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Engine Specific Info and Questions => IDI Engine => Topic started by: NintendoKD on October 14, 2009, 10:31:55 pm

Title: can a 1.6T bottom end marry to a 1.5 top end?
Post by: NintendoKD on October 14, 2009, 10:31:55 pm
found a bottom end/rotating assy. for cheap and as opposed to building a 1.5 "weak block" build it up from a 1.6 TD block and rotating assy.using the top end from the 1.5....... same? Like lego blocks?  Also the crank is damaged in the TD rotating assy. can I use the perfectly good one from the 1.5 and swap it into the 1.6 bottom end?  I checked the FAQ's and did, in fact, use the search feature.

thanks folks,

Kevin
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: rabbitman on October 14, 2009, 10:36:11 pm
I think you'll get a very high compression ratio. Lotsa talk been done about that.......
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: RabbitJockey on October 15, 2009, 04:31:41 am
yuo can use the 1.5 pistons rods and crank if you want, but you'll need to notch to the pistons for the oil squirters, and a 1.5 head won't work with out modifications
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: maxfax on October 15, 2009, 05:11:18 am
The 1.5 head still uses 11mm head bolts, so you'll either have to drill out the head bolt holes in the head as the TD block (as well as anything 82ish and up) uses 12mm head bolts.... You'll also need a reducer in the front center oil drain such as this http://www.vwdieselparts.com/1.5-1.6.htm (http://www.vwdieselparts.com/1.5-1.6.htm) and a 1.5 head gasket, which once again will need the head bolt holes reamed to fit the 12mm bolts..

THe compression will jump from 23:1 to about 26:1 IIRC..  I've been running a similar combo for a few years now in NA form with no problems..  If you're thinking turbo the story may be different...

If you have an un cracked 1.5 block your better option would be to use that with a set of head studs as that pretty much fixes the weak block problem... 
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: clarkrep on October 15, 2009, 06:54:19 am
I think the 1.5 crankshaft has smaller rod journals than the 1.6td and also a shorter stroke. Can someone confirm that?
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: maxfax on October 15, 2009, 07:15:52 am
Yes the rod journels are smaller and the stroke is shorter on a 1.5..    The difference?

1.5 Rod Journal/Stroke = 45.96mm/80.00mm
1.6 Rod Journal/Stroke = 47.76mm/86.40mm
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: Rabbit on Roids on October 15, 2009, 12:01:16 pm
ok, now im asking you this.
why would you want to put such a weak head on a notably tougher block than a 1.5? it just makes no sense. its not going to work right. the compression ratio will be way too high to be any benefit.
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: Turbinepowered on October 15, 2009, 03:17:21 pm
Yes the rod journels are smaller and the stroke is shorter on a 1.5..    The difference?

1.5 Rod Journal/Stroke = 45.96mm/80.00mm
1.6 Rod Journal/Stroke = 47.76mm/86.40mm

Are the early 11mm 1.6 rod journals the same size as the 1.5s?

I went browsing through the Diesel section of my Dasher Bentley (which covers 1.5s until '80, and then 1.6 in '81) and it only lists one table for crank main and rod journal sizes.

Any chance someone has measurements for 1.6TD and 1.5 rods?
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: maxfax on October 15, 2009, 10:17:39 pm
the compression ratio will be way too high to be any benefit.

It should start pretty darned easy...  ;D    The engine in my daily beater is a conglonmeration of spare parts I had around..   1.5 block and head with 1.6 rods crank and pistons.. I really haven't noticed any down falls, but no gains either.. Other than the easy starting...
Had I not been cheap and thrown studs at the thing it would actually work quite dandy... (Yeah I know.. Now you know why I harp about studs so much)

Turbinepowered,

The 1.6's are the same rod journels across the board, both early and late..   Just the 1.5's got the smaller ones..  About the only difference between the early and late 1.6 rotating assembly is the crank nose...

Are you just looking for the ID's of the rod at the crank and wrist pin??  If no one else has them I can measure a couple rods..   The 1.6 both N/A and TD should be the same on both ends..   The 1.5 of course will be smaller at the crank, and IIRC the wrist pin is smaller too...
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: clarkrep on October 16, 2009, 08:37:12 am
Maybe this will help, thanks MJF for the link. http://www.kotinet.com/matti.farm/img01.jpg
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: Rabbit on Roids on October 16, 2009, 08:47:51 am
idk what the hell it says, but there is differences. over a milimeter. i just wish i knew what parts they were talking about on that german tech article. and you are going about it all wrong Kevin. take a 1.5 rotating assy, balance it, notch the pistons, then throw it in a 1.6 block, or even better yet, a turbo block. and put a 1.6 or 1.9 head on it. then you would have one tough, high revving, piston squirter equipped 1.5. i really dont see the benefits of your engine you want to build. you cant even bolt it right together. my combination bolts together. yours would require drilling the head at very least.
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: Turbinepowered on October 16, 2009, 01:32:12 pm
The 1.6's are the same rod journels across the board, both early and late..   Just the 1.5's got the smaller ones..  About the only difference between the early and late 1.6 rotating assembly is the crank nose...

Are you just looking for the ID's of the rod at the crank and wrist pin??  If no one else has them I can measure a couple rods..   The 1.6 both N/A and TD should be the same on both ends..   The 1.5 of course will be smaller at the crank, and IIRC the wrist pin is smaller too...

Actually I meant the rod lengths. I'm assembling a high compression ethanol burner (she shall see very little gasoline :D) out of an early 11mm headbolt diesel block and crank with 1500 gasser pistons. Trying to work out the proper set of rods to give me a bit of diesel-esque piston protrusion.

I just picked up a buret clamp to go with the buret I bought for use with biodiesel titration (then promptly lost, only recently refound) so I'll be measuring the chamber volumes on the 1.6 gasser head I have to determine how much I need to get to shaving. I'll do the piston dishes, too.

Small valves for air velocity (Probably just going to leave them stock, honestly) and throw a small daily-driver type turbo to put me at right around 90-100hp for passing and merging, and we'll then start tuning for economy in my daily driver. :D
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: NintendoKD on October 22, 2009, 10:31:41 pm
So the short answer is .... a resounding NO!??? ??? um........ so now what? my best bet is to rebuild the block I have and go n/a with ARP studs? or should I go with the 1.6 bottom end and keep the 1.5 head? better compression is good right??? plus, I have a recently acquired audi 5000 intake mani for better flow, If I am doing the 1.6 bottom end conv. I will need solid answers and how to's etc. instead of wishy washy stuff like which snout to use, which rotating assy to use, do I have to modify the head? etc.  sorry for all of the questions folks but if this is going to be unique I want it to be done right or not at all.  I would prefer to compile a list of all of the parts to use for this build to make thing a great deal easier. 8)

Thanks,

Kevin
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: maxfax on October 22, 2009, 11:07:45 pm
I think it was all already said earlier in this post, scroll up and read...   If you want it done best, build a 1.6 with a 1.6 head using an 82 or newer engine...  Next down the line would be to have your 1.5 block checked, if it is good, rebuild it with arp head studs..  The same could be said about an early (1981) 1.6 with 11mm head bolts... 


Mixing and matching a 1.5 head on a 1.6 bottom end has been done in many forms.. As mentioned earlier starting may be easier, but otherwise no gains to be had, possibly more downfalls due to the increased compression..   As mentioned earlier, a turbo on this getup would most likely be very bad...
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: NintendoKD on October 23, 2009, 06:05:40 am
I think, that I will just rebuild my 1.5 with ARP head studs :)
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: VWSmokr on October 23, 2009, 06:55:42 am
NintendoKD, if you still want to get a rebuild kit, Turbo City  http://www.turbocity.com/  sells them. They have a good reputation with many folks for rebuilding, and will do some switching/swapping, I understand. They may even cut you a deal to swap for a more appropriate-to-diesel-use turbo, since most of their business on the small turbos is probably with the ricer gas-burners. They're @ 137 W. Katella, Orange, CA 92867 phone: 714.639.4933. Seem like good people & knowledgeable, though I haven't a whole lot of business with them yet.

Hopefully in the near future, I'll be putting together a 1.6TD in a 1.5 block, and, due to costs and availability, I may just use a cherry 1.5N.A. head, with some heat-rejecting coatings appropriately applied to combustion surfaces, valve faces, and exhaust ports. The block already has had piston squirters installed, and the 1.5 pistons have been notched for them, as well as the whole rotating assembly balanced(Rev-Power). I will coat the piston tops, and am using head studs (from RaceTech). Even though it will have an air-to-water I/C, I don't plan on running much over 10-12psi. This project is about economy and clean running, not raw power.  Currently the car has 2.25" exhaust all the way back (big difference, even with the N.A.), and I have a very short glasspack to install on it if it's too loud running open after the turbo.

Best wishes with your engine build.

J.R.
SoCal
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: Rabbit on Roids on October 23, 2009, 08:27:26 am
NintendoKD, if you still want to get a rebuild kit, Turbo City  http://www.turbocity.com/  sells them. They have a good reputation with many folks for rebuilding, and will do some switching/swapping, I understand. They may even cut you a deal to swap for a more appropriate-to-diesel-use turbo, since most of their business on the small turbos is probably with the ricer gas-burners. They're @ 137 W. Katella, Orange, CA 92867 phone: 714.639.4933. Seem like good people & knowledgeable, though I haven't a whole lot of business with them yet.

Hopefully in the near future, I'll be putting together a 1.6TD in a 1.5 block, and, due to costs and availability, I may just use a cherry 1.5N.A. head, with some heat-rejecting coatings appropriately applied to combustion surfaces, valve faces, and exhaust ports. The block already has had piston squirters installed, and the 1.5 pistons have been notched for them, as well as the whole rotating assembly balanced(Rev-Power). I will coat the piston tops, and am using head studs (from RaceTech). Even though it will have an air-to-water I/C, I don't plan on running much over 10-12psi. This project is about economy and clean running, not raw power.  Currently the car has 2.25" exhaust all the way back (big difference, even with the N.A.), and I have a very short glasspack to install on it if it's too loud running open after the turbo.

Best wishes with your engine build.

J.R.
SoCal

i would do the exact opposite dude. take a turbo block and dump a 1.5 rotating assy in one. instant high revving, more boost friendly engine. bolt an AAZ head on top too, then you might have something worth while. 1.5 blocks are just so weak.. they are like, stupidly weak.
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: maxfax on October 23, 2009, 02:08:31 pm
And once again a 1.6 rotating assembly under a 1.5 head makes the compression high..   Throw some boost at it and you'll see how weak that block is...


X2 about Turbo City though...  Been very happy with them.
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: NintendoKD on October 23, 2009, 02:32:48 pm
sooooooo.. anyone got a 1.6 td block for me?  local would be nice, still in the market for one, theres money and a perfectly good "non-cracked" 1.5 block in it for ya too I want the td block because of the oil squirters. any takers tried craigslist and stealbay, I have other stuff too like the stock diesel intake mani, t61 greddy tc, and LOTS! of interior mk 1 parts from my 78 gasser
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: RustyCaddy on October 24, 2009, 08:14:30 am
Jack at VW diesel parts said to use a 1.6 liter head gasket when I got the oil return reducer and gasket from him; not the 1.5 liter headgasket.

i have a 1.5 head with head studs on a 11mm 1.6 liter block...ready to install.  I have read the compression should be 25.3:1 instead of the usual 23.5:1 for a 11 head/block.  All i am needing is a dependable commuter with good mpg; Jezz...i hope this thing works out :-\.
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: Rabbit on Roids on October 24, 2009, 09:20:14 am
what the hell is the difference if you use the 1.5 or 1.6 gasket? they are both made from the same thing. FIBER
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: RustyCaddy on October 24, 2009, 10:32:04 am
The 1.5 liter gasket is made for the small owl return opening so when it is fitted to the large oil return opening of the 1.6 liter block the extra fiber of the headgasket is exposed at the interface and maybe breaks down overtime...i think this can be an extra source of gasket failure....you'd have to ask Jack for more info cause he is the man selling the oil reducers.  i thought i would use the 1.5 liter gasket and he corrected me.
Title: Re: can a 1.6T bottom end marry to a 1.5 top end?
Post by: maxfax on October 24, 2009, 10:44:30 am
Rusty pretty much has it..    Actually the hole in the 1.6 gasket is just plain too big for the 1.5 block and head.. Or the 1.5 gasket is just too small for the 1.6 block and head... Here's a fizzy pic of a 1.6 head with a 1.5 gasket sitting on it.. Note the very slight gap where the arrow is pointing...

(http://i295.photobucket.com/albums/mm124/maxfax3/DSCF1611.jpg)