potdog

Hi guys been collecting parts over some time , Now the time has come to get engine overhaul started. Need advise please ,This will be supercharged ie a Raptor one bought a stage 2 kit. Will be getting the head bolts and graphite composite steel head gaskets got the Gates racing belt of Roger and Porken tensioner the tensioner is the black one is not the newer one silver whats the differance can the black one be modified? . whats the best type of piston rings hopefully will be in speck will need a set of cam followers got the chance of having cams re profiled to GT+ Lizard . Thinking about having engine balanced new crank damper for got to say S4 all adivce greatly needed than in anticipation have a great day everyone cheers Peter.

FredR

Peter,

How many miles has your motor done? Are you planning to splt the girdle and remove the crank for inspection?

Rgds

Fred

potdog

Thanks Fred for reply yes completr engine overhaul 100k cheers.

FredR

Peter,

Well used and maintained examples have covered 300k miles and still been in serviceable condition. If your motor is fully apart and if you are going down the power adder route then I would think it makes every sense to replace mains, big ends and piston rings and check that items like your pistons are fully serviceable with no deterioration of the piston coating that is essential to the longevity of the motor so if you are handling, inspecting and cleaning pistons do ensure you know exactly how to handle such to avoid damage. Also good time to consider GB's harmonic damper kit or something to replace a tired unit rather than add ever more grief to it.

Regarding the mains and the big ends take good advice from someone who knows what they are doing. The very thought of getting the tolerance groups correct for the shells is rather scary.

Do it once, do it right and you will be a happy bunny! I know someone in the UK who is into this - whether he can/would advise you no idea- I can enquire if of interest.

Regards

Fred

outbackgeorgia

Only 100k miles? Are there symptoms or issues? Low compression? Poor performance? Excessive oil consumption? Just trying to understand the reason, mileage is certanly not the single indicator for a rebuild.
Dave

potdog

Just want to do once belt and braces job cheers

jcorenman

Let's try again: With only 100K miles on the engine there is a great likelihood of no net gain after a long and expensive exercise. Keep in mind that Tuomo here has pushed his well-used S4 motor to 700rhp if I recall correctly, and failed in his endeavor to break that motor.

Do you know the history from new? Has it been properly maintained?

Is this an auto or manual? If auto, what is the crankshaft end-play? Any reason to suspect thrust-bearing issues?

How much oil does it use between changes? How often was oil changed? What oil has been used? Has a used-oil analysis been done recently?

How do the spark plugs look? Uniform in color, not wet or oily?

Have you checked the bores with a scope? Cylinder walls OK? No signs of excessive oil usage? Compression and leak-down OK?

If all that checks out then I would get right down to the fun part. You will probably want to refresh the MAF if not already done, and for stage-2 you will likely want a super-MAF from John Speake.

You will also need a Sharktuner if you don't already have one, John can help with that. There is a learning curve there, so it wouldn't hurt to get an early start on that.

ptuomov

My opinion is the following.

If you are planning to mildly supercharge an S4 motor that has 100k miles on it and that doesn't have specific known problems, opening the motor is a fool's errand. By mildly supercharging I mean, say, 450 rwhp. All you need to do, in my opinion, is to get the base motor to good working condition with all the maintenance done and no known problems. The stock engine can take everything else except very high cornering g forces or very high rpms. We run out of compressor mass flow capacity (2x3071r) on the dyno before we saw any problems with a bone stock S4 motor, but that of course was at low 6000's rpms and the engine stationary.

If you have one of those inferior GTS models, sell it and buy two S4s or one and half GTs, instead of trying to fix that one compounded design error.

potdog

This is a used donkey that i want overhauld 100k do not know history auto had an SE want more fun

ptuomov

You are of course entitled to do whatever you want to it, it's your car and your hobby. Because I want to and because I can are good enough reasons to open an engine. If, however, you don't want to then you don't need to, that's my opinion.

FredR

[QUOTE=ptuomov;13987990

Because I want to and because I can are good enough reasons to open an engine. [/QUOTE]

Tuomo,

Assuming Peter has done his homework and made a firm decision I am sure any insights about inspecting and rebuilding the engine folks like yourself can offer would be very much appreciated not to mention informative for those of us who may go down a similar road in the future.

Rgds

Fred