crower 272 instal now cylinder 4 is dead.

[97eclipsespyder]

So this last weekend I put a set of crower 272s (not BC) in the car and cylinder 4 doesn't fire it is completely dead. It's not spark its not fuel. I have swapped injectors between cylinders, pulled my c.o.p. setup and swapped in stock coil packs, swapped spark plugs an wires.

BUT It does however fire and run for about 30 min to an hour when I bleed out the hlas but as soon as they pump up it dies. Also I have checked valve timing. An ignition timing is close but not perfect.

I did a leak down. 25% leakage on all four cylinders. It is not leaking through intake or exhaust but into the crankcase. I turned the engine over by hand 6 times to make sure none of the valves would hit on start up. I didn't bleed the lifters, I let sit for 2+ hrs. For them to bleed down on there own. Why is it running fine during the time it takes the lifters to fill up/pressurise.

oh and I have also swaped in 2 sets of different lifters in that cylinder with the same result.

I also disconnected the injector on my way home from work last night to verify its dead all through the rpms The car lost almost all power. So its firing above 2k rpm just not very strong.

So I did some more testing...

I did a leak down at 15psi an 10 psi per a local dsmers recomendation, and there is still no leakage through the valves.

I also did a compression test with the lifters pumped up and it maxed out at 90psi. Then I did the compression test with the lifters bled, and it jumped up to 155. The result was with a wet and dry test.

The compression test with the lifters bled read 1:165#, 2:155#, 3:160#, 4:158#.
The copression test with the lifters pumped up read the same except for #4 which was at 90#.

I am pretty lost as to why the lifters pumping up would cause the cylinder to drop. maybe it is valve spring fatigue?

ideas?

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[BlackTsi1992]

I know it would be a pain but have you tried putting the stock cams back in to see if you have the same problem? Seems you have alleviated any other possibility on that cylinder.

 

[clipto]

Hopefully you didnt mess up your timing bent some valves.

 

[got_psi]

Hopefully you didnt mess up your timing bent some valves.

ya my thoughts as well since ive actually done that, bent valves like that...not fun....best of luck with your build sounds tight!

 

[97eclipsespyder]

I know it would be a pain but have you tried putting the stock cams back in to see if you have the same problem? Seems you have alleviated any other possibility on that cylinder.

I think that is going to be my next step. That's if now one has any other ideas befor next weekend

 

[BogusSVO]

If you search around, there has been a few reports of this issue with the crower cams having to large a base circle on the cam causing the valves to hang open a touch.

I would suggest you pull the cams and do another quick leak down test, if you have no leakage, then it is the cams.

The head can be set up to run those cams with the over sized base circle, but the head will have to come off and the valves adjust for those cams. Then the head will only be good for those crower cams only.

Some have said you can machine the bottoms of the HLAs to gain the clearance needed for the cams. I do not recommend this method .

 

[97eclipsespyder]

If you search around, there has been a few reports of this issue with the crower cams having to large a base circle on the cam causing the valves to hang open a touch.

I would suggest you pull the cams and do another quick leak down test, if you have no leakage, then it is the cams.

The head can be set up to run those cams with the over sized base circle, but the head will have to come off and the valves adjust for those cams. Then the head will only be good for those crower cams only.

Some have said you can machine the bottoms of the HLAs to gain the clearance needed for the cams. I do not recommend this method .

Thanks for the info! The weird thing is these ran fine in my friends 1g auto car, befor he sold the car when he found a 5spd an sold me the cams. So I assumed it was something with my car/head. It is only the intake cam that is giving me issuses. I was thinking that the valve springs may be fatigued an due to the differences in base circle it wasnt enough pressure to compress the hlas. Leaving the valves to hang open.

As for machining the hlas. I had a similar idea except with out the machining. . It was to find 2g lifters since they are shorter in over all height to install.

 

[BogusSVO]

That could be one issue..

Read this thread...

http://www.dsmtuners.com/forums/cyl...-but-dont-bleed-back-then-no-compression.html

Starting at post 7, seems you both have the same issue at the same time.

Normally the intake intake valve tip height is taller than the exhaust, so if your head has had a VJ that may be the issue due to the reason they were fine in your friends engine.

 

[97eclipsespyder]

Thank you for the link and the help bogussvo I really appreciate it. That does look nearly I identical to my issue. Am I just searching wrong I couldnt find anything really like my issue.

How can I fix the valves tip heigh can I do that with the head on the car or am I going to have to take the head off an take it in to a machine shop?

 

[97eclipsespyder]

So over the fourth I pulled the intake cam and put in the stock intake cam. The car fired right up like in the other thread. But i also measured the heights of the base circle on the crower and stock. The crower measured 1.25 mm where as the stock only measured 1mm. So it appears that the cam base circle was off like bogussvo stated.

Now my next question is what is the best way to fix this. I bought the cams second hand so I don't think crower is going to do anything for me. Should I file down the valve tip height or have the cam ground to spec? I really can't afford to have the head off and the car down.

What are your opinions

 

[BogusSVO]

Well if you want to tip the valve, the head will have to come off and have tip height adjusted, but you still may not be able to have the valves cut down enough to run the cam, you may gain another issue like the follower hitting the retainer and not the valve tip.

You may want to contact crower and see if they will do anything, if they will not, then contact Delta cams and see what it would cost to have the base circle brought to the oe spec.

 

[jayson427]

Same thing happened to me my lope was off 5-7 hundreths which held my valve open. Had to send it back to crower for a regrind and Polish. No issues after that but it took me forever to figure it out.

 

[97eclipsespyder]

Thanks for the advise. I just got done talking to crower and they gave me a Rma for the cam without hessitation. I will update as soon as I hear back or get the cam back.