Cam Test With Stock Pushrods?

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Dec 29, 2012 | 09:42 PM

Rx7Rob

Thread Starter

Drifting

Joined: Mar 2000

Posts: 1,956

Likes: 135

From: Maryland

Cam Test With Stock Pushrods?

Would it be ok to start the engine with a 228/228 @ .588/.588 cam, dual springs, and stock pushrods? Or would that be asking for trouble?

I checked the PR length with the comp cams checker and came up with 7.375 (checked 10 locations). Checked two locations using the rocker bolt method and came up with 7.417". Checked by measuring the base circle of the OEM and new cam and got 7.437". I was setting preload at .062".

If I can run the motor up to about 3000 rpm I should be able to listen for the "sewing machine" noise with the stock 7.38" PR's. If its noisy I'll try some 7.425".

Here are the spring specs:
Closed Spring Pressure: 145lbs @ 1.800"
Open Spring Pressure: 450lbs @ 1.150"
Spring Rate: 469lbs/in

Thanks!

Dec 30, 2012 | 02:24 AM

RonSSNova

Safety Car

Joined: Aug 2011

Posts: 4,449

Likes: 409

From: Portland OR

Sounds like a Mamo package....heads springs and cam.....
I think you would be fine, but get the right heavy wall pushrods asap.
I have a set of slightly used trick flow 7.4 if you need some.

Ron

Dec 30, 2012 | 09:07 AM

Rx7Rob

Thread Starter

Drifting

Joined: Mar 2000

Posts: 1,956

Likes: 135

From: Maryland

Its the TSP 228R with PRC 650 springs. They sent 7.4" pushrods but I don't want to open the package until I figure out if its the correct length. There needs to be a pushrod lending library!

Dec 30, 2012 | 09:09 AM

kmetros

Racer

Joined: Jul 2008

Posts: 293

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From: South Bend IN

Quote:

Originally Posted by RonSSNova

I think you would be fine, but get the right heavy wall pushrods asap.

This would be my only concern. I went with 'less' lash to cut down on the sewing machine sound. Worked well.

Dec 30, 2012 | 09:56 AM

Paul 75 L82

Le Mans Master

Joined: Dec 2000

Posts: 5,245

Likes: 25

From: Blue Ridge Georgia

Rob, the TS 228R and spring kit with the TS 7.4 pushrods worked great for me. I would say to put the 7.4 in, worked great for me.

Dec 30, 2012 | 10:02 AM

vettenuts

Team Owner

Joined: Mar 1999

Posts: 22,025

Likes: 192

From: At the beach in little Rhody

You should be OK, but frankly I would go with 11/32" pushrods with those valve springs. I found I had flex with slightly lighter stiffness valve springs.