TheSamba.com Forums
 
  View original topic: 36hp not firing ....help
thesman Fri Mar 03, 2017 11:47 am

I am try to bench test a 36 hp engine and cannot get it to fire . It has a 28 pci carb . I have established spark to all plugs . I definitely have fuel going into the carb but the engine won't fire.
I have checked rechecked firing order 1 4 3 2 and have set pulley at tdc mark before firing and have timed it with a test light making sure rotor is at plug 1 . I did a compression check and the figures are ( cold engine )
cyl 1 80
cyl 2 100
cyl 3 100
cyl 4 100

I have try to set the valve clearance correctly but I have noticed that the rockers in cylinder 1 and 2 do not hold there the correct valve clearance but they get tight again after a few turns with a starter. Then at times the top of the rocker arms get to loose therefore increasing the valve clearance making the push rods feel loose on the lower arm of the rocker . Any Ideas / Advice appreciated . Thanks on advance . Tucker

Danwvw Fri Mar 03, 2017 11:57 am

Sounds like it may have a rusted out cam lobe to me. Well if your adjusting the valves correctly? Has it been parked for a long time outside?

thesman Fri Mar 03, 2017 12:01 pm

the engine has been stored for a few years ....but moved / rotated freely

Danwvw Fri Mar 03, 2017 7:22 pm

Well if the valve train is loosing adjustment then it should be pretty easy to figure out if it's something like the adjuster or something there. But, it could be the head is coming loose I suppose. Did you remove the rocker arm and try torquing the lower head bolts yet. But That doesn't add up if the compression test is recent?

It is hard to say what is going on with your engine here, It could start if you pushed the car maybe. But you know it's possible that there would be other things like the carb just need a good cleaning or the manifold gaskets have gotten bad and it has a vacuum leak. Double check Spark plug wires and their position and plugs that they are not old messed up plugs. I t may just need new plugs after setting all that time. Also you could have the timing somewhere wrong.

I am not sure on the loose 1,2 tight 1,2 valve adjusters, How loose do they get? Just .006" or a little more is ok, it is normal, right!

It could be it just needs to run and then it will settle down and be ok on valve adjustment.

thesman Sat Mar 04, 2017 6:01 am

Update.... I removed the rocker arms and inspected the push rod / lifters . Cylinder 1 push rods completely worn with deep groove of about 3 to 4 mm leaving a deep ridge on one side , Cylinders 2,3,4 also worn badly but no ridges but not as bad as cylinder 1 push rods.
This must explain why the valves lash would not hold after a few turns on the starter ? Also why compression is low on Cylinder 1 ? Also probably why the engine would not fire ?
Is it possible to put in a set of good used lifters ? or is a complete rebuild better as the cam must be badly worn. Thanks in advance .

Danwvw Sat Mar 04, 2017 12:38 pm

Well, I am sure a lot of people have just replaced the lifter push-rods on them. How much lift are you getting on the cam for #1, The cam could be messed up also. If the cam lift is good just try another push-rod lifter. If it keeps changing valve adjustment over time then you will need a new cam for sure. WolfsBurgWest, AirCooledResearch, Cip1. It probably would be good to treat it with cam break-in compound and give it a good run when you get it started. Are you running a ZDDP oil additive or Lucus?



Powered by phpBB © 2001, 2005 phpBB Group