+- STD (https://www.superturbodiesel.com/std)
+-- Forum: Other (https://www.superturbodiesel.com/std/forumdisplay.php?fid=19)
+--- Forum: Non MBZ Diesel (https://www.superturbodiesel.com/std/forumdisplay.php?fid=10)
+--- Thread: 4 cyl perkins only firing on two cylinders at idle? (/showthread.php?tid=2622)
4 cyl perkins only firing on two cylinders at idle? - MFSuper90 - 05-15-2011
I have a 318 perkins in my "farm stock" pulling tractor. It has been bored and stroked to be almost 390 ci, also has a ground cam in it from crower. No head work except the angles on the valve have been touched up.
When at idle cylinders 1 & 2 do not fire, but when it is at WOT it runs fine?
Any input is greatly appreciated.
RE: 4 cyl perkins only firing on two cylinders at idle? - dieselboy - 05-15-2011
Id pull a injector line off a missing cylinder and do a ghetto jar timed cc test and compatr it ti a good cylinder If they are close then pop test the injectors.
Ve or inline pump?
RE: 4 cyl perkins only firing on two cylinders at idle? - MFSuper90 - 05-15-2011
(05-15-2011, 06:30 PM)dieselboy Ve or inline pump?
Lucas CAV Ve. Stock pump, but the injectors are laser cut 8 hole, not sure what size. It would be a good idea to test injectors.
The guy that does our pump work said he has seen this happen to engines where the valves in the cylinder head are not all seated equally (at the same depth)?
Thanks for the input
RE: 4 cyl perkins only firing on two cylinders at idle? - HoleshotHolset - 05-16-2011
(05-15-2011, 12:57 PM)MFSuper90 When at idle cylinders 1 & 2 do not fire, but when it is at WOT it runs fine?
It's a pulling tractor, it's supposed to idle funny and then run like a recently violated primate at WOT...
Beers,
Matt
RE: 4 cyl perkins only firing on two cylinders at idle? - MFSuper90 - 05-16-2011
(05-16-2011, 09:28 AM)HoleshotHolset It's a pulling tractor, it's supposed to idle funny and then run like a recently violated primate at WOT...
Hahahaha
yes, but not firing at all on the front two isnt healthy. I only wish my cam was that big 
RE: 4 cyl perkins only firing on two cylinders at idle? - Biohazard - 05-16-2011
recently violated primate... Jebus, I'm gonna steal that line from you. LOL My coworker was looking at me funny when I started laughing over here!
Have you checked leakdown on the cylinders?
RE: 4 cyl perkins only firing on two cylinders at idle? - MFSuper90 - 05-16-2011
(05-16-2011, 07:32 PM)Biohazard Have you checked leakdown on the cylinders?
Unless the rings did not seat up correctly there shouldnt be hardly any considering we just built this engine about a year ago.
but i suppose it wouldnt hurt to check
thanks for everyones input
RE: 4 cyl perkins only firing on two cylinders at idle? - john - 01-11-2014
i think they have some strange prechambers where some things can come loose? Then it dont run on all cylinders when cold
RE: 4 cyl perkins only firing on two cylinders at idle? - MFSuper90 - 01-13-2014
John, It's direct injection.
As after I converted it to a VE pump it helped with the miss some.
But I think it's mainly from the big cam and wild timing
RE: 4 cyl perkins only firing on two cylinders at idle? - hansendk - 01-15-2014
well its some time since I played with 4.318 but for me it sounds like the valves have you checked the valve clearance if you run std exhaust valves the beating and heat can make so the valves are going up in the head so there is no compression when its idle but at rpm they are forced up so it running on all 4
is it worse when its hot then its a possibility
I have seen it on a lot on old tractors where nobody have adjusted the valves for decades symptom to look for it more difficult to start when its hot.
RE: 4 cyl perkins only firing on two cylinders at idle? - MFSuper90 - 03-08-2016
Hansendlk, you were correct partially correct. Two valve were sunk into the head not seating correctly and the port job that was done had a pinhole in the intake side cause it to suck a tiny bit of coolant in the cylinder. And it had two bad injectors. I just got all this taken apart and check the past month or two lol.
It's changed some though, now it has a Bosch VE on it and I just fabbed up a Borg Warner s257sxe on it, waiting for my injectors to come back now...