18rg Problems

[hoges]

Hello everyone. i have an ongoing problem with an 18rg engine and any help would be greatly appreciated. i perchased the engine two years ago in a 1980 ra40 celica. Its bearings were gone and it had been sitting for a while, so i decided to get the bottom end restored. (I didnt bother with the head as it had been reconditioned less than eight months beforehand).

so i had the block resleaved, new rings, crank reground, new bearings, flywheel ground, new clutch, and the whole lot balanced. I kept the original pistons because they were high compression, hard to replace, and also seemed ok.

since the reco job i have added 2 inch extractors and a 2 1/4 inch exhaust, had the distributor recurved, and taken the car to three different workshops to get it tuned (all of which told me they had experience with this engine). despite all this the engine seems to me to a very lame and overly loud performer. it will rev to 7500 rpm happilly, but the power it makes accelerates the celica slower than our company hyundai accents.

Is this to be expected or is my engine grossly underperforming? i would expect more from an engine which is reputedly good for 140 hp in stock form. this kind of power should give my car similar accelleration to that of a v6 holden commodore. can anyone help? does anyone know of a firm in brisbane (australia) with real experience in these old twin cam engines? any help would be greatly appreciated.

ps. carbs are mikuni solex 40mm with ramflo filters. fuel pump is standard mechanical unit which seems to be up to the task.

[harvey]

Were your timing chains replaced at the rebuild?as worn chains can cause the cam timing to be incorrect resulting in flat performance,is your cam profiles standard?and if so the remapped dizzy might be a problem.The mikkuni solex's are only good for paperweights once they get old,delortto's or webber's are a better carb,but get the basics establised on your engine first ie cam timing,ignition set up correctly then troubleshoot from there

cheers Harvey.

[hoges]

aaah yes! good point Harvey. timing chains were replaced but not chain guides, which would mean the cam timing is perhaps a little retarded. I understand this increases low end torque at the expence of high end power, and could possibly account for the engine's loudness too. Could a little wear in the timing guides have this effect?

My cams are stock items. I believe everything in this motor is stock except for the dizzy, which is a remapped 18ru transplant.

thanks for the pointers,

Hoges

[MyV6Flys]

Old or leaking carbs will cause all kinds of power loss. Does it seem to take longer to start now also??

Thinking air is leaking through the old gaskets in the carb, making the setting (air fuel mixture screws) out of adjustment, so it runs ruffer and starts harder.

How is the cat (cathletic converter) not sure of spelling. When they clog up they cause extra back pressure making more noise and less power.

Good luck.

[Scot]

Whats the timing like? dose it sound like your leaking air? have you done a compression test on all cylinders? When was the last time u changed the fuel filter? Have you done all the basic things?

[hoges]

Timing: runs best at 9.5 btdc with vacuum advance disconnected. any more advance and it tends to lose power and sound rough over about 4000 rpm. I would say the guys who did the dizzy work did not do a real good job. compressionwise all cylinders are at around 160 psi. When the engine ws reconditioned we has trouble sourcing the right pistons, so we used the old ones which were apparently ok.

I guess my question is not so much what is wrong with the engine- it could be any number of things. my question is, is it an engine worth fixing? is it worth spending a deal of money on? The feedback i have had so far from mechanics etc is mostly that the 18rg was always a horrible engine and that mine is actually running quite well. I would like to believe that they are wrong.

Thanks to everyone who has tried to help me with this with this.

cheers

[Steve M]

Sorry, forgot to look at the date! :(

Does it work now?

[3tg]

i have a spare complete 18rg running very sweet