View Poll Results: Pull the Holbert engine and transplant it with the 6.5 liter Rennlist engine?
Pull the engine and replace it now and start winning some races!
31
54.39%
Run the Holbert engine 'til it blows, or run mobil 1 in it and see what happens
3
5.26%
Replace it after this season
17
29.82%
Sell the Holbert car on the aution TV show and put the 6.5 liter in a stock S4 race car conversion
6
10.53%
Voters: 57. You may not vote on this poll
Should The Holbert 928 get an engine transplant mid season, or ever?
08-03-2008, 07:48 AM
#122
Former Vendor
Join Date: Feb 2004
Posts: 2,139
Likes: 0
Received 0 Likes
on
0 Posts
This engine change out will be very interesting.
Best wishes,
Constantine
P.S. I guess getting the Holbert engine methodically torn down by someone like Greg Brown and checked for any Porsche build magic is gone?
Best wishes,
Constantine
P.S. I guess getting the Holbert engine methodically torn down by someone like Greg Brown and checked for any Porsche build magic is gone?
08-03-2008, 12:56 PM
#123
Rennlist Member
Thread Starter
Thanks Tim. That was the information i was looking for. I actually spun the engine upside down and rocked the piston and your right, due to the short skirt and the pistons being larger at the skirt, the clearance was MUCH lower. by how much, i cant tell, but i couldnt get a 10mm feeler guage in there so thats good 
. (on top its .024" which got me worring that maybe something was up)
If the pistons are 4.076 and i measure 4.080, then thats the spec of .004" that JE quotes.
By the way, I understand the concern for head work, etc. I dont have the cash, but want the performance to be a little better than the stock stuff from devek that put only 320hp to the ground out of a 6 liter.
the other end of the spectrum, just head work alone with a stock intake has made 420rwhp, using the same cams, headers and intake as the Holbert car.
If heads are worth 30hp, im still in the right range. (ie 390rwhp) I can always put on some better heads later. These heads by the way ONLY had the 968 valves and some minor port matching.) I might be able to help things out by taking some of the material out of the intake manifold, cleaning it up, port matching it as well.
by the way, its a little to late, the engine is out and its starting to come apart.
Ill post some pictures soon. Bill helped out ! (THANKS BILL)
Mk
. (on top its .024" which got me worring that maybe something was up) If the pistons are 4.076 and i measure 4.080, then thats the spec of .004" that JE quotes.
By the way, I understand the concern for head work, etc. I dont have the cash, but want the performance to be a little better than the stock stuff from devek that put only 320hp to the ground out of a 6 liter.
the other end of the spectrum, just head work alone with a stock intake has made 420rwhp, using the same cams, headers and intake as the Holbert car.
If heads are worth 30hp, im still in the right range. (ie 390rwhp) I can always put on some better heads later. These heads by the way ONLY had the 968 valves and some minor port matching.) I might be able to help things out by taking some of the material out of the intake manifold, cleaning it up, port matching it as well.
by the way, its a little to late, the engine is out and its starting to come apart.
Ill post some pictures soon. Bill helped out ! (THANKS BILL)
Mk
Piston diameter is 4.076" measured 0.5" from the bottom. I do not know if that is the max or the min since the pistons are not round. Yes the tops are smaller because of more material and thus more expansion, but I do not know by how much. Once again, I do not think they are perfectly round either. Call JE and ask them. We are not piston manufacturing experts so we left all those details up to them.
BTW, I vote keep running the engine you have in the car now. When ready, take it out and set the entire motor aside and drop in the new one. You will need to do some head and intake work to get the performance you are looking for. If you just bolt on the stock stuff the engine will make a bunch of grunt at low rpm but will fall on its face upstairs because it won't be able to breath. Look up some of the old Devek dyno sheets and you will see just what I am saying. Maybe you already have plans to do this but I have not seen you mention it anywhere.
BTW, I vote keep running the engine you have in the car now. When ready, take it out and set the entire motor aside and drop in the new one. You will need to do some head and intake work to get the performance you are looking for. If you just bolt on the stock stuff the engine will make a bunch of grunt at low rpm but will fall on its face upstairs because it won't be able to breath. Look up some of the old Devek dyno sheets and you will see just what I am saying. Maybe you already have plans to do this but I have not seen you mention it anywhere.
