B275 poor compression/ Pre combustion Chambers

neil33

New User
Hello All,

I'm kind of new to the vintage tractor thing and have just take over a part restored B275 that had already had some work to the cylinder head (skimmed and valves re ground) but on turning the engine over by hand it seemed to be loosing compression past 2 of the pre combustion chambers (obvious hissing) so I figured that the upper and lower injector seals needed changing.

As the pre combustion chambers could not be removed externally. I had to remove the head to push them out form the inside (they were held in pretty tight with some sort of sealant around the sides). anyway...once removed (all 4 of them) the were cleaned up and replaced with new upper and lower injector seals but I saw no reason to use extra sealant. Which brings me to my problem..... I now seem to have poor compression (turning engine by hand) on all 4 cylinders, but no apparent hissing past the pre chambers



So what went wrong? should I have used sealant around the Pre chambers, as I had found it? or if the valves had been put back in different positions during when I re assembled the head, could that be the cause? ...although they seemed air tight.

Any other possible issues?



Any advice for a newbie very welcome......
 
I have rebuilt several BD144 engines in B275 tractors. Precombustion
chambers are sealed with brass or copper washers, not sealant. Pretty
simple engines. If the engine is getting air to compress- it has to be
a matter of piston and cylinder, valves/head-gasket, or big chamber
leaks. Is it an early B275 with an air-governor? If so, make sure the
throttle is open so air can get in.
 
(quoted from post at 20:33:35 05/26/17) I have rebuilt several BD144 engines in B275 tractors. Precombustion
chambers are sealed with brass or copper washers, not sealant. Pretty
simple engines. If the engine is getting air to compress- it has to be
a matter of piston and cylinder, valves/head-gasket, or big chamber
leaks. Is it an early B275 with an air-governor? If so, make sure the
throttle is open so air can get in.

Thanks JDEM...... The chambers did indeed have both upper and lower copper seals in place (as well as the mysterious sealant) my only thought was that maybe the seat of the lower seals might be corroded and the seal washers not sealing well....hence someone using an additional sealant around the pre chambers. Ill check out the governor thing as it is indeed a very early 275. I did however re use the head gasket as it was new and the engine had not even been started since it was fitted but think I will replace it anyway as a precaution.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top