1.5/1.6 hybrid build

[Hazybunny]

Well I have been planning to build a 1.6d into a turbo for a long time and have read through loads of build threads. Recently I started to make progress. A friend opened up the spare 1.6 to find it missing rods and pistons which has somewhat changed my plans. The car currently has a 1.5 that has been running on and off for 4 years, first it was injection pump problems, then it was a starter and v-belt issues and most recently it caught on fire after the battery strap (chain) sparked off the terminal. Luckily the only real damage was to the battery grounds and hood. When i bought this car i was sure it was life long love at first sight but 4 years and countless dollars later she is in probably worse condition than i received her in. At this point I'm not entirely sure if I can afford to hang onto her for much longer, but if she is running reliably then there is no reason to sell such a sexy little machine that gets 50 mpg. Having done much reading I can see that a turbo is not in my budget or know how at the moment so i have decided to just rebuild the 1.6 with the 1.5 internals. I know there is a plethora of knowledge on this forum so I wanted to get some opinions and do's and don'ts. The plan is to use the 1.6 block (more material around the studs) and 1.5 pistons and rods (as the are all I have) but I am undecided on which crank, and head to use. Are the cam specs the same?  The 1.6 is a cr code so both blocks are solid lifter. I plan on having some light machine work done to clean up the block maybe balance the rods and pistons and a light port on the head to help with economy and maybe off set some of the turtle like qualities of the na 1.6.

[ORCoaster]

Are the parts compatible as you describe?  Are the 1.5 pistons and rods the same length as the 1.6?  Somewhere in my fog infused brain I am thinking they are not.  Diameter yes but stroke?  No time to look it up to be sure.  Perhaps some of these pro engine builders will verify or nullify your plan. 

[Blocksmith]

The cylinder diameter is the same, but you will need to use the 1.5 crank for sure--different stroke / connecting rods / wrist pin height between 1.5 & 1.6, so one has to keep all the rotating assembly matched together. As for the head, they are both 11mm head bolt holes, so you're in good shape there. I would pick the one in better condition and use it, as I don't believe there are any known problems with the 1.5 heads being weaker like the blocks are. I don't have numbers or a source to quote on the cam, but I believe they interchange 100%; afaik it's only the mech/hydro cams that are different.

[Jetmugg]

I built a "Franken" engine with a 1.6 turbo block, 1.5 rotating assembly, and a 1.9L AAZ head.  It all bolts together, but you have to be careful, and you have to know what you are doing to have it work out properly.

The rotating assembly from the 1.5 has to be used as a set (crank, rods, and pistons) regardless of which block you use.  You cannot mix and match cranks, rods and pistons between the 2 setups.

The heads are physically interchangeable.  The rest is up to you.

If I was building for a daily driver, and I was in your position, I would rebuild it as a 1.6.  You said you are going to have the block cleaned up (bored out, presumably).  Oversized 1.6 pistons are easy to come by and comparatively cheap.  Oversized 1.5 pistons are hard to come by and are expensive.

If you want more power than the 1.6, then switching to a 1.5 is going the wrong direction, in my opinion.

Steve.

[Hazybunny]

Not looking to build a 1.5 just planning on using the rotating assembly, as I only have the crank from the 1.6. Won't the engine rev slightly higher than a 1.6 would with the crank/rods/pistons from the 1.5?

If the 1.5 pistons don't look very good then I will probably just invest in kolbenschmidt pistons and start "pre-building" the motor for a smaller turbo. It seems as though one can get by without oil squirters running moderate boost, intercooler, keeping an eye of egt's ect

I know its a really vague question but i have never had serious machine work done before so how around what should I be expecting to pay? I don't know of any super reputable vw diesel machinists in the area (southwest Florida) but I have been recommended to a dual service automotive and marine shop. Their website features numerous old yarmar diesels as well as multiple old big blocks and straight sixes ect so its seems a logical starting point.

[vanbcguy]

I had my block cleaned, bored and decked, crank polished, bottom end built with new bearings, freeze plugs and bolts, valves ground, head surfaced, new valve guides and seals, block painted and head painted for about $1500.

[Jetmugg]

Not looking to build a 1.5 just planning on using the rotating assembly, as I only have the crank from the 1.6. Won't the engine rev slightly higher than a 1.6 would with the crank/rods/pistons from the 1.5?

If the 1.5 pistons don't look very good then I will probably just invest in kolbenschmidt pistons and start "pre-building" the motor for a smaller turbo. It seems as though one can get by without oil squirters running moderate boost, intercooler, keeping an eye of egt's ect

I know its a really vague question but i have never had serious machine work done before so how around what should I be expecting to pay? I don't know of any super reputable vw diesel machinists in the area (southwest Florida) but I have been recommended to a dual service automotive and marine shop. Their website features numerous old yarmar diesels as well as multiple old big blocks and straight sixes ect so its seems a logical starting point.

If you put the crank, rods, and pistons from the 1.5L, then you would have a 1.5L.  The block has no impact on the displacement.  If you put a 1.5 rotating assembly into a 1.6 block, then you have a 1.5.

It has been said that the 1.5's will rev higher, but that won't help get your vehicle moving.  Displacement is your friend when it comes to low-speed acceleration.

If you are going to the trouble of building a turbo engine, then you would be a long way ahead by simply purchasing a turbo block as a basis for the build ($250-ish).

Good machine work is expensive.  The machine shop bill for my 1.5 Franken-deal was right at $2K.  Yes - $2K.  That did not include the hard parts that I provided (block,crank, rods, pistons, valvetrain).  It did include very careful, precision work on every surface that was touched, all bearings, re-working the head, etc.

Steve.