Upgrade Cylinders/Pistons

Potter · 10-22-2003, 08:00 AM

Here's the deal: I have a 73 2.0 with low compression on two cylinders and a tough time starting. I have the shop working on it. They have adjusted the valves, timing, and all of that. Still low compression (of course) but she fires right up now. So now we are looking at a complete valve job.

I don't really have a clue as to what is involved. All I know is that the engine is now pretty much out of the car and that they estimate between $800 and $1400 is going to be sucked out of my pocket when all is said and done. Frankly, I am happy to pay $1,000 to have a great running car when this is completed.

But the mechanic, who I don't know but trust and am confident in, has advised that if it becomes necessary to replace pistons and cylinders (I am not quoting....that is just what I "heard") that I should upgrade to European High Compression pistons that will boost the horsepower by another 15 or 20. And that will cost an additional $550.

I am hoping I just have some bad valves going on and don't have to venture into this decision.........but if I do have to, what do you think??? Does any of this make sense? If I do have to get new pistons, is this a logical upgrade?? I'm just a weekend driver, so is it worth it for a moron like me? Am I getting screwed? Will Aquaman make it to the sunken submarine in time to save the hapless captain and crew? Is it sick and perverted that I gently whisper "goodnight Anna Kournikova" each night just before I fall asleep?

HELP!!

Alfred1 · 10-22-2003, 08:17 AM

IF you need to replace your pistons and cylinders, the Euros are the way to go. They have an 8:1 compresion ratio and you'll pick up ~ 5 hp (not 15). The Euros are made by the same OEM (Mahle).

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Anna? No, not sick and perverted--just hopelessly optimistic.

The mechanic is being optimistic in quoting a 15 or 20 HP between European and US spec pistons. The rated difference from the factory was 5 HP, 95 for the US-spec motors and 100 HP for the European-spec ones. Worth doing if the pistons need replacement. Not to mention that the US spec P&Cs were, last I checked, about $50 or so more expensive than the European ones...

--DD

Tidybuoy · 10-22-2003, 08:23 AM

I'm not sure if the prices are reasonable because I have not done this myself (yet). But, If I was as far as having the engine removed, and getting new (or rebuilt) heads, I would do the pistons at the same time. It's not very often that you have the engine pulled & now would be a good time to do some major work. Pistons & cylinders are easy to replace.

Although I'm not an expert, I would think that if the heads are bad, the pistons are probably worn too. As far as the Euro pistons - I would do that too.

$1500 sounds like a lot, but if you look at the boards out there, a set of heads is usually around $500 (not rebuilt) and a new set of pistons can easily reach $500 depending on the brand.

skline · skline's Garage

Well, in my opinion, I got a quote from Ray Stevens to rebuild my 2.0 liter engine complete for 1500.00. I just did not want to spend that much on a stock motor so I did it myself. Looking back, Maybe I should have just had Ray do it. Hind sight is 20/20 right? Oh well. I have seen euro P/C for less than $550.00. In fact, I have seen them for around $350.00. If you are going to replace the P/C you should just go ahead and have the whole thing done including all the bearings and cam and lifters. Since you have it out and apart, start with a totally fresh engine. That way you do not have to worry about it for a long time to come. Again, just my opinion.

seventythree · 09:19 PM

Once the heads come off, you will end up needing at least new guides and exhaust valves. Both heads will have some cracks in them, which will require costly repairs. Proper machine work and parts for the heads will easily cost upward of $1000. Add labor and misc. expenses, you will get over $2000 very easily. So, your shop is giving you very optimistic cost figures, and it is for one of three reasons. 1) They don't know what they are dealing with here. 2) They know more realistic estimates upfront will deter you from going forward. 3) They plan on doing a half-assed job.

Redoing the entire engine is sound advice, and if all goes reasonably well, you will end up spending $2.5~3.5K. Subtract $500~750 and add 4~6 months if you do the tear down and assembly yourself. Either way, you won't get garanteed results unless you have it done through a specialty shop. $$$$$

Best of luck

Joe Ricard · Joe Ricard's Garage

Na go with a god set of 96 mm pistons and cylinders. Heads may or may not be cracked. Depends if they have been over heated.

Good set of 96's and you are set.

Potter · 10-24-2003, 05:49 AM

OK...here is the update. You were all right on the mark with your predictions, etc. The exhaust valves were shot, as were all the seats and guides. Machine shop costs hit $500. The semi-unexpected bad news is that the rod bearings on the crank shaft are shot. The mechanic advised that if this is the case, it is pretty likely that the main bearings are toast too.

Good news is that the cylinders and pistons are fine.

Sooooo, the engine got split and the bearings are all getting replaced.......new seals, gastkets, wingdings, widgets, and so forth.

Total cost for the whole operation: $2500

(The mechanic had warned me of possible escalating costs before we started on this....he is a good guy.....I was the one leaning to the optimistic side)

seventythree · 10-24-2003, 06:14 AM

At this point, a new set of P&Cs will cost an extra $500, possibly less. You should seriously consider not reusing the old ones. Be very careful on the head work. Getting new seats installed is a ver wise move.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

New cam and lifters!!! The old ones are almost always wiped or on their way out.

--DD

DDS · 10-24-2003, 02:23 PM

How many miles? Sounds beat like mine was and if so I can't belive the cam isn't showing serious wear. Are they measuring the crank properly and resizing the rods? They checked the ring grooves and they are OK? They cleaned the heads and found NO cracks?
BTW, I'm with those who say do the whole thing, you almost have already

Zeke · 10-25-2003, 06:47 AM

While doing the heads, they will resurface the cylinder head recess. With a little off there and reassembly w/o head gaskets, you will find a small bump in comprression. So, some more hp is there for the taking.