Farmall 300 gas compression

My 300 lost power in 2000. The compression was 85.90 #.
I put in rings and the compression was still the same. Then i put in new sleeves, pistons main bearings etc. and still I had only 85-90 #.
From the internet I learned the compression was supposed to be 6.6:1 ratio or 140 #.
People thee me that the rings are not seeted. They were put in in 2004 and have 230 hours on them. I have another 300 that was running at one time and the compression on it was 130/140 #. I took the head off it and put it on the tractor and I still get 90 #.
I adjust the valves to .017 as the book says. I bring no. 1 piston up on the compression stroke and put the pointer on the top dead center mark.
Then I turn the engine 1/2 revolution and adjust no. 3 cyl. valves. Another 1/2 rev. and adjust the valves for no. 4 cyl. etc.
If the timing jumped one tooth --would the engine even run?/

Please help

I can"t recall from memory what the cranking compression should be for 300/350, however 90 is pretty low and 140 seems reasonable. I have never experienced the cam gear jumping a tooth, but I have experienced the cam gear key failing and causing the cam to retard to the point the engine would not run. I had this happen in a 300U and a 450 three different times. Once it starts to go it drops compression and power, and will eventually quit running. I did the same as you, new rings pistons sleeves and bearings with no change, very disappointing. I finally had an old IH mechanic come and check it out when I gave up. He listened to it crank over two times then put his hand over the exhaust manifold and cranked it over until it sucked his hand tight. He then told me that the exhaust should always push, not suck, and to get a new cam, cam gear and key.

Well with new pistons and sleeves as long as the valves are sealing then ya should have what your suppose to have . . Now as for timing and jumping timing , well she may have vary well started to shear the key off the either the cam , or the pump drive or both . but really it should not affect the compression. Now what may affect it is a plum slap wore out cam , Keep in mind here that these tractors have had extensive FIELD TESTING and you do not know how it was treated over the many years . even though you set the lash that cam maybe wore down enough that she is not opening the valves like it should. Thus she is not getting the gulp of air and fuel that it should be getting. People use oils that are not meant to be in tractors and yes it will sorta lube it but excess ware will result. The oil that goes into your car is not for old tractors as todays engines DO NOT use flat tappets and use ROLLER LIFTERS and they have now removed the zink from the oils . Just like you read hear all the time for plug fouling and this and that , a lot of times it is the fact that TODAYS GAS is not the same as it was when these tractors were new . And it is causing problems with old tractors . I have seen it first hand on fuel problems and around my neck of the woods we have small farms that are still using OLD tractors everyday to get work done like they did when the tractor was new 40-to 60 years ago . I keep a half dozen 706 gasser going along with 460'560's And five Super M/TA's plus a couple H's and one S/H and i hate to admit as i will probably be banned for here a couple of them Green thinks that no matter how ya tune them they always only run on two cylinder. We have no problems with them as long as we spend the little extra and get the 93 octane gas get cheap and put 87 in them and we have problems . My buddy's 706 gasser is used each and everyday and is pushing 4800+ hours since rebuild and it is a gasser other then one piston that got trashed because the new guy that brought fuel to the farm brought 87 and not the 93 the one time . They paid the bill on that . Yea i know it is a lot of work to tear into and engine But if ya can not find the problem in the timing either in the initial setting of the dist. or in the centrifugal advance then ya got to dig deeper .

thanks for the information, sounds like that may be my problem. going to try reground head this week, and if it doesn't improve compression I going to pull front in out and try to get cam out. is this difficut?

I do not find it that hard just a lot of wrench twisten and handling heavy pieces and parts.

The tractor may have a kerosene or distillate head. Also, you certainly don't need high octane gas in a Farmall 300. In fact, during cold weather, the more volatile 87 octane will make the tractor start better.

WHEN i GET THE TIMING COVER OFF WILL THE CAM SHAFT JUST SLIDE OUT OR IS THERE SOMETHING ON THE OTHER END THAT MUST BE LOOSEDED??

Well, first you want to have even compression (within 10%) between all four cylinders. That is more important than having 125-140 psi. And, don't believe everything you read on the internet.
Second, you have not told us whether or not the tractor has flat-top pistons or stepped pistons, or power crater pistons. I have a rebuilt Super M with overbore (4-1/8") stepped pistons (around 1/4" step) and it registers 125+/- per cylinder with an 8060 head. If it had the stock flat-tops, I'd guess it would be around 90 to 95. It runs very well, by the way - and many tractors do with 85-95 psi while making a ample power.
You sure as heck don't need 93 octane with an 85-90 psi compression.
After 10 years of not running good, I'd look into worn cam, worn distributor, etc., before I worried about 90lb compression.
That is another thing..... did you swap distributors? Various models have different advance curves and different maximum advance degrees.
Let us know what cures your problem when you find out. We all learn from each other.
Mike

Don't know where ya get your info from but the 87 does not work well in a WORKING tractor . And after spending lots of money at a lab testing gas i can only go by what the chemits told me and from MAKEN A LIVING keeping old tractors running to there best so UNTILL ya have the years under your belt WORKING ON THEM and knowen what your talken about don;t try and tell me about what they need or don't I know what works and what does not . And the 93 will start well even down to 35 below and after that i'll wait for a warmer day.

Ya got to remove the valve cover and remove the rocker arms then the push rods then the lifter under the side cover . Then ya take the retaining bolts out of the thrust plate then the cam will side out .

Pressure specs are for a warm engine with all spark plugs removed and throttle wide open, cranking speed at 150 RPM. Before pulling the camshaft it may be a good idea to check valve lift first to make sure thats needed. You also need to remove the oil pan and pump to remove camshaft. If someone already mentioned that I didn't notice.

Well maybe you should try it before ya say that ya don't need it as you will NOT have the plug problems . I have been thru this more times then you will ever know . And i am telling ya it does work .

I dont understand why you need high octane gas for these older tractors. My Dad has been running 87 octane in them for years, he doesnt have plug problems, the tractors get worked hard and last thousands of hours. Why do they need the high octane fuel.?

I like it because it burns cooler and longer . Now the big reason is that todays 87 is a lot lower in octane then what was at the /pump back then . And IF people would look at the Minim fuel requirements you would know more. And if ya think 93 is tomuch for and old tractor it really isn't. Reg gas back in the day was 93 or BETTER and most reg gas was 95 and high test was over 100 , more like 105 and better . Then ya add in a over bore and step head pistons and your comp. ratio is higher throw in a higher compression head . Now as for how hard you work your tractor i do not know but the ones i take care of get worked hard. with running the hightest as they call it today helps to keep them running about 20-30 degrees cooler on the temp gauge. . The hightest of today would make a old 6cylinder cheve ping and knock. Up until gas went over 2.25 a gallon i ran it in the wifes Durango and it would do 18 -18.5 out on the road on the 87 we are lucky to see 16-17 For the Durango only a mile or so a gallon does not pencil out . On the tractors one melted piston and the time to fix the extra expense does.

Check your compression tester; if the Schrader valve core (looks llike a tire valve core) is not one specifically for a tester and was replaced with a standard tire valve core your test results will be low. The standard tire valve core has a stronger spring so will not substitute correctly for the original compression tester valve core.
BTDT! Experience is a great teacher.

When I took the cover off the can shaft nut fell off. The key had sheared over approx. 20 deg. Will order a new shaft.
Thanks for all the help from you guyes.

It was the cam gear key as you stated.

Thank you so much.

Glad I could help. While you got it apart you may want to pull the crank gear and check the key there also. I had the cam key fail on the same tractor within a year and the second time apart I found a bad key in the crank gear when I pulled it. I suspect the loose key there made the cam fail in less than a year, I just missed it the first time.

Welded the key seat up to fit the key. Put in back together and I now have 145 lbs. of compression on each cyl.
Thanks for all the help from you guys.

Another problem: The torque ampflier worked at one time but now it wont. I adjusted it like the book says too. When I pull the leaver I can hear what sounds like clutches slipping. Can anyone help ??
Thanks
add300