Head removal of Perkins 4.108

[rbk]

Originally Posted by Ecos

Because he installed +.020 bearings in Guatemala a couple of years ago. Ivan has had some engine problems but he is intrepid.

I missed this too Jim

[pr2501]

I have low oil pressure.

Bearings which I have now are "MXF 31131212 010"
And from text which I marked red we may know that they are .010
Bearings which I had before were "050 D DB Perkins 31131212"
(check the image in previous post)
My question: From what in "050 D DB Perkins 31131212" is possible to conclude that they are .010 ?

If the dimension "A" has to be 56,85min / 56,86max ,how much ± can it be to be in acceptable tolerance to not grind the CS?
I want to know what are they doing, and to check, if the result will be then correct.
(like somebody wrote in one of previous answers:"Measure what You get.")

[rbk]

Buy a plastiguage and check each bearing to see what you actually have. Having not read your previous post, how low is your oil pressure? These engines can run perfectly fine at very low pressure. Have you checked the limits on the oil pump? Was the filter screen clogged? Have you checked your oil cooler for crud? Blockage in the oil galleries (sand case head can have left over material rattling around in there)? You do know you can get different bearings depending. On how much wear there is and they’re cheap.

[jimbunyard]

Originally Posted by pr2501

I have low oil pressure.

Bearings which I have now are "MXF 31131212 010"
And from text which I marked red we may know that they are .010
Bearings which I had before were "050 D DB Perkins 31131212"
(check the image in previous post)
My question: From what in "050 D DB Perkins 31131212" is possible to conclude that they are .010 ?

If the dimension "A" has to be 56,85min / 56,86max ,how much ± can it be to be in acceptable tolerance to not grind the CS?
I want to know what are they doing, and to check, if the result will be then correct.
(like somebody wrote in one of previous answers:"Measure what You get.")

If you have the wrong bearings for the crankshaft size certainly there could be too much clearance and this could result in low oil pressure.

Check with plastigage as suggested above. .001 inch clearance is kinda an accepted norm, check this out for more information than you probably need.

https://www.google.com/search?biw=12...63.Jzmhz2RaK7I

Regarding the 31131212, I am going by my experience in the parts business; numbers are specific to a particular dimensional part. If they were different they'd have different part numbers. If the A, B, C convention wasn't followed they would have a different number as in 31131212 for .010, 31131213 .020 and so on. You could also measure the bottom halves thicknesses at 90 degrees to the parting lines, if there are differences that match the .010 increments that would indicate a problem. I am very sure that the brgs are the same, but it doesn't hurt to be sure.

There's also this

Historical CONROD BIG END BEARING 85037A

The list of replaced parts is given as an indication. If the item you are looking for is in this list, please contact us before your purchase to make sure it matches your need.

• 41159416A replaces 41159416 since 22/02/1989.
• 85037A replaces 41159416A since 12/05/1989.
• 85037A replaces 31131212 since 15/8/1980

By the way, the number I gave for the .010 rod brg is wrong, it should be 85037A.

According to the service manual, the wear limit for the mains journal is .001", so anything more than .001 inch less than 2.238 inches is grounds for a regrind. So if the first or second journal measure less that 2.237, or 56.8198, it needs to be reground, and so on for the other journals.



Also, the 'ovality', or lack of concentricity needs to be checked, it should be less than .0005 inches or .0127 mm. Taper is usually checked also, but a number isn't given in the specs, so you'll have to rely on the judgement of the machinist.

I would also check the relief valve on the oil pump for internal wear, as well as for wear on the oil pump internal gears, the cam bearings and the piping and connections in the oil distribution system.

[arcticmonkey]

I loved my perkins 108... a rebuilt cab motor from great britain
I started my search at the local tractor shop looking for a shop manual
As it was an older model I didn't have success
I was steered to a local truck shop... located a boat owner who worked there who kindly assisted on my first re and re..
did some on line research and luckily located british dealership who gave me info ... long story short the search located a book store that had a shop manual
stayed with the boat when I sold her
always new head bolts... smooth runnings

[pr2501]

0,001in/0,03mm

I did't want to pay 170$ for caliper, so I don't have enough accurate readings.
Taper, ovality. Everything will be clear at the shop. I will go on Monday.

Thank you very much.

[pr2501]

If I can not find any signs of wear by visual inspection and if I can not notice any edge scratching with nails over the camshaft, can I take it as OK?

[pr2501]

I will bring camshaft also with me to the shop for inspection. I am not sure how many pistons with rod will I also take.

Once I will order for spare parts. I will then discus about why I am rebuilding the engine.

If needed I will buy also the oil pump.

[pr2501]

I am rebuilding engine because of:

New
1.Water in cylinders
2.Water in the boat: inside of flywheel area was 2/5 and also engine starter was immersed in water
3.Repainting of engine and transmission

Old
4.Low oil pressure
5.Leaking of injection pump
6.Leaking of transmission

[pr2501]

Water in cylinders

After switching of engine starter for new one, I connected intake for cooling salt water
to system directly to marina water supply.

But I did not start the engine at once, but after 8 hours.
The water was then in the cylinders.

Where did water penetrate to cylinders?

[lifeofreilly57]

Originally Posted by pr2501

And manual which lifeofreilly57 has sent does not have salt water pump.

Was this a raw water cooled engine or does it have a heat exchanger? which means you'd have two water pumps, one run off the belt drive for the fresh water/closed system, the other for the raw water driven off the timing gear assembly attached to the timing gear cover?
If the engine had only one pump you've got a raw water cooled engine.

[lifeofreilly57]

From what I've read someones mucked about in this engine before, .010 oversize bearings are not standard.
Having everything measured accurately would be a wise expenditure.
I have all the measuring equipment so I was able to spec out my parts, the machine shop reaffirmed my findings and did a great job machining the parts, matching the new pistons to each cylinder.
When using plasitgage to measure crank clearance do not use oil on the bearing.Todays oils, even the cheapest ones have enough film strength to alter the plastigage results. put the crank in dry, with the plastigage in place, do not rotate it, then put back on the crank mains and torque to the correct values n three steps.
Then remove the bearing caps, pull the crank straight out without rotating it and use the guide on the package to measure the actual clearance.
I found tht when used correctly, plastigae was quite accurate. I checked that out by using it and the measuring with accurate measuring devices when I finally had the right tools in hand. Good stuff.

[model 10]

[QUOTE=
Where did water penetrate to cylinders?[/QUOTE]


Water leaked past the vanes in the salt water pump under marina water pressure, filled the muffler and then back into the engine. Just like cranking the engine without turning off the through hull.

[lifeofreilly57]

My rebuilt 4108 underwent it's break in moving south down the Eastern Seaboard, one break in oil change later at 30 hours it's running smoothly and efficiently.
Oil pressure 25 psi t idle, 50PSI at 2800 rpm with 15 w 40 oil. 180 F temp steady.
The shop manual is excellent, a bit wordy, but has excellent detail, if you follow their instructions you should have no problems.
DOn't mess around buying individual parts, once your motor has been measured and evaluated, order a complete kit from TAD, it's the most bang for the buck.
I rebuilt mine for under $2000.00 us, which $800.00 of cost was for rebuilding the distribution pump and servicing the injectors, without that cost the total rebuild would have been about $1200.00 US, with the machining included. Thats for the block and head totally rebuilt with new parts, with me doing the assembly labor of course. That's really cheap for an essentially new engine.

[jimbunyard]

Originally Posted by pr2501

If I can not find any signs of wear by visual inspection and if I can not notice any edge scratching with nails over the camshaft, can I take it as OK?

Generally if it looks good it probably is good, but the machine shop can measure it to be sure.

Originally Posted by pr2501

Water in cylinders

After switching of engine starter for new one, I connected intake for cooling salt water
to system directly to marina water supply.

But I did not start the engine at once, but after 8 hours.
The water was then in the cylinders.

Where did water penetrate to cylinders?

Originally Posted by Ecos

Water leaked past the vanes in the salt water pump under marina water pressure, filled the muffler and then back into the engine. Just like cranking the engine without turning off the through hull.

More completely, and then the water filled the exhaust manifold and entered the cylinders through whichever exhaust valves were open...