Dragster from New Zealand

Fast Eddie said:

Oil past the guides is a thing if badly fitted etc, certainly won’t be a thing on your Maney head !

Surprised you’re running 30wt break in oil in such arduous situations, what’s your reasoning there if I may ask?

Very surprised and saddened to hear about your issues with Molnar parts.

It’s looking like the wicking loctite is you favoured next step.

What rimgs are you using? Might be worth trying gapless total seal jobs if you’re not already.

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30 weight oil - not running big clearances on big ends and oil pressure 60lb+ cold and 45lb after a run measured at the head rocker inlet. Run that particular oil for high zinc content and I like a mono grade under load. Add the additional TB plus designed for extreme loading. Nil detergents and limited modifiers so oil gets changed frequently.
What would you consider to be more relevant?
Currently using gap rings supplied by Jim Schmidt - considering an option he has for gapless rings. I have nil experience with these so need to do some work on understanding.
Welcome further comments.

gortnipper said:

Where are you located, Alex? I am just NW Auckland.

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Based in Palmerston North.
We run in the IHRA series so get up to Meremere, NAPA dragway, a couple of times a year.

CUin11.2sec said:

Based in Palmerston North.
We run in the IHRA series so get up to Meremere, NAPA dragway, a couple of times a year.

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Our NOCNZ VP organizes most of the Auckland rides as area rep, and as he lives out Bombay most of them cross back and forth near enough to cut down to Meremere.

Let us know when you plan on racing up there, and I'll organize a club ride down.

I'm sure you'd get plenty of shade tree advice!

CUin11.2sec said:

30 weight oil - not running big clearances on big ends and oil pressure 60lb+ cold and 45lb after a run measured at the head rocker inlet. Run that particular oil for high zinc content and I like a mono grade under load. Add the additional TB plus designed for extreme loading. Nil detergents and limited modifiers so oil gets changed frequently.
What would you consider to be more relevant?

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Follow the science.

CUin11.2sec said:

30 weight oil - not running big clearances on big ends and oil pressure 60lb+ cold and 45lb after a run measured at the head rocker inlet. Run that particular oil for high zinc content and I like a mono grade under load. Add the additional TB plus designed for extreme loading. Nil detergents and limited modifiers so oil gets changed frequently.
What would you consider to be more relevant?
Currently using gap rings supplied by Jim Schmidt - considering an option he has for gapless rings. I have nil experience with these so need to do some work on understanding.
Welcome further comments.

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Wouldn’t want to start an oil thread!

I wouldn’t use 30wt personally. Nor would I use break in oil in extreme conditions. I use 10/40 in my track bikes and thicker on the road where I believe a broader margin is helpful (sitting in traffic, higher mileage between changes, etc) but that’s just me.

If you haven’t already, the link gortnipper posted above is a good read.

gortnipper said:

Our NOCNZ VP organizes most of the Auckland rides as area rep, and as he lives out Bombay most of them cross back and forth near enough to cut down to Meremere.

Let us know when you plan on racing up there, and I'll organize a club ride down.

I'm sure you'd get plenty of shade tree advice!

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That sounds interesting, I belong to the NOCNZ but have not attended any events, read the newsletters with interest. Our next meeting at Meremere is around the middle of January, called the Wellington Invasion meeting. Will try and let you know a date when it is confirmed.

CUin11.2sec said:

Hi Jim, yes I used Pliobond on a previous motor which was excellent. Unfortunately it was very difficult to get apart again, sticking too well. Considered not worth the aggravation as usually I have not had issues with sealing.

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I would try loosening the head bolts a couple turns and kicking it over to break loose the pliobond (should probably turn off ignition). Or just tap upward the bottom of the exhaust nut with a wooden block and hammer. Its worth it if it solves your problem.

jseng1 said:

I would try loosening the head bolts a couple turns and kicking it over to break loose the pliobond (should probably turn off ignition). Or just tap upward the bottom of the exhaust nut with a wooden block and hammer. Its worth it if it solves your problem.

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Hi Jim, I did, use those techniques but the head remained stuck, glue really worked a treat. Ended up having to strop under the exhaust and inlet ports and lift against the frame. Really wrecked a copper gasket . That was on our last 750 iron barrel motor so a little different.
I do have a couple of questions for you if you can assist.
I installed the exhaust D port rings you supply - very nice bit of kit and fitted very well. I do however feel like they reduced performance in our engine configuration. Do you have any feedback on using these with open megaphone exhausts mostly with WOT?
Also, the gapless rings option for the Hi-comp pistons I have of yours. Is it possible to retro-fit these now?

Wow I haven't had the pliobond stick that tight. Maybe its because you put a short amount of time on it. It looks like you would have to loosen the head bolts a couple turns and then start it. I'm sure it would either break loose right away or when it warmed up. In your case it looks like the pliobond works a little too well. BTW I have Maney cylinders and pliobond is the only thing that would seal it oil tight.

I've had reports from customers who installed the port floors on stock street bikes and noticed an improvement. But for an all out racer or dragster like yours you would need to do some porting. The floors raise the bottom and give you a better downward angle to the valve. But to get racing flow you would need to raise the port cobra head style - leave it alone just in front of the guide but raise it 1 or 2 mm through the tight spot leading up to the guide and around the guide at around 10:00 and 2:00 similar to Harley XR 750 image below. For a race port you certainly don't want any cross section of the race port to have less area that the stock port.



Yes you can retrofit the total seal rings.

CUin11.2sec said:

That sounds interesting, I belong to the NOCNZ but have not attended any events, read the newsletters with interest. Our next meeting at Meremere is around the middle of January, called the Wellington Invasion meeting. Will try and let you know a date when it is confirmed.

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You should bring your drag bike to the AGM on a trailer, along with a road bike to ride around. Good group of guys and we would all love to have a natter about your bike. We like our brown tea.

2027 AGM Rally will be held in Canterbury, somewhere between 26th Feb and 12th March. Keep your eyes on the newsletter, and if you want to plug your event, Stu, Alan and myself can make that happen and we are all in AKL.

jseng1 said:

Wow I haven't had the pliobond stick that tight. Maybe its because you put a short amount of time on it. It looks like you would have to loosen the head bolts a couple turns and then start it. I'm sure it would either break loose right away or when it warmed up. In your case it looks like the pliobond works a little too well. BTW I have Maney cylinders and pliobond is the only thing that would seal it oil tight.

I've had reports from customers who installed the port floors on stock street bikes and noticed an improvement. But for an all out racer or dragster like yours you would need to do some porting. The floors raise the bottom and give you a better downward angle to the valve. But to get racing flow you would need to raise the port cobra head style - leave it alone just in front of the guide but raise it 1 or 2 mm through the tight spot leading up to the guide and around the guide at around 10:00 and 2:00 similar to Harley XR 750 image below. For a race port you certainly don't want any cross section of the race port to have less area that the stock port.

Yes you can retrofit the total seal rings.

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Thanks Jim, will order gapless rings shortly.
The head I have is a stage II Maney head. I have had it flow tested and the results are considered to be very good with no recommendations to modify the exhaust port.
I will remove the exhaust D ports and note any observed changes.

CUin11.2sec said:

Thanks Jim, will order gapless rings shortly.
The head I have is a stage II Maney head. I have had it flow tested and the results are considered to be very good with no recommendations to modify the exhaust port.
I will remove the exhaust D ports and note any observed changes.

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I would hypothesise that if your exhaust and megas have been calculated to work properly, then the inserts will be counter productive.

See the different floors illustrated below. The XR750 port floor is raised, widened and offers the best flow and HP. This is a better option than the stock floor that wasn't previously available. Before we just had a round port with no way to raise the floor other than welding which is problematic. The raised COBRAHEAD shape has been proved on the dyno and on the track.




The cobrahead shape as below is the direction to go but you don't see many Nortons using it.