QUAD 4 SOHC Questions

[hywypatrl05]

Got to wondering...

Q1.Would the motor start (at all) if thae head was cracked???

Q2. Would the cracked head, lead to melted sparkplug boots???? Causing it to overheat???

[GTP Dad]

An engine will run with a cracked head although not very well. The melted spark plug boots and overheating can be due to a blocked cat that is forcing the heat to stay inside the engine. You can check for a cracked head with a compression tester. You will see a decrease in compression in the cylinder where the head is cracked.

The other issue due to overheating may be water entering the combustion chamber through a leak where the head is cracked.

[hywypatrl05]

Originally Posted by GTP Dad

The melted spark plug boots and overheating can be due to a blocked cat that is forcing the heat to stay inside the engine. You can check for a cracked head with a compression tester. You will see a decrease in compression in the cylinder where the head is cracked.

The other issue due to overheating may be water entering the combustion chamber through a leak where the head is cracked.

I just replaced my Cat with a Catco HiFlow converter because my other was old and rattling...plus it went well with my flowmaster system...lol...hahaha...

but anyways, after my friend stupidily put water into it (radiator reserve) about 2 mins later it made a hissing sound and bam went the water out the bottom of the car...

*NOTE* as he poured the water in the reserve...the exhaust manifold was red hot....(BRIGHT ORANGE)

But now all the car does now is rotates but wont start...On the back of cylinder head where the plugs go is riged lines (About 1 1/2" long) with white stuff around the cracks...would that be the water leaking through or just corrosion or something????

[GTP Dad]

The stuff around the cracks is coolant that is boiling off, having been forced though the cracks. I would say to pull the head and replace it. You will need basic hand tools, a torque wrench, a gasket scraper and a shop manual. It will take some time to do it but it won't cost a lot. Finally, make sure you use new head bolts when you change the head, you don't want to do the job twice.

[hywypatrl05]

Yea ive got one on the way....(the head)....would I have to remove the entire engine??? or just pull off the intake mani....the exhaust mani....and the cams....

[skibum1111]

I have a dohc quad, took us 11 hours to change the head and gasket. You have to pull the exhaust manifold, intake, fuel injectors, timing chain, cam(s), crank pulley, alternator, water pump (there are 2 head bolts behind the timing chain housing), I pulled the battery for the room, air cleaner, air ducts, and I think that was it. The motor can stay in the car, but some of the bolts on the timing chain cover can be a bitch to get at. I have big hands, was kinda tight stuffing them in there to turn bolts. Also, the motor mount on the passenger side has to come off as well. Good luck, I've heard sohc heads are a bitch to find as they crack so often due to overheating.

[hywypatrl05]

yea...they get expensive (the heads) but i found one that was promised not to be cracked and warped. So when it comes in within the week ill get started on the replacement....plus what are some of the "MOST" imporant tools that I will need???? Ive got this manual on my car, so that will aid me through the process when i need help.

[GTP Dad]

The most important tool you will need is a torque wrench. A good complete set of hand tools, metric, will be next. Otherwise you shouldn't have any problems.

[gmack221]

Just got to thinking, you have an expensive head coming in that you were promised wasn't cracked, might be worth your time to take that head and get it checked for cracks, and while your at it have them check the valve guides & replace the valve seals (so it doesn't burn oil). Once you put that head on they could claim you did something to it to crack it, just my , not sure how much extra money you have now, but if you can swing it get someone to check the head out.

Also the torque wrench you will need will be an inch-lb torque wrench, not a ft-lb torque wrench like you torque your lugnuts with, find a buddy that has one (thats the cheapest way), oh yeah and use it on your cam housing bolts!

[skibum1111]

yup 132 inch pounds works out to around 10 foot pounds, most torque wrenches don't go that low. Also, you need a harmonic balancer puller to pull the crank pulley off, run a tap through the bolt holes so you don't bust the bolts off in the pulley. If I remember correctly, its a 8mmX1.5 tap. Also, lots of beer for when the job is done, you're gonna need it. I'm not trying to discourage you, but its alot of work. Plus it feels good when you are done, most mechanics want at least $1k to do the job. Good luck, let us know if you have anymore questions.

[hywypatrl05]

Thanks guys, ill keep you updated....Oh yea and gmack ill take your advice and get them checked out for any cracks before the install....