300tdi Rebuild

[edwardbahaw]

Hi Guys

I have removed the cylinder head from my 300tdi in preparation for an engine rebuild.

The cylinder liners are worn about 1/4 mm.

Putting cost aside, what is the best option for this rebuild?

Bigger pistons or replace liners?

Regards
Ed

 

[redhawkrovers]

have it bored and bigger pistons is the best bet

 

[piper109]

Having the block rebored is just about your only option. Its a solid block that has no liners.
Parts will not be cheap. I would recommend Rovah Farm if you are in North America. 300tdi's are pretty rare and few places have parts for them.

 

[edwardbahaw]

Are you sure they don't have liners?

 

[redhawkrovers]

There are no liner's the block is cast as one piece

 

[German Gr?ner]

There are standard pistons and new liners from MAHLE (Brazil made). The most quantity of 300TDI rebuids are done in this way. You have to rebore block and insert special made liners.

As this engine, with the Maxxion brand, was equipped in different cars here in South America such as Ford, Mercedes and Chevrolet, there are different pistons diameters as standard size for each model, but rebuild is normally made with inserted liners, i think in UK also.

Regards

 

[edwardbahaw]

Hi Guys

Just sending an update!

I had the block bored and the new liners pressed in.

The guy at the machine shop said he skimmed 3 thou from on top of the block.

Will this cause any problems such as the pistons hitting the valves?

Regards
Ed

 

[edwardbahaw]

Will skimming the block 3 thou from on top cause any problems such as the pistons hitting the valves?

Anyone?

 

[German Gr?ner]

Hi Edward
it is very important to warranty that the plain in the block is perfect, specially in the liner zones. You should rework the plain from head too.
You have different head gasket types from different row materials, and different height.
You must measure how much the piston goes out and, choose the greater value in order to select the proper gasket height:
Resalto 0,50 a 0,60 mm - choose the gasket with 1 identification hole
Resalto 0,61 a 0,70 mm - choose the gasket with 2 identification holes
Resalto de 0,71 a 0,80 mm - choose the gasket with 3 identification holes
Resalto de 0,81 a 0,90 mm - choose the gasket with no identification hole

The better gasket material, as original, is the metal sheet made. The other asbest type gaskets are better if You are in doubt from the surfaces, and will last less wear...

You will find all this data and a lot more at 300TDI Overhaul Manual (RAVE)
Try here: http://rebornco.com/manuals/300TDi_overhaul_manual.pdf

Regards

 

[German Gr?ner]

Sorry, I didn?t knew about "thou"(Imperial system)
As each thou is 0,0254 mm, that the change will be less than 0,1mm, so may be you will use the same gasket size without problems.

Regards

 

[piper109]

The all metal gaskets are a bit tricky to find and on other forums have mixed reviews. There is some debate as to whether the tightening torque of the headbolts should be different from the composite gaskets.
If the machine shop has a lot of experience with Land Rover diesels (sounds like they do ) then you may want to get their advice also.

Where in the UK are you having the work done?

Steve

 

[piper109]

Whoops, I see now that you are on Trinidad and Tobago.
Your local options for parts may be limited.

Steve

 

[edwardbahaw]

Thanks so much for your input guys!
Yes Steve, the guys at this shop are accustomed to working on the 300 tdis.
The guy I spoke to said he has done this before as well (3 thou skimmed from the block)
I was checking to make sure he was not bullshitting me!
I also did some research as well.
The one hole head gasket is 1.37mm
The two hole head gasket is 1.48mm or 4 thousand of an inch thicker than the 1 hole
The three hole head gasket is 1.48mm or 9 thousand of an inch thicker than the 1 hole
Of course when the head bolts are torqued, this will compress it bit ... at least I think so!
I'm thinking that the 3 hole should be appropriate.
When the crankshaft and pistons are refitted I will see how far up the pistons come up on top of the block.
I will also check to see if the head gasket would provide sufficient space to avoid the pistons from hitting the cylinder head or valves.

 

[piper109]

Sounds good.
I see you post the same questions on the LRx4 forum. Those guys in the old country know the 300tdi Disco much better than many on discoweb which mostly has contributors from North America. Not many 300 tdis in use here. Just in a few Defenders and some privately imported Disco engines like mine.

If you do not yet have a Rave CD, I would strongly recommend you get one. There is a site where you can download it which escapes me at present. It contains all the info necessary to measure the deck to piston heights and gasket selection as well as everything else on the entire engine and vehicle.
Many seem to say that if in doubt use the 3 hole gasket which is a copout in my opinion.

Steve

 

[German Gr?ner]

Piper 109, is the link I posted http://rebornco.com/manuals/300TDi_overhaul_manual.pdf
possible to see for You?
Just curious because I find more LR docs in the web than in my rave CD.

Another forum with most 300TDI users is AULRO, there are many experts that can help You.

Regards

 

[piper109]

Yes I can bring up that link and I assumed it was just the part of the Rave manual pertinent to the engine. I have a CD and I have it on memory stick so I always have it with me.
I also subscribe to the AULRO forum.

Steve

 

[edwardbahaw]

Guys

I need some advice about this, AGAIN! :blink:

We're finally at the re-assembly stage and noticed that when we fit the new ring (top compression ring) about halfway down the bore, there is a clearance of about 15 to 20 thousandth of inch at the gap (where the two ends of the ring meet.

Can such a clearance be tolerated, or would it loose compression?

Regards
Ed

 

[mbrummal]

Here is what the rave says about the piston rings:

Piston rings
Type:
- Top ........................................................................ Barrel edge, chrome plated
- Second .................................................................. Taper faced
- Oil control .............................................................. Expander and rails
Gap in bore:
- Top ........................................................................ 0,40 - 0,60 mm
- Second .................................................................. 0,30 - 0,50 mm
- Oil control .............................................................. 0,3 - 0,6 mm
Clearance in piston grooves:
- Second .................................................................. 0,050 - 0,085 mm
- Oil control .............................................................. 0,050 - 0,085 mm


Since 0.015-0.020in. is about 0.381-0.508mm I would (based purely on those specs) say the 0.015in. gap is a little narrow and the 0.020in. gap is fine.



Edit: those figures were from the D1 Workshop manual. The 300 Tdi overhaul manual linked earlier in the thread has a different specification for the top ring:
Piston rings

Fitted gap in cylinder bore:
Top compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.40 to 0.65 mm
2nd compression . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.30 to 0.50 mm
Oil control rails . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.30 to 0.60 mm

It also says to:
"Position piston ring gaps at 60 °to each other
and away from thrust side of piston (left hand
side of piston when viewed from front)."

 

[edwardbahaw]

Hi Guys

Any idea on how snug the piston should fit in the piston bores (without the rings fitted)?

Just doing some anecdotal checks before we complete the re-assembly!

I noted this with mines and noticed that the pistons are able to shake a small bit while in there. Hope this is normal!

Regards
Ed

 

[MC22958]

Ed,
There are several good articles in the UK forums on how to estimate the thickness needed for the head gasket. Once you have the pistons in you can measure how much the piston protrudes from the block. This will be how you gauge what thickness you use. If a block had been skimmed more than the zero hole gasket will tolerate you can get a metal shim to use to increase the thickness. They can be found in the UK but are very expensive.