Watch for evidence of exhaust back pressure if you re-use an SSI exhaust system.

At high load (when the restriction is the greatest) a restrictive exhaust will HOLD the heat in and this is a killer thing on an engine that is cooling system weak like the T4.

I'm not sure what the back pressure limit is on an air cooled T4.

Performance water pumper needs less than 1/2 a psi.

Normal appliance car needs less than 2 psi.

Water pumpers get noticeable weak at high load at 5 psi.

I'm guessing an air-cooled will be MORE critical regarding back pressure than a water-cooled.

You can plumb an old school fuel pressure gauge into the exhaust with a long piece of stainless tubing before the vacuum tubing as a heat sink. Never run this un-connected.
The trapped air bubble keeps 1000-degree exhaust gasses away from your gauge.

Here is a picture of Marks 2270 RAT built 2005 Engen built by Jake in 2005

Note the shims and there was a thin coper head gasket.

This bad boy spun a bearing and had a knock. George at EMS helped us with all machining parts and advice. We even took the Eng over to EMS to test fire it up on a pallet. Then EMS sent it over to PMB for the install in my old Blue 74

The pistons are KB and they are flat tops. I believe the pistons are used for Harley Davidsons. Note the positions of the wrist pins. Cylinder light hone and new rings. Rebuilt the HAM RAT heads all the parts came from EMS Note the oil tray with the RAT Jake touch.

Jakes CD/DVD covered a lot, but it took advice from EMS as well as video review of Ian Karrs Utube and all the ones on Utube to just CK . Had to look at them over and over

Jakes Vid helps but a person will still have a lot of questions.

This is the video of Marks Start up. Frist time


Vid of Marks 2170 RAT rebuild 1st startup https://youtu.be/gxArcFBDGGQ

Best Bob B
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@vjb206 Based on your measurements, I think your rods are 5.325. Your going to end up with a .140 shim. I don't think it is going to be worth the effort and expense to source a custom ground shim. It would be interesting to compare the sealing surface measurements of your cylinders to my honed OEM cylinders. I have a set of cylinders from EMW that I purchased when he was getting them made in Mexico. They are the same subject to my measurement tools and skill using them.

I see a valve pocket. Are those JE pistons? Mine are flat top. Did you measure the volume and add it into your chamber volume? @Tom Perso used KB pistons and ran 9.5:1. I believe he used 163/86b also. He kept me in the game when these were mystery motors. See his comments on this necro threaddark age 2270 build

@technicalninja I rode my 2270 hard and put it away wet for 20 years. I leaked it down before I took it apart. It was around 96%. No signs of detonation. I had to replace bearings because of a self-induced bench stand running issue. Now you're going to have me looking for a knock sensor solution.

Mark to show shim on the RAT rebuild 2270

Bob B

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OOOHHHH!
Pretty pictures!
Thanks Bob!

What's up with the pic of the intake port?
It looks like the gasket overhangs both the head below and the intake above (from the print in the gasket)

Yes, noticed that too. We run phenolic spacers which avoids that problem and insulates the carbs from the heads.

Another question that's somewhat/is related to this build thread. Is the windage tray modification good or bad for oil and windage issues??

I cut my own gaskets. CSP linkage threaded rods too short to use the phenolic spacers. It appears from the video that he uses Sync-Link of CFR cable linkage. Maybe not enough thread engagement on the studs with his manifold.

Based on description in the video, it appears it was a crate motor. Who knows who touched it between delivery and scorching a bearing.


Hopefully I don't torched for goring someone's sacred cow.

The picture of intake port is from the moment of tear down and my comment was (this should be blueprinted and there should be no extra material to cause any flow turbulence) . You can see the port work on the RAT HAM heads.

The Windage tray modification was a RAT deal innless this Eng. was rebuilt after Jake built it.
No matter what you see the spun bearing. We opted for Tuna Can as it must have been oil starved at one point. It had a rear next to trans auxiliary oil cooler, and the decision was made to change that out to a front GT style cooler at PMB Performance

This Engen was in Oscars blue car and the guy that bought the car just wanted the body and sold us the Engen and trans. He was going to a huge Mopar and custom trans. His car is a spare no expense resto mod. He also did some great hot rods so that body should end up as a nice car.

Best Bob B

When I'm "finished" with port matching you cannot feel the parting lines on anything including the gasket...

Phenolics are used if available.

Often, if I have room, I'll put two little roll pins through the perfectly matched assembly to "fix" the position of everything. All of my previous intake manifold have been far larger than T4 stuff and the roll pins help, especially on straight 6s.

I'll normally do 2 extra intake gaskets at the same time in the same "stack" as putting the little dowel holes in a replacement gasket down the road is a BITCH!

An overhung gasket that like, by someone that was working for me would be,

STRIKE 1!

Still a very nice engine!

There was a time when Raby advised doing this to all windage trays to ensure oil got back into the sump fast enough. Around 2009 when I did my engine I did the same to my tray. I don't know what the current advice is.

Zach