My '65 suddenly started running bad today

[Jim_Gruber]

Good news on the metal slapping sound. This thing sounds fixable all of a sudden.

 

[bug_sixty]

???? Am I missing something here... Why are we putting a 1275 head on a 1998 low end?

 

[Jim_Gruber]

Bigger valves?

 

[mgless]

The previous owner built it. I have no idea why he did it.

 

[bug_sixty]

Opps meant 1098... Well as a previously FYI, the jackets either don't match or have to be altered... I know racer's back when used 1098 cranks and other things in 950's.. but 1275 's no....but I'm no expert....

 

[bug_sixty]

Daaa....if the water jackets didn't match in the back two cylinders you would have enough heat to do the damage described...

 

[David_Doan]

So pull the head off already and post some pics....

 

[AN5Sprite]

P.O.'s....

Glad to hear that the death rattle was the bumper bracket.

Shouldn't be too hard to find a good 12G295 head if it turns out you need one.

 

[Gerard]

The previous owner built it. I have no idea why he did it.

This was a pretty common combination for race Mini engines, even on 850's. I have one that's already been machined I'm going to try to get up and running at some point. Might be a good setup to try my Judson with HIF44. Yes on the bigger valves.

 

[cdsmith]

It sounds a little like my car did with stuck valve... Maybe check for blow-back through carb? That was the first indicator of what was possibly wrong - pulling valve cover was confirmation of stuck valve...

For me - a quick valve job and everything is fine (at least as "fine" as fine can be for my car...)

cd

 

[mgless]

Pulled the head off today. You can clearly see the blown gasket between the back two cylinders. I purchased a new Payen 1275 gasket from Worldwide to replace it with. Looks like it will work, but it doesn't quite match the old one with the elongated cylinder holes.

A few noob questions... I assume the surfaces need to be immaculately clean. Anyone have a preferred cleaning method?

I tried to be careful pulling the pushrods out, but on two of them I heard a sound like a falling bolt. Was that the tappet? Will that be a problem when I re-install?

I searched the forum and saw that some people recommend re-torquing the head after a certain number of miles, and one person that uses threadlocker. I didn't see mention of these in the manual. Thoughts?

Thanks!

 

[Trevor Jessie]

Is it an optical illusion? The #4 piston looks different shaped than the rest.

 

[mgless]

Is it an optical illusion? The #4 piston looks different shaped than the rest.

The pistons are all the same size. The old gasket has elongated holes.

 

[AN5Sprite]

I tried to be careful pulling the pushrods out, but on two of them I heard a sound like a falling bolt. Was that the tappet? Will that be a problem when I re-install?

I've had this happen to me. It is possible to pull the tappet out of it's home and drop it. You should be able to see if this happened by shining a light down the pushrod hole. If it did you'll have to pull the side cover off and put the little guy back in his hole. Not really a big deal. (unless you fail to realize/correct the situation)

I've always used paraffin oil and/or acetone to clean the surface. Razor blade if I need to scrape off a little gasket hanger-on.

Hope that helps.

 

[nomad]

When removing push rod's I learned early that you should push firmly to the side as you lift them out to avoid the tendency for them to stick to the tappet's. As mentioned sometimes the tappet will stick till it comes out of its guide and cause you more work.
Most will say its not necessary but I like to use copper seal on the head gasket, block and head. Just a little.

Kurt.

 

[Jim_Gruber]

I know 1098's and 948 have side covers and I thought those went away on 1275's. So is there a problem with 1275's in removing pushrods and possibly pulling out the tappets? If so how do you get them back in place? And if side cover is to be removed, guessing that cannot be done with engine in the car? Carious as I need to pull the head off of my spare 1275 that will go into Bugsy II.

 

[Trevor Jessie]

1275 lifters are captured, so no problem there.

 

[Jim_Gruber]

Thanks Trevor. Didn't want to cause a problem I could avoid with knowledge up front. I do enough of htat as is.