Petrol engine rebuild parts

[pjjms]

Well not much interest from buyers for the petrol Dexta so time to make it well again and get it into some work.

I took the engine out today and stripped it down. Liners are in bad shape but the crank looks ok, although a measure up may tell another story.

So now for parts. Nobody lists parts for them any more but am I correct in saying they are the same parts as the MF 35/135 engines? If so do all the parts fit, or are there some traps?

Peter

[The Swanndri Guy]

Peter, I would say it's most likely that engine parts for the petrol Dexta are the same as MF 35/135 petrols, but no doubt there will be exceptions as there will be unique parts for the petrol Dexta.(Like the top and bottem radiator hoses.)Let us know what you get and where you source your parts and how you get on with the engine rebuild. TSG.

[pjjms]

I'll get some pictures up after its all been through the parts washer.

[Brian]

I have got a Petrol Dexta parts list if you need anything copied. The MF35 has a similar engine except for the starter position top hose fittings and exhaust pipe bend, so there should be plenty of parts out there.

[pjjms]

Had a measure up this morning. Crank is standard but worn beyond limits. Looks like the knock that started last time it ran was the number 2 big end which is about 0.1mm under the others. 1st undersize should take care of that. Did'nt measure the linders as there is a big lip at the top of the bore, guessing bigger than 0.25, so new liners. Any body had any experance with MF liners? Will protrusion need shimming? Gave the liners a tap from the bottom and they are solid so I will turn a disc for pulling then out.

One valve is stuck open through setting idle and I will reface the valves and cut the seats.

Not as bad as I was expecting givin the tractor is is poor condition. MF35 engine kits are available and I am waiting for some prices to come back. Out work should be limited to crank grindng so I think the cost to overhaul will be better than expected.

Peter

[pjjms]

Top ring and groove worn

#2 big end shells, no the groove is not supposed to be there. Caused by the wrong oil filter (too short) being fitted when I got the tractor. I have a MF filter on order and it will be interesting to see if that fits correctly. One thing I won't do again is run a tractor that has been sitting for years without checking this and dropping the sump. Half a hedge in the sump.


I have a MF35 overhaul kit on order from the local BareCo agent (www.bareco.com.au), complete with a new crank. Worked out about the same as having the crank ground.

[Bensdexta]

How do you know the groove in the big end shells is the result of fitting the wrong filter? Is that the effect ofthe hedge in the sump - lack of oil filtration?
Thanks for the pics, look forward to hearing how it goes.

[pjjms]

The oil was not being filtered at all. The filter is about 2" too short so the oil is just passing around it. So yes, you are correct that the crud in the sump has clearly been reaching the bearings with a lot of particles embedded in the white metal, and my assumption is that effective filtration would have stopped that.

What I am keen to find out is if the MF filter fits this engine or did Ford put another filter housing on this engine to align service parts with the diesel Dextas. Guess I'll find out when the parts arrive.

[pjjms]

Yellow filter is the new one. BareCo part numbe B7700. Fits a MF TE20, 35, 135 petrol models. Maybe somebody here can tell me if the old filter is for a diesel or just completly wrong for any Dexta?

[Brian]

The yellow one is the one I use on my TE20 and Petrol Dexta. The metal one looks too short for a diesel as well but I do not have one to compare at the moment.

[Lesfen]

The aftermarket replacement filters for the diesels all seem to be around 4.5" high. (4.496", 4.53", 4.5")
Cheers,
Les

[pjjms]

Well I have the short block assembled. The BareCo parts seem fine but the ring gaps were worth checking. Documents that came with them said they were pre gapped but two of the oil rings needed the gap opening up. One had no gap at all.

I have one concern. The #2 small end boss is right over one side of the piston. I pressed the bush flush on that side and it turns over without any binding. Should I be concerned.

Peter

[Brian]

Have you had the con rods checked for alignment? Might be worthwhile. Normally they run in the centre of the piston.

[Aussie Frank]

Hi Peter,

How tight were the pistons on the rods when you assembled them? The rule of thumb that I was told for new gudgeon pins was that the piston should be firm enough to just hold it's own weight when leant over. If it flops about you need to fit new small end bushes. If they are loose I would get new bushes fitted as the last thing you want to have to do is strip it later because a gudgeon has let go. As for why one was out of place, it could be wear and is loose in the rod or it may just have been badly assembled originally. In either case I would have a very close look at it just to make sure it is OK.

At least you should have no trouble getting bushes. Not like the perkins P6 I am building at the moment, small end bushes have been NLA for years and 4 of mine are out of spec.

Regards, Frank.

[pjjms]

I replaced the small end bushes and have reamed them to the spec in the manual. They fit well needing a push with my thumb to get the pin in place. I have not checked the alignment of the rod. I think I will pull this one out again and have a good look. All the others are running evenly between the bosses in the pistons. I guess as a check I could lay the rod on the surface plate flat on the big end and measure the gap under the small end, flip it over and compare to see if the rod is bent? Then the same setup with the pin in the see if its at 90 degrees.
This was the first rod I reamed the bush on and did one pass by hand, then jigged it in the lathe for the remaining passes with the reamer. The other 3 were all done in the lathe from the start. I wonder if this one is reamed a little off true? Got to love expanding reamers eh.
Peter

[pjjms]

Yes, I had screwed up the small end. Sorted that and jigged it up in the lathe for reaming as per the other three this time. Timing cover is back on and the sump will go on tomorrow assuming it can be fitted out of frame. The block can go back in the tractor next then onto cutting valve seats etc.

All of the BareCo MF35 kit fits with the only problem so far being I can't find a gasket for the fuel lift pump in the kit. Easy to make so not a problem. Quality seems good too. The only thing I could find was one big end crank bearing surface that measured 0.01mm, 0.0004in under the correct measurement, but clearly that is well within spec.

Peter

[Lesfen]

I have got a Petrol Dexta parts list if you need anything copied. The MF35 has a similar engine except for the starter position top hose fittings and exhaust pipe bend, so there should be plenty of parts out there.

Hi Brian,

Can you tell me the difference between the two exhaust pipe bends?
From ebay websites, it looks as though the MF has a different bend for the Standard diesel vs the Standard petrol?
Would you know if both fit on a petrol manifold and is one a closer match to the original Petrol Dexta?

Thanks,
Les

[Brian]

Les,

The bend on the petrol Dexta is very sharp and has a web down the inside. I use the TE bend on Dotty which in a more gentle curve and sets the pipe away from the bonnet. The MF35 petrol is the nearest one to the original. That has a bracing strip from the bend to a manifold bolt.



Dotty.



Petrol Dexta original.

[Lesfen]

Thanks Brian,

A thousand words....,

Well,,,err,,2000!!!

Les