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

[river]

Hi,

Go search for Solex csrbs in the tech section on these forums and you should find a tuning guide. It sounds as though the second set (closest to the firewall) of carbs needs some tuning.

seeyuzz
river

[TRD184]

^i have that very guide printed off and in a neat little "car info folder" actually, very handy. i also brought a solex CD-rom manual off ebay. i tuned them a few months ago using that guide, ( thought i did an ok job ) its been parked up for a while now though..
how often should/would one check the carburetor tune with these?

[o_man_ra23]

Regularly... unfortunately they aren't a set and forget unit.

[ian]

Ian,

I can think of a few reasons why this might happen.

1. Incorrect cam cap (either put in the wrong location or from a different head, as per O man's post). You should be able to feel if the caps don't align with the head. If you can feel any diffference between their surfaces where they meet, then it is the wrong cap. Measuring left to right diameter and top-bottom diameter could also reveal a problem.

2. Blockage within the camshaft oil supply gallery.
It could be in the oilfeed to the head / #1 camshaft journal, limiting flow to all journals on that cam.
It could be in the camshaft itsself. If a foreign body (eg. separated sealant bead) gets into the camshaft it doesn't come out unless you pull out the welsh plug from the end or back flush it from cylinder 4 cam oil hole through the inlet hole.

3. Camshaft is bent, causing more friction. Straighten or replace camshaft.

4. Cam or journal has a foreign inclusion/burr that is hooking the two together or causing a tighter clearance. Remove foreign inclusion or burr.

5. Head is warped, causing more friction on the journals through misalignment. Line bore may fix. Straighten head may fix.


The journal sizes are the same for all 18R-G engines. We've tried all cams from 88210 - 88270 and they've been fine in an 88270 head. 88210 cams had a little more clearance because they're older and been used more.

thanks for the replys
he found the problem
it was the washers that go on the end of the cam were blocking the oil feed hole or something similar
hopefully not to much damage done

[river]

Hi,

Good to hear the problem was found, and yeah... hope there's not too much damage.

As for the carbs... yes, they need to be tweaked. Maybe once per annum. It's not a hard job, and quite relaxing really and fun. Very pleasing to fiddle about and get the engine singing nicely.

seeyuzz
river

[o_man_ra23]

Ian,

I don't know about any washers that go on the end of the cams?? Other than the ones which are on the cam sprocket retaining bolt, however these are well away from any oil feed.

[JustenGT8]

Yeah that sounds very weird? the oil feed is on the journals so there's no way even a misplaced washer could effect it?

[SilverRA23]

He described it similar to me... washers were missing from the end of the cam.. which led to bolt screwing in that bit too far and blocking off an oil feed.

[o_man_ra23]

Hmm... never had troubles with my first RG, which was missing the washer in question from the end of the cams.

There is only one bolt which goes into an oil gallery that I know of, it is in the block and has a copper washer. Removal requires the head, sump and timing cover to be removed. But that bolt isn't able to block the gallery, it would only allow excessive leakage into the timing chain area.

A diagram would be a big help right about now.

[JustenGT8]

ah that could make sense? i would have thought the thread would have run out before it got to the oil journal but can't say i had ever checked. of more concern is that without that washer the cam lock pin can drop out and then things get really ugly

[o_man_ra23]

Justen, there are 2 washers. One is really thin and stops the pin from dropping out. The other is much thicker and holds the aformentioned washer at the pin face, preventing it from deforming against the end of the pin.

[egamirrorim]

My 18RGU is getting rebuilt at the moment, 10.2:1 pistons with 89.5mm bore and some good street cams are going in.
What was the standard bore size of the 18RGU?
What was the compression ratio of the original model 18RG?

[lilcrash]

88mm bore I think, I'm open to correction. And compression depends on what engine you have

[hosking1991]

pretty sure they are standard at 88.5mm and the earliest models 18rg 88210 compression was around 9.7:1

Luke

[o_man_ra23]

88210 and 88230 head (18R-G) were 9.7:1, 88250 and 88253 (18R-GU) were 9.3:1, and 88270 (18R-GUE) was 8.5:1.