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Thinking something is funny about my engine...


CommanderToasty

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I bought my R1 with a newly rebuilt engine, and it runs darn fine. But I am suspicious the shop didn't rebuild it as an Avanti engine, or they actually installed a non-Avanti 289.

It burns regular with no trouble. It has way less power than my last Avanti R1. It has a single points distributor.

Is there a way to ID the engine? Maybe it's some Lark or base engine. Or, if it is the original Avanti engine maybe they rebuilt it to base specs.

Thoughts?

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If it burns regular with no trouble on a hot day, chances are it's not an R1. Will it idle down to 500 RPMs easily and steadily?

Easiest place to start is pull a front spark plug and look at the piston top. An R1 piston will have a flat top and the standard piston is dished.

The R1 cam and springs will rev to 5,000 easily and 5,500 most times. A standard cam and springs floats the valves about 4,500 RPMs and power falls off a cliff.

Run the cold cranking compression. An R1 should blow at least 185#.

jack vines

Edited by PackardV8
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There should be stampings on a machined pad on the drivers side front of the engine. If it's a genuine Avanti engine, the number should begin with R- or RS- plus the engine number. If it's an Avanti engine originally installed in a Hawk or Lark, the engine number should start with (I think) an JT- or JTS-. Someone please correct me if I'm wrong on that. If the engine number begins with anything else (other than a "B"), it's not an R-engine. It wouldn't be unheard of to find a 259 installed by someone in place of a 289.

All that assumes the markings haven't been remarked by someone, which does happen.

Even if it's a genuine Avanti engine, that doesn't mean it wasn't rebuilt to non-"R" standards...no matter how smoothly it runs. An original engine would have a dual point distributor, so at minimum that's been swapped.

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Apart from the engine ID tags and markings why not talk to the rebuilder and and get a detailed list of new and rebuilt components. I recently had the original 289 R2 rebuilt, eye balled the work, and was pleased with the result.

Having recently bought your R1 what recourse to you have if not as you expected? During 'break in' the engine may seem a little slow.

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Optimize the timing. On a Stude V-8 just like a SBC the service manual idle degrees of advance may not be the optimum advance for YOUR engine (especially after rebuild). 90% of the time on my buddies' cars in 20 minutes using only a digital timing light, I can get them 20 hp and 40 Ft# of torque on a small block V-8.

The factory timing is chosen to function over all cars coming down the the assembly line, so nearly all drivers are satisfied. However, there is an OPTIMUM advance timing for YOUR engine. 95% of carb problems are simple timing adjustments.

Use a digital timing light that has RPM and DEGREE advance read out. Unhook your vacuum advance and plug the line (golf tee is great). Check the non-vacuum advance at 1000 rpm, 1500, 2000, 2400, 2800, 3000 (record this curve). The total non-vacuum advance (centrifugal mechanical) should be all in at 2500-3000 which is the operating rpm's of the engine while driving

The R1 manual says timing should be set 4 degree@ 650 rpm; however, your engine may perform better at 6 , 8, 10 degree initial advance. Do not worry about the idle degree of advance. Adjust the distributor so the you achieve max mechanical advance (30+ ???) at your driving RPM's 2500-3000.

Note the initial 6, 8, 10 ? degrees. reconnect the vacuum advance and drive it. If you get a little detonation (ping, knock, rattle), back off timing 1 degree at a time untill it stops, if no detonation add 1 degree at a time until you get a liitle detonation (then back-off 1-2 degrees.

You will notice much improved throttle response and more torque at acceleration.

Second thing, I shame my buddies by testing for "carpet" horse power. 90% do not have their throttle linkage adjust properly. Put the throttle to the floor and have some one hold it down. Check the throttle linkage at the carb and see if the throttle plates a full open... probably only 3/4 open. Simply adjust the linkage or bend the linkage under the gas peddle to be sure the carpet is not blocking full travel.

People add carpet, insulation, etc. and block the throttle travel.

Also, with max advance the engine will run cooler

Cheapest horsepower and torque you can find...free

Joe

Edited by Devildog
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