For the love of a tractor engine: The life and times of the 18R-G

[o_man_ra23]

Dave, that will have a slight effect, but I think it is more a case of you have not yet bedded the rings in. Check cam timing, shim levels, and check the compression after 1000kms of bedding in.

[floppy]

Yeah I've done about 700k's on it now.

Organising shims now to give me the clearances to keep it within the min specs.

So will do another compression test after its all back together.

First time was only after about 200k's

Dave

[o_man_ra23]

Yeah, 200ks will show a low compression.

[swan86]

With reference to the statement below,

I checked some of mine out, 3 x 88250 and 3 x 88270. I have 1 x 88253, but it has been used as a door stop for a few years (seriously), i doubt it is servicable.

I am trying to bring the RA35 GT back to factory specs, i am told it should have a 88253 head.

I know it's a stupid question, but does anyone out there know how common the 88253 head is? Will i have difficulty in finding one?
Even better, what are the chances of finding a whole engine with factory emissions, carb and air box? lol

The 18R-GU, number 8825*

These are the most commonly found today, and from all accounts were produced in the most numbers back in their day. Again using Solex carbies, the biggest change moving into this phase of the 18RG was the addition of emission controls (EGR etc), shorter cam duration and lower compression pistons (down to 8.7:1). Of course this brought the rated power down to around 120hp.
There were improvements with this new generation of 18RGs though - the head received a little bit of a working over, receiving larger porting, better casting design and larger valves (now 45mm intake and 38.5mm exhaust).
The very last of the 18R-GUs was the 88253. Virtually the same as previous 18R-GU's except that the head was yet again updated with dual valve springs, larger ports again, better casting, larger exhaust studs, and other little improvements.

[Steve M]

I seen quite a few 88253 heads, my spare one has almost no corrosion at all, and I don't think it's been resurfaced either. It was one of the best condition heads I've seen.

[Sagluren]

ive got one, ripping it of the engine, tommorow.

[hosking1991]

i have 2 253 heads

[swan86]

Good, i didn't think they were overly rare, just figured it strange that i hadn't come across one before (aside from the door stop).
Now i just have to consider emissions, air box etc... I figure there is no point swapping engines until i can get all the parts i need to do it properly.

[Omegaman]

Just while your all on the subject of 253 heads.
I took my 253 head off today, dueto no. 3 cyl not holding compression. Changed it back to a 270 head.
Since I was there a took a pic of both andnoticed the casting differences you all speak off.
The 253 has a full casting under the front guide, where the 270 has this area open. Also the obvious thick castings that are circled in the pics
This is a F.Y.I edition.

[EldarO]

ive got a set of 8.7 pistons sitting in a block round the side of my house.

im about to dump the block in the bin, i was wondering whether its worth keeping any of the parts?

sump/oil pump/crank/rods/pistons?! or even the block!?

[timbosaurus]

Eldar... grab the oil pump.

It's the only thing really worth keeping unless u've got the space.

The crank and sump are common with the 18R, and aren't worth keeping. The rods and 8.7 pistons are nothing to write home about, but someone may find a use for them... especially if they are 20 thou over.

Block is the same as the 18R too... so i'd dump it.

Cheers,
Timbo

[roadkill]

Hi Eldaro,

I'd be keen on getting those pistons from ya if the'yre not furked.

Lemme know,

bEn

[Omegaman]

I would probably keep the dizzy shaft and the bits that can be use to tranform a 18r into an rg. there seems to be interest in this build. Best way to keep the same block in cars, just rebuild them.

[Steve M]

I would be keeping the rods, oil pump, dummy shaft and block off plates.
The pre-88270 rods have square shapes cast into them half way down and are different; they have chunkier small ends.

Also take note that if the dipstick is on the correct side, that's one less thing to deal with compared to a converted 18R block. I'd probably keep the whole thing and rebuild it.

[o_man_ra23]

Easy to move the dipstick, all blocks have castings to allow both.

Keep the aux shaft, timing cover, dizzy, oil pump drive, oil pump, swinging chain slipper, dizzy drive sprocket. As mentioned check the rods. If the block is still good, then try and sell it whole even if cheap, the more of these motors still around, the more companies are going to make rebuild parts for them, and the better that will be for all of us.