After abit of help over the last few months had a few problems with my brothers rs turbo.

He went to have it setup and when they did a compression test it only had 70 psi across all the bores. So has the bottom end was a fresh build from the previous owner thought it might be the head so we fitted a new head that had been checked etc still the same compression

So today I dropped the engine out to see what was going on with the pistons etc.

There's no play in the pistons when there fitted in the bores

All bearings are like brand new and the pistons look just has good.

We were told its a 1.9 block ?

This is what I've found could someone tell me what the block is and the pistons and rods.



















Also there's about a 7mm gap when the piston is on TDC between the top of the piston and the deck of the block. Does this sound right.

Any help would be great thank you.

 

Slightly off topic but is your compression tester a known good item?

edit to add, my bad, upon reading again I see you rechecked comp so I presume you used a different tester.

 

Yeah I've had a couple of compression testers on it same reading give or take a couple of psi.

 

7mm is a massive amount between piston and deck height !..its a cvh block ? has it been machined for something like coopers rings or is it linered ? as the rods say FoMoCo on there from a later ford as most will just have a ford badge on...pistons look N/A... strange mix of engine parts????

 

7mm is way too much, the pistons are definitely not correct for that engine. They are from a BDD 1600 Atlantic! I'm not surprised it only has 70psi per cylinder.

Edited to add, Rods are from a crossflow!

 

Well I'm guessing its a Cvh block but can't be sure if I google the sm6015 stamping in the side it comes up has rs1600i but again that's another strafe one has this has the oil return for the turbo.

The pistons have cosworth in the casting with pm0067 this when googled brought up Subarus

 

It's still running the 16v pistons... I don't think that's helping..

 

You have a rather unusual mismatch of parts in your engine! As correctly mentioned you have a set of BDD1600 cosworth pistons and Xflow based con-rods and an early 1600 CVH block. Im not quite sure what has been done with the crank to allow xflow size big end bearings though!

Either way the pistons being 7mm down the bore at TDC is where the problem lies!

Std for a 1600cc is 2mm proud of block face, and certainly nothing lower than flush with block face (around 7.2:1) is required.

Id suggest you start with a new bottom end build, as most of what you have is unsuitable.

 

just out of curiousity what do low comp engines usually run at? Maybe this was built with large amounts of boost in mind

 

Engine code says "FU6"!?

I've only got engine codes 92 and older, but FUx were 1.4 CVH engines!?

 

CR or depth in MM? Karl points out above that pistons flush with the block gives around 7.2:1 and this is very low.... stock CR of 8.5:1 (or 8.2:1 can't remember which now) can take 2 bar of boost with a .48 T3 housing for example so what you see above has been built totally wrong no matter what boost you had in mind! lol

 

I have built similar bottom end using vw rods many years ago before steel options were cheap.. It requires the block to be decked for the CR to work right. It will make decent power if it's built properly again. The head will also require the correct height to work.

 

Are the valves seated properly?