Point #1)

Octane measures the ability to resist ignition...the higher the number the higher the temperature/pressure before ignition occurs.  There are various ways to measure the "Octane" number but if we stick to the Reasearch Octane Number (RON), today's auto gasolines are in the 90s, diesel fuel is near zero, kerosene and jet fuels are 15-20.  I think C Carl you have the Jet Fuel number confused with High Octane Aviation Fuel (Gasoline) which for the military was around 130.

 

Point #2)

Gasoline engines compress an air-fuel mixture and the octane rating of the fuel is important so the mixture does not ignite before the spark occurs.  Diesel and jet engines INJECT the fuel into compressed air so the octane rating of the fuel is not that important as only the air is being compressed not an air-fuel mixture.  So looking at a diesel....the air is compressed in the cylinder then the fuel is injected at the right time. How quickly that fuel ignites and burns is the Cetane number for the fuel.

 

Scott

[Gotfredson]

If I mixed about 25% kerosene with 87 octane gas, what would be the advantages and effect on horsepower, torque, engine lubrication, carbon deposits on the spark plugs, smoke from exhaust pipe, etc?  I understand the octane rating would be lowered.  But what would it do and would I even notice the difference?  I live in San Diego so I never start the engine below freezing temp.

 

As you can see from the photo above, the intake manifold is somewhat wrapped around the exhaust manifold.  I read in an old Buda manual that the company made different intake/exhaust manifolds, depending on whether the vehicle was going to run on gasoline or kerosene.  I have the gasoline variety (I think).  The manual says the intake and exhaust manifolds can only be sold together because the ports are machined flat after the two manifolds are mated during assembly.

 

By the way, this truck is not going to be worked hard and it starts every time with 87 octane gas.  It does have a bit of an audible miss you can hear at the exhaust pipe when it idles (a very minimal miss).  The miss seems to go away at higher RPMs.

 

Thanks all!

Edited January 12, 2016 by Gotfredson (see edit history)

[Rusty_OToole]

Many cars and trucks back then had heated manifolds to vaporize the regular gas that was available then, that had a lot of heavy ends or kerosene like compounds in it.

 

There are owners of cars trucks and motorcycles, from the twenties, who use the kerosene mix. They report easier starting, smoother running, more power and cooler running. We have had several long threads on this. One owner of a 1932 Buick reported that he drove thousands of miles in the seventies, pulling a trailer, using his Buick as a tour car on 25% kerosene.

 

If you are satisfied with the way the truck runs now keep on doing what you are doing. It was only a suggestion. You could try mixing a gallon of gas with 10% kerosene and see how it works.

 

It would make more difference if you worked the truck hard but I doubt you carry heavy loads up steep hills or anything like that.

Edited January 12, 2016 by Rusty_OToole (see edit history)

[Gotfredson]

I found this old article on Google Books from 1919 (my Buda WTU is a 1926).  I may as well post it here. There's a PDF of the article also attached.

 

I am curious about your thoughts concerning the section of the the article I outlined in a red box, re: using Kerosene to clean out the crank case.  If it is possible, it seems like a good idea seeing as the engine does not have an oil filter.  Thanks again!

 

1919 Buda Operation, Care, Repair.pdf

Edited January 12, 2016 by Gotfredson (see edit history)

[Rusty_OToole]

I would sooner take the pan off and clean it out by hand. Then install a bypass type oil filter even if it is not 'period authentic'. I like the Frantz filters for this but there are other brands like WIX and Purolator. I would also add an air filter like a K&N filter stuck on the carb that can be removed for shows.

 

If you clean out the crankcase and valve chamber so there are no large amounts of dirt and sludge there is no reason not to use detergent oil.

 

I should think the conditions you drive it under would be much cleaner than the dirt roads, farm fields and construction sites it was meant for. Given decent filters for air, oil, and crankcase ventilator it should not be necessary to change oil oftener than every 2000 to 3000 miles or once a year.

 

It also depends how much you use it. If it is only taken to shows and driven a hundred miles a year then the filters are not necessary.

[Gotfredson]

Thanks Rusty.  I am looking at these.  

 

http://www.frantzfilters.com/product/universal-kit/

 

http://www.ebay.com/itm/Ford-Model-A-B-air-cleaner-K-N-filter-system-vintage-new-Tillotson-Zenith-Carb-/160908017894

 

Never thought about the crankcase ventilator.  I have to look for it.

[Gotfredson]

Tried 25% kerosene.  Ran really smooth (on jack stands).

[Bud Tierney]

On kerosene flush (red box) question---yes, we used that regularly on old low compression engines, especially when the oil was black-black...

Can't say, looking at my watch now, that we ever ran them two minutes--more like 30 seconds to one minute, at most, and even one minute seems long now, but then we tried to run the flush every two or so oil changes  (unfiltered engines) and, in an excess of caution, or fear of dislodging too much gunk at one time, usually added a little 10W oil to the kero...

Those old unfiltered engines, before detergent oils, could accumulate an astounding amount of gunk---I've seen lots of oil pump screens 75 to 85 percent blocked...

[Rusty_OToole]

Bud with all due respect I would not want to flush out an irreplaceable old engine that might have up to 90 years accumulation of dirt and sludge. I would not want all that dirt circulating in the oil. I would sooner take the pan off and clean it out by hand first. Likewise the valve chamber if it has one.

 

Then install some kind of oil filter. If it has a pressure lubrication system this should be possible, if it is pure splash oiling maybe not. But as I said before, a good air filter and a good oil filter, plus running on modern paved roads (less dust) will save a lot of dirt and wear.