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

[Panda]

Hmm, thats what i thought. So not knowing the manufacturer or who did the work, im pretty much screwed then?

[RA35GT]

Not necassarily.

Are they any part numbers on the cam itself that you can try googling?

[Willofan]

Hey, I asked this question a little while back and the best advice I got was - buy a timing wheel and a dial guage. I worked out from there its basically all white mans magic and rocket science added together when setting up big cams.

The factory settings are great for std cams using the notch on the top of the shaft etc. However, when you go up to longer duration/high lift cams you will need to know how it has been set up. Using the std specs on performance cams will decrease engine power/vacumm etc.

Cams like the 288 degrees are set up with the dial guage on top of the valve bucket, if you know true tdc (the ign timing TDC mark is not always accurate) turn the crank to 288 dgrs and measure the amount of lift when the cam starts to lift the valve. You will need to know the specs to set it at depending on who has set the cams up.

Also important to know the valve clearance between the piston crown recess and valve as any error in timing will bend a valve and damage the piston.

Google "18RG camshaft timing" and all sorts of info comes back. Also google timing wheel and samples you can download, print off and make are there too. Working out how to interperate it all is where the rocket science degree comes in handy.

[Panda]

Hmm, thank willo. Were checking if they are out of time now. Seems like a good idea to do that before we take them off anyway to check the tappits.

Checked the part numbers and all i found out was that it was made by Nippon Piston Rings, couldn't get a part detail on them.

Thanks for the help! hopeing well get there soon....

[Steve M]

Yeah, cams are one of those things that you really need to know the manufacturer's specs to have great success with.

Some companies (e.g. Wade) stamp their grind number into the face of teh camshaft where the timing gear is mounted to it.

The other option is to use a spare head, single inner valve spring, bucket and use a dial indicator and degree wheel to measure, recod and graph the lobe-lift measurements. From that graph (if you do enough points in the right area) you can make a guess at what the clearance should be and the timing should be.

I have a set up such graphs and measurements for all of the 18RG standard cams and some custom grinds in an Excel Spreadsheet. I find them very useful.

[Steve M]

For the record, the half moon plugs also came with the part number 11183-88210 but there are none left in Australia because I bought them all (There were only enough for my rebuild and my brother's rebuild).

I didn't try the 11183-88260 part number, so perhaps there are some of those around still.

[o_man_ra23]

If it was the 88260 part number that I bought, then there were 3 in Melbourne until I bought 2 of them...

[INSANE_PAINT]

i'm going to give this a bump since i notice a few people are asking about the 18rg... this is one of the definitive posts and would probably need it own section in the tech section, maybe some sub catergories, thanks to everyone who posted..

-Vic

[Javal]

Ok hombres, who does off the shelf con-rods for the 18R-G? I figure i might as well go the whole hog on the guts of it.

Alternatively, who's got the specs required to have some made?

[JustenGT8]

Ok hombres, who does off the shelf con-rods for the 18R-G? I figure i might as well go the whole hog on the guts of it.

Alternatively, who's got the specs required to have some made?

For what it's worth i have never seen a broken 18RG rod? On my turbo engine i jusy had the stock ones linished (destressed) and shot peened. Saw 8000rpm regularly and as much as 30psi on a few occasions too

Crank and rods are bullet proof i reckon

[o_man_ra23]

Justen - Under Presha racing might disagree with you there. Might not help that they were running 38psi on an almost completely stock engine with high RPM for several seasons in full blown drag racing They set the class record several times over on a virtually stock carby-turbo 18R-GT before blowing it though, so the conrods will be fairly strong with a 30psi 8krpm engine...

That said I will be getting my stock rods peened, polished and de-stressed.

[ra_28]

Ok hombres, who does off the shelf con-rods for the 18R-G? I figure i might as well go the whole hog on the guts of it.

Alternatively, who's got the specs required to have some made?

I agree spend the money on something better like head work or 12.5:1 92mm pistons or some 45mm ITB.

Cheers
Alex

[JustenGT8]

Justen - Under Presha racing might disagree with you there. Might not help that they were running 38psi on an almost completely stock engine with high RPM for several seasons in full blown drag racing They set the class record several times over on a virtually stock carby-turbo 18R-GT before blowing it though, so the conrods will be fairly strong with a 30psi 8krpm engine...

That said I will be getting my stock rods peened, polished and de-stressed.

He was pushing the boundaries alright

Even so, i think he broke a piston which led to the rod going out the block...he didn't break a rod per se?

[o_man_ra23]

Don't know exactly, but if the rod is outside the block, I can't see it being of much use afterwards

But you are right, that was indeed pushing the boundaries, and I would challenge any other NA engine's factory conrods (unprepped) to accept that kind of use for that period of time. For a street car, I can't see there being any issue with using prepped factory rods.

[Javal]

I agree spend the money on something better like head work or 12.5:1 92mm pistons or some 45mm ITB.

Cheers
Alex

Already have 92mm's and 4AG Blacktop ITB's

I just saw old man rivers' sparkly new rods and had a hole burning in my wallet for a moment there.

In light of this information i will have them properly prepared and be done with it. I just want to make sure it'll hang together my desired 8-8.5k rpm. ARP rod-bolts are a must obviously.

Now i get to spend the money on other treats