Saturday Night Racer

Saturday Night Racer
http://www.latemodelracer.com/cgi-bin/yabb2/YaBB.pl
Saturday Night Racer >> RACE TECH >> head dowel pin
http://www.latemodelracer.com/cgi-bin/yabb2/YaBB.pl?num=1295930994

Message started by propit21 on 01/24/11 at 8:49pm

Title: head dowel pin
Post by propit21 on 01/24/11 at 8:49pm

will water leak into your oil if you do not have the dowel pins installed between the head and block?

i keep getting water in my oil with only about 10 min of run time, get a white foam all over the head and lower end. i got the right gaskets and had put sealant on the head bolts. just need to know where the water is coming from. ALso these are brand new dart heads a 010 block with work done to it, just a used performance product intake on it. please help. thank you

Title: Re: head dowel pin
Post by imracin68j on 01/24/11 at 9:13pm

Since you have water in your engine you're going to need to take the engine down, or you should if you care about that motor. You need to pressure test the block and heads. Usually slow mysterious milkshakes are hidden crack problems somewhere. You also may want to make sure your intake isn't leaking. I just had a deal where I dropped in a motor someone thought they could run an 18 degree intake on a 23 degree head. FAIL. Those are the places I would start. I'd put a dowel in for sure as it lines up your gasket. There is a significant amount of slop between head bolts and gasket holes. A 60 thousands shift in the gasket during the torque phase could cause a mess of errors.

Title: Re: head dowel pin
Post by larryc17lm on 01/24/11 at 10:27pm

Are you running alcohol?

Title: Re: head dowel pin
Post by propit21 on 01/25/11 at 7:31am

gas motor

Title: Re: head dowel pin
Post by hogracer3d on 01/25/11 at 8:15am

I have seen offset dowel pins before, don't really know what necessitates the need for them, but they do make them.

Moroso, I think

Title: Re: head dowel pin
Post by ka_jd7and1 on 01/25/11 at 8:22am

hogracer3d wrote on 01/25/11 at 8:15am:

I have seen offset dowel pins before, don't really know what necessitates the need for them, but they do make them.

Moroso, I think

Quote from product page (don't know if it actually works or not......)

Offset cylinder head dowels reposition the cylinder heads upwards on the block (toward the lifter valley), moving valves away from cylinder wall for improved intake flow.

Title: Re: head dowel pin
Post by chevy68pickup on 01/25/11 at 9:20am

I had a motor done 2 years ago and keep getting water in the oil like you are. I had a crack in the intake vally that you couldnt see untill you have 60psi in the block.

Title: Re: head dowel pin
Post by TIM_BEWLEY on 01/25/11 at 11:20am

check your rocker arm studs. they need to be sealed like the head bolts. i once had a crack in a head that was overlooked until the machine shop heated the heads up then found the crack.

Title: Re: head dowel pin
Post by hogracer3d on 01/26/11 at 12:59pm

My machinist always mag checks the right(I think) rear of the lifter valley, near the lifter bores for cracks, whenever you bring in a prospective core block.

He says there is alot of cracking problems there, but I have never seen one

Title: Re: head dowel pin
Post by Dietzsch_Racing25 on 01/26/11 at 1:17pm

I had a machine shop tell me the block I had was junk because of a crack there. I almost didn't believe him at the time because I didn't understand what would cause a crack there (still don't) but after talking to other people sounds like it is not uncommon on 350 blocks.

Title: Re: head dowel pin
Post by OLD SCHOOL#6 on 01/26/11 at 3:01pm

It is not uncommon. It is caused by "core shift". Core shift is a thing that happens during the casting process where the casting does not settle and cool uniformly. This in turn makes one side of the block thinner than the other, and the thin side has a tendancy to crack. I have seen it MANY times, and it is NOT always fatal. I had a motor crack there and I was able to weld it and was able to use it until I finally (for other reasons) blew it up.

Title: Re: head dowel pin
Post by Chad_E._Jeffreys on 01/29/11 at 2:56pm

You definetly have to have the dowls in the block, wiyhout them the heads will leak water. Chad

Title: Re: head dowel pin
Post by Ian on 03/03/11 at 2:30am

OLD SCHOOL#6 wrote on 01/26/11 at 3:01pm:

Kirk,

core shift isn't really the reason the lifter valley cracks.... it's due to excessive heat in the engine and a thin casting (usually in later model blocks)

typically, any time we get an 80s+ sbc in the shop with a blown head gasket, the first thing we do is mag the heads and the lifter valley. If the crack is small enough, you can pin it or weld it, but it's typically not worth the labor hours seeing how 350 blocks are so common.

back to the subject.....

....may I ask why you didn't have dowl pins to begin with...? :-?

Title: Re: head dowel pin
Post by propit21 on 03/03/11 at 8:19am

didn't have any ::) put we do now and no water in the oil.
his other motor didn't have thme and it doesn't leak water and we changed the heads on that one without even putting sealant on the head bolts and it doesn't leak at all.
long story short it doesn't leak water into the oil anymore and we won at cocopah with it on the first race out.

Title: Re: head dowel pin
Post by hogracer3d on 03/03/11 at 9:58pm

propit21 wrote on 03/03/11 at 8:19am:

.50 head dowels taught you an important lesson about $100 head gaskets huh?

it'd have been funnier, if I hadn't done the something similar

Title: Re: head dowel pin
Post by propit21 on 03/04/11 at 7:36am

such cheap little things that make such a expensive big thing. what was the worst and best part is taking the top end off so many times, feel like we were in NHRA there for a while.
Ran the car for 10 mins and take the top end apart, did that like 5 times before we got it figured out.

side note hog did you ever figure out why you guys are bending push rods in theat motor?

Title: Re: head dowel pin
Post by hogracer3d on 03/04/11 at 10:22am

no, I hadn't even got the car out of the trailer from that event, still pissed about the wrecker driver smashing the whole rear in a foot

Title: Re: head dowel pin
Post by propit21 on 03/04/11 at 4:36pm

oh i bet, i hate sheet metal work. make you wonder if some people think before they do or just don't care