Liners on a 3C Mk3

[agrimax]

Yes,you can change the liners etc with the engine in situ.Ideally,a liner dolly/puller is best but the liners should knock out with a piece of good hardwood and hammer. Don't forget the rubber orings.... It would also be better to have the old liners out (perhaps your just thinking of replacing the one?)and the dimensions checked before you order the new ones as I believe there are a number of variations in them irrespective of the engine number.
Between 300 and 450psi would be ideal for the compression test. You might just have badly seating valves on the cylinder with poor compression.......

[MrF]

Thanks, think its bore or ring damage, its always blown smoke rings at tickover from one pot when cold in the ten years I've owned it and I've turned a blind eye to that as part of its charm, but now its started blowing oil out of gaskets & breather bad it has to be sorted before it catches fire and suddenly I have time to work on it for the obvious reasons. I have a leakdown tester & air source with 120psi so I'll give it a check with that too this am before I start disassembling it further but bad valves I can't see causing the crankcase/oil pressurisation. If I have to match up what's in there and not rely on engine numbers I'll hold off on ordering parts until I've got the liner out if they vary on the same engine number series. Noted on ordering new liner outer o-ring too.

Yes I'm going to change just the one liner if the others are ok at 300psi as much to keep the time down to a minimum rather than undertaking a complete rebuild project as I have found another good 4/98 in drivable distance if its still there when the lockdown lifts and it has good dpa pump and other bits that it would be handy to have two of also. And by then we might have a floor into the barn to work in to do a engine swap easier.

[MrF]

Disassembly done.


There was carbon behind the missing ring land area...


With the obligatory score and bit welded to the top of the liner from some previous carnage.


I'll order up a replacement and give the sump and bashplate a good going over with the hot washer now its apart.

[agrimax]

You're not hanging about anyway! Nice to find a definite problem too.

[Jeremy Rowland]

Well done Phil, I think you will find the carnage at the top of the liner is the aluminium from the piston which has melted; I have seen this happen in the past with Cummins engines.

Jeremy

[FOWLER MAN]

Hi Phill,
As has been said, good progress.
The piston you have removed , with the broken rings, lands and the other carnage Jeremy referred to in his last post is clearly the result of a partial seizure of what must have been a very hot engine.
You have gone to the trouble of removing the head and sump and the expense of obtaining the gaskets and a piston and liner, don't spoil the ship for a half-penny-worth of tar.

That bore did not get hot on its own. The whole engine must have overheated. Your compression test results are barely adequate so for the sake of six bolts why not drop the remaining three caps and draw the remaining three pistons.
If they look OK then it's up to you if you want to put them back in as they are but at least you will have peace of mind that all is well.
Personally, if the pistons are OK I would re-ring them and hone the bores before replacing them.

When you fit your new liner it must stand at least 3 thou. above the block face and not more than 6 thou. Drop the liner in without the seals to check this first. The shims are available in 3, 4, and 5 thou thickness. The liner should come out with a hammer and a good hardwood block as Agrimax has said.

Looking foreword to seeing your progress on here. If you require any build info please ask.


Good luck.
Fred

[Unknown1875]

Hi Phil, good luck with your engine rebuilt. Please keep us up to date and how you went on with the liner change. I might have to face this problem one day ^^
Louis

[MrF]

I was thinking about popping the other 3 for a look (as all 3 suspiciously also have foreign objects embedded in the tops of the crown so it'd be cheap insurance to make sure all the rings are ok), but currently I don't have the oil pump/balancer assembly removed, and I didn't think on looking that it would be possible to do on the other cylinders without removal. I'll look at what that will entail as I imagine the balancer will need retiming etc.
I'm still working full time through all this (not that I'm complaining, I still have a job) so it'll have to wait until next weekend now. I have a rigid hone I can clean up with as long as I don't break any more pistons extracting them and re-ringing would be fairly cheap so I'll order 3 sets of rings so I have the parts to hand to do this too while its apart.

[essexpete]

Following on from what the others have said have you had the rad out? Definitely worth a back flush and a good clean of the external core that cannot be seen very easily insitu.

[FOWLER MAN]

I was thinking about popping the other 3 for a look (as all 3 suspiciously also have foreign objects embedded in the tops of the crown so it'd be cheap insurance to make sure all the rings are ok), but currently I don't have the oil pump/balancer assembly removed, and I didn't think on looking that it would be possible to do on the other cylinders without removal. I'll look at what that will entail as I imagine the balancer will need retiming etc.
I'm still working full time through all this (not that I'm complaining, I still have a job) so it'll have to wait until next weekend now. I have a rigid hone I can clean up with as long as I don't break any more pistons extracting them and re-ringing would be fairly cheap so I'll order 3 sets of rings so I have the parts to hand to do this too while its apart.

Hi Phil,
It's a long time since I worked on one of these and I hadn't thought out the work involved till I read your last post. That reminded me of the balancer.
Not only will you have to remove the balancer which you have to strip down and remove in bits but also the oil pump and I think, the timing case cover.
From memory I don't think you will able to retime the balancer without access to the timing gears.
I have vague memories of scratching my head over these some 30 and more years ago, but I still think "pistons all out" is the way to go. Fred