Ok folks,

I have, through a series of events, aqcuired two AJ27 motors with issues. I want one built and ready to go for when the next "fantastic opportunity" comes along.

Engine 1: (slightly) bent rod from hydrolock (coolant)
Engine 2: Rod knock (runs fine, but it is a loud enough knock that I know its an issue)

Which one should I fix? If I fix the rod knock one, can I just replace the bearings without removing the heads and be on my merry way?

If I fix the one with the bent rod, can I just take the rod off the other and be on my merry way?

Engine 1 already hase the heads off, so there are already more costs there so I am leaning towards Engine 2-

What say ye all?

 

Engine 2, but go through it! You've got the engine out of the car! Go through the entire motor and replace every seal and gasket; check the heads, replace anything you can get at that is a wear part or something that deteriorates from age (rubber+plastic). It'll extend the dead reliable service life quite a bit.

Part out the Engine 1 and pay for making engine two like new.

 

I like it! I wonder if I can use a bearing from #1 for #2...

Hopefully the crank is still ok- the rod knock (form my limited knowledge) sounds like it is halfway between perfectly ok and wasted, so maybe just the bearing is damaged?

 

So far, out of pocket these two engines have cost me $150, less once I sell on some parts.

 

Its been a while, but getting the block bearings n without dropping the bedplate.....i'd assess each, and make a cracker out the 2.
Crank, best one
New bearings
Match a set of pistons and rods
Gentle mop of liners to remove glaze on best block after bore mic check
Best heads
Everything minty clean on assembly,
Check ebay for n.o.s. parts, time on your side if a crate engine.

 

If you can hear a rod knock, figure crankshaft damage. The bearings are individually selected and a code is stamped on the block for each one. They may be the same size, but I would think it's false economy to switch them.

 

Whenever I see a rod knock I am not that concerned with the rod knock (yes I do fix it right away!) but I'm more concerned what caused the bearing to excessively wear. I'd be inspecting everywhere oil travels and is supposed to be. Rods don't just knock and bearings don't just fail.

If I have a motor out of the car, I'm touching it all. I don't want to assume something is good and later wish I'd spent a little time and $ when it was out. Doing things like every gasket, seal, oring, etc; it's cheap and easy now, but in car is a whole different ball game. Things like a rear main seal are never expensive part wise...

Can you go the route of a crank grind with new appropriately sized rod and main bearings? I've done that numerous times on lesser cars (Domestic and Japanese).

 

I think you can now with a company called RacingGreen in the UK.

 

I the past I just did that and Clevite always had the main and rod bearings I needed but these were cars like a Toyota Camry, Lincoln Town Car and Chevy Trucks.

I'm pulling the 2.8L 30V V6 from my 1998 Audi A4 due to a rod knock (bought this way) and I'm hoping I can do that, otherwise parts are plentiful for A4s if I need to go used/reconditioned/new. It was a massive oil leak that led to oil starvation that led to a rod knock.

 

Ok- so it looks like the plan is to disassemble both engines, balance all of the pistons and rods, then choose the ones with the closest weight, then sell off the rest of the parts to fund the rebuild which Ifigure will be somewhere in the $1000 range for parts and machine shop work.