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5th gen engine in 6th gen


168sierra

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I am considering installing a 5th gen (2000) engine into a 6th gen (2003) to take advantage of the power of the 5th gen engine and gear driven cams (love the sound) and the handling of the 6th gen with an RC51 front end.

Has anyone used the 6th gen FI on a 5th gen motor? From what I have read, the throttle bodies bolt on. I was palnning to use the 330 ohm resistors to bypass the O2 sensors and run a catless header. I am thinking of trying to reflash the ECU with a 5 th gen fuel map. This should be close but will probably need some fine tuning.

Does anyone have any experience with this? I can't be the only one who wants this combination.

Pics to follow

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You need to scrap that project and put a 5th gen motor in the 8th gen. Shouldn't be that much harder.

I would love to see a photo with the 5th engine in a 6th/8th frame. Carver starting the teasing long ago.

--I'm thinking a 5/8ths VFR would be awesome!

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Got an email from the cam grinders today saying the cams are on there way back to me. At long last.

Should see them tomorrow but I probably won't get anything done over the weekend as I'm at a race meeting all weekend long.

I'll get back in to the motor build on Monday.

Lucky I keep a list of jobs to be done on a whiteboard as I have no idea as to where I'm up to now. Too much time as passed.

I'll keep everyone posted as to progress.

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You need to scrap that project and put a 5th gen motor in the 8th gen. Shouldn't be that much harder.

Thats what Im waiting on.

If I ever burn out my 5th gen - that's exactly my next VFR

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Yeh, you're probably right but I still cannot understand why the didn't put USD forks in the Gen8 instead of trying to make them look like USDs.

Just defeats the purpose and make the whole bike look like a wannabe.

I've got the cams in my hot little hands.

Need to measure them up just to be sure that they haven't done something else crazy.

It looks like the weather here is going to be crap on Sunday so might start on the motor again.

Need to time up the cams and check the valve to piston clearances.

If all looks OK at zero cam/bucket clearance then it should be all go from here on in.

I can finally build up the bottom end once and for all, and get the heads finished.

Just need to match the throttle bodies to the insulators and finish the port to insulator matching.

Valves are lapped and ready to be assembled.

It seems like it has been a long process. LOL

Originally I was going to have it all completed and in the bike about 4 weeks ago.

Phil

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Yep, the cams look all OK this time. Apart from slightly different grind on the exhaust cams.

Just zeroed a pair of valves on number one and installed the soft testing springs.

Ready to drop the head on once I get the bottom end sewn up with # 1 piston.

If the clearances work out OK on #1 the other should be OK as well as they are all pretty identical.

Might get a chance tomorrow night to get some more done. The bottom end and the head on, cams in.

I wish Honda had designed the heads with a bit more clearance around the buckets.

It's going to be a bit tight getting the dial indicator stem to sit on the bucket to test the clearances and to check the lobe centres.

Gee I like Suzuki for their designs so much more.

Oh well, it's what i've got.

I may need to advance the exhaust cam a couple of degrees as it looks like they have ground them at 43/13 not 45/10 as requested. They got the inlet right at 15/45 so can't complain too much. The exhaust has 236 deg duration not 235

From what you were saying in an earlier post Mohawk, the exhaust is pretty close at chasing the piston. If I need to pull the timing back to 45/11, I'll need to press the gears off and move them 1 deg at the cam, or back 1.5 deg to make 46/10. If I do this it will make the lobe centres 105 inlet and 108 exhaust. At the 43/13 I'd be looking at 105/105 where your specs are 105/107.5

Such a shame that there is no adjustment method on these. I'm sure it wouldn't have been that hard to design it with a bolted flange on the inside of the drive gear and threaded holes in the gear itself. The flanges could have them been slotted.

The extra 3 deg on closing might pose a problem. Time will tell I expect.

Phil

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I think you'll be fine with those exhaust timings. When I came up with my specs, I didn't want anything to radical & didn't have the facilities to strip & measure the heads & valves clearances, so just extrapolated from the published HRC & standard RC45 timings. I thought it strange that the RC45 as standard did not have any longer exhaust closing, so I stuck with standard exhaust valve closing.

You can obviously check this, so I'd be very interested in the results. HRC race cam only pushes the exhaust to 20atdc & only additional .3mm lift,so implies its quite tight in there. Where as the push the intake forward 23btdc & lift to 9.5mm.

So RC45 STD HRC

Inlet open 15 ------ 23 btdc

Inlet close 40 ------ 52 abdc

ex open 45 ------ 50 bbdc

ex close 10 ------ 20 atdc

in lift 8.0 ------ 9.5mm

ex lift 8.0 ------ 8.3mm

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Yes I'd much rather not have to press the gears off and on to get the timing.

A slightly longer close on the exhaust should help with power.

I looked at the HRC figures and thought that they may have had larger pockets in the pistons to cover for that.

Don't know what was included in the HRC kit so hard to make that call.

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Well got the 5th Gen engine finished and put it in the 6th Gen frame today.

The engine build process is all covered over at http://www.vfrdiscussion.com/forum/index.php/topic/75067-anyone-ever-reboredoverbored-a-56th-gen/

Here are some images of the transfer.

Backend fully removed and bike supported on frame stand

post-25941-0-91569400-1414831136.jpg

post-25941-0-58509900-1414831147.jpg

Draining the oil cooler etc. before engine removal

post-25941-0-85291800-1414831164.jpg

Lifter in place taking weight of engine with mount bolts out

post-25941-0-16132300-1414831182.jpg

Engine out and sitting on the lifter. Engine dolly in forground

post-25941-0-81566500-1414831198.jpg

6th Gen engine in dolly and 5th Gen engine ready to fit to frame

post-25941-0-58706400-1414831214.jpg

Lifting engine in to place

post-25941-0-64538300-1414831230.jpg

In place and bolted up

post-25941-0-62622400-1414831248.jpg

Exhaust and throttle bodies to go tomorrow and then I'll fire it up.

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Sorry forgot to mention.

I discovered today that the 5th Gen clutch slave cylinder piston is 2mm larger in diameter then the 6th Gen.

Also, if you have ever had a 6th Gen motor out of the frame, you will have noticed how tight it is in the frame due to the oilway plugs on the head for the VTec stuff sticking out quite a long way.

They get caught up on the wiring loom on the left side.

Well the 5th Gen slides in with plenty of room to spare.

One problem you face is due to the 16mm shorter cylinder heads. The hole in the frame on the right hand side to allow you to check the cam timing mark doesn't line up anymore for the rear exhaust cam.

Another is again due to the shorter heads is the bottom brackets for the radiators need a bit of bending to get the rads to fit.

Apart from the above, I've not come across anything that is a real problem.

Phil

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Sorry forgot to mention.

I discovered today that the 5th Gen clutch slave cylinder piston is 2mm larger in diameter then the 6th Gen.

Also, if you have ever had a 6th Gen motor out of the frame, you will have noticed how tight it is in the frame due to the oilway plugs on the head for the VTec stuff sticking out quite a long way.

They get caught up on the wiring loom on the left side.

Well the 5th Gen slides in with plenty of room to spare.

One problem you face is due to the 16mm shorter cylinder heads. The hole in the frame on the right hand side to allow you to check the cam timing mark doesn't line up anymore for the rear exhaust cam.

Another is again due to the shorter heads is the bottom brackets for the radiators need a bit of bending to get the rads to fit.

Apart from the above, I've not come across anything that is a real problem.

Phil

Phil - this is awesome! Thanks for the photos on your build work.. :fing02:

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Well the beast lives.

Fired it up today and whoohoo

Had a bit of a scare to start with as it wouldn't start.

Plenty of spark but the plugs were bone dry. No fuel.

I was trying out the new to me throttle bodies/injectors that I'd ported and matched.

So went back to the stock units of my 6th Gen engine and away she went.

Took it for a 10k ride just to make sure all was as it should be and I was amazed at the smoothness of the transmission.

It feel like it will pull well once I've run it in.

Definitely less down low compared to the 6th Gen but it feels that it wants to run.

I'll post the final images and a short video later.

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As promised here is a pic of the finished product and a short video of the first fire up.

post-25941-0-28443400-1414917278.jpg

Sorry don't seem to be able to upload mp4 files so no video at this stage.

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As promised here is a pic of the finished product and a short video of the first fire up.

attachicon.gif20141102_173429.jpg

Sorry don't seem to be able to upload mp4 files so no video at this stage.

That bike (and video) should be in the VFR hall of fame!

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Thanks guys.

I must say I'm pretty happy with how it has turned out.

Ask me again in a couple of months and I'll let you know if it was all worth the effort.

Cheers

Phil

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