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Thu Oct 23, 2008 9:36 am

Some Newbie questions...I did some searching but couldn't really find what I was looking for...please point me in the right direction if these questions have already been discussed:

I'm looking to get a used motor I can rebuild as a stock motor, not a racer. I need to keep it simple so I can follow along in the books and easily get parts. Other than the obvious 100cc and the difference in horse power, are there any real differences between stock 1500 and stock 1600 engines?
Is there any true advantage to one over the other like reliability, getting replacement parts, ease of repairs, etc?

I think I have a handle on single port v dual port...SP gives more low end torque and DP gives more high end torque...and this is just a preference thing. Are there any mechanical advantages to one over the other, like reliability, replacements parts, ease of repairs, etc?

Like I said, I'm interested in keeping things as close to stock as possible...not a custom or high performance engine. Thanks for your help in advance.

Thu Oct 23, 2008 10:41 am

Well, SP cylinder heads are not as plentiful as they once were. Especially for new ones.

There really aren't many true 1500s left out there, since the 70s, it's been cheaper and easier to buy 1600 piston/cylinder sets, and thus, most all 1500s have been rebuilt with them during the last 30 years at some point. ( Finding 1500 pistons and cylinders, you have to search for new-old-stock parts there. I got a set on eBay a couple of years ago.)

The later 1600 dual port engine blocks are better built - dual oil pressure relief valves, and the better case savers/8mm head studs were added a year or two into DP production. And the oldest 1500 blocks still had the small 6mm oil pump and smaller oil galleries. That's not to say that if you had a 68-69 vintage H-case engine wit the 8mm oil pump, that wasn't ever abused, nice and tight and unwarped and the like, that it wouldn't be a good candidate for a stock SP rebuild. But I think I'd rather use a later block myself.
Reliability - I've seen engines built in the mid/late 60s have issues with kind of weak metal on the blocks - head studs and sometimes 8mm case half studs pulling their threads out. I've heli-coiled the 8mm ones when they've failed. For head studs, if have "case saver" metal thread inserts put in when the engine is apart, that'll take care of that issue.

Maintenance, they are pretty much similar. SP's have a little easier access around the spark plug area, but that's about it.

You do get a different power curve with a DP - but if you like smoother running at lower speeds though, SPs are usually better.

-Andy

Thu Oct 23, 2008 12:03 pm

I've toyed around with the idea of building a little gem of a 1600 DP w/ a counterweighted crankshaft, Engle W100 or similar cam, and ported/polished stock heads running dual Dellorto 36 DRLAs, but then I'll just get carried away with it and end up building a 1776. :P

Thu Oct 23, 2008 12:13 pm

sactojesse wrote: I've toyed around with the idea of building a little gem of a 1600 DP w/ a counterweighted crankshaft, Engle W100 or similar cam, and ported/polished stock heads running dual Dellorto 36 DRLAs, but then I'll just get carried away with it and end up building a 1776. :P

That's exactly what I just built, I'll let you know how it works out.

Thu Oct 23, 2008 12:41 pm

Yeah, let us know. But try a new or different thread when you do. The guy that started this thread was asking about stock engines, DP or SP, and their pros and cons, not hopped up ones. :wink:

Thu Oct 23, 2008 2:56 pm

glutamodo wrote: There really aren't many true 1500s left out there, since the 70s, it's been cheaper and easier to buy 1600 piston/cylinder sets, and thus, most all 1500s have been rebuilt with them

Thanks for the info. Does changing from 1500 to 1600 heads require machining of the case or is it just the heads and whatever is in them that is different? If machining is required I think it would be better to find a 1600 as a starting block instead of paying that extra labor charge. I'm trying to do something on the relative cheap, but don't see the point in buying something that will just cause more problems and cost more later. The problem is I'm only finding used 1500s.

I do know a guy with a 67 1500 SP. I heard 67 was supposed to be a great year for strong motors. Any thought there?

So it sounds like it's difficult to find replacement SP parts, and that DP may be the better way to go for that. It sounds like that is better for highway driving anyway.

Thanks again...

Thu Oct 23, 2008 3:28 pm

Karmann Paul wrote: Does changing from 1500 to 1600 heads require machining of the case or is it just the heads and whatever is in them that is different?
1300/1500/1600 cylinders have the same external diameter at the base, so no case machining is required. (However, they have different internal cylinder diameters to accommodate the respective piston bores: 77/83/85.5 mm, hence the larger displacement.) 1500 SP and 1600 SP used the same heads (35.5mm intake/32 mm exhaust) w/ the same diameter at top of cylinder. On the other hand, 1300s have the same diameter at base of cylinder as the 1500/1600s, but are smaller at the top of cylinder and used different heads w/ smaller valve sizes (33mm intake/30mm exhaust) than the 1500/1600 SP. Thus, no machining is required at either end to go from 1500 to 1600.

Thu Oct 23, 2008 6:15 pm

Karmann Paul wrote:
I do know a guy with a 67 1500 SP. I heard 67 was supposed to be a great year for strong motors. Any thought there?

So it sounds like it's difficult to find replacement SP parts, and that DP may be the better way to go for that. It sounds like that is better for highway driving anyway.
...

I don't know about that - the only really hard to find part are new heads, and there are still a lot of them in the used/rebuilt market. Dual ports are Ok, I have one in my baja bug, but I have an old big-bore 40HP in my other one and I like how that one runs too.

Now the 1967 block - could be OK but might not be. That was the last year for the small 6mm oil pump studs - late in the year they changed to 8mm. It really depends on how good of a life its had, as to if the block is really that great inside.

-Andy

Thu Oct 23, 2008 7:35 pm

start out with a good to very good late model case, dual releif. Then the crank shaft get one that is balanced, then on to what size engine you want. 1600 or 1776 is realiable. Now the heads let the engine breath larger valves and mild porting. Cam keep it mild as you seem like you want a lil more get up and go and MPG also. Full flow oiling..all of this does cost $$$. at least 2500 for a realible quality parts build engine.

Fri Oct 24, 2008 4:59 am

glutamodo wrote: Yeah, let us know. But try a new or different thread when you do. The guy that started this thread was asking about stock engines, DP or SP, and their pros and cons, not hopped up ones. :wink:

Yes I know, It just caught my attention. I know a few guys with buggy's who run a 1600 as41 case single port heads. If you wanted to keep it correct for that car, I would build it to factory specs. Just keep it simple. That's my 2 cent's worth, but what do I know.

Fri Oct 24, 2008 5:51 am

I had my 1300cc bored (heads only) for 87mm cylinders, and with the centermounted 40IDF it seems to have a lot of umpf, with the SP heads. The block I used is a F-block, line-bored 0,50mm.

Fri Oct 24, 2008 7:11 am

My 66 had a 1500 case, so I assumed it was. When I tore it down, someone had installed 1600 pistons/cylinders. 1600SP runs nice and I average 28mpg.