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Discussion Starter · #1 · (Edited)
Im actually looking for more of the usable engine building information:

J30/32/35 Deck Heights =
J30/32/35 Bore Spacing =
J30/32/35 Connecting Rod Lengths/Widths =
J30/32/35 Connecting Rod BE Bore Sizes = 2.204 (J30)
J30/32/35 Piston Compression Heights =
J30/32/35 Wrist Pin Diameters =
J30/32/35 Rod Journal Diameters (Crankshaft) = 2.0857 - 2.0866 (J30)
J30/32/35 Combustion Chamber Volume (Cylinder Heads) =
J30/32/35 Valve Diameter =
J30/32/35 Head Gasket Thickness =

If that information is available, I can add some of my experience into the mix. I have an extensive background in Honda performance engines, dealing primarely with the H/F series 4 cylinder engines. I have recently taken a liking to Hondas J series V6 engines and plan to take on a few R&D and product development projects for the J series V6 over the next 1-2 years. I really like this site and have to give a big thumbs up to the current contributers for going out and doing something new.

Id like to look into the different potential combinations of connecting rods and crankshafts as well as a few other aspects of these motors. Id need the information above to get started on that.

For those who are interested, here is an article I wrote on offset grinding H/F series crankshafts that can definitely be applied to the bad boy V6 as well.

Rick Solis said:
I have received several e-mails and IM's over the last few months requesting that I re-post the offset grind article I wrote mid last year. I had taken a long break from the Honda scene (I still am on an extended hiatus in a away) and pretty much deleted everything on my computer that had anything to do with Honda's, the offset grind article included. So, I’ve decided to write another:

Offset Grinding Rod Journals H/F Series V2.0

There will be some updated info and a few new specs in this version, Ill also be doing a follow up article this time around so stay tuned.

Well, to start Im going to cover the basics of offset grinding the rod journals on a crankshaft...

Introduction - What is offset grinding?

The word 'offset" in the term, "offset grind" is in reference to the centerline of the rod journal being relocated, or, offset +/- .xxx from its original location. By changing the centerline of the journal you can increase or decrease stroke as much as the material on the journal, available rod bearings and rod BE bore options will allow. The actual diameter of the journal itself is reduced with material being removed from the top or bottom of the journal to either raise or lower the journal centerline which in turn increases or decreases stroke.

Confusing? Well, to make it a little easier to understand, here is a detailed illustration of an offset ground journal:

One of the nice things about the H/F crankshafts is that the majority of them start out with 1.890 rod journals (excluding the F23 and F20B) which is the largest of Hondas 3 1988+ 4 cylinder rod journal sizes.. Now the reason the larger journal is nice to have is simply for the fact that you can decrease journal diameter to either of the 2 smaller Honda journal sizes to increase/decrease stroke.

The most common Honda journal sizes and diameter differences from the H/F crankshafts are as follows:

H/F/K series

1.771 - .119
B/D16 F23/F20B

1.653 - .237

Offset Grinding - How is it done?

The first step of the process is to change the journal centerline by removing material from either side of the journal (dependent on either the increase or decrease of stroke). The amount of material to be removed is largely based upon the calculation of the distance from the original centerline of the journal to the centerline of the new journal diameter and or desired stroke.

Here's an example of what was described above:

The next part of the process involves the actual journal shaping and finishing. To do this process correctly, with out the possibility of error or journal deformity you are required to do a complete 360 removal pass of the journal. This usually removes .019 from the top, or if decreasing stroke, bottom of the journal to ensure that the journal is exact in round. So by stepping down one journal size (1.890 to 1.771) you are increasing/decreasing stroke by a maximum of .100. You also have the option of the D15/1.653 rod journal which can increase/decrease your H/F series stroke by a total of .218. Looking at the figures for the 1.653 journal can be a bit confusing, so here’s a calculation to break down the journal size differences between the 1.890 and 1.653 journals and the final stroke measurements.

1.890 - .237 - .019 = .218

The .019 is the material removed for the final shaping and finishing of the journal as described above.

Here's an example of the above described:

Now keep in mind, the actual centerline can be placed anywhere within the stock location and maximum of +/- .100 with the 1.771 journal and .218 with the 1.653 journal. This means you can have, for example, anything from a 3.470/87.1mm to 3.670/93.2 stroke with the 1.771 journal and anything from a 3.352/85.1 to 3.788/96.2 with the 1.653 journal.

Here is an example showing the range in which you can place the new journal centerline when stepping down 1 journal size:

For the most part, that covers the basics of the actual process of offset grinding. Im going to go ahead and skip the heat treating, balancing and micro polishing steps. Although very important, and, all very vital steps in the offset grinding process, I feel as if they are all pretty commonly understood and, IMO, don’t require a detailed description.

I hope this can be of help to those who are trying to gain better understanding of what offset grinding is, how it is done and how it can be used to broaden the currently available stroke options.

Stay tuned, there is more to come!
Honda generally sticks with the same basic journal sizes for their crankshafts and the same BE bores for their connecting rods on all of their 4 and 6 cylinder engines. Thats one of the reasons I requested the info above, to see if maybe some of the aftermarket rods availabe for the B/H/F/K motors might work with he J series V6. This would broaden the r/s rato possibilites of each possible combination as well as keep costs down for forged rods (there are many off the shelf rods for 4 cylinder Honda's that are quite affordable).

Id like to also cover piston combinations, both custom and OEM as well.

Anyways, sorry for the long introduction. Im here to learn, learn, learn and contribute where I can.


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If you want i can email a section of Helm service manual that talks about spec and service limits for J30A1 engine.

J30A1 engine for 97-99 Acura CL 3.0 and 98-02 Accord V6
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