5 GT Turbo c1j pushrods thread.

[Clarkey]

If I were doing a big power C1J, I would use a billet cam, not a recut, to reduce the pushrod length problems.

We need a new thread for pushrods.....
Some good points there Dave, I have some longer adjusters but not needed yet as still have the longer pushrods.
Been back to standard length this year due to reducing the pedestal height on the rocker assembly, which brings the pushrods away from head.
I thought we had solved the problem until Donington where we bent a few.

keep the wife happy.

That's the main thing, then you can play cars

All of my pushrods have witness marks on where they have caught the head so the hole definitely needs opening up. Still all these years and i have not actually managed to bend one yet

Your not trying hard enough

 

[Fordy]

Is it just me or do those holes look unnormally small for a Gt head? [emoji848]

 

[Mark Davis]

See I was trying to judge how much they've opened mine up but found it hard to tell. Could do with comparing to another head.

 

[Fordy]

What headgasket are you using Clarkey?

 

[Clarkey]

What headgasket are you using Clarkey?

Thickness ?? 1.9mm, not sure on make...

 

[Fordy]

Wondering if headgasket thickness pushes the head up too high causing push rod to rub on head issues

 

[Clarkey]

We have always run the thicker gasket, never had any issues until this cam went in.
Going to check everything, seat pressures etc to make sure springs are correct.
The oe pushrods will be getting upgraded.

 

[DaveL485]

never had any issues until this cam went in.

Recut? The bottom of the pushrods will sit a lot lower, I guess thats why...

 

[Clarkey]

Recut? The bottom of the pushrods will sit a lot lower, I guess thats why...

This one is supposed to be from a blank.
We have always run longer pushrods 5mm to compensate.
This is a lift and pushrod issue , will be checking seat pressures as something's not right to bend 6/8 pushrods I took out.

New pushrods are sorted just got to open everything up.

 

[Mark Davis]

What did you do about pushrods in the end @Clarkey ? My engine comes back this weekend and ideally I'd love to just buy some stronger ones off the shelf. CTM have widened the head but not sure if this will cure issues bending them.

 

[RanjD]

I would be interested in a set too , price ?

 

[Mark Davis]

Well the Isky rods fit. A mate bought a set so tried them on mine today. They are huge in comparison and much lighter. My push rod holes were extended slightly and there is plenty of clearance, we still think they'd clear standard head holes too.

I've ordered my set from US £175 inc shipping and taxes.

 

[DaveL485]

They look great, good find!

 

[Mark Davis]

One less thing to worry about but with 270 cam might not be too much of an issue.

The picture doesn't do it justice, they are huge in comparison.

I have read some interesting articles though about how push rod flex can have a negative effect on performance. These should be pretty solid, made from forged chromoly.

 

[Brigsy]

Test them to destruction Mark any comparison pics with original ??

 

[Woznaldo]

Great thread. Lots of good tech info and an area that the C1J needs a little help when pushing the limit.

 

[Mark Davis]

 

[Mark Davis]

See above @Brigsy

 

[Mark Davis]

They do not clear on standard head. Will need push rods holes elongated.

 

[ren5gord]

Good to see the Isky push rods fit with a bit of fetteling.

At work we have a Spintron rig just for valve gear development and you would be amazed at the deflections that came be seen and how small changed to key parts can make huge differences to performance.

 

[Mark Davis]

Good to see the Isky push rods fit with a bit of fetteling.

At work we have a Spintron rig just for valve gear development and you would be amazed at the deflections that came be seen and how small changed to key parts can make huge differences to performance.

I've been reading a fair bit on US sites about the significant improvements seen by fitting a stronger pushrod. I'm not sure if it will be noticeable on mine but I should be able to rev high now without fearing bent pushrods. Hopefully it doesn't cause issues anywhere else. Manton Pushrods in US claim that less deflection from push rods ensure that valves are working as they should increasing the engines potential to breathe.

For anyone that's interested- Pushrods - Key To Performance - Engine Builder Magazine