Is the DOHC 3.4 an interference engine

[SappySE107]

It doesnt make sense to me either. The site I saw this on is here.

http://www.ny-jbodies.org/forum/library/3.4dohc/3.4DOHC.htm

Looks like the info came from a GM manual but I can't verify the springs yet.

[jmgtp]

It doesnt make sense to me either. The site I saw this on is here.

http://www.ny-jbodies.org/forum/library/3.4dohc/3.4DOHC.htm

Looks like the info came from a GM manual but I can't verify the springs yet.

Dunno if I would trust the info on that link. It claims the LQ1 is 240 cubic inches?! 207ci is what the numbers seem to crunch out to.

[SappySE107]

Probably a typo for 204. I have seen 204 being quoted as well but I have 207 in my manuals.

[RidgeRunner]

Assuming exactly 92mm bore and 84mm stroke, that's right at 204.45ci.

[4spdz34]

Valve Spring

Free Length
42.04
1.6551

Load (Closed)-All
289 N @ 35.56
65 lb @ 1.400

Load (Open)-All
711 N @ 26.16
160 lb @ 1.030

Approximate Number of Active Coils
--
4

thats right from gm si2k for a 97 3.4 dohc, just looked it up. need anything else?

[SappySE107]

Do you have a link to that on GM?

[4spdz34]

i can give u a link but it won't work, it will ask u for a password, which i can not give out cause everyone has there own. but if u need something just ask

[chevanater]

if the 96/97 motors are interference engines then why did my TB snap in traffic and no major problem?

[AWeb80]

if the 96/97 motors are interference engines then why did my TB snap in traffic and no major problem?

well I don't know much, but i'm assuming when you said "IN Traffic", you were prolly just idleing, that might have made a difference.

[4spdz34]

ya at idle it is not interfernence cause there is not enough oil pressure to pump up the lifters fully, so the valves aren't opening all the way at idle