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It is going to be a little while until I can collect my chassis etc because of a hundred annoying practical reasons however, i am considering starting on the engine. Now, it was running well when removed at 100,000+ miles. I could just strip and rebuild however, i have the desire ever present to modify it for more, road useable, power or to fit a different, more powerful engine.
I have seen Patrick and Richard's M20B28 stroker mod (excellent site btw, thankyou) and am considering this but i thought I would ask you all what you think before I commit!
I am really sorry if I am going over old ground here.
John
Mod Chip (I can highly recommend the e30zone ones done by ant@atech fastbimmer.co.uk)
Big Bore Throttle Body (you can do a bit of grinding on the take manifold to make full use of the bigger hole in the throttle
BTB 6 branch stainless manifold (which on it's own has show dyno'd improvements of close to 18bhp)
By passing the hot water pipe connections on the throttle body (just run from front of engine to back)
hotter cam
new stronger valve springs to go with hotter cam
Individual throttle bodies (dblias - these are very pricey)
Stand alone engine management (megasquirt, emerald etc) - allows for individual coil pack, remove the AFM which is quite restrictive to be replaced with MAP.
There's also an option to use a MAF with a piggy back ECU which would be a step between stand alone and standard.
Live mapping on a rolling road, I think some people can do this with the standard Motronic ECU - its the best option for getting the mapping right, a chip will always be a compromise. It something I plan to get done someday.
Clean ups:
check compression in each cylinder
sonic clean injectors (send away for clean + flow test is a good option, I just ultrasonic cleaned mine)
clean out the oil spray bar in the head
check for gunk in the oil return pipe and give it a clean
At 100k the head will be getting a bit tired so:
valves re-grind them as there will be marks and possibly pits
new oil seals and other rubber bits
cam and rockers should be fine but worth checking for wear, can be a problem is the oil spray bar was blocked at any time
Worth getting the head check of leaks and cracks - possible problem are is between cylinder 5 and 6
Check the electrical connections between the engine loom and the injectors, these rot
Check the oil pump tolerances, replace if damaged
Check water pump, might be worth replacing
New belts if they look damaged
Replace the thermostat
Check rotor arm and distributor cap
Check leads to the plugs
Check the plugs
If you take the bottom end to bits cleaning is all you'll need, bottom end should look like it just came out the factory.
while the engine is out - new clutch
Check the gear box linkage parts too the T piece and bottom of the gear stick can be quite worn over 100k.
Patrick,
Thanks very much for the comprehensive reply. I really do admire both your build and the documentation of it, especially the website which is stellar for a newbie! In fact, I have to confess that I wrote this thread before I had read the FAQ's bit on your site which of course was also thorough in its analysis of the tuning options.
One question, if you were to go down the replacement engine route which would you choose? I am wary of the electronic complication of later engines...
Personally I would go for an M54B30 - smooth engine with loads of power. As long as you have all the EWS parts I can't see it being a massive issue on the wiring front. I'd check on E30Zone for M54 swaps see what kind of issues they've run into matching it up with an E30 loom.
VANOS is an non-issue really, even if they have a problem what goes is the seals, and you can replace those: http://www.beisansystems.com
EWS that could be a be an issue, but as long as you have matching ECU, EWS and a set of keys it should be fine if it's plumbed in as per the wiring diagrams.
When we swapped a M52B28 into Richard's compact (http://328compact.co.uk) it was just a case of swapping out the ECU, EWS and chip inside the keys/. That obviously already had the wiring and the boxes for EWS that the previous 4 pot engine had so it was straight forward.
I have the standard 2.5 M20 engine. It's done 170k and still requires a change of underwear if your right foot is heavy. I would build with a standard engine and then change it after if you aren't happy.
As a footnote - on another forum I have noticed that the SVA people seem to be getting much tighter on the rules about proving the age of your engine. Using a different engine to the one in your donor is only going to make that worse. Off course you can always change it after....
After considering all the options Ihave decided to stick with the standard engine. Martinclan has a very good point about SVA and i think I will have more than enough to deal with completing the build as it is. I will strip and rebuild the engine and hopefully not find anything too grim! Once its built, SVA'd and running I can consider the options.
Thanks for all your help and advice.
