jhg41977

Millenium technologies. http://www.mt-llc.com
They came back looking like new. Warning though, the 993 cylinders tend to be porous just below the surface. When your cylinders are bored out and replated, sometimes a spot shows up and you junk the cylinder. Some say you can reuse it, others no. Cost per cylinder was around $200 each. I had one bad cylinder due to porosity, so had to buy another and send it to them.

996scott

Wow, can't wait to follow the progress. Good luck.

ReinerFink

The idea is RS sized valves, but I don't know the exact setup (Na cooled?)

For springs/retainers/seats aasco is the plan.

-reiner

bcameron59

Think this might be the first Drexler post on this forum. What led you to land on that choice? Just curious, haven't heard a lot about them.

ReinerFink

Yes -- the Guards unit is the 'gold standard' on the group and deservedly so. I use my car as a daily driver, so I was interested in a diff with a zero preload, that also performs well on the track. The Drexler seemed to have those requirements, and I sourced one from Austria that was only a bit more expensive than the Guards. The ramps are setup for 50/60 (I think -- I'll have to find the paperwork for it to double check). I'm excited to get on the track this spring and see what difference it makes.

-reiner

ReinerFink

It didn't look like that before I spend 2 days cleaning it up (hehe). Thanks for the encouragement!

Also, as this is my first engine rebuild, I have discovered that the "engine rebuild gnomes" come in at night and pour more dirty oil back into your crankcase and all over your garage floor... beware of those baddies!

-reiner

ReinerFink

I was hoping to have Gordon Ledbetter do the rebuild but he very busy currently. Since I am taking the bus to work in the mean time I can't wait for time to open up so it will be dropped off at Jeff Gamroth's.

-reiner

pipingken1

Stolen from other more knowledgable people.

993 RS intakes are 51.5mm, exhausts are 43.5mm both are Na filled.

non VRAM 993 intakes are 49mm Na filled and exhaust are 42.5mm hollow.

VRAM intakes are 50mm Na filled and exhausts are 43.5mm hollow.

I have a VRAM model and was planning to have the heads opened up for the RS inlets but assume I can keep the 43.5mm outlet valves. Can anybody explain how much difference the Na valves would make? I assume the lengths etc are all standard.

Steve Weiner-Rennsport Systems

There isn't sufficient material to open your heads to RS spec; those are a totally different casting. Further, they are VERY crack-prone and we've replaced many of them.

Lastly, you'd not see any benefit of RS-spec heads over V-Ram ones unless you used a different intake, cams, and pistons.

Valve lengths are standard, only the head diameter (and sometimes stem diameter) varies between models. Larger valves flow more air if the seats are replaced, or in some cases, machined differently. The HP benefits vary with camshaft profile.

pipingken1

Thanks. So I can run RS cams (or similar aftermarket) and have the VRAM seats opened/adjusted to take RS inlet valves with no cracking issues? And have a minor increase in power.

Mike J

It would be interesting to see the current financial costs to this - I also debated the RS values/new seats/camshafts when I did my rebuild since the heads were being done anyways - and quickly came to the conclusion that the additional power (which is not that much) was very very expensive. I ended up going 100% stock and the resulting engine pulled very strong (and still does 6+ years later according to the current owner).

What are your expectations on the resulting engine? You might get more power just from adding a Vram for less money.

Maybe I am just cheap!

Cheers,

Mike

Steve Weiner-Rennsport Systems

That's basically correct. RS valves require the RS seats and that won't be inexpensive to do.

Stick with RS cams for software purposes.

NP993

Why not split the case? If you're standing over a case with the rods already removed, splitting it takes about 15 minutes. And reassembling it takes an hour. I tore down my engine last week and the only wear I found was the small layshaft bearings. But they were showing copper. Just seems like false economy to not split the case when it's such a tiny, tiny amount of additional labor and you're already in there. Plus, you'll want to install new through-bolt o-rings, a common leak area.

Also, note that you'll have to take your rods to a machine shop to have the old bolts pressed out, the ARP's pressed in, and the big ends honed.

Mike J

I think you are unusually speedy so your time estimates do not count for us normal humans. It took me quite a bit more time and money when I split the case, I had to:

- replace the bearings, including the mains, layshaft and nose
- new seals and gaskets (including RMS, etc.)
- polish and clean the crankshaft
- clean the crankcase and passages
- measure everything

But then again, I did split the case for exactly the reasons you say - I was that deep into it, then I knew the engine from the bottom up, and knew exactly what I had. I also caught a lot of wear on the layshaft bearings.

It also gives you an opportunity to replace the chains if required, or the lay shaft sprockets. I also like to use a stretch gauge on the ARP rod bolts, and you can only do that with the crankshaft out.

if you have not done this before, putting the case together is a bit of a skill and time challenge as well - it's not that bad, but still it takes time.

Cheers,

Mike

ntmatter

Do you have a preliminary time/$ budget in mind for this? I'd be interesting to see over time how the estimate aligns with how it actually goes. I have a low-mile '95 that seeps just a tiny bit of oil - Larson in Tacoma quoted about $14K to rebuild everything that would need to be done (including splitting the case) which seemed a bit much to not drip a half pint of oil per year. But, one of these years I'll need to think about an engine refresh and knowing the scope would be valuable.