Perkins A107-108 top end issues

[Go.Fish]

Got the old girl running yesterday! Had ordered a new thermostart to have as a backup and hadn’t actually checked to see if the original was working. Turns out it wasn’t.
Being new to diesels was thinking it looked odd having a fuel line going into the glow plug (thermostart), googled what it was and how it worked. What an AWESOME idea! Anyways, still took about 10secs of cranking with the nice yellow flame getting sucked into the intake but she sputtered and chugged and fired up a classic cloud of gray smoke... smoked really bad at first, ran for 1/2hr and by the end just smoked bad but not really bad.

So I still have an issue. Next step, continuing to find a way to adapt my diesel compression test set to fit. May just need a new schrader valve now as I get 200psi, zero, 200, zero, it just isn’t holding pressure

To touch on some recent posts. No leaking compression around the head gasket or injectors, didn’t touch the injection pump, except to bleed it. I may have come up with a nifty idea of bleeding the fuel system. Remove fuel line connection at the inlet pipe going into the injection pump. Then use a Mighty Vac brake bleeding tool to draw all the air out until straight fuel. Then all left to do is the 2 bleeder screws on the pump and each injector. It goes into siphon mode and never need to touch the fuel pump primer

The Machine shop guy sounded like he was very aware of the minimal machining that could be done on these heads. Explained to me about depth of valves on the relation to deck height. They’ve been in business for nearly 50 years and a member or AERA Engine Builders Association.

Before getting involved in the job. It ran, but was hard starting and smoked like crazy, just about as bad as does now. The engine has been tinkered with in the past based on little things I’ve seen, possibly injection pump timing. But not mucking about with anything other than compression for now

Will update when I have a better idea of the cause of smoking. Thanks for the all the input, POV’s and advice. Smart bunch of people you all are

[Compass790]

Yep it still sounds like compression issue.
Need to make a dummy injector to test compression. Not hard if you have access to a lathe. You'd need something like 300 psi as a minimum. eg our yanmar is 397-454 psi std pressure at 200 rpm but its minimum is 355.
Good luck with it.

[Go.Fish]

Got the compression testing sorted out today.
#1. 370
#2. 380
#3. 380
#4. 360

So might not be a compression issue after all. I found a set of 108 injectors on Craigslist which look different than these. Perhaps I might be able to install shorter hold down studs and use them? Current injectors in the 1st pic, the hold down clamps go on after the injectors are sitting in the heads Vs 4108 injectors which have the clamps installed along with the nozzle cap by the looks of it

Or possibly that the injection pump is out of timing? I can see a couple marks made by a chisel both on the pump flange and engine block that don’t line up, maybe a sign?

I definitely don’t recommend the compression tester in the photo. It leaked at every joint, new o-rings, Teflon tape, and totally sealing off the quick thumb release button were what it took to get it holding air also had to McGyver a way to get the lower left piece to clamp down in there

[Uncle Bob]

Originally Posted by Go.Fish

Got the compression testing sorted out today.
#1. 370
#2. 380
#3. 380
#4. 360

So might not be a compression issue after all. I found a set of 108 injectors on Craigslist which look different than these. Perhaps I might be able to install shorter hold down studs and use them? Current injectors in the 1st pic, the hold down clamps go on after the injectors are sitting in the heads Vs 4108 injectors which have the clamps installed along with the nozzle cap by the looks of it

Or possibly that the injection pump is out of timing? I can see a couple marks made by a chisel both on the pump flange and engine block that don’t line up, maybe a sign?

I definitely don’t recommend the compression tester in the photo. It leaked at every joint, new o-rings, Teflon tape, and totally sealing off the quick thumb release button were what it took to get it holding air also had to McGyver a way to get the lower left piece to clamp down in there

Hi, may I humbly suggest that you find (if you haven't already) a competent diesel injection shop,enquire about having your own injectors serviced and tested and having them come and check and if necessary adjust the timing. Quite often this approach to a situation that one is unsure of is the cheapest long term solution.
Or so it has been for me....

[Compass790]

Originally Posted by Go.Fish

Got the compression testing sorted out today.
#1. 370
#2. 380
#3. 380
#4. 360

So might not be a compression issue after all. I found a set of 108 injectors on Craigslist which look different than these. Perhaps I might be able to install shorter hold down studs and use them? Current injectors in the 1st pic, the hold down clamps go on after the injectors are sitting in the heads Vs 4108 injectors which have the clamps installed along with the nozzle cap by the looks of it

Or possibly that the injection pump is out of timing? I can see a couple marks made by a chisel both on the pump flange and engine block that don’t line up, maybe a sign?

I definitely don’t recommend the compression tester in the photo. It leaked at every joint, new o-rings, Teflon tape, and totally sealing off the quick thumb release button were what it took to get it holding air also had to McGyver a way to get the lower left piece to clamp down in there

Yea it should run with that much compression but what's it supposed to be?
Cannot comment on using different injectors but FWIW I used a non-Yanmr nozzle in our Yanmar injector & it worked fine.

My guess would be worth a shot but I'd try timing as well or first.

[Go.Fish]

Think I got it sorted! The injection pump timing was out so previous owner must’ve done some work to it.
The timing mark on the pump was slightly lower than the one on the flange (block). I moved it to the other side of the line as it was running and the smoke cut wayyy back. Not perfect as I still need at least 1 new injector nozzle but much better

Took the injectors apart again to make sure they were clean. Combination of cleaner, polish and lube when doing so.

Thanks for all the discussion and advice!

Approx movement of pump shown with reds marks before...

[Compass790]

Yaay!,
Good on you. So you aren't going to try the injectors for a different model now?
Be interested to know what happens with that or if you get a new injector.
Glad you got a win

[rbk]

https://oregonfuelinjection.com

Try these guys (I haven’t) they used to have the best price for Perkins injectors ($55usd ea) best to have a spare set anyways, throw new ones in and rebuild the old set for spares.

[Go.Fish]

Originally Posted by Compass790

Yaay!,
Good on you. So you aren't going to try the injectors for a different model now?
Be interested to know what happens with that or if you get a new injector.
Glad you got a win

Thank you kind sir
No not going to try the 4.108 injectors. Pretty certain I’d have to replace the hold down studs which isn’t a big deal. This may be...
From service manual
4.107
41 bhp (30,6 kW)
at 3000 rev/min
79 Ibf ft (10,9 kgf m) at 1900 rev/min

4.108
55 bhp (41 kW)
at 4000 rev/min
83 Ibf ft (11,5 kgf m) at 2200 rev/min

So they have different HP ouputs and compression ratio. I read on another thread the reason is the 107 and 108 use different injection pumps as well as injectors to achieve more power. They may work but I don’t think this is a long term solution

Local shop said nozzles are a couple weeks away and $60 CAD each ($45usd). If I build or buy a pop tester than no need to pay anyone to rebuild them

#winning

[Compass790]

Yes I can see your worry.
However the injector doesn't set the fuel quantity in yanmars at least, the injection pump does that. The 30hp yanmar uses the same injector as our 8hp.


I was just curious to see what happened, but yes at $45 for a nozzle its not worth the experiment. I havent rebuilt a Perkins so I'm just guessing. I'd be surprised if the other injectors didn't work but I've been surprised before.



No surprise you had trouble with your compression tester. I can guess where it was made. I had the same issues with one.


How do those injectors adjust? Be interested to hear if you make pop-tester.
Keep up the winning!

[rbk]

You can buy cheap pop testers online for around $100 not sure the quality though.

[jimbunyard]

You can get rebuilt, calibrated injectors for 69.00 each from these people, provided you have a core.

https://oregonfuelinjection.com/shop...ns-bg-5352102/

The conmpression you list should be fine.

If it were me, I'd mark the injection pump position, and then move it in slight increments, say 1/8" or so, either way to see if things improve. You won't hurt anything.

How easy (or not) does it start. Does the engine run up linearly to max no-load RPM?

[col50]

Originally Posted by Go.Fish

Thank you kind sir
No not going to try the 4.108 injectors. Pretty certain I’d have to replace the hold down studs which isn’t a big deal. This may be...
From service manual
4.107
41 bhp (30,6 kW)
at 3000 rev/min
79 Ibf ft (10,9 kgf m) at 1900 rev/min

4.108
55 bhp (41 kW)
at 4000 rev/min
83 Ibf ft (11,5 kgf m) at 2200 rev/min

So they have different HP ouputs and compression ratio. I read on another thread the reason is the 107 and 108 use different injection pumps as well as injectors to achieve more power. They may work but I don’t think this is a long term solution

Local shop said nozzles are a couple weeks away and $60 CAD each ($45usd). If I build or buy a pop tester than no need to pay anyone to rebuild them

#winning

Those are very misleading performance figures for the 4.108.
HP = RPM X torque (in lbs ft) divided by 5252.
If the 4.108 were measured at 3000 RPM it's output would be nearly identical to the 4.107. Without looking at the manual, maximum sustained RPM for the 4.107 is 3100 RPM. The engine would not be reliable a constant 4000 RPM.

[Ox76]

You'll find that the injector pumps on the older mechanical injection diesel engines need to run advanced timing from what they say in the manuals. Today's diesel isn't as good or potent as the old diesel fuel. For instance, I rebuilt a backhoe engine from a 1964 machine - manual said something like 8 degrees BTDC (this is an indirect injection engine) and I ended up going up to around 14 degrees BTDC to make it run and start well. It exhibited all the symptoms you're talking about with your engine. All better with more advancement to the injection timing.

[norena of white]

go fish i have a 4-107 that is trashed. but i still have many good parts for it if you are interested i am in chilliwack.