Model A? Blown Head Gasket or Thrown Rod Bearing?

Can a Blown Head Gasket sound like A Thrown Rod?

It sounds like a thrown rod knocking, only when taking off in gear, in majority of the power range with a loss of power, even sounds like detonation but Plugs are clean. It can drive fast enough at a certain certain rpm with no knocking until I step on it.

I really don't hear knocking nor tapping when Idling & Idles rough which makes me think it's no a rod bearing.

 

Either one, the head has to come off, right? ...

 

Aren't those poured in babbit bearings in them things ?

Blown head gasket #1 detection is a compression test.
Bad bearings usually don't show low compression if they are relatively fresh condition.

 

Somebody once told me a miss timed banger would make a knocking sound. Dont know how true it is. Worth checking right?


Wanted: 28-29 Model a Roadster Quarter Panels

 

Well I did notice little bubbling around the #3 piston gasket area, so I'm hoping the headgasket fixes it.

Should I use some Gasket Prep this time.

 

It aint no thing to pull the pan and check the bearings, take a shim out and what not. Worked on mine. And the timing is very important on bangers, check the points gap!!!! In the back of the model a handbook it tells you what most engine sounds mean.

 

It starts, idles, & revs fine, well idles a little rough so timing is good, it just knocks when taking off in first through its power range, but it runs good at 60 until I ask for power then it'll knock. It kind of does sound like timing, huh.

The distributor system was all tight when I pulled the distributor to Re-Torque the HeadBolts which did make it run little better, a little less knock.

I'll let y'all know if the Head Gasket worked. I really just wanted to put it out there cause I read here on the HAMB how others want to change engines cause their Model A Banger has developed a "Bad Rod Knock".

 

Did you have to buy any new gaskets/seals or did you just tune it up with a little Ultra-Black?

 

Oh i always use new gaskets and seals so i dont have to do it again. It might be fine with some ultra black though. I soak the front seal in oil for at least a few hours before install. The back one i curl up in a glass of water and microwave it for 5 minutes, when its pulled out of the water it has a nice curve to it so i can easily stick it up to the rear main cap or whatever.

 

Why isn't the knocking sound from timing advanced too much? Back off timing and see if knock goes away.

Neal

 

what dizzy you runnin now? I got the fs and it will turn on its own no matter how tight i make that screw, granted not easily, but over time. Not sure what im gunna do about it tho.

 

Retard the timing while driving ans see if the sound changes (goes away?). Bangers make all kinds of noises not normal to others. A tough one to determine is the cam moving for & aft, sounds bad but its not.

Also you can set it on a fast idle and short out each plug one by one and see if sound changes.

 

Mine rotor spins to sometimes. It's Funny. You could feel it sometimes on the freeway, but it pops back in place & it's no big deal, I just on driving. I got a stock distributor with modern points/condenser

 

Right! Yesterday, #3 & #4 not much change, but #1 made it turn off

 

Sometimes the plugs look good but are shit. Mine never seem to last to long.

 

Thanks Mejo,

I'm gonna file this one. I'm a SBC guy & I've gotten away with used Head Gaskets & a little engine paint. Head, Timing Gear, & Flywheel is how deep I've gone on a Model A. SO FAR!!!

 

Really??? Wow. I would say, I'm having simptoms of Bad Plugs. I took them out & wirewheel brushed them & re-gaped & no improvement. Something is weeping out the head gasket though.

 

sounds like you are running on 2 cylinders
my guess is you blew the head gasket in between 3-4
tk

 

What did the plugs look like before you wire brushed them?

 

Like they were burning fine. Like they didn't even need it. gap was fine too

 

And that's where it was weeping from.

 

And . . . . There was a finger size gap between 3 & 4.

Remember: That sound is not a bad bearing, it's a blown head gasket.

 

when i got my flat head 6 it rand great till ya let the clutch out then it sounded like a diesel when i tore it down to rebuild it had .020 clearance on the rods

 

Bearings are fine. Drove it down Valley Blvd @ 60mph to work in Walnut and it drove like a champ.

Watch your back people. A Model A head w/ the waterpump can get heavy hunched over. I stood on the frame & straddled the motor with my elbows pivoting off my knees.

 

Good deal! Glad you got it sorted out...drive safe on those LA freeways

 

I was an apprentice in 1957, doing a head gasket on a Model A would be a blessing then!
Instead, I seemed to get all the DeSoto and Chrysler hemis to R&R heads on...and they were IN Chryslers and DeSotos.
My 140-lb. frame would get the head hoisted O.K., but over-the-fender to where it belonged was the part that tended to suck me down into the engine compartment.

If I was lucky, I could hang the head on the hollow dowels on my way past, towards the basement!

 

I recommend using Snyders Best head gasket. It needs no sealer

 

Here's a Funny: I go online & do a little HeadGasket schooling. Then, call Early Ford Store in San Dimas & and ask Bill about different gaskets, he says, "I don't know, all I know is we got the Best Gasket". I send my mom to pick it up for me. When I get home from work, she left it at my house, and the name of the gasket . . . BESTGASKET. Yeah, Snyders I think. I thought Bill was giving me feedback when he said, "the Best Gasket".

 

Oh yeah,

Around 10:30 last night, Test drove it down the 60 frwy to the GrayHound station on 7 & Alameda in LA, to pick up a cousin from Tejas, then dropped him off at LAX this morning at 6:30. "FRICKEN A"