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Old 25-12-2012, 12:33   #1
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Perkins 4-108Injection Pump Alignment

Ever since I installed a rebuilt IP on my Perkins 4-108, my engine is unable to attain more than 1800 RPM at full throttle in gear. Out of gear there is no limit to the RPM's available. It can easily achieve 3500 and more. I used to get 2200 RPM under load before the IP broke.
I haven't changed props and agree that a dirty prop inhibits RPM's. Right now with a dirty prop I only get max 1400 RPM's under load.
My question is: can this IP be installed out of major alignment? And if so, would it run as well as it does now? (no smoke, does take a little more time to start than before the IP broke)
Since installing the IP I've read that the IP must be installed while with number one cyl is at TDC (exhaust closing and intake opening). But because there is a spline on this IP shaft, it appears that it can only go in one way. After installing the IP, I found I had to retard (or advance, not sure) the timing mark by 1/8" using the marks on the IP flange and engine mark (my original IP aligned exactly on the marks).
Removing/replacing the IP on this engine is a major job so I want to be sure that it is necessary before doing it again. So I need to know if this IP can be installed out of time considering the spline on the IP shaft? And if so, could this engine run fine -- except with lower power -- if the IP was installed out of time?
PS: I've replaced or rebuilt everything -- fuel lines (exhaust & intake), lift pump, and fuel injectors.
If the IP cannot be installed out of time and still run decent (though without full throttle RPMs) then could it be in the governor or some other part of the rebuilt IP? I had it done by a mechanic in S. Calif. who rebuilds these IP's for a living. Though I don't think he has that expensive tool for syncronizing these pumps before sending them out.
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Old 25-12-2012, 13:45   #2
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Re: Perkins 4-108 fuel injection pump alignment

Not sure if I can help at all as I haven't worked on ours to this point but do you have the workshop manual? It is online here....

http://www.endeavourowners.com/dscsn...p%20Manual.pdf

...and reading that it sounds like there is a screw that can adjust the maximum speed under load....



I'm wondering if that now needs adjustment (it is in section N of the manual).

If you get this figured out I'd like to hear how it was resolved.

Here are two more links to possible help if you don't have them...

http://www.endeavourowners.com/dscsn...8%20Manual.pdf

http://www.endeavourowners.com/dscsn...rts%20Book.pdf

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Old 30-12-2012, 13:19   #3
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Re: Perkins 4-108 fuel injection pump alignment

I like your suggestion about adjusting the speed screw. However, I'm a little afraid to mess with that screw in case that is not the cause of my problem.
And I have recently discovered in the Continental Diesel Engines Operators Guide & Repair Manual (TMD SERIES) that "this engine will run with the injection pump installed 180 degrees out of time. However, it runs very poorly in that condition." I realize this is engine is not a Perkins 4-108, but it sure looks like the same engine from the front view of the engine outline components.
The Perkins shop manual states that to refit the fuel injectio pump:
1. Replace fuel pump, ensuring that master spline on it's quill shaft is positioned to engage with female spline within drive hub.
2. Before tightening, align timing marks scribed on fuel pump mounting flanges as shown in Fig. M.2.
And that's about it. It next states that the maximum speed screw is set and sealed by the manufacturers and must not be altered or tampered with in any way, unless factory authority is first obtained.
So now my only real question is: Can the CAV type DPA fuel injection pump be installed 180 degrees (or 360 degrees) out of time on the Perkins marine 4-108 and still have the engine run, though run poorly (without maximum RPM)?
I really think I need a Perkins pro to answer this question. This must have come up before, but I can't find the answer any place. I'd like to get this answer before fiddling with the speed control screw, which is factory set, or even worse -- removing and replacing the fuel injection pump, which is about week worth of tormenting work (trust me, I've done this several times already (the exhaust manifold even needs to be taken off nad those bolts are insane as well as that back allen screw which is almost impossible to tighten.
Actually, I have two questions: #2: Is the IP suppose to be timed to a specific position before it is installed while number one cylinder is at top of compression stroke. Is the cover plate suppose to be removed to look inside the pump to determine when it is timed to #1.(and I think I had my compression stroke figured out wrong too. Now I'm finding that when #1 cyl is at top of compression stroke neither one of the lifters are moving at that moment. ) It's funny that when I bought the IP nobody mentioned anything about not turning the spindle or that it was set and ready to install to align with number 1 cyl compression stroke.
Any help appreciated.
Thanks again
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Old 30-12-2012, 13:43   #4
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Re: Perkins 4-108 fuel injection pump alignment

Quote:
Now I'm finding that when #1 cyl is at top of compression stroke neither one of the lifters are moving at that moment. )
That is correct. Both intake and exhaust valves should be closed when the piston for that cyl. is at TDC on the compression stroke. When you rotate the piston down to the bottom of the power stroke the exhaust valve should just begin to open.

Sorry I can't help you with your other questions.

Did you scribe lines on the pump housing and the block before removing the pump? You may be able to adjust the pump rotation and get better performance.
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Old 30-12-2012, 13:54   #5
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Re: Perkins 4-108 fuel injection pump alignment

An injector pump is just like a distributor in a petrol engine in that it determines timing. Install as per the book. Some pumps have slotted adjustment for finer adjustment. If all timing methods aren't outlined clearly in a book I will "spill time" a pump.This is where a clear dummy injector line is fitted and you can see the fuel start to rise in it to determine the firing point.


However, all that fun stuff aside, your pump can be out 1-3 degrees and not make a massive difference. What I believe has happened is, when the pump was rebuilt and setup on the test bench they have set the governor and max revs to where they are now. If you call the guy the rebuilt it and explain you need a few more revs he will tell you which cover plate to take off if necessary or just adjust the external stopper screw.

This is not uncommon to have to do as the pump shop will err normally on the side of caution and set a pump to manufacturers lower specs unless aware of the needs. I have done quite a few of these tweaks over the years in pumps, tractors,trucks etc.
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Old 30-12-2012, 14:30   #6
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Re: Perkins 4-108Injection Pump Alignment

You need to time the eng first. You need to know the "degrees before top dead center" that the eng needs to be timed to, in relationship to the pump. This is done by aligning the timing marks on the flywheel or the damper pulley on the crankshaft to the corresponding degree number ( 6 deg before top dead center). Then without rotating the eng you mount your pump and align the timing marks, again without letting the eng rotate. Do not mess with the high speed screw, ever!! You have a 4 cycle eng (the number of cylinders mean nothing), this means that the eng will rotate 4 full turns from TDC on number 1 cylinder to the next TDC on Number 1. Rotating the eng (in the direction it runs) and watching the intake valve on #1, when that valve closes the compression stroke begins. Contimue rotating as the timing marks appear and align with a pointer, stop on the degree before TDC that is specified. I find it very helpfull to time the eng with the old pump in place, then remove it. As long as the eng remains unchanged you just slip the new pump in and eleminate a lot of hassle. So when you get your eng in time, you should be able to just loosen the pump and move it to the new relocated pumps mark(a small but significant difference). Good luck
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Old 30-12-2012, 21:08   #7
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Re: Perkins 4-108Injection Pump Alignment

Thank you guys for all your help. I think I'm in for a big job pulling and replacing this IP. I just received a personal email from somebody who read this post. I thought his thread would also be valuable to this thread so here it is, minus his name:
"Get in touch with North Land Diesel. This is all they do and they are experts.
http://www.northlanddiesel.com/
Did you have your pump replaced or rebuilt? [I had it replaced with a rebuilt pump. My original pump had a broken main shaft] A different pump will have a different aliegnment mark. As the previous post .. look at the RPM on label. Maybe they made the pump wrong. Use the manual and re-align the pump. Go to TDC, remove the alignment cover on the pump and rotate the pump.
Not saying I'm an expert but I've just been through all this. Rebuilt my own diesel and had NLD rebuild, not replace, the engine's original pump." END OF EMAIL MESSAGE.

YES, I did see on the CAV manual that the cover needed to be removed to align the IP properly on number one. Hope that works in my case. I've only got one IP remove/replace operation left in me, if that.
I hope this thread helps some body down the road to avoid having to redo this job a second or even third (as in my case) time.
Thanks for all the help. I'll let you all know how it turns out. First I will try the speed adjustment screw (and check the plate numbers too), then if that doesn't increase my RPM's, I got a big job cut out for me.
thanks to all
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Old 30-12-2012, 22:31   #8
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Re: Perkins 4-108Injection Pump Alignment

I think from the posts here and on this earlier thread....

Timing a Perkins 4.108

.... I would not mess with the screw until the last thing. As was mentioned in that link the timing is like turning the distributor in an older car.

I would re-read the manual section K and check as much of that as possible, but at this point after reading that if there are no big red flags try loosening the screws and moving the pump as mentioned in the other thread....

Quote:
I agree....But..... play with the timing buy rotating the pump a tad until it sounds and or preforms like it use to....rather the marks realign or not.

The pumps internal timing may have gotten changed just a tad and its not going to be the same external line up if that's the case.
They also talk on there about how to get to the 3rd hard screw/bolt on the pump.

Also you will be at TDC (top dead center) on compression on every second revolution of the engine.

Good luck and get back on how things went,

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Old 01-01-2013, 08:59   #9
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Re: Perkins 4-108Injection Pump Alignment

Sumner, thanks for correcting my 4 cycle reference to 4 strokes. You are correct that every 2nd rev brings one back to a compression stroke not the 4 revs I refered to.
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Old 01-01-2013, 11:02   #10
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Re: Perkins 4-108Injection Pump Alignment

Quote:
Originally Posted by Mark Zarley View Post
Sumner, thanks for correcting my 4 cycle reference to 4 strokes. You are correct that every 2nd rev brings one back to a compression stroke not the 4 revs I refered to.
Every 4th revolution will also bring it to TDC if you start there .

For anyone that is interested and I'm sure you knew this, for a 4 stroke engine the ....

1st revolution === The piston goes down and the air/gas (for a gas engine)/air only on the Perkins is taken in (intake stroke/cycle). Next the piston comes up and the air/gas or air charge is compressed.

Just before piston gets to top dead center the spark plugs are fired if there are any which our gas engine will for sure have. This is the important part on the Perkins where the fuel pump has to inject the fuel just before the piston gets to TDC. To soon and it will ping and possibly hurt something by trying to send the piston back down instead of letting it come over the top. To late after the piston gets over the top and there will be less power. So maybe in this case, the OP's, if it is not pinging then it might be injecting too late in the cycle. If that is the case the pump needs to be advanced so that it is injecting sooner. If it is pinging then it needs to be retarded so that it injects later.

There are no spark plugs on the Perkins. The charge is ignited by the heat generated in the compressed gases on the compression stroke, the reason diesels run such high compression ratios. With the gas engine you don't want the gases igniting until the spark plug fires. If they per-ignite then you have detonation and "knock" and can hurt the engine (firing too soon on the diesel can also hurt it)..

2nd revolution === The piston is forced down on the power stroke by the expanding gases as they burn. Finally the piston starts back up again and the exhaust valve opens and the burnt gases are force out by the piston coming back up. Then the whole process repeats (2 revolutions...4 strokes...4 cycles) .

A 2 stroke gas or diesel does the 4 different cycles in just one revolution and there are different ways to accomplish the intake charge coming in and the exhaust charge going out via valves or ports or a combination.

Thanks to the OP for posting as I read more of my manual and now know the Perkins a little better, but still hope that I don't have to do anything major to it. I just put a new engine and rebuilt tranny in our Suburban and hope to never do that again either. My street rod...



... is much simpler to work on.

Sorry for the long rant ,

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Old 04-01-2013, 09:18   #11
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Re: Perkins 4-108Injection Pump Alignment

Update:
I tried adjusting the high speed screw (the one that was locked down with a twisted wire) on the IP, but it didn't increase my RPM's under load.
So I then removed my IP and brought it into our local diesel mechanic who estimated it would take about 2.5 hrs ($225.00+) to check out it out. I then called the guy in California who sold me this unit two years ago and he was eager to check it our for me along with all my injectors at no cost except shipping. I asked him if he owned the big machine to test this IP professionally with a load on it. He said yes he did have that machine, but there was no way to test the IP with a load on it. Is this true???
He said the IP would function the same with or without a load on it. But now that I think about it, I think I remember reading some place that the governor has some weights on it that are there for when a load was put on the IP. Maybe those weights are not correct??
He also told me that it is possible that when my IP shaft broke (two years ago) in two pieces that that high torque force could have somehow messed up my timing gear where the IP aligns with the water pump">raw water pump gear. He advised I remove my raw water pump and check the gear area for damage.

I then removed the Jabsco raw water pump (I was getting a slight leak in this pump anyway and wanted to check it out(. I was careful not to remove or loosen the plate that the pump is attached to in order to avoid aligning problems. Upon removal, I found the coupler on the end of the pump (the round female sleeve that is cut out to fit over the mail flat drive gear where it mates with the IP gear was damaged (a huge chunk was broken off the coupler). I doubt this broken coupler could effect the IP pump, but I may be wrong. I imagine this broken coupler probably happened when the IP shaft broke. Maybe I got seaweed or something into raw water pump, which froze it up and thus broke the IP shaft.

I did see on Jabsco's website that this coupler can be bought separate, which I plan to attempt if I can figure out how to remove/replace this coupler, or if I can even buy it. Otherwise, I need to buy a new raw water pump, which means I need to decide which pump to buy. If I buy the original Jabsco pump that came with my engine, then I will probably need to rent the special alignment tool to set it up. But I have read on this forum that the Sherwood G65 raw water pump will also fit this engine and it has the adjusting plate attached to it so it doesn't need the alignment tool to install. But when I see these pumps on line, they look very similar to the Jabsco. SHERWOOD G65 - Sherwood Sherwood Raw Water Pump G65 - Boaters Plus

My question now is if I can leave the raw water pump attachment plate attached to the large gear cover so that I can remove the gear cover to check my timing marks and gears for damage and not have to realign this raw water plate later (which will involve renting the aligning tool if I can even find one).

My other question is how to remove that big 1 1/2" bolt on the end of the crank shaft that holds the fan belt pulley on the crank. I know I need a big 1/2" drive socket to break it loose, but how to prevent the engine from turning when I try to break the bolt loose.
I'll probably need a special wheel puller too to pull that fan belt pulley off the crank shaft.

any suggestions appreciated.
Thank you
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Old 04-01-2013, 16:31   #12
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Re: Perkins 4-108Injection Pump Alignment

There is no extra load put on the pump between ide and wot ony output quanity varies.
Depends which fuel pump your engine is fitted with hydraulic or mechanical govener only mech has a fly weight system.We quite often come across the drive coupler with one side brocken or bady worn and have to have a new unit machined.
Yes, you can remove the cover with the adapter in place, but I never seen this gear problem arise.Along breaker bar and a sharp SMITwith decent hammer does the job on the crank nut.
I have not read all the other posts so might be going over old ground have you checked the folowing? Air intake screen, Cold start shutting off, Fuel fiters clean, Lift pump filter clean, Stop lever returns to 100% run position, Hull & prop clean and vessel free running not tied to berth.
There should be a long pointed nut on the Sw pump side of the timing cover behind the btm crank pully this screws out and fits into a dimple in the backside of the pulley to indicate TDC .
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Old 05-01-2013, 12:28   #13
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Re: Perkins 4-108Injection Pump Alignment

Thanks Shakey Doug for all your detailed input. I needed to hear everything you had to say.
It's nice to know that the high RPM problem cannot be affected by the IP due to high load. And I think my IP is of the hydraulic type, which would explain why my mechanic told me it doesn't have the governor fly weights.
I'm surprised to hear that you could machine a new drive coupler for the raw water pump, as that metal looks pretty hard. I did see that coupler for sale on Jabsco's site and will try ordering it today.
And I'll try the hammer and breaker bar on the crank nut. thanks again.
Air Intake filters? Yes, I recently replaced the old screened cap with a standard air filter system. No improvement.
Cold start shutting off? After installing the rebuilt IP, I found I couldn't start the motor without repairing the diesel intake heater. I never had to use it before, but now it is absolutely necessary when the engine is cold. After it warms up, all is fine. Somebody said this could be a sign that I have a leak in the fuel lines which would make it necessary to reprime the IP every time I cold start it. And I guess a small fuel line air intake leak could be the cause of my problem. After I get it all back together, if I still have the same problem, I will run the diesel direct from a can to an electric lift pump and then to the IP just to verify if it is a fuel line leak. I do have a new lift pump installed recently with no noticeable difference.
What is peculiar is how the new rebuilt IP had to be retarded 5/16" to even idle decent. But no amount of adjusting (5/16" is max adjustment possible) could improve the RPM's in gear (under load).
Yes, the lever does return to 100% run position.
The Hull is clean but the prop does currently have barnacles on it, which would explain why I'm only getting 1400 RPM's now as opposed to 1700 RPM's when the prop is clean. (Still not enough) And I'm on a buoy. Not tied to the dock. 1400 rpm's with barnicals on prop barely even moves the boat.
Not sure what you are talking about regarding the long pointed nut on the sea water pump side of the timing cover. I'll look for it when I get the timing cover off and see what that's all about.
I'm currently in the process of building a leak down tester to test the compression etc on the cylinders. I realize that even with only 900 hours on the engine, it could still have some compression problems that could be the cause of this low RPM problem I've got. It's just strange that my problems didn't start until I replaced the IP.
I will keep everybody posted as the outcome of this.
thanks again
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Old 10-01-2013, 16:53   #14
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Re: Perkins 4-108Injection Pump Alignment

Update:
IP mechanic diagnosed my IP and injectors and reported everything in excellent condition.
I pulled off the timing cover today and was delighted to find the timing didn't seem to be right. The situation was I had number one cyl. on TDC on the compression stroke (the #1 rocker arms are not moving, while number four exhaust is closing and intake opening). I checked the cam gear and it was in proper position, but the idler gear was not meshing on the two dots. The dots must have been at least 7 gears away. Okay, I thought maybe the gears slipped out of sync when the IP shaft broke. Everything seemed pretty tight, except there was a little extra play between the idler gear and the cam gear. I didn't have my feeler guage but I could tell there was some slop, not much, but probably more than the .0015 in. that is allowed. Other than that, the gears all look to be in perfect condition.
So I then removed the idler gear and reinstalled it to line up with the cam gear marks and the the crank gear marks and the IP gear (raw water pump) marks. I then rotated the motor in a clock wise manner hoping that in two complete rotations, my marks would line up again. But no way Jose. The more times I turned the crank the farther away the marks were getting. After 16 complete turns of the crank, I decided I better reverse my direction and bring it back to where it was when I set the gears to match properly.
So my question now is: are these gears ever supposed to realign again after they have been set to specs with the other gears, or will they for now on appear to be out of synk.
My other question is: When I turn the crank in clockwise manner (probably counter clockwise too), I hear a clicking or knocking sound in the engine. Not sure where it is coming from, but the sound comes on every half rotation of the crank shaft. It kinda sounds like that knocking sound that diesel engines make when they are running. Is this sound normal? Or am I in trouble here too?
Thanks again for whoever can help me here.
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Old 10-01-2013, 18:13   #15
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Re: Perkins 4-108Injection Pump Alignment

Many engines have timing marks that will align a complex geartrain at assembly and they may never all line up again for a zillion rotations. Time it as per the book. Do it carefully, do it once, forget about it.
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