Suggestions for 3.6 upper end rebuild?

[earossi]

I have a 98 993 with a bone stock motor that just turned over 106K miles. Records were spotty on the car when I purchased it about a year ago; but, I believe that the motor has not had any upper end work since new. Compression was OK on the car from the PPI, but leakdowns were in the 6 to 8% range which I "think" is a little on the high side. Oil consumption is now at about one quart every 1000 miles, so a bit high but not terrible. There is essentially no leakage of oil......just some "minor" weeping, but seldom enough accumulates to drip on my garage floor.

So, I am starting to think about doing a valve job on the motor. Having owned 5 911's, I believe that the bottom ends of the motors are bullet proof and believe that I should easily be able to go to 200K miles before having to split the case......so, I would want to limit my engine work to top end and other work that can be done without disturbing the case. So, here is my question: what work can I do with the heads pulled that would give me a major bump in horsepower and especially low end torque? Obviously, I will do a good valve job on the heads with new valves, guides, seals, lifters, etc. But, is there a better cam setup than the stock cams for a street motor? And, is there a cost effective way to bump up displacement.....say by going to a 3.8 P/C kit?

Since 99.9% of my driving is at speeds less than 110 mph, I would gladly give up some top speed in exchange for better acceleration in the 0 to 80 range.

If I pull the motor to do any mods, I'll also take advantage of having the tranny out to have it rebuilt. Though it shifts fine, I can tell that the 1-2 and 2-3 syncros are weak. But, is there an effective mod to change out gears to sacrifice top end for better and closer ratios more useable around town?

Just starting to think about this!! Comments would be appreciated.

[berni29]

Hi There

I think you should leave the engine alone for now and have the car ecu remapped and fit some 100 cell cats.

Berni.

[earossi]

Originally Posted by berni29

Hi There

I think you should leave the engine alone for now and have the car ecu remapped and fit some 100 cell cats.

Berni.

Berni,

What will each of those mods get me? And, do you have an idea of approximate costs or who to go to for the ECU remapping?

Thanks.

[Bill Verburg]

Originally Posted by earossi

I have a 98 993 with a bone stock motor that just turned over 106K miles. Records were spotty on the car when I purchased it about a year ago; but, I believe that the motor has not had any upper end work since new. Compression was OK on the car from the PPI, but leakdowns were in the 6 to 8% range which I "think" is a little on the high side. Oil consumption is now at about one quart every 1000 miles, so a bit high but not terrible. There is essentially no leakage of oil......just some "minor" weeping, but seldom enough accumulates to drip on my garage floor.

So, I am starting to think about doing a valve job on the motor. Having owned 5 911's, I believe that the bottom ends of the motors are bullet proof and believe that I should easily be able to go to 200K miles before having to split the case......so, I would want to limit my engine work to top end and other work that can be done without disturbing the case. So, here is my question: what work can I do with the heads pulled that would give me a major bump in horsepower and especially low end torque? Obviously, I will do a good valve job on the heads with new valves, guides, seals, lifters, etc. But, is there a better cam setup than the stock cams for a street motor? And, is there a cost effective way to bump up displacement.....say by going to a 3.8 P/C kit?

Since 99.9% of my driving is at speeds less than 110 mph, I would gladly give up some top speed in exchange for better acceleration in the 0 to 80 range.

If I pull the motor to do any mods, I'll also take advantage of having the tranny out to have it rebuilt. Though it shifts fine, I can tell that the 1-2 and 2-3 syncros are weak. But, is there an effective mod to change out gears to sacrifice top end for better and closer ratios more useable around town?

Just starting to think about this!! Comments would be appreciated.

As far as the motor goes 102mm Mahle RSR p/c give a nice across the board torque boost, add some RS hyd. or Ss non-hyd cams for a little more top end punch.

Re-gearing the trans is what will really wake up, the car it makes a huge difference. Unfortunately the late g50/20 in your car has fixed 1 & 2, so w/o purchasing a new mainshaft only 3 - 6 can be changed out, but there are lots of ways to re do those 4 gears.

the cheapest way out is to move 5 to 6, then fill in 3, 4 & 5 between the stock 2 and 6(which is the old 5), while you are in there billet shift forks and steel syncros are nice additions.

[earossi]

Originally Posted by Bill Verburg

As far as the motor goes 102mm Mahle RSR p/c give a nice across the board torque boost, add some RS hyd. or Ss non-hyd cams for a little more top end punch.

Re-gearing the trans is what will really wake up, the car it makes a huge difference. Unfortunately the late g50/20 in your car has fixed 1 & 2, so w/o purchasing a new mainshaft only 3 - 6 can be changed out, but there are lots of ways to re do those 4 gears.

the cheapest way out is to move 5 to 6, then fill in 3, 4 & 5 between the stock 2 and 6(which is the old 5), while you are in there billet shift forks and steel syncros are nice additions.

Thanks Bill. Is there a "best" place to source the RS P/C set? And, on cams, can I have the 993 cams re-ground ti the RS specs? Or, am I on the hool for a new set from Porsche? Second, on the gearbox mods, I would just be on board for a standard rebuiild plus the price of the new parts, right? Any idea of what the rebuild might be with the new gears?

[Bill Verburg]

Originally Posted by earossi

Thanks Bill. Is there a "best" place to source the RS P/C set? And, on cams, can I have the 993 cams re-ground ti the RS specs? Or, am I on the hool for a new set from Porsche? Second, on the gearbox mods, I would just be on board for a standard rebuiild plus the price of the new parts, right? Any idea of what the rebuild might be with the new gears?

You;'ll have to shop around I don't think that they are ever discounted

talk to a cam maker i don't know, I bought new RS cams when I did mine

a new gear set from someone like GT gears is probably somewhat north of a $1k per set, so 3 sets is north of ~$3k, some of the better parts like billet shift forks and steel syncros are more expensive than the standard brass parts but yes regearing is just a matter of rebuilding w/ different parts.

here's a comparison of a bunch of different 993 6 spds that I put together

[RideSober]

Camgrinder on this board AKA Dougherty Racing Cams seems to have a very good reputation for Porsche cam regrinds.