H-beams and oil feeds. help

[appletree]

For my supercharged build i planned to upgrade to these rods from PPM http://www.pureperformancemotorsport.com/ and bought them abit back, however now ive got them and after a chat with the Ant whos building my bottom end i'm not sure i can/should use them?

We were looking at the feed to the small end/grudgen pin on the stock conrod and theres a 3/4mm hole on the top of the small end (directly under the piston) and an oil squirter from the top of the main shell housing( i do mean main not big end) which looks like it squirts oil directly at the centre of the underside of the piston so that it lubes the skirt and also splashes back on to the hole in the top to lube the small end/grudgen pin area, theres also a small half round hole cut in to the top of the conrod clamp big end ( the conrod part as aposed to the clamp half) which i'm not sure if this is to also squirt the oil up wards? Any any onw know for sure?

the problem is the new rods dont have a hole on the top but instead have two slightly smaller holes at the bottom on either side pointing down at around 25degrees, these will be hidden in gapes of the "H" when the new rods are in place? do people think this will be a problem and the small end wont get lubed properly? is this a normal design for H/custom rods??

Would i be better to sell them and use the standard ones as rob_e30 proved they stand 18psi on track all day long and 27psi when the waste gate jammed on track ??

Cheers matt

[Demlotcrew]

All aftermarket performance H and I beam rods i have for the S14 all have the upper wrist pin oil catch bath.

Can they not drill you one there? Arrow make nice rods at £160 each with bolts.

Why are you going for H beam rods anyway?

Andrew

[appletree]

The main reason was that when i bought them the general consensis was that the m42 pistons were forged and the rods were lightened so i wanted to replace the potentionaly weak part.

as it turns out now it was infact the other way round, the rods are forged and the pistons lightened.

Just stripped one down so you can see, not so much a oil catch bath as you can see...






This is what i have.

And i think this is what i should have got...


Wonder if the wrong ones have been put in the box?

You can just see the oil squirters in No.3/4 cylinder there the shiney bit pointing up wards.



Hope tim doesnt mind me using a pic of his engine but i couldnt find any others on google images.

[Demlotcrew]

IT looks to me they have done that to keep the weight down on the rods.

Im not sure about this design as ive had no experience running them, its best to stick with tried and tested.

Andrew

[appletree]

PPM tried and tested or BMW's tried and tested? there garanted at 1000bhp and 9000rpm

guess you mean BMWs though,

[Demlotcrew]

ITs not so much the rod which governs the max RMP but the Bolt, if you wanted higher RPM on a rod you would upgrade the bolt. ARP make their 2000 range which is what i guess you have with those rods and the next ones up are the ARP 625's which will handle 16000 rpm.

I would enquire about a riffle hole to be added to the rod (they drill a hole from the big end all the way to the wrist pin and the oil flows upto the pin that way, you will also need to drill your big ends to match)

Tried and Tested as in BMW, ARROW, PANKL etc

Andrew

[appletree]

Been thinking about it and as theres going to be oil spraying out the side of the bigends plus the spray from the squirters and 7krpm theres going to be a fair bit of oil about and any that hits the side of the rod in the gap of the 'H' will be forced up the gap and into the holes as the piston rosipricates (probly spelt that wrong but it sounds good ).
Think ive been worrying about nothing, there rods for the GT2 porsch are the same design.

[ShakeyC]

Think ive been worrying about nothing, there rods for the GT2 porsch are the same design.

But Porkers are flat inline engines same with Subaru flat four design the rods lay horizontal not vertical as per your M42 application meaning oil won't be carried along the shaft to wrist pin in the way you think it will.

[Demlotcrew]

Think ive been worrying about nothing, there rods for the GT2 porsch are the same design.

But Porkers are flat inline engines same with Subaru flat four design the rods lay horizontal not vertical as per your M42 application meaning oil won't be carried along the shaft to wrist pin in the way you think it will.

Exactly what i was going to say.

Andrew

[appletree]

They put one in the bottom of the porker ones to, there isnt oil falling up is there they do use them in other car to,its just the porker was the first i saw.

if you think about it any oil that gets on the surface of the rod will move in the opposite direction the rod is moving
an be forced in to the small holes and then the small end, theres actualy not much chance of the oil getting in the small hole in the top of the standard rod when you look, the grudgen pin housings are stopping the oil gettin in from the side and you relying on squirt hitting the top of the piston and being deflected down on to a small hole with no catch area.

Done abit more research and carrillo rods use the same design in mr2 supercharerd engines, i happy now some intresting reading, look nearer the bottom.


http://www.mr2supercharger.com/conrods.html


"Comparison of a Carrillo rod on the top and a Modified Early model small journal Rod on the bottom. Notice the total differences, but the weight is nearly identical. This Carrillo rod’s inside diameter small end is 19mm. This Carrillo rod has no provision to squirt oil to the side of the cylinder wall or to the top of the piston. There is no lubrication hole on top. Lubrication to the piston pin is provided for by holes just under the small end. The rod is symmetric. There is no right, left or front or back. Also notice the extra clearance between the block and rod shoulders by using a screw type fastener rather than a bolt. "

[ShakeyC]

Bit of misunderstanding on my part maybe, the rods with small holes on underside of the small end is how flat engines like Subaru and Porsche lubricate the small end/wrist pin shunting the oil sideways along the 'valley' in the H section. The one in your example where the hole is on top of the small end in upright engines the oil splashes underside of the piston and drops down some of which funnels into the small hole lubricating the wrist pin from above.

I see your point regarding the Carrillo rods in the 4AGE, im not 100% sure if M42 oil squiters are inline with the rod as in the 4AGE? if they are your ok if not I would not risk it for reasons above.

[appletree]

Hi Matts dad here, this is the reply from the rod people in OZ

Hi Matthew,
There is no need for the hole in the top of the conrod. It was used with the OEM pistons and done nothing.
If you use aftermarket rods and forged pistons there is no need for that hole.
The main important thing is to keep the pin lubricated that’s why we did 2 holes in the Small end!
We manufacture H-Beam rods for over 20 years and we never had any problems with the design of our rods.
If you look at US Carrillo they do the same way their rods!
So there won’t be any problems with the rods!
If you have any more questions please let me know,
Best regards

Thomas

www.ppmracing.com

Australia

[Demlotcrew]

Im not sure if thats the answer i would have liked to have received, the OEM 'hole' actually does 'do something' if it didnt the very top end rod makes for F1 and race engines would not be using it.

Im sure it will be ok for your setup

[drjim]

I thought the oil got squirted up the rod and into the bush/pin through the holes in the small end bush.

JIm