Blew the motor

[LETZRIDE]

Re: Blew the motor

I lied earlier (accidently) I realized when I pulled the other head off just now that the exhaust valve that smashed this time IS infact one of the NEW valves...this opens up a whole new realm of possibilities.

see, we reamed the guides ourselves...it's possible either A) there wasn't enough clearance (even though I am almost 100% sure we were within spec, or B) its possible we didnt ream 100% straight, because from my reading...the guides never are 100% straight in the head...

what we should of done is pulled the guide, and measured everything out 100% then did it...but we were in a hurry...and I am gunna guess this is what caused failure. Otherwise, how is it that only one head would heat up and not the other...and only 1 cylinder on the damn head out of 3?

[LETZRIDE]

Re: Blew the motor

Alright...I just got my heads back, and Im ready to fully reassemble this motor. I need it done before this coming weekend...

I am a bit worried though, Im revisiting why this happened in the first place. The machine shop is adement that this occured due to the head overheating and that caused the guide to slip down. He is convinced that that is the only thing that caused the issue. This scares that crap out of me because why/what would cause the head to overheat? My coolant temps never ever went up...they've never even hit the half way mark...always sit at the first quarter. When he reconditioned the heads he had to take roughly 5 thou to straighten them up. What should I be looking for on the reassembly to make sure my head will not overheat? I honestly can't think of anything?

I personally still think it had something to do with not reaming the guide 100% straight possibly, or maybe the guide being knocked cockeye...but he seems to think that in order for the valve to have been stuck from this cause would mean that we would have reamed it wayyyyy off...like noticeable to the eye off, and this wasnt the case...

Keep in mind the cylinder that this happened on, is the same exact cylinder that on the original motor the rod snapped and tried to throw the piston through the head at that point...

[PalmHarbor]

Re: Blew the motor

This job will raise your compression ratio and demand premium gas (at $3.45 a gallon)
Thats a lot of money to drive 14 to 16 miles.

[flamingchicken]

Re: Blew the motor

5 thousandths shouldnt call for premium fuel. may raise the compression by .8 or so.

[LETZRIDE]

Re: Blew the motor

there has been a total of 0.010 taken off the heads since the beginning, and I am using a 0.045 headgasket which is 0.016 thinner than stock so I should be at a 9:8:1 to 9:9:1 compression ratio roughly...car will be run on 91 premium fuel like always.

Im worried about what can cause a head to overheat though?

[ssms5411]

Re: Blew the motor

Too much timing causing KR , no water in the jackets.

[LETZRIDE]

Re: Blew the motor

Timing was already very low...what could cause no water in the jackets? I don't see any blockages

[ssms5411]

Re: Blew the motor

Valve hitting becuase of off timing. Timing adavance

[LETZRIDE]

Re: Blew the motor

Ok, I just got done with the valve to piston clearance...looks like I got 30-40 thou clearance with the headgasket on...is this ok?

[ssms5411]

Re: Blew the motor

I do not know off hand, I think the Haynes manual might have that in there. Or if someone knows for sure please post up.

[LETZRIDE]

Re: Blew the motor

not in the haines manual, unless I over looked it.

[ssms5411]

Re: Blew the motor

Might try on the other forum but I'm pretty sure thats really close. I was thinking .050-.060 was about it.

[LETZRIDE]

Re: Blew the motor

bump...

[97rs4life]

Re: Blew the motor

From Alldata:

Piston Clearance:
39 mm From Top Of Piston 0.010 - 0.051 mm (0.0004 - 0.0020 inch)
Piston Ring Groove Depth:
Top Compression 4.019 - 4.146 mm (0.158 - 0.163 inch)
2nd Compression 4.214 - 4.341 mm (0.0166 - 0.171 inch)
Oil Control 3.814 - 3.941 mm (0.150 - 0.155 inch)

[LETZRIDE]

Re: Blew the motor

From Alldata:

Piston Clearance:
39 mm From Top Of Piston 0.010 - 0.051 mm (0.0004 - 0.0020 inch)Piston Ring Groove Depth:
Top Compression 4.019 - 4.146 mm (0.158 - 0.163 inch)
2nd Compression 4.214 - 4.341 mm (0.0166 - 0.171 inch)
Oil Control 3.814 - 3.941 mm (0.150 - 0.155 inch)

so is that the piston/valve clearance? that seems very close?

seems like if you had your spring get weak, or any valve float and you'll lose a valve?