h25 motor?

Tech tips and how to's

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SLOroadster
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Post by SLOroadster »

For your information, the only parts that havent been replaced are 8 valves and seats (all checked by by machinest) 4 gears, 2 tensioners, 1 guide, and the jackshaft. Every single other part is new or rebuilt (crank, rods, pistons, rings, cam, rockers, bearings, chains, valve seals, valve springs, and all other gaskets.) I haven't had a single problem with the engine its self, yes the electricals had an issue, ok, its the original harness. The trany was in need of a rebuild, the 2nd and 3rd synros were bad, 5th gear was just the final straw. The rear end however is really irritating because I was told that it was NOS and assembled by a pro who knew what he was doing, however other things that I have found tell me otherwise. Would these have happened on the old engine in the same # of miles, my guess is yes.
Am I embarrased that my car doesn't work even though it has a ton of trick parts, hell yes. The problems I have are related to things I haven't touched, not because I tried to fix them and screwed up. I don't need people rubbing salt into open wounds.
On the topic of buying new timing sets, Ralleye charges an arm and a leg for their stuff. There are other vendors out there.
On the solex topic, I wouldn't spend what Ralley wants for any set of carbs, $200 will get you an intake and another $400 will get you a set of carbs, and $120 will buy a new set of linkages that are better than the stock ones. Will the stuff be new, I doubt it, some of it perhaps, but will it all work just as well in the long run, yes. Any 510 guy is in the same boat with the 44phhs. If I were to build a stroker R16, I'd still spend the $$ for a set of 40phhs.

I'm sure you had issues with your 510 wagon that just irritated the heck out of you; or do you have the car that never gets driven and never has had or will have a problem let alone 2 big ones at the same time?

Will
Sorry, I find modern engine swaps revolting. Keep your G, R, or U series in your Roadster!
toolsnob

Engine

Post by toolsnob »

Hey Will,

To start:

1- You never rebuild a engine without rebuilding or replacing the ancillaries. Just bad practice.

2- You don't stick a bad tranny behind a good motor. If you knew it was bad then you should of had it fixed BEFORE you reinstalled it.

3- I'm not blaming you on the traction control. You might as well chuck it though because parts are nla.

And as far as the wagon is concerned it is sold because I bought the roadster....wanna race roadsters????

And yes there are times that I had my head against the wall but it wasn't because of my lack of competence. Everything I pulled I went through and repaired as needed. Try making a custom engine harness for the fuel injection then give me a call.

Alexi
TR

Post by TR »

Maybe we should all agree not to post to this topic anymore - It has gone beyond offering advice and opinions, etc. to a bit of personal attack and slander.

So yes, Will has all the trick parts and has nothing but trouble with the car. Is it bad luck? People make their own luck the old saw says...We all know that a performance modified car is less reliable than stock. Many reasons for this; it is driven harder, a lot of performance gains are made at the sacrifice of the engineer's safety factors, etc..When was the last time you got a warranty with a performance bolt on?

And maybe he took a path that others would call shortcuts. But with limited resources he had to take risks and he put his car money where he wanted it. Maybe it would have been better to fix the tranny with some of the cash than buy a LSD. His choice, I don't think anyone else needs to point out the consequences...(I remember 10 years ago when my only transportation was a 510 that I modified to the point of non functionality, luckily though I could make it limp over hwy 17 with all the stock equipment otherwise I would not have been able to get to work - lesson learned)

And about that wagon and the wiring harness - Alexi was making great progress on it and figuring out all of the details...But I never did hear that engine fire up...

So, lets get the forum back to the helping each other solve issues and parts availability, etc. discussions and away from the my car is better, name calling, character attacks, etc...If your entire persona and ego is made up of these little cars, it is really time to re-evaluate what you are doing with your life.

Off the soapbox

Here's to lots of car project progress during the cold months, TR
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67 1/2 1600

Post by 67 1/2 1600 »

spl310 wrote:

I was just bustin' his balls a little


That's gross, Sid
Sid didn't say that, Mark did.
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spl310
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Post by spl310 »

To quote one of the accidental philosophers of our time:

"Can't we all just get along?" Rodney King, 1992

Back on topic, has anyone on the list ACTUALLY laid eyes (or better, hands) on an H25? Just curious...
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toolsnob

H25

Post by toolsnob »

I have never seen one but the H20 has like an 8 to 1 ratio or close, so if you can't increase its compression and open up the head it sounds like a real fork lift motor.

Alexi
steve68

Post by steve68 »

you have to put a realyl cut down r16 head on it.....or get custom pistons made then the r16 head (but not cut) i think this is the route i may go


there is a 1500 engine on ebay if anyone is intrested..just block and internals

steve
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RE:H25

Post by S Allen »

A guy on this forum was going to try to locate an H25 some time ago. I think he ran out of luck. The H20 blocks are not much easier plus they are exspensive new. I priced the H20 crank from several forklift dealers and it was around $525.00. Not cheap either. The very same crank was avialble from NISMO for around $325.00. It is listed as a stroker crank. Not sure if you can still get them but the H series engines whole are very pricy. The after market parts such as timing components are cheap and work just fine.

Steve
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dbrick
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Post by dbrick »

Found the spec's for the H25, may not be a bad base to start from.
http://www.frontierequip.ca/nissan/nissanH25.htm.

I don't think the photo is correct, . Has approx 1.375 intake valves, and 1.18 exhaust. Also, it's a big bore/short stroke so properly balanced high RPM is possible.
Also noticed that both the hH20 and H25 have an integrated coil electronic distributor, anyone know if that fits a R16?

Here's a link to dimensions


[/url]http://www.zenithpowerproducts.com/imag ... ic.jpg[url]



H25

Intermittent output (SAE gross J1349)
62hp / 3,200rpm

Continuous output (SAE gross J1349)
56hp / 3,200rpm

Peak torque (SAE gross J1349)
132 ft-lb / 1,600rpm

Minimum fuel consumption
210g/hp-hr / 2,600rpm

Fuel & type
gasoline, lpg & ng 4-cycle, O.H.V.

Cylinder arrangement
4 in-line

Combustion chamber
wedge shape

Bore x Stroke
3.61 x 3.26 in

Total piston displacement
150.85 cu in

Compression ratio
8.7:1

Length x width x height (standard model)
30.31 x 22.10 x 26.42 in

Dry weight (standard model)
345.4 lbs


[/url]

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TR

Post by TR »

I'm thinking large displacement for torque and no ability to climb to useful RPM for street driving. 2.5L is a very large set of pistons and for an inline 4 and without a counter shaft, which I bet this engine does not have, it will tear itself apart at higher RPM.

If this engine was capable of making more RPM/HP in any form, Nissan would spec it as such...TR
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dbrick
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Post by dbrick »

I guess the real question is if the H25 goes on the factory motor mounts and bellhousing/transmission match up. If not, it's not worth the effort. There are stronger lighter more high tech motor trans combos that would be much more powerful to run, and cost less to install.

The cool thing would , of course be, to build the 2.5 liter and have it look like a stock R16.

Dave Brisco

Take my advice, I'm not using it"

66 2000 The Bobster
64 1500 in pieces for sale
1980 Fiat X1/9
2009 Volvo C-70
08 Expedition EL, STUPID huge but comfy
1962 Thompson Sea Lancer, possible money pit
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