Mpi engine rebuild
Turbo Mini Forums

Hi guys

Right the problem with the mpi never went away and now there is the terminal knocking noise has arrived so the engine is coming out for a full rebuild hopefully solve some of the non stop problems I have had recently, so while it is out I am looking to maybe do a few bits but on a budget so what would you guys recommend, any little tricks you have come across when doing yours maybe parts you install that you would recommend using?

you need to give us an idea of what your aiming for? road? track? both? 100bhp, 200bhp?

Fit a Kent 274 (not 276!!!) cam

I am looking for sort of a fast day to day runner nothing to to racing with but has some go

The Kent 274 will give you what you want.

You could go with a Swiftune SW5, but the Kent 274 will give you just that little more.

I ran one in the 1400 and with a few other bits, it gave 100bhp and 100lbft. Jackman runs the 274 SP and gave 80bhp on a pretty standard engine.

One thing that is VERY important though on the MPi is timing in the cam accurately, one or two degrees out and it messes up the sequential injection timing

Edited by Sprocket on 3rd Oct, 2008.

Hi,
^ What he said about the timing
Cheers,
Gavin :)

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i already have the minisport fast road cam is that not a good option i got it when i bought the tuning kit from them with the head and the rockers, this is going to sound really stupid but is it possible to change the timing on the mpi because i bought some duplex timing gears and then i just lined up the dot lol, i spoke to minispeed and they recommended changing to a 3.1 diff or shall i stick with my mpi one

dot to dot could mean anything!!!

it needs properly timing in to get it right. you may have been lucky however.

but the dots are for a std cam, and all cams like different timings.

3.1 will obviously feel "nipper" but if you like a good cruising speed keep the MPI 2.9/2.7?

Edited by Sprocket on 3rd Oct, 2008.

when measuring degrees at full lift is that done with a dial gauge? set the dial gauge up and then turn the cam when its at its max measure what the degrees are on a timing disc. then the degrees that the timing disc reads - 106 = the offset key you need to buy?

just trying to make sure ive got this right in my head and i know where it is for future reading if my memory goes to poop.

Setting up the cam timing is done in two stages

First you need to find true TDC

Set the dial gauge up in the center of number one piston at an aproximate TDC and zero it. Fit a cam timing disc onto the crank pulley and set up a pointer that indicates 0 degrees/ TDC.

Now turn the engine anticlockwise so the dial gauge reads a value, doesnt matter what value, not too big not too small, lets assume 0.4mm, read off the indicated degrees on the timing disc, lets say for example its 23 degrees.

Now turn the engine clockwise past TDC and again until the dial gauge reads the same value of 0.4mm, again read off the indicated degrees from the timing disc, lets say its 19 degrees.

Now add the two together, then divide by two, 23+19=42/2=21

Now turn the engine anticlockwise 21 degrees, and reset the timing disc to read 0 degrees/ TDC.

You have now set true TDC on the timing disc

Edited by Sprocket on 3rd Oct, 2008.

Secondly

reading the timing of the cam at full lift.

This is done in a similar fashion.

Set the engine to the desired degrees at full lift ATDC, set ip the dial gauge on a pushrod on cylinder 1 inlet lobe/ follower, make sure its nice and central. zero the gauge. turn the engine anticlockwise untill the gauge reads a value, doesnt matter what it is, say 0.4mm and read off the degrees from the timing disc, lets assume 69 degrees.

Now turn the engine clockwise untill the dial gauge again reads 0.4mm and read off the degrees, lets assume 143 degrees

Now add the two together then divide by 2

69 +143=212/2=106

In this example the cam is set for full lift at 106 degrees, which is perfect. If it read 108 degrees, subtract the desired value of 106 from the measured value, giving 2 degrees, and this is the size of the offset key you need, or the amount you need to adjust the verniers by

so do what you said first to get the pistons at True TDC, and then do what i said after to set the cam at the desired/optimum Degrees of advance

You need to follow the above pretty closely.

Both the piston and the cam have a dwell period of several degrees where nothing looks as if its moving up or down, you need to find the center of this and the way to do that is described above. Just because the dial gauge has stopped moving doesnt mean that that is full lift or TDC

http://www.burtonpower.com/technical_1/cam...ing_timing.aspx

ahh i posted what i said before i seen your second post. all is clear now.