My porting was too aggressive!

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ken5124

ken5124

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Found out this weekend, after plumes of white smoke that my newly rebuilt motor is sucking coolant into the # 8 cylinder. Once apart and at the machine shop, found a small hole near the valve seat.

I know different / new heads would be the best answer, but being that I don't have the budget to do that at this point.. my machinist has suggested he may be able to put a plug in to repair the issue.

Anyone else had a plug installedto keep a cylinder head in action ?
Is it worth the 200 bucks, which includes the pre and post pressure testing?
 
100 bucks max that plug job isnt too hard hes just trying to get money out of u
 
Sorry to hear about that one...something tells me though, if you have it in one port, there's other places that may be as close and will eventually cause you similar issues. Can you afford not to drive it until you can purchase replacements?

Can you buy a set from one of the members here and bolt them on, or is there a good deal of work done to bring stock heads up to your requirement?

If you absolutely NEED the car, and have NO alternatives, I'd say proceed with caution, and start looking for replacements :( or take the bus
 
bignasty123 said:
100 bucks max that plug job isnt too hard hes just trying to get money out of u
Click to expand...

Always learning here...

I've been led to believe for years repairing holes in cast iron heads is almost fruitless unless you're trying to go for a numbers matching restoration...
 
I agree I charge 125.00 to tap & plug a hole (more for a crack) and then you have to pressure test head to make sure no more leaks
 
If you ported all the ports the same you might get more holes after more heat/cool cycles. i would pull the parts off these heads and find another pair and port them more conservatively.
 
Thanks for the thoughts. It is not my daily driver, so bus will not be in my future.

It is not numbers matching.

I was thinking too that at best it would be a bandaid ( in the event other ports are similar).

I may fix it and drive it till it worsens, or until I can get a different set of heads.
It won't get driven much more with winter coming in a couple of months.

Good news is when I pulled my chipped up semi fenderwell headers off, the better half suggested they should be ceramic coated and look like chrome.. Nice when she suggests it LOL
 
EL5DEMON340 said:
If you ported all the ports the same you might get more holes after more heat/cool cycles. i would pull the parts off these heads and find another pair and port them more conservatively.
Click to expand...

I suspect my next set of heads will be sanding rolls only..
 
A lot of the pretty ports you see here are heavilly worked in the bowl areas. That's a good place to make numbers but a rotton one in terms of risks of core shift, porosity, and lack of thickness. I tend to avoid going far into the short side of the bowl trying to make it pretty. The approach to the seat should be smaller diameter and round fo the entire circumference - not as as large as the seat angle - especially on the edge of the transistion area beside the guide bump in the bowl.
 
ken5124 said:
Thanks for the thoughts. It is not my daily driver, so bus will not be in my future.

It is not numbers matching.

I was thinking too that at best it would be a bandaid ( in the event other ports are similar).

I may fix it and drive it till it worsens, or until I can get a different set of heads.
It won't get driven much more with winter coming in a couple of months.

Good news is when I pulled my chipped up semi fenderwell headers off, the better half suggested they should be ceramic coated and look like chrome.. Nice when she suggests it LOL
Click to expand...
problem with that is if you fix it and drive the next crack might be bad enough to hydrolic lock the engine causing major damage. if you have a junk bottom end then go for it but if the bottom end has some nice parts i wouldn't risk it!
 
Porting is tricky. That's why I leave it to the people that do it for a living. I'll do most anything else but you have to know what you're doing with a die grinder after a head. I don't, so I reluctantly pay someone else. I'm cheap. LOL.
 
EL5DEMON340 said:
problem with that is if you fix it and drive the next crack might be bad enough to hydrolic lock the engine causing major damage. if you have a junk bottom end then go for it but if the bottom end has some nice parts i wouldn't risk it!
Click to expand...

I was just getting ready to post the same thing.
It could also leak and fill the cylinder while sitting over night.
Go hit the key the next morning and good-bye bottem end..

Toss the heads and start over, not worth it.
 
sireland67 said:
I was just getting ready to post the same thing.
It could also leak and fill the cylinder while sitting over night.
Go hit the key the next morning and good-bye bottem end..

Toss the heads and start over, not worth it.
Click to expand...

Agreed, Looking for a set of 302 casting heads .. I like working on it about as much as driving it anyway.
 
Picked up the bad head from the machine shop this afternoon. Small hole just under the intake seat, right beside the exhaust side. That's an area where I really hardly touched. Oh well, I had fun "trying" porting last winter. This winter I can assemble without porting( clean up with sanding rolls only) and not worry about the same thing happening.

least I know it wasn't because I didn't install the heads or put the rest of the motor together correctly.. motor was running great till it started fogging..
 
That sounds like either a casting flaw (I won't go as far as to say porous...) or an anomoly to that head based on that spot.
 
I ported a set of J heads. Had to find another head as I went into the water jacket raising an exhaust port. The heads worked OK. I ran 11.08 and 119.81 in my 67 Barracuda. I had to put in 2.055 and 1.625 valves after a couple of seasons. The verdict from a racer at the machine shop is that they were "junk" but worked good.
 
Mopar Performance used to sell porting templates.You would port the runners just till they fit.
 
ken5124 said:
Found out this weekend, after plumes of white smoke that my newly rebuilt motor is sucking coolant into the # 8 cylinder. Once apart and at the machine shop, found a small hole near the valve seat.

I know different / new heads would be the best answer, but being that I don't have the budget to do that at this point.. my machinist has suggested he may be able to put a plug in to repair the issue.

Anyone else had a plug installedto keep a cylinder head in action ?
Is it worth the 200 bucks, which includes the pre and post pressure testing?
Click to expand...


I bought the MPP porting templates and had my machinest port my 906's. They leaked in 5 of the 8 cylinders.

He fixed them with epoxy rather then use the pinning method. They held, however I sold them to a DARE program in TExas. I could'n't trust those heads after that especially with my intention of mainly street use.
 
Tapered plugs don't work well if the area is thin or porous, and your machinist won't know until he drills a hole if there's enough material to hold. Epoxy probably won't last that close to the valve seat. If you can get the casting clean enough you may be able to flow some brass over the hole and then grind it back down. But it sounds like your best bet would be to try again with another casting.
 
Oh Man...that sucks.!

if it were me I'd go the brass route..I've fixed plenty of holes in the bowls with brass.
Plus these were holes.!.. not little pin holes.
Take a sharp hammer and tap around the hole that you have and expose the whole weak or thin spot,then go about filing it up with brass..
just my take on problems like this...
 
I know of 2 sets of 302 casting heads here at the Upullandpay in Colorado Springs. Total for both heads would be approximately $93 plus shipping; which might be ton to Canada.
I'll probably be up there tomorrow getting parts for other members.
 
Thanks Rob R and 64 SRT8 Dart. I am leaning towards a new set at this time. And Not in too much of a rush.

Rob R.. it would seem to make sense to tap around in all the bowls on both sets , just to make sure there are no more thin spots? ( if I decide to try fixing them)
 
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