Mechanics hours to rebuild 993 engine....

[Mike Juzenas]

I am planning my next venture...the top end rebuild my car needs. I am still debating getting it done or a DIY. I am pretty busy at the moment so getting the time is a problem. However I have encountered some differences in opinions on the effort required.

1 - Wayne Dempsey in the rebuild bible says a good mechanic will take about 40 hours to totally rebuild a 911 engine. This includeds splitting the case. This is outside machining etc.

2 - Bruce Anderson in his Performance Handbook quotes about 40 hrs to RR&R and rebuild an entire 911 engine. This also includeds splitting the case.

3 - A local reputable shop quoted my 40 hours to perform a top end rebuild. This involves everything but splitting case and outside machining. That would be an extra 8-10 hours.

4 - A local large and high end shop also quoted 40 hours to do my top end, this time allowing to for changing the rings if required. Splitting the case is extra.

So what time is the actual time? It seems that (3) and (4) are charging the same amount of hours to do way less work? The difference is substantial (10 hours). Or is it reasonable because the 993 is the most complex air cooled engine so an engine rebuild will take longer?

I know it varies depending on the wear and damage to an engine but I would like to get a good handle on the time required if I end up paying for it. I also understand that for a DIY it will take at approx. twice as many hours as a mechanic, especially if you have not done it before.

Is a 993 that much more work?

Cheers,

Mike

[YTNUKLR]

I have never worked on a 993 but the basic principles are the same as any earlier 911...possibly a bit easier!

Personally, (3) sounds pretty ridiculous. I usually charge no more than 20 hours for a top-end on a pre-'89 911 (with rocker arms you need to adjust!).

(4) sounds ridiculous as well, albeit less so.

Bottom line: I cannot see how the 993 could be that much more work, but I may be wrong. Don't get raped.

Best, Scott

[Bill Verburg]

the only part of a stock 993 rebuild that will be substantially different from the earlier rebuilds is the rocker arm r/r which is much easier and cam timing which is much harder w/o the proper tools or more fussy w/ the proper tools. Neither will add or subtract hours to the job.

[Tyson Schmidt]

You have to remember that it's one thing to rebuild a motor that someone brings you, you rebuild it, then hand it back to them.

Quite another to bring them an entire car, they remove the engine, rebuild it, reinstall it, make it run, check for leaks, break it in, change the oil, tune it, and readjust the valves.

And then there's the "while you're in there's". There's always something else, like bad oil lines, etc.


So which were they quoting for?

[Tyson Schmidt]

BTW, make sure to have them replace the through-bolt o-rings when the cylinders are off the case. Have them use the green viton seals, and not the squishy purple ones that come in most kits.


As a point of reference, it took me over 60 hours (probably closer to 70) to do a full rebuild on 993 3.6 recently. That was also a full restoration to make it look pretty, and also some extra things like port-matching, backdating the cam drive to use upgraded cams, etc., and all the little stuff that goes along with adapting this 3.6 to go into an early car, which required some fabrication, and lots of painting, etc.

The most complicated thing on the 993 motors, is all the routing of the plug wires, fuel lines and engine wiring harness on top of the motor. It's like "spaghetti meets pick-up-sticks".

[JeremyD]

If you are short on time, I would not recommend you doing a rebuild yourself. I probably have 80-100 hours in mine. (3.2) that includes the cleaning, powdercoating, r & r, new rocker shafts, yada yada yada.

Most mechanics will run the parts through a "dishwasher" then stick them back on the car. Most DIY engine builders clean and inspect every single part - use a tooth brush to clean off all the gunk, take their time assembling, double and triple check things like timinig, hoses, etc. These all add up... believe me.

[john walker's workshop]

60 hours easy for a complete. 40 hours easy for just the valve grind work. the 993 engine is a LOT more work than even the 964. those damn allen bolts add a lot of cussing to the job. a lot of them strip, the ones through the plastic intake sleeves break, grrrr! you need special cam timing tools because you don't use a dial gauge. i challenge anyone to do a quality top end in 20 hours on a 993, even a 964, hell, even a pre 90 911, which takes about 30 hours. 964s and 993s really should have a complete teardown and reseal, because of all their pesky oil leaks. at least do the through bolt o-rings and cylinder base o-rings when it's down, which will take another 3 hours minimum with all the cleaning required. your quote is fine.

[Bill Verburg]

I must have gotten lucky, my billable hours for a total crank out rebuild, w/ new guides etc, including update to 993RS spec was 40hrs

[Steve@Rennsport]

JW is right on the money,...

These Varioram engines take a lot more time to do (properly) than their predecessors.

[Bill Verburg]

I'm really curious as to where all the extra hours are

please remember that I have build sheets from various shops for a dozen 3.8RS or 3.8cup or 3.8 RSR engines to compare w/

[Dan J]

I agree with Jw and Steve. 60 hrs seems to be the going pro rate on a full rebuild ( it is at my shop).
As to where the extra hours are:
It takes much longer to R&R not to mention the alignment required upon reinstallation
There are considerably more parts to the intake and Ignition that need to be removed, cleaned, evaluated, reinstalled
There are many more small plastic clip and fasteners that love to break upon disassembly.
If your comparing to a carbureted 911 motor it's a different animal
Even the Cup and RSR motors have much less crap on them.
My $.02
Dan Jacobs