Author Topic: any diesel mechanics out there (Read 2039 times)

2wheels · « **on:** November 27, 2019, 12:51:15 PM »

I am trying for find the valve overlap for a tractor diesel. John Deere 5030T
Or just the typical valve overlap, if there is such a thing as typical.
Thanks

dave500 · « **Reply #1 on:** November 27, 2019, 03:09:52 PM »

diesels have slightly more overlap than petrol engines

2wheels · « **Reply #2 on:** November 27, 2019, 03:55:17 PM »

Thanks Dave
Are you sure?

I know nothing about the subject. Really nothing.
And i think different people have different descriptions for what "starts opening" means. Some say when the valve opens 0.050 that is the start. Others use different numbers.

valve events: for ford 289 mustang
Intake opens 16 deg. BTDC @ .004", closes 70 deg. ATDC @ .006"
Exhaust opens 52 deg. BBDC @ .002", closes 24 deg. ATDC @ .005"

Massey Ferguson 35 3 cylinder diesel.
Intake starts opening at 13 degrees BTDC
Exhaust closes at 10 degrees ATDC

dave500 · « **Reply #3 on:** November 27, 2019, 06:17:29 PM »

to keep things consistant and repeatable the opening and closing is measured once the lifter is at 50 thou on cars engines and 40 thou on bike engines for some reason,a 289 or any automotive motor could've had three or four different cams during its model years depending on things like market destination power and smog etc,if ya gonna be checking cams make sure you have a decent dial indicator and the largest degree wheel you can get.

2wheels · « **Reply #4 on:** November 28, 2019, 05:07:12 AM »

Good information.
Thanks

edit. What i am doing is trying to time the cam of a diesel engine that has no key way in the camshaft, or any markings. Because it is a tractor there are no details about the cam. I am hoping to use the valve overlap to time it. Then make sure the piston doesn't hit the exhaust valve on the exhaust cycle. And see what happens. Chances of success, I don't know.

edit. Just to add more complication, this is a turbo engine. So I am reading that that effects how much valve overlap is desired.

edit "opening and closing is measured once the lifter is at 50 thou on cars engines and 40 thou on bike engines" that is in the US and others use 1mm, i have just read

dave500 · « **Reply #5 on:** November 28, 2019, 12:50:32 PM »

look closer for any marks,maybe a dot filled with crud on a tooth? or between two teeth.

2wheels · « **Reply #6 on:** November 28, 2019, 12:59:02 PM »

No, no marks. I have the John Deere service manual and it describes the timing process in detail. But requires tools that cost a lot. Also it is a lengthy process that would take the dealer at least a day to do. I know that sound dump but that is how this engine is.
So I am going to guess on the timing. The skidsteer cost us less than scrap price so we won't loose money if we don't spend a lot.

dave500 · « **Reply #7 on:** November 28, 2019, 01:07:58 PM »

is the tool something you can make?does it go in the injector hole?can you copy one easy?

2wheels · « **Reply #8 on:** November 28, 2019, 05:21:41 PM »

Yes it does go into the injector pump hole. Apperently it is a precission tool, it locks the cam in position. Then another piece goes into the #5 cyl exhaust lifter hole. Thus locking the cam in position so it cannot rotate.

The bit that goes into the injector pump hole is precission length. But i dont know what that length is.

Once the injector pump is removed then a procedure has to be followed, with more special tools, to get the injectors all setup.
Quite the design.
Maybe this is normal for diesel engines? I have never been inside one before.

dave500 · « **Reply #9 on:** November 29, 2019, 03:12:17 AM »

its not normal but special for those engines and the designers EGO?punch dot marks have worked forever but some #$%* has to get special?there are a few weird obscure formats with cam timing marks, for example the you beaut aussie holden v8,was a 253 or 308 cubic inch and a very good engine,it has a chain driven camshaft and dots on the crank gear and cam gear,however you don't line em up like you might a ford or chevy!the timing chain has blue or other colourered links 9 links apart,you square these up to those dots on the cam gears!some chains after market have none,heavy duty after market mostly have none its just something ya gotta know if building these engines,square the dots up as nature would tell you and ya got bent valves instantly!!just dumb #$%* full stop!!??still haul arse though!

2wheels · « **Reply #10 on:** November 29, 2019, 11:46:28 AM »

Thanks for the help Dave.

jgger · « **Reply #11 on:** November 29, 2019, 04:07:05 PM »

I recently did a timing chain on a VW 2.5 5 cylinder and boy o boy does v- dub like it's special tools. Since this was a one off job for me I went the cheap Chinese route for $30 vs. $175 or more for pro quality stuff. I got the special pin to hold the crank at TDC and the bar to lock the cams in place. Made it pretty straight forward. Cylinder 5 at TDC then the cam bar lines up to a flat on each cam and bolts in place, they make it sound very tricky but it was pretty simple. The hardest part was getting all the other junk out of the way!

Maybe the tools and process would be similar for you. The ONLY alignment mark for me was the TDC notch on the front crank pulley. The cams also have no key or marks.

Good luck.

dave500 · « **Reply #12 on:** November 29, 2019, 05:25:49 PM »

how about next time before its pulled apart line up cyl 1(or in vw case 5)and stamp your own dots?

2wheels · « **Reply #13 on:** November 29, 2019, 05:41:26 PM »

Hey jgger
Can you explain what you mean by "the flats"

Just added a picture of my engine, for fun.

jgger · « **Reply #14 on:** November 29, 2019, 06:36:27 PM »

I was looking for a picture but all I had is with the cam holder in place. Where the bolts are is a threaded hole in the cam with a flat spot to receive the cam holder. Hope that makes sense.

dave500 · « **Reply #15 on:** November 29, 2019, 06:44:56 PM »

ktm bikes have a bolt you remove at the front of the crank and insert a longer bolt locates into the crank at tdc,plenty of ways to do it?

jgger · « **Reply #16 on:** November 29, 2019, 06:49:57 PM »

I should add I'm not a diesel mechanic or even a mechanic, it's a hobby. Plus the V-dub is a gas motor. I just wanted to maybe let you see there new and weird ways to time modern engines, and I hope it helps.

jgger · « **Reply #17 on:** November 29, 2019, 06:54:11 PM »

Quote from: dave500 on November 29, 2019, 06:44:56 PM

ktm bikes have a bolt you remove at the front of the crank and insert a longer bolt locates into the crank at tdc,plenty of ways to do it?

That VW has a simular set up on the side of the motor. You have to lock the crank and cams to do the chains.

2wheels · « **Reply #18 on:** November 29, 2019, 06:57:12 PM »

The picture is clear, i get it.

Since the John Deere has no marks no flats, no nothing. When i get it to what i think is good i will get the dremel tool out and mark the shaft and gear. At least i will know if it slips. I tried to scratch the metal to see if that would mark it but it is really hard.

dave500 · « **Reply #19 on:** November 29, 2019, 07:20:20 PM »

centre punch a dot.

2wheels · « **Reply #20 on:** November 30, 2019, 05:36:52 AM »

Yes, a center punch would be easier.

2wheels · « **Reply #21 on:** January 21, 2020, 06:52:46 AM »

Just to finish this thread off.
I ended up finding the degrees on the camshaft where the intake started to open. Then finding where the exhaust closes. Finding the spot in the middle of those 2 and leave the camshaft there. Then (keeping in mind the camshaft and crankshaft are NOT locked together at this time) I moved the crankshaft to 3 or 4 degrees before top dead center. Then locked the camshaft sprocket into place (which locked the camshaft and crankshaft together). Then called it done.

I went through each of the 5 cylinders to make sure the rising piston (on exhaust stroke) did not hit the closing exhaust valve. this was just to give myself that warm fuzzy feeling that i did not screw up somehow.

Put it all back together and the engine starts and runs really good. Just exactly what i would expect from a diesel.

dave500 · « **Reply #22 on:** January 21, 2020, 12:02:10 PM »

good job.

jgger · « **Reply #23 on:** January 21, 2020, 04:25:23 PM »

Atta boy!

2wheels · « **Reply #24 on:** January 22, 2020, 06:11:33 AM »

Lots of fun. Could not have done it without the "forums" and a good amount of luck. Thanks

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Author Topic: any diesel mechanics out there (Read 2039 times)