1.8--->2.0 Big Bore vs. stock 2.0, Cheeper to build a Big Bore from a 1.8? Options

[thomasotten]

I need some advise as to which direction to take my project. I have a 1.8 engine that is already out of my car. It could use a rebuild. I was wondering, for a street car with miild performance increases desired, what are the pros and cons of rebuilding a 1.8 engine to a big bore 2.0, as opposed to just buying a stock 2.0L and rebuilding that? Would I come out about the same, cost and performance wise? Either system will have 2.0L heat exhangers/exhaust.

[seanery]

Webcam $158
Lifters $140
96mm Pistons/Cylinders $349 - $2000
Engine Seal Kit - $60

I think cost would be the same either way with more fun bigger.

[tat2dphreak]

the cost would be similar... you would have to factor in a crank too Sean... that ain't cheap...

if you already got the 1.8 though... it would be cheaper than finding a rebuildable 2.0... the heads alone make the 2.0 more expensive and you can get almost as good performace from 1.8 heads, esp if you open them up some with the money you save

[anthony]

Since labor and machining costs would be the same whether you rebuild a 1.8 or 2L I'd go with a 2L. For an extra couple hundred you could find a good 2L crank and rods and use your 1.8L case. The 914 cases are mostly all the same. When you have the heads redone you can have the spark plug relocated to the 2L (better) position. I'd also do the smaller spark plug modification like Jake does. With work 1.8L heads should flow almost as well as 2L heads.

[thomasotten]

So does the 1.8/1.7 case need to be machined to accept the 96 mm (or 94 mm) pistons/cylinders?

[tat2dphreak]

So does the 1.8/1.7 case need to be machined to accept the 96 mm (or 94 mm) pistons/cylinders?

no the case should be fine up to about 103mm if I remember...

the heads on the 1.7 would need machining for 96mm+

but all of the cases are about the same...

see this for more info:

type 4 secrets revealed

[thomasotten]

So what about reliability? Do 2.0 L heads last longer than 1.8 heads machined for big bore? Are they a better design, do they cool better? There is just such a big price difference in 1.8 and 2.0 heads, I am trying to find the justification for the difference in price.

[lapuwali]

The 2.0 heads flow better, and have a better spark plug position than the earlier heads. They're highly prized by the entire T4 community (bug/bus conversion guys, too), which is why the price is so high.

Since you're going for a mild increase, just adding the 96mm P&Cs to your 1.8 and a slightly hotter cam is probably plenty.

[newdeal2]

There are other things to consider before you do this. I am in the middle of a 2.0 rebuild for the first time [and BTW, I have a 73 Grind webcam for $138.00 brand new].

In addition to what has been mentioned you will also need to rebush your rods, measure and check the crank, align bore the case, replace all bearings and seals, rebuild the heads, posibly modify the oil pump [Jake can sell you a kit] , and one of the most inportant issues up front is carbs vs fuel injection .

As a guess look at about $2,000.00 for the parts and machine shop work.

[lapuwali]

Align boring the case is almost never required on a Type IV. This is commonplace on Type Is, and far too many Type I mechanics do it unnecessarily on the Type IV, too.

For a mild upgrade on a street engine, just replacing the pistons and cylinders is adequate. No need to split the case at all. You can, if you really want to, but it isn't required. The bottom ends on these engines are well known to last 250K miles w/o rebuilding. Heads regularly need attention after 50-60K miles, so you ARE looking at either getting your 1.8 heads rebuilt, or buying some remanufactured heads.

[thomasotten]

posibly modify the oil pump [Jake can sell you a kit] ,

When I last rebuilt the engine, I bought an upgraded oil pump from tweeks, that was a long time ago. Is this the same thing that Jake sells, and if not, what kind of volume does it push compared to the stock, or the traditional upgrade like I have? Also, what is Jake's price for that upgrade?

[newdeal2]

I have yet to get an answer on the cost but I have been told it's a good upgrade. No specifics on performance.

It is true you may not have to align bore the case but it doesn't hurt to check it before assembly.

I don't know the exact milage on my engine [the po says 130,000 so but he lied a lot]
When I checked my lifters they were starting to cup slightly so I dug into the case. I wanted
to learn anyway so am doing any corrections/upgrades to keep it running for a while.

I have been told that unless you are going to use the car for other than street driving balancing the crank, etc isn't critical but there are many opnions on the subject.

Webcam has matching lifters for about $100.00 for their cams and they have a new design [which I have] that are two piece. Esentially the core has some movement [held in with a circlip]. It will be interesting to see what the results are from Jake. I hope it's good news.

[Dave_Darling]

The 2.0 heads, in stock form, make better power than the other Type IV heads. They are, however, more fragile and prone to cracks. Particularly at the spark plug holes, and on the short-radius side of the exhaust port.

The other Type IV heads all seem to have more material in those areas and are more robust. You can probably re-work a 1.8 head so that it flows as well as or better than a 2.0 one, but of course it will cost you some money.

With a 94x71 motor (2.0), you will have 1971cc of displacement. With a 96x66 motor (1.8 with "big bore" kit) you will have 1911cc. 60cc isn't exactly nothing, but it's not a whole heap of displacement either. You can make either one the better performer than the other by throwing enough money at it...

I think the 1.9 is an attractive option, myself.

--DD

[tat2dphreak]

you should at least check the align bore... it doesn't need as often as the type 1s need it... but these ARE 30 year old cases :|

in stock form the 2.0s do flow better and get better performance... but they also tend to crack more often around the spark plug... which is why Jake goes to a 12mm plug..(I'm sure there are other reasons too...

the 1.8 heads can be made to flow as well or better and get equal performance as well...

an upgraded (type 1, 30mm) oil pump can be had from aircooled.net as well..

Ipersonally would invest in the ceramic lifters if you plan to keep the engine for a long time... $400 is cheap when you can use them in the next engine too (IMG:style_emoticons/default/biggrin.gif)

[thomasotten]

Is aircooled.net's upgraded oil pump the same as Jake's?

[tat2dphreak]

I don't know if they are EXACTLY the same... but they are very similar... Jake highly recommended the ac.net one as well!

[p914]

As a guess look at about $2,000.00 for the parts and machine shop work.

What would the avg labor hours be on that?

[Cap'n Krusty]

Ya might want to consider using a 2 litre crank and rods with your 96s (different from the 1.7/1.8 96s, BTW, with a different pin location). Lot of 'em out there, being they came in all the busses from '76-'79. The Cap'n