Mi16 Down On Power

[Turbo7379 3]

I've just finished the installation of a 1.9 alloy block MI16 into my 205 GTI race/rally car . The car is definately quicker than before but the 1.9 8v I took out was down on power already . It just doesn't have the acceleration I was expecting from a 160 bhp engine . I did my 1st event yesterday & cars I should've been thrashing were able to stay with me .

 

A guy who is another 205 nut & has owned 2 MI'd 205's told me that it looked slower than it should .

 

I rebuilt the engine using new bearings & gaskets all around . The liners were slightly worn but I couldn't afford to replace them so I left them untouched along with the rings . It was all correctly timed up before fitting . Everything is standard on the engine so where am I losing power ?

 

I carried out a compression test tonight & I got between 170 & 180 psi on all cylinders using my home-made tester . Adding a few squirts of oil added 5 psi to the readings . My proper comp tester only reads to 200 psi & when I used it to test I was getting readings of approx 210 psi .

 

I might try a leakage test - anyone got any tips on how to do this ? I tried doing these before by setting the piston so that the valves are closed but when I pressurised the cylinder the piston pushed back down the bore & the valve opened !

 

I might try getting the injectors cleaned - is it worth it ?

 

I might be able to get a decent set of 2/h MI liners but I hate the thought of having to strip the engine again to fit them . I also have a couple of 8v blocks with good liners but I've read that you shouldn't use them in a 16v .

 

Any thoughts greatly appreciated .

[Pug_101 0]

I would recheck all the electrics first before taking the engine back out.

Also check for air leaks etc.

If the engine does have to come back out I would suspect timing or valve gaps first.

If compressions are equal and as high as you mention I would say things are ok.

Cheers

[taylorspug 7]

Check the basics like AFM before you start thinking about liners and the like! 9 times out of 10 when a standard MI is down on power its either incorrect timing or AFM knackered, so look to these 2 things first.

 

The timing in particular has to be PERFECT on these engines or they wont run right. With the crank timing pin inserted the cam timing pins should easily slide into their dowell holes.

[smckeown 1]

What gearbox are you running ? Running anything other than an mi16 final drive will seem dull

[C_W 3 1 Cars]

What engine management are you running (ie Mi16 motronic?)

 

What gearbox is it (this will make a big difference).

 

When I first fitted my Mi16 engine I was dissappointed too, running on the 1,9 8v gearbox it was fast but never felt loads quicker (although top speed was faster).

 

A 1.6 final drive transformed it, but aswell as that it seemed to get quicker and quicker sine I put it in, so it might need a bit of runing in (although I didn't really rebuild mine )

[16v205 9]

I know this might sound like a simple thing but double check the throttle butterflies are opening fully. Get a mate to depress the pedal and you swing the butterflies to see if theres any extra travel. Ive seen a few throttle cables not set correctly on mi16.

 

Rich

[rapidmi 4]

i had a probelm with my first engine conversion and we spent weeks and weeks trying to source it the car was right down on power and it ended up being my injectors once they were changed it made an enormous difference, was a weird one

[Turbo7379 3]

I'm running on std Motronic 4.1 ecu & loom . I'm also using the MI gearbox & final drive but I know what you mean about gearboxes affecting performance . I had the MI gearbox on the 1.9 8v for 2 events & the gearing was totally wrong , especially 2nd & 3rd gear .

 

Anyway , I went to check the timing tonight & I got a surprise on removing the cover . The exhaust cam idler pulley was sitting crooked & let the belt run against the outer cover ! I checked the timing & thankfully it was still ok , all 3 timing pins went in easily .

 

I thought the idler bearing had collapsed but what had actually happened was that the pulley wasn't located properly on the spigot that screws into the block . Because the centre of the idler is hollow this meant that the idler was only located at its base & was able to tilt over when it was under load .

 

Not sure what caused this as it was all lined up properly when I was building the engine . There is damage to the inside of the pulley & the spigot . I'm hopefully picking up a spare block tomorrow which should yield a new spigot & I'll be phoning QEP for a timing belt kit .

 

Hopefully this is the cause of my power loss , though I don't see how as the static timing was still ok . As the car is laid up I'm going to get the injectors cleaned anyway , can't do any harm .

 

As I was finishing the installation in a rush the exhaust was botched together using the 405 MI downpipe onto 2" piping straight through to a large bore noisy back box , unknown make . This system means very little back pressure but I might be picking up a spare shell with a magnex centre & rear section fitted , would that system give better power ?

 

I think my alternator is overcharging , not sure if that will affect performance . At idle it is putting out 13.5v but when you rev the car you get a fluctuating voltage which is difficult to read on my digital meter but it seems to be over 15v !