kickingclutches

Hello everyone,

My name is Nicholas, I am from South Florida, and I am the owner of a 1985 Toyota Corolla GTS Coupe also known as an AE86.





I am running a 2003 S2000 F20C1 Engine and 6-Speed Manual Transmission. I have been running this setup for less than 6 months and developed a misfire under normal driving conditions.

The S2000 shop, I purchased the engine from and installed it for me, diagnosed it as compression loss from the cylinder head and quoted me $1200 plus parts to repair.

I decided to personally inspected the cylinder head, and noticed sunken valve keepers in multiple cylinders. Which is a usually sign of cracked valve retainers, a well known issue with AP1 engines. Under further inspection, I confirmed cracked retainers in multiple cylinders.

From my research I understand AP1 retainers do not crack simply because of constant 9000rpm or even bouncing off the rev limiter. AP1 retainers crack because of an over rev from a mis-shift situation due to user error, such as 9000rpm in 3rd gear and accidentally engaging 2nd gear instead of 4th gear for example.

I have personally never had a mis-shift situation. According to Billman cracked retainers can go up to 30,000 miles undetected and I have owned this motor for less than 5000 miles, which means I was sold a engine that already had valve retainer damage due to negligence from the previous owner.

Moving forward I purchased a resurfaced cylinder head with upgraded AP2 springs, retainers, and keepers. Also used Ferrea bronze valve guides, and valve seals. Along with replacing a couple valves.





When I removed my original cylinder head with damaged internals, I noticed scored cylinder walls in multiple cylinders.

From my research I understand scored cylinder walls are from poor Lubrication, Cooling, and also Detonation.

I have not abused this engine, and it has had severe oil consumption issues since day 1. Which means I was sold a engine that already had cylinder wall damage due to negligence from the previous owner.

The S2000 shop I purchased the engine from suggested it was normal, but I personally do not consider consuming multiple quarts between 3000 mile oil changes normal.

My previous 2001 S2000 did not burn any oil between 3000 mile oil changes.

Here is a picture of cylinder 2.





One of the marks run the whole length of the cylinder AND catches my fingernail which is exactly what Honda states to be considered a problem.

I will be talking to the owner of the S2000 shop about the possibility of needing a new motor.

The point of this thread is to educate other S2000 owners with similar problems, and get opinions on what I should do.

From my research and understanding I have multiple options.

1. I can leave as is, install new cylinder head, and hope to get another year out of this engine. $

2. Used short block from S2000 shop. $$

3. Bore over within Honda limits (0.025") to retain FRM cylinder lining and use Honda 0.025" over-sized pistons with new rings and bearings. $$$

4. Full build including aftermarket Cylinder Sleeves, and aftermarket Forged Pistons, etc. $$$$

THANK YOU so much for taking the time to read, I appreciate all thoughts and opinions.

Sincerely,
Nicholas

Billman250

Broken retainers can go up to 30k miles undetected. So it is very likely you bought the engine that way.

If the oil burn was noticed since day 1, the cylinder walls likely came that way too.

Success rate for building this engine is very low, especially with scored cylinders. Sure you could sleeve the motor, but it will no longer have the frm liner.

chubbys2k

How about a ap2 long block. Im sure thats what most do. Less work and headache then the 4 options u mentioned. My ap1 started to smoke a little now after changing the valve seals, retainers and keepers. Doesnt matter what brand of oil, my ap1 eats it. I plan to just grab a ap2 long block and toss it in over the weekend with some friends. Good luck with ur car.

V6 Donut

First off beautiful car! I love the AE86 platform.

Depending on what you want to do with the car is what it boils down to. Id personally look into purchasing a new short block from Honda.

Otherwise id be sending it to Inline Pro for a signature series short block build with your goals.

kickingclutches

Thank you for the response Billman. The information you provide is invaluable to everyone on s2ki.


I prefer the higher rpm of the AP1 engine than the extra displacement of the AP2 engine.

I assume you have similar cylinder wall or piston ring issue with your AP1 if you are still consuming oil after replacing valve seals.

Thank you, good luck with your car.


Thank you! This AE86 is my two favorite cars in one.

A new block from Honda or a built Inline Pro block would be ideal but are not cost effective at this time.

I believe it would be fair for my motor to be replaced by the S2000 shop who sold it to me and installed it less than 6 months ago considering I paid full price.