Oil inside intake and the cause: Cracked Intake

Rich Thomson

Registered User
Well the car started to miss at Carlisle this month and after tracking down the cause I found fresh oil inside the intake. :mad: The welding CMRE did to remove the triangle had two cracks when I got it back last year and I paid the local fab shop to weld up the two cracks. Now I either missed a hair line crack and/or a new crack developed on the bottom of the intake allowing oil to get into the intake. The oil causes the misfire and the engine dies. The car won't idle now and I will have to replace the intake. :mad:

The next intake welding will be done by the local fab shop and porting by me.

Rich
 
Rich Thomson said:
Well the car started to miss at Carlisle this month and after tracking down the cause I found fresh oil inside the intake. :mad: The welding CMRE did to remove the triangle had two cracks when I got it back last year and I paid the local fab shop to weld up the two cracks. Now I either missed a hair line crack and/or a new crack developed on the bottom of the intake allowing oil to get into the intake. The oil causes the misfire and the engine dies. The car won't idle now and I will have to replace the intake. :mad:

The next intake welding will be done by the local fab shop and porting by me.

Rich
My car has a lot of oil in the intake too but in my case I'm pretty sure it's a piston ring. :(
 
pcv

Rich Thomson said:
Well the car started to miss at Carlisle this month and after tracking down the cause I found fresh oil inside the intake. :mad: The welding CMRE did to remove the triangle had two cracks when I got it back last year and I paid the local fab shop to weld up the two cracks. Now I either missed a hair line crack and/or a new crack developed on the bottom of the intake allowing oil to get into the intake. The oil causes the misfire and the engine dies. The car won't idle now and I will have to replace the intake. :mad:

The next intake welding will be done by the local fab shop and porting by me.

Rich
check the pcv they can sometimes pull oil into the intake .
 
If the manifold is not pre-heated it may crack.

If the shop temp is 75 degrees and lower it Will crack.

If you have a fan running in the shop while welding,it may crack

If the temp in welding booth is below 100 degrees,it may crack.

If the weld is not gased purged on both sides during welding,it may crack.

If the weld area and weld are not clean enough to eat on,it will crack.

If the manifold is welded it should be kept over 125 degrees for overnight
& bolted down to block and heads used for jig.& cooled to 100 degrees.

If the right alloy filler rod is not use it may crack.

If penetration is not complete, it may crack.

If the alloy of the filler aluminum peice is not right it may crack.

If the manifold is not cooled at the proper time rate it may crack.

If the manifold is not bolted down to block & heads then heat stress releived
and left setting for a couple days in the proper temp range, it may crack.

If you don't heat cycle the manifold after stress releaf,it may crack.

If you do every step perfectly right, it may still crack.
So far none of mine have,but one will someday.

GOOD LUCK Randy
 
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I would use 6061 aluminum for the patch.

Filler rod to use 4043.

I would cut the old weld & patch out.

Clean parts and area to be welded with alcohol.
Also clean filler rod with alcohol

Pre-heat manifold & parts in oven up two around 300+

Randy
 
Randy N Connie said:
I would use 6061 aluminum for the patch.

Filler rod to use 4043.

I would cut the old weld & patch out.

Clean parts and area to be welded with alcohol.
Also clean filler rod with alcohol

Pre-heat manifold & parts in oven up two around 300+

Randy

Tell you what you fix my cracked intake I'll pay you for it. I am pulling the intake over the 4th weekend.

Rich
 
Rich .The only time I have removed the triangle ,Is when I raise
the manifold top.The reason,I can then double weld both side
of the removed triangle.

I would think one of the reasons for the weld failure.Would be because
both sides (or just the inside) of manifold were not cleaned proper before welding.

I have a raised manifold I bought from Jim Demmitt.I think it came from
CMRE.It was welded ,then some one later epoxied every weld seam.
So your not the first.

I would think you could get this fix in your area for a lot less money.
Because of Shipping cost.I would think that you could drill three or
four holes,enough room to get a jig-saw in the manifold to cut the
triangle filler peice out.Then clean the inside and outside of the
manifold area to be welded.

Then take the manifold to a shop that welds aluminum only,or as there
main sorce of weld income.Clean the weld area with alcohol and have them
use 4043 aluminum filler rod to tig weld.

I can send you a spare manifold to install now.This will get you
by until I mod the one you have on your SC now.Then
return my manifold when you receive your new modified
manifold.





Thanks Randy
 
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Thanks, Randy.

I already purchased a stock intake manifold. I am going to install it this weekend after some porting but I need to get the car back up and running ASAP. I'll have to get back to you on the manifold.

Rich
 
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