rBERNY

I'm looking into buying an FD

I'm comming accross all these cars with reman engines. Atkins, Rotary Performance, Gotham racing, LA motorsports, 2mm seals vs 3mm seals.

Peoples views and experiences with these companies and components is twisting my head around my spin here. My goal is to buy an FD that I wont have to replace the engine for a few years, 40,000 miles, is that too hard to ask?
I will prolly Autocross the car a couple times a year.

Whats the compression on stock engine from the factory?

stock engine with say 60k miles on it?

rebuilt engine with 2mm seals?

rebuilt engine with port job and 2mm seals?

rebuilt engine with 3mm seals?

rebuilt engine with port job and 3mm seals?

where do I buy the premix if I decide to get a a rebuilt 3mm seal engine?

I've heard bad things about Atkins engines, should I even concider buy a car with one that has 17k on the motor? or does that mean its one they did a good job on?

thanks for the info guys

rBERNY

Cummon guys,

I just wanna know some basic findings of what you guys have found out about engine compressions when factoring in porting and remanufactured engines from various companies.

RotaryResurrection

iTrader: (8)

The compression the engine makes is a measure of how well it is sealing internally, nothing more. Different seals, given the same housing surfaces, seal pretty much the same when running a test. You cannot distinguish between a 3mm seal engine and a 2mm seal engine by a compression test, if they recieved equivalent housings (wear or lack thereof). Many people think that 3mm seals don't seal as well as 2mm seals, or that 2mm 2pc seals don't seal as well as 2mm 3pc seals. OR that solid cornerseals do not seal as well as stock corner seals. My FD engine has 3mm seals and solid corners and is currently making 124-130psi on a mazda digital gauge. Spec for a factory fresh 2mm/3pc seal motor with new housings and stock cornerseals is 120-125psi.

Port work can change compression numbers, but not a whole lot. They affect vacuum at idle readings more than compression readings. THe difference in an equivalently built stockport or large port motor could be less than 5psi on a test, but the difference in vacuum @ 800rpm could be 4-6 in-hg.

Bottom line, the single biggest factor in how good compression an engine makes is the rotorhousings that were used in it. The quality of the parts used to build an engine matters more than the builder in many cases.