*****

 

another question on the Wiseco 536M89's. Are they 4032 or 2618?

 

The pistons are intended for low compression, high boost setups and are manufactured from 2618 alloy.

 

sorry to bother you again, Robert, but the debate on v6p is what are the negative affects of putting j37 heads on the 3.0. Does the combustion chamber on the j37 heads measure 90mm? Bore on the 3.0 is 86mm, so if we put 3.7 heads on the 3.0 will that cause a compression loss? Sorry to derail the thread, but we would like this question answered, and you have the knowledge to answer it. We've tried getting others to chime in, and no one is answering. Thanks again for helping us all out!

 

I would think you would increase compression since there would be less combustion chamber volume. Think about it. Your compression ratio is the amount of air you are squishing into the space between the piston top and the combusion chamber. You are forcing the same swept volume of air into less overaall space since your combusion chamber is reduced by 4mm. I didn't think about it, but I think that could possibly be the source of your 'insufficient' gains with the 3.7 heads. That's a 2mm overhang of the combustion chamber all the way around.

It may also mess up tumble and swirl properties and potentially limit overall timing capabilities. How much timing are you running? I forget if you tuned it yourself or if you had it tuned. If you had it tuned, did they say anything about it knocking early or if they had to reduce timing from what they would normally see in a J37 or even a J30?

 

yungone (I think it's Robert?),

I read your entire build thread in the CL forum and have to say, wow! Amazing not only the work you have done, but the amount of info you have shared.

I know this is slightly off topic from the piston compatibility, but related. You found the 5.4 Ford rods that you are going to modify for your 2.8 motor. Have you found anything remotely close to working for a stock J32 rod other than Pauters? It would be awesome to find an off the shelf piston that needs minimal machining that would work. I guess if there was one though, the company would probably machine them and offer them for the J32.

The only 162mm rod I can find is a Manley Turbo Tuff rod for the 4G63 and none of the other specs are remotely close.

 

Before going any further and expanding on the results I got today, I'm posting my original response/answer to Accord325's question that I typed last night:

If we're talking about installing the 3.7 heads on a 3.0 than yes, I'd feel its safe to say that there undoubtably be issues. Here's why, Honda made different part numbers/castings for the j30's than they did for the 3.2 and larger displacement engines. To my knowledge, the 3.2's and larger displacement engines all use a chamber diameters slightly above 88mm...this includes the j37 heads as well. This is why they're interchangeable between displacements. Though I've never even seen a j30 head or had any interest in doing so, logic tells me Honda more than likely made the chamber diameter slightly smaller the bore as they've done with other engines larger in size. So, to answer your question, I'd say there would be a HUGE impact on the engine due to the chambers being larger than the bore of the cylinder they sit on. You would probably be looking at a 1-1.5mm interference between the chamber and deck. Again, logic tells me flame propagation would be greatly afflicted by turbulence and this would impact performance severely...as well as numerous other things.

Anyone that's thinking about doing this should definitely take a few measurements between the j37 and the j30 chambers and confirm wether or not this is true. If nobody has any j30 heads readily accessible for this, let me know. I have a pair of heads that came off of a JDM j25 that I purchased for my current 2.7 build. I'm wondering if they too would have the same heads as the j30 since the 2.5 was also a 86mm bore engine.

I will answer your questions by revealing the results of measuring some combustion chambers today at the shop. Firstly, as I initially presumed, the 2.5 combustion chambers measured at a diameter of 85.59mm or 3.37". It's also worth mentioning that the j25a uses the exact same heads (matched by part numbers) as the j30a1. Secondly, no. The j37 head chambers measure slightly above 88mm (I think they were 88.20mm last time I measured them) and work well with any 3.2, 3.5 or 3.7 j-series engine. The same goes for all other heads...to my knowledge.

As far as what issues this would cause, go back and read the response I gave at the beginning of this post to Accord325. To reiterate, it would appear to primarily affect the flame propagation and potentially create preignition due to the sharp edges being exposed within the chambers. Especially with forced induction engines.

One thing that I keep thinking of is I thought I read somewhere on V6P where someone installed j35a8 heads on a j30 once before. I believe they were having some issues with the engine not warming up properly but can't be certain of this. Perhaps you could recall or confirm this. My point here is that this would, in essence, be the same thing as using the j37 head on a j30 as they have the same chamber diameters. If I'm correct I'm my recollection, maybe you reread through his thread and see what type of other issues he had....if there were any other issues at all.

Thank you. I have a unusual passion for engines that seems to dominate any other interest or hobby I once had. Its not hard to see that 99.9% of my build thread highlights the engine build moreover than the car itself.

I'll have to look back through my blueprinting notes but I believe I found a usable aftermarket rod for all but one of the j-series. And by "usable" I mean, with basic machining, the rod would be able to meet factory rod specs and measurements.

 

I measured the J30a5 heads CC and it came to 86mm (cheap micro meter) and the J37's are 90mm (again cheap micro meter).

The lack of power indicated the set up not bein optimal and having issues on a J30. Car warms up fine but power just isn't there. I greatly appreciate the response and will be swapping heads yet again.

Also apologize for thread bombing. I read your threads like its a car bible

 

What is the casting code on the j37 heads you're measuring here, RYE or R70?

The reason I ask is because I've measured every j37 chamber including the RKG and the R70. However, I have yet to measure a RYE casting which is the 07-09 MDX j37a1 head.

 

If you had a bunch of money laying aside you could have the chambers welded on a head off a J37 and not only bump compression up but change the quench and force the air fuel mixture right into a pocket on the spark plug.

Like these:



I considered it and had the heads that I'm now selling modeled for welded chambers, and they said they could've got the J35A8 heads to a 50cc combustion chamber if I had decided to go that route. Stock they're 53cc for J35A8, I'd think it's probably pretty similar for the J37.

Then you'd get the most out of putting the J37 heads on a J30.

Naturally with a larger chamber you're going to drop compression, I'm not all that familiar with how it will effect the combustion process though having a chamber that is wider than the bore.

 

I believe the chambers on the head in the picture is something like from Theoldone.com. Guy is a mad scientist with that stuff. Unfortunately, other than chamber size, the j37 has no advantage over any other j-series head. I'm quite certain they're all shaped the same.

Also, reshaping the chamber to a smaller diameter would be a lot of work.

 

So I wasted $1,000 on a heads swap that would've essentially lost power.....

 

wow... wtf? OKay so will a j37a1 block be a direct replacement for a j30a4/5 or a j32a3? I found a short block j37a1 for sale

 

I doubt the trans will bolt up to the J37a1.

 

I don't think so. I think the J37 has a different bellhousing pattern, and depending on which J37, maybe not even manual compatible.

I suspect, and am looking for confirmation that the J35A6 and 7 from a 05 - 06 Odyssey will work with the 'old school' J30/J32 transmissions.

The a7 has piston oil squirters as well. There is rumor that they are FRM liners, but I really don't care about that. The CR is only 10:1 as well, but that is better for FI.

The part number is the same on the following blocks, except for the 3 letters which indicates what vehicle they came in first.

J32A1 - 1999 - 2003 TL
J32A1 - 2001 - 2003 CL
J35A1 - 2003 - 2004 PILOT
J35A1 - 1999 - 2004 ODYSSEY
J32A3 - 2004 - 2006 TL
J32A2 - 2002 - 2003 TL-S
J32A2 - 2001 - 2003 CL-S
J35A3 - 2001 - 2002 MDX
J35A6 - 2005 - PILOT
J35A6 - 2005 - 2006 ODYSSEY
J35A7 - 2005 - 2006 ODYSSEY EX-L
J30A1 - 1998 - 2002 ACCORD
J30A4 - 2003 - 2004 ACCORD
J30A5 - 2005 - 2007 ACCORD

While I guess techincally you could use any of these with your transmission, ideally, you'd want one of these engines that has the single port exhaust so you don't have to rethink the exhaust:

All of these use the same single port exhasust, and RV6 lists their PCDs as compatible:

TL 04-08
MDX 03-09
RL 05-08
Accord V6 03-07
Odyssey 05-10
Pilot 03-08
Ridgeline 06-08

So, no J37s in the mix. The Odyssey/Pilot is the 'best choice' I'd think for largest displacement and lower CR. From my investigation, they are a bit more expensive than a TL 3.2, but not that much, maybe a couple hundred bucks.

If you have some J37 heads, I guess you could rock a J35 shortblock and slap those heads on it. But I think it HAS to be the A6 and A7. The A4 has a different oil passage if I recall. I'll try and find that.

 

no j37a1 even with a TL-S tranney... thats a bummer.. Second option was a j35a8 with the TL-S tranney. Last choice is j32a3.

I have the tl-s heads on my j30a5, but I want more powar! either new block or blower.


Hmm if you can confirm that the j35a7 is a direct block on that would be sweet since there are thousands and thousands of those in mini vans.

 

At least you didn't spend money to have them installed. I wish I could go back in time and use different heads when I built my motor

 

Well, it muddies the waters because the 04-06 and 07-08 is different.

Apparently Robert (yungone)has a J35A8 from an RL with an auto (not sure what its from though, I thought an Accord). He also said that an A6 won't work, but I don't know if the autos were different between cars and years. EDIT: I went thru Roberts thread and the A6 does work with the 04-06 TL and older gen transmissions. He switched to an A8 that needs the 07-08 style. Till looking for info on the J37.

If you are using a TL-S transmission from an 07-08, that's already a J35.

I don't think any manual works with the J37, unless you are rocking the 09 TL SH-AWD M6 trans...

 

The 2007-2008 TL-S clutch and 6mt (as a pair) could be used on the j37a1. There is only one open question remaining as an alternative to this, which is if a j37a4 clutch could be used on a 07-08 TLS 6mt or a 8th gen Accord 6mt (transmission casing part #'s and gears 1 through 6 are same part numbers on the 3G TL-S vs 8th gen Accord 6mt by the way. 8th genAccord just lacks factory equipped LSD, but parts are interchangeable with the tl-s). There is a thread open on this ( https://acurazine.com/forums/perform...utches-906678/ ), but we are awaiting the car to be up and running. We see that the j37a4 2010-2013 SH-AWD TL flywheel and pressure plate bolt up fine and have the same offset as the 07-08 TL-S flywheel. It comes down to fork dimensions.

 

Hmm I'm thinking about ripping out the whole subframe from a wreck tls that was t boned and just dropping the tranney, motor and etc in as plug and play. Since the j37a1 is a no go

 

Funny how this got avoided after these heads were so highly recommended to you

 

Pretty sure you're referring to me here and if so, I apologize about anyone with a j30 that went for the j37 heads...specifically Bryan (Sonnick). It was the first time I've ever made a suggestion based off of information I myself didn't acquire. If you go back to the discussion on the matter here (J37a4 Rocker Swap with J30a4 (VTEC intake & Exhaust) - Page 4 - Honda Accord Forum : V6 Performance Accord Forums) and scroll down to post 119, I took this persons information as fact and upheld it. Until recently, I didn't know what the actual chamber size was and as seen in the previous post in this thread when I actually had to obtain measurements from j30 heads I had at the shop and prior to this, I've never measured them. Hopefully anyone else considering the swap realizes that the idea of the 89.2mm chambers sitting atop the 86mm cylinders sounds silly and wouldn't make an optimal match.

 

I wouldn't recommend j37 heads to anyone. J35a8 heads flow better

 

Depends what area of the powerband you're talking about and from there, it also has much to do with what the engines purpose will be. Honda says that the new port shape adds more power (approximately 7hp) over the previous shape. I'm sure if the other heads "flowed" more on average throughout the powerband, they wouldn't have changed all current j-series heads to the j37a1's port shape.

That being said, its a known fact that the tumble ports wide and short port shape is not ideal for higher engine speeds and has been known to actually cause the fuel in the mixture to hit the cylinder wall in such a way that it begins separating. I assume this is why even though Honda has known about the tumble port design with the S2000 around, they still stuck with the older port shape like that of the j35a8....because it's better at higher engine speeds.

So yes, the j35a8 flow better. But I believe that if you are one that has a stock or even mildly built motor, you will want to use the j37a1 heads. And that would be 95% of the people out there. Hard to argue with Honda that the heads don't add power over the previous design. And to me, following their guidance is the smartest way to go.

 

I wish I had known that info when I built my j36. I think you or I didn't know the ill affects the tumble ports had on higher rpm operation when you recommended them for my build. This probably explains why my low end torque is so good and the also why my DYNO numbers suck

 

I looked for a build thread on your J36 but couldnt find it. What did you do and how much power did it make? I saw a post on v6p where you said you made 290 on a J32 - what all mods did that have at the time?

 

289.6 /239.6 j32 full bolt ons -type s cams -Oem ecu

298/271 j36 full bolt ons- rl cams tuned on flashpro

The way Robert describes how the tumble ports are designed, is exactly how my powerband is. I have 250ftlbs of tq from 2500 rpm and it peaks at 271. The high end is where the motor really struggles and loses steam. I don't even enjoy driving the car because top end power is GARBAGE

 

You should see about proving the theory right and install some other heads with the old port design on them just to see if you gain the top end back. I'm curious to know myself if that's been the case.

 

I think the point is already proven with all the other j36 builds yielding 310+ hp, and that was with aem fic for tuning.

In the end, I can only blame myself for not doing more research. Live and learn.

 

Got a link to the graphs of the J36? I'd like to see it. Also, was it the same type of dyno?

 

There is a pic of it in my car for sale thread on v6p. Yes, dynojet

 

If my numbers didn't Fuc$ing blow with the J37a1 heads (J30 here), I dont think anyone would thought of figuring the CC size of these heads. I fully worked and decked J37's on my J30 and gained 9whp-5wtq from adding them, PCD's, and Tuned on Pro.

You think Sonnick was disappointed? As Simi said, it's no one's fault but our own. "Live and Learn". Just sucks I was the guinea pig who actually got around to installing them.

Worked J30a5 heads in progress.........

I think these heads will yield good gains on a J32, J35, J37, obviously the now "mushroom shape" CC on the J30 is not good.

 

I don't think my J37a1 chambers are 89.2, they looked slightly smaller than 89. Plus the more aggressive came and lighter valvetrain may prove to be better in the 2010+ heads. Anyone want to find out?

 

I saw your graph. I see what you mean about it running out of steam. Torque begins to decline around 5500, and HP peaks at just under 300right before 6000, and then starts dropping around 6400.

Everyone has their own opinion, but I don't think the heads are the problem. I think you need a good seat of cams. I fail to see the logic in using a set of cams designed for a smaller displacement engine, that focuses more on idle quality and pulling a 4000lb boat out into traffic and lugging the motor like typical Americans do, rather than using a performance set of cams designed for high rpm power.

To me, other than the lower peak rpm, your car seems like it would be a blast to drive. Hell, if you could even degree the cams to carry the power out longer, you might get another 3 -500 rpms worth. Do you have any pulls that you carried to fuel cut or redline? I wonder how bad it drops above 6500, because it looks like it would be fun as hell driving that and shifting at 7K.

I think you're probably leaving a good 30 WHP or more on the table with those OEM cams though.

 

those pulls were done to 6700. I raised the rev limit to 6900 and I went back to the dyno a few weeks ago with the same result. I went to the dyno with an extra top plate to the intake manifold with the butterfly plates removed. I lost 20 ftlbs across the board. The tuner could on gain 6 back through tuning. I put the top plate with the butterflies back in, and power was restored. The car will hopefully be gone this weekend so I can just wash my hands of it
Here is a little vid I made. Excuse the missed 4th, lol. You can see how the motor struggles to make power up top, especially in 4th

 

It makes me sad you are selling your car...

 

Lol, he told me that nearly one year ago. Honestly, I've been too busy here lately to make a response to the past few posts in this thread but I'd like to say I think Simi should take another look back at the engine as screaminz above said. I'll elaborate more here shortly...

 

Im loosing lots of power up top, you can feel it start to struggle around 5500-6k (even though vtec is giving it a nice boost) but i know my issue is my puny 67mm tb. My motor simply isnt getting enough air (though that will be resolved once the body work is done)

 

Not sure if the tb is your problem. ILC went from the 80 mm TL tb back to the stock tb and only lost 1 hp IIRC. At least you have the better heads and can utilize true exhaust manifolds

 

Air is the issue, id place money on it that there isnt enough getting in. Especially watching the live data while driving it as it hits those areas