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Discussion Starter · #1 ·
Here's some pictures of a couple of cylinders I ported.

Below, the cylinder on the left is an '87 (67x76) that now is cracked and leaks water. It made 56.4 hp / 34.6 tq last trip to the dyno. Cylinder on the right is an '89 that I am currently working on. The '89 has an aluminum sleeve. Still have some work left to do to the transfer openings into the cylinder, but nearly complete.


Below is are the intakes; again the '87 is on the left, the '89 on the right


Below, is the '89 intake,


Below is the '87 intake.


Below '87 exhaust.



'89 Exhaust.



My plan was to build a 72 mm bore on the aluminum sleeve, but I'm running into trouble obtaining a 72mm o-ringed dome for my Pro-Design Cool Head. Apparantly the largest Pro-Design will go is a 68mm dome (they will supply a dome to LA Sleeve but not to me.....
)

Any one have any ideas regarding a head/dome that'll seal off on the OEM cylinder? Really don't want to do a gasket....

I had hoped to build a 310 OEM sleeper, but may have to re-think my build.....

Regards,

Rog
 

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I think if you can get a blank they come with a larger OD...which means you can machine the shell and fit the larger bore dome. Its been years since I have done a 295, but thats one way I did it.

Also as above- oring it and do up a stock head.
 

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Discussion Starter · #4 ·
Thanks for the replies.

I will have to post some more pictures (be tomorrow at the earliest...).

I have measured the distance between the cylinder head stud holes, and it is right at 78.2mm's.

By going to a 72 mm bore (and assuming that the bore would be just a hair under or so...) that would only leave ~ 3.1 mm or so of surface to seal an o-ring on. Not much area when you consider that the 0-ring I am currently using (from a Banshee Cool Head dome) measures right at 1.5mm in diameter.

The domes I have measure about 1.7 mm in width for the o-ring groove.

The 3 domes I have for the 250R cool head measure just a bit under 78 mm (73.94mm or so) which means I am not going to have much area to support an oring in the dome itself or even in the cylinder for that matter.

The Cool Head shell has some areas that don't support the dome (coolant passages) so that would leave very minimal, if any, support for an o-ring by the dome.

The stock head done up would perhaps be the best bet at getting it to seal on a 72 bore. I would prefer to run the Cool Head, however, if possible.

Thanks.

Rog
 

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Discussion Starter · #7 ·
Yes, they're counterbored for the flanged stock stud. The insert idea sounds good. Thanks.

I've even considered having those counterbores welded up (local guy here does excellent work.... - in fact, he welded the cylinder on the '87 in the pic's above after I broke it a year ago) and using "normal" studs.
 

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QUOTE (Buttermilk @ Mar 18 2009, 03:17 PM) index.php?act=findpost&pid=34965I believe those ESR heads have a different bolt pattern.
ESR makes em for stock cylinders I had one.

Awesome work by the way, Thats impressive numbers from a stock cylinder, My esr 314 72.5 x 76 (trx 11) makes 58.7hp 37.8 tq...
on gas
 

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Discussion Starter · #10 ·
Thanks JP400R. I believe there was a couple more hp in my '87 cylinder. I had plans to try some different ignition maps in the Dyna FS on the dyno, but never got to before I cracked the cylinder. I was expecting to see some gains there....

I will have to check into the ESR heads, but don't expect them to be any better suited for my application than the Cool Head. Have to check into them non the less.

I think if I can maintain the same state of tune on a 310 OEM jug as I got with the smaller motor, I can break 60+ hp on gas, but who knows. Gotta try though. My calculations show that it's doable maintaining the same BMEP (break mean effective pressure). Even taking into consideration some effeciency losses, 60+ hp should be reachable.

Regards,

Rog
 

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QUOTE (Buttermilk @ Mar 19 2009, 09:03 AM) index.php?act=findpost&pid=35045Thanks JP400R. I believe there was a couple more hp in my '87 cylinder. I had plans to try some different ignition maps in the Dyna FS on the dyno, but never got to before I cracked the cylinder. I was expecting to see some gains there....

I will have to check into the ESR heads, but don't expect them to be any better suited for my application than the Cool Head. Have to check into them non the less.

I think if I can maintain the same state of tune on a 310 OEM jug as I got with the smaller motor, I can break 60+ hp on gas, but who knows. Gotta try though. My calculations show that it's doable maintaining the same BMEP (break mean effective pressure). Even taking into consideration some effeciency losses, 60+ hp should be reachable.

Regards,

Rog

When you get to that 60ish hp range, start thinkin about reinfording the the area around the case studs. That will be a week spot.
 

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QUOTE (Buttermilk @ Jun 25 2009, 07:48 PM) index.php?act=findpost&pid=48134Got the cylinder ported and plated. It is installed on the motor and the motor is in the frame. Currently waiting on a dome.....


Shouldn't be too much longer..... I hope.


Rog

Many moons ago when I had my OEM 295 kit. I think the brand of head that I had was a Torqueline (if I remember correctly) I am not sure if you can still get these heads any more. My buddy has my old set up now, I can verify the name of the head if you still need some help.
 

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Discussion Starter · #15 ·
After several conversations with Pro Design and other engine builders, I decided to save myself a potential headache and went with a 68 bore. If I had pursued the 72 bore, I'd probably had as much money in that setup as an aftermarket cylinder, and I didn't want that.

Thanks.

Rog
 

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touqline is RK tech heads they are still in business call them before you give up on the bigger bore..

OR SERIOUSLY talk to backcountry about a stock head.. if your gonna stock look it then do it all the way!!

also check with turbo bobby around the forums he did a LOT with stock cylinder'd r's and made really good hp out of them.. he has a lot of experience with weird rod, piston combo's and higher rpm #s.
 

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I did a 72 mm aluminum sleeve 89 cylinder for my wifes bike, 4 mil stroke yz 490 rod KTM 300 72 mm piston. I had milinium Tech put the sleeve in and I gave them instructions to no counter bore the head stud holes so I could use Pro-X style head studs. My idea was to use a ESR 250r head shell, and a ESR pro-X 72 mm blank dome and machine the 250r shell to receive the larger dome. Since milinium didn't do what I wanted and counterbore the head stud holes, that all went out the window. I ended up using the stock head cut to 72 mm and a copper gasket. It leaked dry of course so I ended up gluing it on and haven't looked back. If the stock head studs aren't used, I believe there was enough room to o-ring the stock head.

I love this setup, 309 cc's in a stock jug, stock head, and doesn't use a cylinder spacer plate. Looks completely stock. Runs well too.
 

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Discussion Starter · #18 ·
Well, Looks like my little project has come to a halt.

Unfortunately, the aluminum sleeve is not holding water in. Not sure that it's the fault of the sleeve since water seeps out between the sleeve and the cylinder at the exhaust port and at the intake as well.

Pressurizing the cylinder with the head on and the radiator hoses attached with no heat shows leakage.

Also, just heating up the cylinder to ~ 200 degrees or so and putting water in the water jackets will show some leakage.

Based on my findings, I think the cylinder water jackets are porous and allowing water to leak into the ports. Don't know for sure how to fix something like this, or if it can even be fixed. I suspect I'd be chasing leaks for a while trying to fix it.


I had originally thought that the water was leaking coming top down between the cylinder and sleeve, but it appears that that's not the case, based on my findings.

I am a bit dissappointed, since I really thought getting some "good" hp from an OEM jug was possible.

Now, I am gonna move on to another cylinder, probably aftermarket, and quit wasting money on this OEM stuff. Seems I've been wrenching more than riding......
 

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It does get old wrenching and not riding and racing. Im with you there. I've gotten burned out a couple times on projects. Just shelf that cyl for a cpl months and when you get an itch to work on it get at it. Do you know Turbo Bobby? He can tinker and fix about anything 250r related. U might ck with him and see if he'd look at it.
 

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You might want to give the "coolant system sealant tablets" that GM dealers sell and is installed from the factory on some known pourous engine blocks.

GM Part # is 12378254

I know of a few guys that swear by this stuff so you might want to give it a shot before giving up on that cylinder.
 
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