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

[JustenGT8]

What's wrong with the higher comp? even turbo i know an 18RG will still handle boost just fine up to 11.5:1 (Jag pistons). We`ran 6psi but ran out of injector to try any more boost....on E85 it would take 12-15psi i reckon and just add WI for further insurance.....even on 6psi it was a torque monster

[jabbatron]

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[bholmberg]

hi - does anyone know why the 18rg inlet manifold gasket only has 2 water jacket openings when the head has 3? - should I go ahead and cut the third hole? more detail: between 1 and 2 there is a hole, between 3 and 4 there is a hole, but between 2 and 3 there is a hole in the head, but not in the gasket.

[Sagluren]

leave the gasket as is... it is used to block of the water gallery afik...


cheers

[RAd28]

hi - does anyone know why the 18rg inlet manifold gasket only has 2 water jacket openings when the head has 3? - should I go ahead and cut the third hole? more detail: between 1 and 2 there is a hole, between 3 and 4 there is a hole, but between 2 and 3 there is a hole in the head, but not in the gasket.

Does the manifold have a hole between 2 and 3?

Another question, Does anyone know where I can get some ARP head studs (if they're available at all) for the RG?

[jabbatron]

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[Steve M]

None of the 18RG manifolds have water galleries in their middle, only on the front/back.

The gasket does a good job of protecting your manifold from corrosion and protecting against leaks, so I'm with Sagluren and recommend not cutting the hole for the centre head water port.

[o_man_ra23]

Jabbatron - I don't know what you have been smoking, but if you are planning on boosting your engine, then cut down cast pistons won't cut it, and when you have succeeded in putting the ringlands into your sump, you will refer back to this (and my experience).

AU$750 landed was all that was required to get my 92mm forged Arias 8.5:1 compression pistons from Paradise Racing in the states at the start of the year. This included a full set of rings (chromed top ring) and heavy duty piston pins. It also uses higher quality piston pin retainers than the PITA factory items.

Cometic 92mm HG is advertised as US$86 plus freight.

If you are interested in the contact details for the pistons, please send me a PM, and I will give you full contact details. You won't need to supply any more details than the job number used for my pistons.

[bholmberg]

Thanks guys.
The reason for my question is that I had some trouble with the gasket leaking at the centre water gallery.

While my gasket has the holes for the outer 2 of the 3 galleries on the head, my manifold doesn't have any correlating holes. Each of the galleries just hits a dead end as soon as the water hits the manifold.

I tried a new gasket, with a smear of grease, and it still didn't seal(I did not end up cutting the third hole on saglurens advise). Today i spoke to my local mechanic and have ended up using a silicone gasket (the stuff that comes in a tube) - it will be equivalent to having 3 holes rather than 2, but i'm guessing the only way to avoid that is to get the manifold machined flatter so the gasket can seal...

if anyone thinks it is going to cause problems; do let me know, and i'll have to rethink this leak, but i'm guessing/hoping it will be fine. Otherwise, I will be starting the engine mid tomorrow when the silicone gasket cures, with high hopes this annoying leak is gone!

[Unda Presha]

Why dont you just buy standard cast pistons? I run standard pistons in my drag car for two years with 38psi of boost at 8100rpm until a valve touched a piston and it cracked. I believe you can still buy them off the shelf from Toyota. I brought a set as early as Dec 09 for a couple hundred dollars.

I understand the cometic head gaskets from Paradise are not the better cometic head gaskets. Could be wrong but send them an email and will know. Option instead of a cometic head gasket you could consider a sealing ring and get the head gasket made in Brisbane as I tried all over USA and Aus for a good head gasket. I use to use a standard head gasket with copper coat and never blew a head gasket and had to rip the gasket apart to get the head off.

I will try and find out for you which Ford Escort the head studs come out of. You dont need to do any modification to the head to fit them.

In regards to harmonic balancers, consider the 18R dont really have a harmonic balancer more like a pulley on the crank, if your interested in a ATI balancer I can put you in touch with one. They are not cheap as I have had a CNC program written to have one fitted to my new stroker motor. The only problem is you will need to bolt on a pulley at the front bringing your alternator forward plus you cant use your mechanical water pump.

[jabbatron]

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[checksix]

New Member here. Call sign Checksix. I'm from California just east of the Bay area (San Francisco) in Vacaville. I'm obviously interested in the 18RG, but being truthful, I'm not exactly positive just what the heck I have. I do know it runs really sweet, but feel I'm missing a few ponies. A few things I do know is the head is an 88210. I have a TON of questions, but figure the best route is to baseline the engine so I know exactly what I have. The engine is in a 1959 Austin Healey MK I (Bugeye / Frogeye ) Sprite. I bought the engine in 1981 from a local wrecker. I was told it was an 18RG. In looking later at the receipt, it says an 18RGU. When I got it, it was stripped of any environmental controls (if there ever was any). I totally rebuilt it (1981), and now regret not keeping better records. The few things I do remember was I replaced the pistons. Not really sure what was used, but they are flat heads. I no longer have a clue what came out, but would think they were the same. So most likely I have a low compression engine. The cams were replaced at the recommendation of my builder with Crane Cams. 288 seems to be a number I remember, but this seems pretty mild. So 1st question: How can I determine what's in there?

My next question is regarding the distributor (dizzy in your world). I'm trying to sort out the vacuum advance. For all these years I've run it disconnected. I had read somewhere that the hose routing was off the carb ports to the thermal sensing valve in the back of the thermostat housing, then to the dizzy. Advance was applied when the engine was cold, and shut off when warmed up via this thermal sensor in the water outlet housing. Is this correct? I've run disconnected, attached directly to the carb port, and directly to the intake manifold port, and it runs pretty good no matter what! Reason it's been disconnected, is that the thermal valve is frozen in the no vacuum position. I've recently found a housing off a 1981 Cressida. Found a thermal valve (open when cold) off an 86 Honda Accord, and the radiator hose off a 93 V6 Camaro (keep in mind the hose is for my set up and is a 90 turn then straight for around 19 inches). This set up gives me a much nicer cold idle, then shuts off. In reading some of the posting of the forum members, it seems I should be running vacuum all the time, but there seems to be disagreement if I should use the carb vacuum ports, or the intake manifold ports.

Thanks in advance to all those that read and perhaps provide advice! I’ll post more questions, but this post is LOOOOONG enough!

Checksix

[o_man_ra23]

Without taking the head off, you would have to look VERY carefully to be able to determine what pistons you have. If they are flat tops, then they are likely 18R-C items, and would give about 7.5:1 compression. 88210 headed engines (18R-G... no U on the end) originally came with 9.7:1 compression pistons, so quite a dramatic drop.

288 is usually a good set of cams for a little bit of top end increase. Not too wild for the street, but certainly a bit hotter than stock. After 19 years, it is probably due for a new set of valve springs. I know that Precision Springs do some, and I think Crow also do. In fact, you are probably due for a set of new pistons and rings in a bit of an oversize (19 years is quite a while for one set of rings in a performance engine).

Can't comment much on the vacuum... I locked my dizzy and am controlling it with the ECU (EFI), but am going one step further and going to use a crank angle sensor too.

Cams should have a number engraved on the end from what I have read. Google search of that number should tell you what profile they are.

Keep us informed of what you find out.

[checksix]

O-Man, thnak you for the comments. While the car has seen a lot of years, not that many miles (only 50K miles). I've been thinking of new pistons, any members with recommendations to get back to the mid to high 9's in compression? From other posts, I understand they can be difficult to find. I'm not planning on any fire breathing set up, but would like to upgrade the pistons, and port and polish the head. When I raced MG's back in the 70's we had a template to grind out the ports. For these heads it seems you need to know someone who is knowledgeable in the process. Any recommendations for someone to do a good head job? (in the states would probably be best, but I am open). What about bumping up valve size while doing this. Any ideas on cost?
1) Port Polish
2) Bigger Valves
3) Harden valve seats (have this now with the stock size)
4) New springs
5) New shims to adjust

[o_man_ra23]

1 - can't help sorry
2 - 88270 had bigger valves from factory. Failing that, do a google search, as they are available. Maybe try www.toyheadauto.com as Rick tends to have a lot of gear for these engines.
3 - 18R-G's came factory with hardened valve seats due to Japan's involvement in the move to unleaded fuels. A new set of valve guides would also be a good thing.
4 - already mentioned what I know - though Toyhead may have something also.
5 - unsure about state side, but here in Aus, Precision Shims do 18R-G shims in 0.05mm (about 2 thou) increments.

For pistons, Arias forged pistons can be made to many different oversizes, with your choice of compression. I would suggest somewhere around 10:1 or 10.5:1 and run it on really high octane fuel. That would sound really horny with your cams. Paradise Racing in the US was the cheapest I could find for the Arias pistons (US$550 from memory). If you go the 92mm overbore, a Cometic head gasket is available at US$86, check the Cometic website.