St rods and pistons in 7 rib small port 16v

[hachi-6 D0ri]

I'm sure this question has been addressed in the passed but I have not been able to find the information in the archives. So please would some mind explaining exactly what steps it would take in order for me to use silver top rods and pistons in my 7 rib small port 16v .

Thank you for your time.

[gotzoom?]

The number of ribs on the block don't have a direct correlation to the rotating parts inside the block. There are two crankshafts. The early largeport engines came with 40mm crankshafts. All other 4AGE engines came with 42mm crankshafts. If you have silvertop rods, you need to make sure you have a 42mm crankshaft. If you don't, you need to get one to use those rods.

[hachi-6 D0ri]

So if I pulled the crank and rods out of a St 20v block I can run that with no issue. Or if I have the 42mm crank "I'm pretty sure I do " and can run the rods and pistons without interface. I keep reading that when you run this set up it becomes interference .

[yoshimitsuspeed]

There is no benefit to running ST rods over 7 rib 16v rods but yes they are interchangeable.
Of course putting pistons designed for a 20v head will most likely become interference on a 16v head. More importantly the topography of the piston is not designed for the head. It will be far from optimal. You would be much better off using pistons designed for your head.
Just remember half ass your build, don't be surprised when you get half ass results.

[hachi-6 D0ri]

There is no benefit to running ST rods over 7 rib 16v rods but yes they are interchangeable.
Of course putting pistons designed for a 20v head will most likely become interference on a 16v head. More importantly the topography of the piston is not designed for the head. It will be far from optimal. You would be much better off using pistons designed for your head.
Just remember half ass your build, don't be surprised when you get half ass results.

I ended up getting the blacktop crank and con rods. They are stronger and light from what read. So hypothetically speaking wouldn't that be a better option. and isn't it possible to run the high comp pistons with the con rods that are meant to be run with the 16v head?

[yoshimitsuspeed]

There is no benefit to running ST rods over 7 rib 16v rods but yes they are interchangeable.
Of course putting pistons designed for a 20v head will most likely become interference on a 16v head. More importantly the topography of the piston is not designed for the head. It will be far from optimal. You would be much better off using pistons designed for your head.
Just remember half ass your build, don't be surprised when you get half ass results.

I ended up getting the blacktop crank and con rods. They are stronger and light from what read. So hypothetically speaking wouldn't that be a better option. and isn't it possible to run the high comp pistons with the con rods that are meant to be run with the 16v head?

Your post is a little too vague for me to really understand where you are going.
The Blacktop rods are lighter and a little weaker. If you aren't spinning over 8500 RPM it's a non issue. If you are spinning over 8500 then it would be better to run 16v or ST rods or aftermarket.
The difference in weight or strength between the ST rods and 42mm 16v rods is not enough to be of any concern.
About the pistons it's not about the compression it's about running a piston designed for the head. 20 valve pistons are designed to be used in the 20v head. It will be far from ideal to use them in any other motor.

[hachi-6 D0ri]

There is no benefit to running ST rods over 7 rib 16v rods but yes they are interchangeable.
Of course putting pistons designed for a 20v head will most likely become interference on a 16v head. More importantly the topography of the piston is not designed for the head. It will be far from optimal. You would be much better off using pistons designed for your head.
Just remember half ass your build, don't be surprised when you get half ass results.

I ended up getting the blacktop crank and con rods. They are stronger and light from what read. So hypothetically speaking wouldn't that be a better option. and isn't it possible to run the high comp pistons with the con rods that are meant to be run with the 16v head?

Your post is a little too vague for me to really understand where you are going.
The Blacktop rods are lighter and a little weaker. If you aren't spinning over 8500 RPM it's a non issue. If you are spinning over 8500 then it would be better to run 16v or ST rods or aftermarket.
The difference in weight or strength between the ST rods and 42mm 16v rods is not enough to be of any concern.
About the pistons it's not about the compression it's about running a piston designed for the head. 20 valve pistons are designed to be used in the 20v head. It will be far from ideal to use them in any other motor.

OK I understand the danger in not using the piston designed for my head. So the last question I have is what would be a more optimum choice. Using my red top con rods that are also 42mm , silver top con rods or the black top con rods? The 20v blacktop crank is lighter and stronger than the 42mm crank that came standard in my engine. My question is such rod is best to incorporate. This is a right up from hachiroku.com that sent me down this road. Check it out and let me know what you take from. And thank you for your insite I truly appreciate it.

http://www.hachiroku.com.au/2008/12/ae8 ... r-bang-na/

[oldeskewltoy]

I ended up getting the blacktop crank and con rods. They are stronger and light from what read. So hypothetically speaking wouldn't that be a better option. and isn't it possible to run the high comp pistons with the con rods that are meant to be run with the 16v head?

Your post is a little too vague for me to really understand where you are going.
The Blacktop rods are lighter and a little weaker. If you aren't spinning over 8500 RPM it's a non issue. If you are spinning over 8500 then it would be better to run 16v or ST rods or aftermarket.
The difference in weight or strength between the ST rods and 42mm 16v rods is not enough to be of any concern.
About the pistons it's not about the compression it's about running a piston designed for the head. 20 valve pistons are designed to be used in the 20v head. It will be far from ideal to use them in any other motor.

OK I understand the danger in not using the piston designed for my head. So the last question I have is what would be a more optimum choice. Using my red top con rods that are also 42mm , silver top con rods or the black top con rods? The 20v blacktop crank is lighter and stronger than the 42mm crank that came standard in my engine. My question is such rod is best to incorporate. This is a right up from hachiroku.com that sent me down this road. Check it out and let me know what you take from. And thank you for your insite I truly appreciate it.

http://www.hachiroku.com.au/2008/12/ae8 ... r-bang-na/

only 2 factory crankshafts... blacktop crank is same crank as was used from 1988 on.

from what I gleened... yes you can put high comp 16V pistons on to any rod that has 20mm small end.



As to rods... blacktop rods are the lightest 42/20 rod of all the 4AG engines. Redtop rods are the heaviest. Silvertop rods are either the same as redtop... OR in later production date cases, a bit lighter the the redtop rods. Rod in far left of photo is earlier 40/18 rod that fits the early (1983-1987) crankshaft

[hachi-6 D0ri]

[quote="hachi-6 D0ri"]

I ended up getting the blacktop crank and con rods. They are stronger and light from what read. So hypothetically speaking wouldn't that be a better option. and isn't it possible to run the high comp pistons with the con rods that are meant to be run with the 16v head?

Your post is a little too vague for me to really understand where you are going.
The Blacktop rods are lighter and a little weaker. If you aren't spinning over 8500 RPM it's a non issue. If you are spinning over 8500 then it would be better to run 16v or ST rods or aftermarket.
The difference in weight or strength between the ST rods and 42mm 16v rods is not enough to be of any concern.
About the pistons it's not about the compression it's about running a piston designed for the head. 20 valve pistons are designed to be used in the 20v head. It will be far from ideal to use them in any other motor.

OK I understand the danger in not using the piston designed for my head. So the last question I have is what would be a more optimum choice. Using my red top con rods that are also 42mm , silver top con rods or the black top con rods? The 20v blacktop crank is lighter and stronger than the 42mm crank that came standard in my engine. My question is such rod is best to incorporate. This is a right up from hachiroku.com that sent me down this road. Check it out and let me know what you take from. And thank you for your insite I truly appreciate it.

http://www.hachiroku.com.au/2008/12/ae8 ... r-bang-na/

only 2 factory crankshafts... blacktop crank is same crank as was used from 1988 on.

from what I gleened... yes you can put high comp 16V pistons on to any rod that has 20mm small end.



As to rods... blacktop rods are the lightest 42/20 rod of all the 4AG engines. Redtop rods are the heaviest. Silvertop rods are either the same as redtop... OR in later production date cases, a bit lighter the the redtop rods. Rod in far left of photo is earlier 40/18 rod that fits the early (1983-1987) crankshaft[/quote]
That is the understanding I had. Now does the blacktop rod have the strength and reliability to spin over 9,000 rpm. I ask this because I was under the impression that the silver top 20/42 rod was stronger and a better choice for hi rpm n/a engines. But the later model blacktop rod is a more advance alloy correct. Theoretically the metallurgy I would imagine Toyota used in the blacktop rod should be far advanced. Correct? I just want to know if I should get silvertop con rods or if it would be good to use the blacktop rods I have.

[gotzoom?]

You're not going to get any benefit from spinning to 9k without cams and valvetrain to support it. If you are serious about spinning the engine that high, you really should be making different decisions. At minimum, you will need to have the rotating parts balanced as a set. That will probably cost around $600 or more and you will need to take the stuff to a race shop that has the ability to balance to that high of RPM. Note: I said all of the rotating parts. That includes flywheel, pressure plate, harmonic balancer, etc.

[hachi-6 D0ri]

You're not going to get any benefit from spinning to 9k without cams and valvetrain to support it. If you are serious about spinning the engine that high, you really should be making different decisions. At minimum, you will need to have the rotating parts balanced as a set. That will probably cost around $600 or more and you will need to take the stuff to a race shop that has the ability to balance to that high of RPM. Note: I said all of the rotating parts. That includes flywheel, pressure plate, harmonic balancer, etc.

I already have an understanding of that. But thank you for the input. I'm wanting to know the difference in structural integrity between the silvertop con rods and blacktop con rods.

[yoshimitsuspeed]

OK I understand the danger in not using the piston designed for my head. So the last question I have is what would be a more optimum choice. Using my red top con rods that are also 42mm , silver top con rods or the black top con rods? The 20v blacktop crank is lighter and stronger than the 42mm crank that came standard in my engine. My question is such rod is best to incorporate. This is a right up from hachiroku.com that sent me down this road. Check it out and let me know what you take from. And thank you for your insite I truly appreciate it.

http://www.hachiroku.com.au/2008/12/ae8 ... r-bang-na/

That page has about as much misinformaiton and or poorly articulated information as it has good information.
For some reason very few AE86 owners seem to realize there was a gen 2 largeport and if they do they know almost nothing about it. That article doesn't even acknowledge it.

The Gen 1 largeport had the 18/40 rotating assembly. It is weaker and also has press fit wrist pins.
The Gen 2 largeport has the 20/42 rotating assembly. While the rods may be slightly different in design for all intents and purposes and as far as strength and reliability go these rods are just as strong as the smallport and the silvertop.
I believe gen 2 through gen 5 cranks were all the same. If not then again for all intents and purposes they are . They are just as strong and have just as good a reputation. Pick a crank from any year and it will do as good a job as any other in that range.

Personally i would throw everything you learned from that page out the window and start fresh.
I haven't done a page like that or like Bill Sherwoods modified page because I feel like any build beyond my 11:1 264 package I offer should be addressed on a case by case basis and every case is different.
What are your goals?
What is your budget?
What do you have already available?
As for the rods if you are staying under 8500 any gen will be fine but I would recommend the 20/42 rotating assembly. If you are maxing between 8500 and 9000 you will be safer sticking to gen 2 (largeport) to gen 4 (Silvertop).

Using top color on the 16 valves is 100% usless. Half the world thinks the gen 2 largeport is the red top. The other half believes the gen 3 smallport is the red top and the other half don't even know there is a gen 2 largeport so by default the smallport must be the red top. I have taken to using gen or defining features such as 7 rib largeport.

[yoshimitsuspeed]

You're not going to get any benefit from spinning to 9k without cams and valvetrain to support it. If you are serious about spinning the engine that high, you really should be making different decisions. At minimum, you will need to have the rotating parts balanced as a set. That will probably cost around $600 or more and you will need to take the stuff to a race shop that has the ability to balance to that high of RPM. Note: I said all of the rotating parts. That includes flywheel, pressure plate, harmonic balancer, etc.

I already have an understanding of that. But thank you for the input. I'm wanting to know the difference in structural integrity between the silvertop con rods and blacktop con rods.

I feel like we have gone over all this already.
The blacktop rods have been proven to spin to 8500 reliably. People who spin them over that for extended periods have noticed a slightly increased risk in rod damage and therefore have switched to gen 2 to gen 4 rods and seen a reduced likelihood of failure.

[hachi-6 D0ri]

OK I understand the danger in not using the piston designed for my head. So the last question I have is what would be a more optimum choice. Using my red top con rods that are also 42mm , silver top con rods or the black top con rods? The 20v blacktop crank is lighter and stronger than the 42mm crank that came standard in my engine. My question is such rod is best to incorporate. This is a right up from hachiroku.com that sent me down this road. Check it out and let me know what you take from. And thank you for your insite I truly appreciate it.

http://www.hachiroku.com.au/2008/12/ae8 ... r-bang-na/

That page has about as much misinformaiton and or poorly articulated information as it has good information.
For some reason very few AE86 owners seem to realize there was a gen 2 largeport and if they do they know almost nothing about it. That article doesn't even acknowledge it.

The Gen 1 largeport had the 18/40 rotating assembly. It is weaker and also has press fit wrist pins.
The Gen 2 largeport has the 20/42 rotating assembly. While the rods may be slightly different in design for all intents and purposes and as far as strength and reliability go these rods are just as strong as the smallport and the silvertop.
I believe gen 2 through gen 5 cranks were all the same. If not then again for all intents and purposes they are . They are just as strong and have just as good a reputation. Pick a crank from any year and it will do as good a job as any other in that range.

Personally i would throw everything you learned from that page out the window and start fresh.
I haven't done a page like that or like Bill Sherwoods modified page because I feel like any build beyond my 11:1 264 package I offer should be addressed on a case by case basis and every case is different.
What are your goals?
What is your budget?
What do you have already available?
As for the rods if you are staying under 8500 any gen will be fine but I would recommend the 20/42 rotating assembly. If you are maxing between 8500 and 9000 you will be safer sticking to gen 2 (largeport) to gen 4 (Silvertop).

Using top color on the 16 valves is 100% usless. Half the world thinks the gen 2 largeport is the red top. The other half believes the gen 3 smallport is the red top and the other half don't even know there is a gen 2 largeport so by default the smallport must be the red top. I have taken to using gen or defining features such as 7 rib largeport.

Here is what I have and here is my plan. I have a 7 rib small port with oil squirters in the block. The internals I have now is the 20/42 crank and blacktop con rods. My goal is to build the bottom end to be able to handle rpms above 8500. I understand the work that needs to be put into the head. That is not the issue. The issue is and I ask again. Can I use the blacktop con rods or should I spend the money on the silvertop con rods. That's the only thing I need to know. So can some on please just answer the question. As far as structural integrity and being able to handle the rpms. Silver top or can I use my blacktop con rods.

[hachi-6 D0ri]

You're not going to get any benefit from spinning to 9k without cams and valvetrain to support it. If you are serious about spinning the engine that high, you really should be making different decisions. At minimum, you will need to have the rotating parts balanced as a set. That will probably cost around $600 or more and you will need to take the stuff to a race shop that has the ability to balance to that high of RPM. Note: I said all of the rotating parts. That includes flywheel, pressure plate, harmonic balancer, etc.

I already have an understanding of that. But thank you for the input. I'm wanting to know the difference in structural integrity between the silvertop con rods and blacktop con rods.

I feel like we have gone over all this already.
The blacktop rods have been proven to spin to 8500 reliably. People who spin them over that for extended periods have noticed a slightly increased risk in rod damage and therefore have switched to gen 2 to gen 4 rods and seen a reduced likelihood of failure.

OK silvertop it is. Thank you gentleman. It has been fun

[yoshimitsuspeed]

Here is what I have and here is my plan. I have a 7 rib small port with oil squirters in the block. The internals I have now is the 20/42 crank and blacktop con rods. My goal is to build the bottom end to be able to handle rpms above 8500. I understand the work that needs to be put into the head. That is not the issue. The issue is and I ask again. Can I use the blacktop con rods or should I spend the money on the silvertop con rods. That's the only thing I need to know. So can some on please just answer the question. As far as structural integrity and being able to handle the rpms. Silver top or can I use my blacktop con rods.

Why would you spend money on silvertop rods? You don't have rods that came with the smallport?
I wouldn't trust buying used rods without getting them carefully inspected. Even then it's a bit of a gamble on a component I wouldn't want to gamble on when you can get good rods for just a little more than new OEM.
http://www.matrixgarage.com/products/cr ... tsman-rods
They will take more than the stock rods will but for over 9000 RPM I would still step up to either BC 625 or the Tomei rods.
http://www.matrixgarage.com/products/cr ... cting-rods
http://www.matrixgarage.com/products/to ... cting-rods
You say you know everything else you need to know for your build but this topic of rods is a fairly elementary part of the build.

[hachi-6 D0ri]

Here is what I have and here is my plan. I have a 7 rib small port with oil squirters in the block. The internals I have now is the 20/42 crank and blacktop con rods. My goal is to build the bottom end to be able to handle rpms above 8500. I understand the work that needs to be put into the head. That is not the issue. The issue is and I ask again. Can I use the blacktop con rods or should I spend the money on the silvertop con rods. That's the only thing I need to know. So can some on please just answer the question. As far as structural integrity and being able to handle the rpms. Silver top or can I use my blacktop con rods.

Why would you spend money on silvertop rods? You don't have rods that came with the smallport?
I wouldn't trust buying used rods without getting them carefully inspected. Even then it's a bit of a gamble on a component I wouldn't want to gamble on when you can get good rods for just a little more than new OEM.
http://www.matrixgarage.com/products/cr ... tsman-rods
They will take more than the stock rods will but for over 9000 RPM I would still step up to either BC 625 or the Tomei rods.
http://www.matrixgarage.com/products/cr ... cting-rods
http://www.matrixgarage.com/products/to ... cting-rods
You say you know everything else you need to know for your build but this topic of rods is a fairly elementary part of the build.

I'm working with what I have . And with in my means.