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

[2004lowlux]

[QUOTE

As for the dowels, you can get away short term with lobbing the end off an appropriate diameter stainless bolt. Have done that to get an engine going after dropping the dowel in the sump (have you pulled the sump off to see if it is in there??) or you could get the diameter and length of one (can measure mine tomorrow if needed) and get a machine shop to chop a few bits of stainless bar off for you, then use a file to round the edges. Should be able to get that for a six pack.[/QUOTE]

pulled the sump off and nothing, no dowel to be found
its ok i sorted it out using a pin i had floating around from an old ford laser caliper had to sand it down to fit then cut it to size did all that with a drill, hacksaw and a peice of 80 grip sand paper.. all good!

[o_man_ra23]

Willo, I was also going to suggest the bypass valve located in the filter housing. If it is sticky, it could stay open after you rev up, which would explain the bad drop in pressure, it can also stick closed, which would explain the spike to 100psi.

[2004lowlux]

unbeliveable even with the 18rg head on the 18rc im still getting about 60-80 psi compression and i know that motor was giving at least 160 psi i tested it before i went and pulled it appart! it couldnt drop that much just from changing the head i think the valves are stuffed maybe? ill pull it back off when i get a chance cant do alot right now as i can only see out of one eye!

[o_man_ra23]

18R-C Pistons? The 18R-C pistons are not domed like the 18R-G units, and your compression will be a lot lower. I have had 120psi compression from a healthy 18R-GUE before with 8.3:1 compression. 18R-C pistons with an 18R-G head would net around 7 to 7.5:1 compression. The 18R-C has a closed chamber head, where the 18R-G is a hemispherical chamber head.

[masterofsinanju]

Willo, I was also going to suggest the bypass valve located in the filter housing. If it is sticky, it could stay open after you rev up, which would explain the bad drop in pressure, it can also stick closed, which would explain the spike to 100psi.

Could this possibly lead to the filter housing blowing off the block? (happened to my old car and caused a rebuild)

[Javal]

unbeliveable even with the 18rg head on the 18rc im still getting about 60-80 psi compression and i know that motor was giving at least 160 psi i tested it before i went and pulled it appart! it couldnt drop that much just from changing the head i think the valves are stuffed maybe? ill pull it back off when i get a chance cant do alot right now as i can only see out of one eye!

Dude, as O-man said, because you used the 18R-C pistons, which are flat top and the 18R-G head, which needs domed pistons to get the comp ratio up, there's no real wonder why your compression ratio is in the shitter.

[2004lowlux]

you think? i knew it would be low but not THAT low. fuck it this motor is just a savage headache, as soon as my crane gets back its comming out
i mean if somebody can flog a motor off without dowels in the cam gears and putting in a timing gear like the one below in no telling just how fucked this motor is and quite frankly if the person who sold this to mad79r initially is reading this YOU SIR SHOULD BE FUCKING ASHAMED OF YOURSELF YOU DODGEY PRICK!

[o_man_ra23]

If the filter housing bolts are unable to take the pressure that is created when the relief valve is jammed, then yeah. At 100psi, the bolts should hold together, however may stretch to the point of gasket failure. If the bolts are weakened through improper installation (overtightening) then they may shear from the force, but this is unlikely.

If the filter housing literally fell off, then I would say there was an underlying problem with the housing bolts.

2004Lowlux, that's pretty nasty, I feel your pain champ.

Due to the cam overlap, the dynamic compression of the 18R-G should be LOWER than that of an 18R-C, even when the 18R-G has higher compression pistons. However, with dropping the compression by a large amount, it will really send the dynamic compression up the shitter.

To get a bit of dynamic compression back, you can retard your intake cam and advance the exhaust. This will make the engine torquier down low at the expense of top end performance, however with such low compression pistons, you won't get much go out of it anyway.

[river]

Hi,

You got it from MAD79R..... then this is Immsy's old engine?

seeyuzz
river

[2004lowlux]

Hi,

You got it from MAD79R..... then this is Immsy's old engine?

maybe somebody could ask him where the rest of that timing gear and dowel is lol! maybe teh piston rings?
youll have to excuse my rant ive had the flu for nearly 2 weeks and im off work because of a lacerated cornea (yes its as painful as it sounds) basically having this happen is just very inconveinient given how much time and money have been wasted on this so ill throw it back together and put the rc back in put the rg on the backburner. was hoping it would make yotafest with the rg but its not possible without bringing it on a tilt tray.

[3jcelica]

Willo,

The oil pressure sounds similar to a problem I had. I.e stuck pressure relief piston, the piston housing in my 3tgte made of alloy with a hardened steel piston, after years of in and out action the alloy wears and the piston kicks off its axis sticking, only solution was a new housing that fixed it perfectly.

Either that or you have bigger problems

Roger

[egamirrorim]

Just found a part number on some old paperwork if anyone is interested.
K&N air filter to fit the carbs on 18RG (they're listed to fit a 2TG as well) is 56-9104
FYI, I bought this from DotComParts in the US who are very reasonably priced, for 2 filters with postage it was less than $140AUD, I was quoted more than that for one filter by local suppliers!

[river]

Hi,

Nice find, but I prefer a CAI set-up. No good sucking in all that hot air from inside the engine bay.

seeyuzz
river

[egamirrorim]

Nice find, but I prefer a CAI set-up. No good sucking in all that hot air from inside the engine bay.

True, but you could spend a looooong time looking for an original air box for one of these, I've not seen one advertised anywhere since I've owned the car and I've been looking...

[o_man_ra23]

Manufacturing one yourself not an option?