Rockers not fitting after cam?

[one_and_only2004]

Hi all, I've had my cam installed (comp cams stage 2 supercharged) this week and was advised by mace that my cam won't fit with my 1.8 rockers. My mechanic put them in (1.8 Yella Terra's) and everything turned over by hand fine, but i told him to put the stockers in - we just did that and the motor refuses to turn over due to the valves hitting the pistons!
Have you got any ideas?

[MACE]

one_and_only2004,

Are you 100% sure that the valves are hitting the pistons?

A few things that come to mind and that is that

The factory rocker haven't been installed incorrectly
The 1.8's may have bent something whilst being tested, or that the lifters weren't pumped up yet as it was being turned by hand. Once pumped up with the stock rockers "true" valve lift occurred
The standard rockers may not have been standard afterall,
It's dropped a valve.

I would be very surprised that it's bent a valve due to the lack of piston to valve clearance, unless the heads you purchased had a significant amount of material off the cylinder block mating surface machined (to increase the compression ratio). I say this because we've installed bigger ecotec cams before (like our comp cam stage 3 item) on standard headed cars without any problems before.

This is all I can think of at the moment as I'm a bit under the weather

Please keep us posted.

Kindest Regards,
Steve

[maldotcom2]

When you put the stock rockers back on did you use the stock pedestals as well?

[one_and_only2004]

one_and_only2004,

The factory rocker haven't been installed incorrectly
The 1.8's may have bent something whilst being tested, or that the lifters weren't pumped up yet as it was being turned by hand. Once pumped up with the stock rockers "true" valve lift occurred
The standard rockers may not have been standard afterall,
It's dropped a valve.

The motor was just turned over by hand ie breaker bar on the crankshaft. The mechanic noticed something was wrong when he was putting the standard rockers (the ones that came with the car) back in and he noticed that he couldn't get them fully screwed down. He turned the motor over and it wouldn't turn because it was hitting the valves.
Stock pedistals have been used, the only thing that wasn't swapped over was the Pushrods because one of my old ones was bent. Is there a difference in length between stock and higher ratio pushrods?

[chevy_big_block_bro]

Shouldn't be

I put stock length hardened push rods in with my 1.95's in the old VT

Do you know the history of the heads/motor? Are they stock rockers as Steve said?

Look for little weld pools around the pushrod seat

The cam is made to go with stock valve train so if its all stock then there's a problem. Can you measure the pushrods?
They should be 7.050" and also stamped on them if they're after market

[one_and_only2004]

Motor was stock when i bought it, 40,000kms on it. We measured the seat to the other one, looked at everything to see what the difference was between everything and the only difference is the valves are bigger and the ports are massive.
The rockers are definately stock - i swapped them out myself.
The mechanic was going to compare the length of the pushrods to the standard ones tonight to try and work out what's going on.

[MACE]

The motor was just turned over by hand ie breaker bar on the crankshaft. The mechanic noticed something was wrong when he was putting the standard rockers (the ones that came with the car) back in and he noticed that he couldn't get them fully screwed down. He turned the motor over and it wouldn't turn because it was hitting the valves.
Stock pedistals have been used, the only thing that wasn't swapped over was the Pushrods because one of my old ones was bent. Is there a difference in length between stock and higher ratio pushrods?

It would most likely be the longer pushrods pushing the valves further open. I don't know the exact different in length but there is a definitely a difference, as also indicated by how your mechanic set the rockers up. When he cranked the motor did it turn over a little and then stop, or just not turn over? Either way I think that there is a good chance the all will be fine once you revert back to the original length rods. This can be verified by doing a compression check once you get the car running again.

I've had valve kiss a piston before when the timing belt gave way when the car was idling. The second time it happened the engine was doing around 4500RPM and bent 5 of the 6 valves (yes it was a 3 cylinder screamer )

[chevy_big_block_bro]

Why would you put longer pushrods in? Is there a benefit. I would have thought that a longer pushrod to the extent of not letting the rocker bolt down on a bigger cam wouldn't let the valve fully close on a standard cam. Maybe i'm missing something like the action of the hydraulic lifters.

[one_and_only2004]

Yeah it turned over a little bit both backwards and forwards, so it's not locked up completely. I guess i'll find out how he went tomorrow. I hope it's all done, i have to head off to the gold coast tomorrow arvo!

[one_and_only2004]

Why would you put longer pushrods in? Is there a benefit. I would have thought that a longer pushrod to the extent of not letting the rocker bolt down on a bigger cam wouldn't let the valve fully close on a standard cam. Maybe i'm missing something like the action of the hydraulic lifters.

These pushrods came with the Yella Terra rockers in the kit, so i just put them in.

[MACE]

Why would you put longer pushrods in? Is there a benefit. I would have thought that a longer pushrod to the extent of not letting the rocker bolt down on a bigger cam wouldn't let the valve fully close on a standard cam. Maybe i'm missing something like the action of the hydraulic lifters.

There is a benefit of installing longer pushrods, to a certain extent, as it can increase lifter crush increasing the effective lift at the valve and also to quieten down lazy/noisy lifter.

Going too long though and it will cause the hydraulic lifter to act as a solid and even longer also keeps the valves open all of the time.

The base circle diameter of the cam we supplied is the same as the factory cam so longer pushrod's weren't required to correct any rocker geometry.

From my understanding the other pushrod set was used as one of his factory pushrods was slightly bent (?)

[MACE]

Ah one_and_only2004, beat me to the answer

I still think it will be right once you put the right rods in. If it was a 4 valve per cylinder head then i would really be worried, as the valve angle relative to the cylinder can cause them to bend easily

[one_and_only2004]

I guess we'll find out tomorrow arvo then - i'll keep you posted on the results.

[acarmody]

When I had my engine rebuilt I discovered I needed shorter pushrods, but I had the block decked and the heads shaved so it was a fair bit off. Did you get the heads or block shaved?

[one_and_only2004]

Nah the block is stock, and the heads haven't been shaved as they were intended for supercharging.

[one_and_only2004]

Turns out it was the pushrods as thought. My ute has an AWESOME lumpy idle to it but runs like an absolute dog above 3000rpm. I rang up chiptorque this arvo and managed to slip in on monday for a dyno tune.

[VS_Pete_1]

good to hear keep us posted after tune good luck

[acarmody]

If you don't mind post up or PM me the cost of the dyno tune as I need to take my car back to Chiptorque to get a retune. But yeah post up the dyno sheet when you have it.

[one_and_only2004]

Okay I'm back. So I ended up going from 206rwkw to 237rwkw and 490nm of torque. Chiptorque costs $200 an hour for dyno tuning - it cost me $500 for mine to be done. I'll post up dyno sheets when i find myself a scanner.

[acarmody]

I just take a picture with my phone since I don't have a scanner.

[MACE]

Okay I'm back. So I ended up going from 206rwkw to 237rwkw and 490nm of torque. Chiptorque costs $200 an hour for dyno tuning - it cost me $500 for mine to be done. I'll post up dyno sheets when i find myself a scanner.

Glad to hear it's all come good

What was exactly done to achieve that gain?

Cheers
Steve

[one_and_only2004]

the 206>237 was done through tuning so suit the new heads and cam.

[VS_Pete_1]

Nice. how does it drive?

[one_and_only2004]

Like a stocker till about 3500rpm when boost REALLY starts setting in!

[MACE]

Ah good figure then

You'll definitely be able to get even more power out of her, but running more boost (would have to run it past Tim though as he know your setup better then me)

You can still do this by not even having to touch the blower pulley, but but running a much larger air filter and smoother filter/blower piping.

Glad it's all sorted though

Cheers
Steve